JPH0965246A - Image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To display a clear image on an entire screen at a broad field angle with a compact size by cancelling an aberration caused on a transparent face of an optical member with a correction optical element so as to correct a residual aberration, especially chromatic aberration. SOLUTION: The eyepiece optical system 10 is made up of an eccentric prism 11 consisting of three optical faces 1-3 and being filled among them with a medium having a refraction factor larger than 1 and a correction optical element 12. A display light incident onto the optical system 10 via the 1st face 1 of the transparent faces arranged opposite to an image display element 9 is made incident onto a 4th face 4 of a reflecting face in common to the 3rd face 3 arranged between a 2nd face 2 and a pupil 7 of a viewer on a viewer visual axis 8, and the light reflected therein is made incident onto the face 2 arranged with excentricity opposite to the pupil 7 on the axis 8 and reflected. The reflected light is emitted from the prism 11 via the transparent face 3 and aberration with a different polarity from that of an aberration generated on the transparent face of the prism 11 is generated by the element 12 arranged between the pupil 7 and the element 9 for the correction and the corrected light is made incident onto the pupil 7 without forming an intermediate image.

Description

Detailed Description of the Invention

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image display device, 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 In recent years, helmet-type or goggle-type head- or face-mounted image display devices have been developed for virtual reality or for the purpose of personally enjoying a large-screen image.

For example, as shown in Japanese Patent Laid-Open No. 6-308424, an image of an image display element is guided to an observer's eye without forming an intermediate image in an optical path without using a relay optical system. Is an important technology in a head-mounted image display device. However, JP-A-6-308424
In the case of No., since the optical path is formed via the half mirror, a loss of light amount occurs, and it is not easy to perform bright display.

Further, as one of head-mounted image display devices capable of displaying a bright image without passing through a half mirror,
There is one of EP 0583116A2, but in this case, there is a drawback that the device becomes large because a relay optical system is used.

In such a situation, the applicant of the present invention has a compact size for guiding the display image of the image display device to the observer's eye without forming an intermediate image on the way, and has a wide angle of view to cover the entire screen. The eyepiece optical system capable of clear display is composed of a single decentered prism composed of three or four optical surfaces,
Several proposals have been made in which at least one of the three or four surfaces is a surface having power. Hereinafter, these will be briefly described.

FIG. 33 shows a sectional view of an eyepiece optical system 10 according to Japanese Patent Application No. 6-256676. This eyepiece optical system 10
Consists of four optical surfaces 1-4, with a refractive index of 1 between them.
Display light from the image display element 9 which is an eccentric prism body filled with a larger medium and is incident on the eyepiece optical system 10 through the first surface 1 of the transmissive surface arranged facing the image display element 9, The light that is incident on the fourth surface 4 of the decentered reflecting surface and reflected there is incident on the second surface 2 of the reflecting surface that is decentered so as to face the pupil 7 of the observer on the observer's visual axis 8. The reflected light crosses the incident light on the fourth surface 4, and then is a transmissive surface disposed between the second surface 2 and the observer's pupil 7 on the observer's visual axis 8. Exits from the eyepiece optical system 10 through the third surface 3 and advances along the observer's visual axis 8, enters the observer's pupil 7 without forming an intermediate image, and forms on the observer's retina. Image.

FIG. 34 shows a sectional view of an eyepiece optical system 10 according to Japanese Patent Application No. 6-290892. This eyepiece optical system 10
Is composed of three optical surfaces 1 to 3, with a refractive index of 1 between them.
Display light from the image display element 9 which is an eccentric prism body filled with a larger medium and is incident on the eyepiece optical system 10 through the first surface 1 of the transmissive surface arranged facing the image display element 9, The light incident on the second surface 2 of the decentered reflecting surface and reflected there is reflected by the third surface of the transmitting surface arranged between the second surface 2 and the pupil 7 of the observer on the observer's visual axis 8. The light exits from the eyepiece optical system 10 through the surface 3, travels along the observer's visual axis 8, enters the observer's pupil 7 without forming an intermediate image, and forms an image on the observer's retina.

FIG. 35 shows a sectional view of an eyepiece optical system 10 according to Japanese Patent Application No. 7-127896. This eyepiece optical system 10
Consists of four optical surfaces 1-4, with a refractive index of 1 between them.
Display light from the image display element 9 which is an eccentric prism body filled with a larger medium and is incident on the eyepiece optical system 10 through the first surface 1 of the transmissive surface arranged facing the image display element 9, The light that is incident on the fourth surface 4 of the decentered reflecting surface and reflected there is incident on the second surface 2 of the reflecting surface that is decentered so as to face the pupil 7 of the observer on the observer's visual axis 8. The reflected light is emitted from the eyepiece optical system 10 through the third surface 3 which is a transmission surface disposed between the second surface 2 and the observer's pupil 7 on the observer's visual axis 8. , Advances along the observer's visual axis 8, enters the observer's pupil 7 without forming an intermediate image, and forms an image on the observer's retina.

FIG. 36 shows a sectional view of an eyepiece optical system 10 according to Japanese Patent Application No. 7-120034. This eyepiece optical system 10
Is composed of three optical surfaces 1 to 3, with a refractive index of 1 between them.
Display light from the image display element 9 which is an eccentric prism body filled with a larger medium and is incident on the eyepiece optical system 10 through the first surface 1 of the transmissive surface arranged facing the image display element 9, The light incident on the fourth surface 4 of the reflecting surface which doubles as the third surface 3 arranged between the second surface 2 and the observer's pupil 7 on the observer's visual axis 8 and is reflected there is observed by the observer. The reflected light is incident on the second surface 2 of the reflecting surface, which is eccentrically arranged so as to face the pupil 7 of the observer on the visual axis 8, and is reflected.
The light is emitted from the eyepiece optical system 10 through the third surface 3 which is a transmission surface arranged between the surface 2 and the observer's pupil 7, and travels along the observer's visual axis 8 to form an intermediate image on the observer's pupil 7. Incident on the observer's retina without being imaged.

37 to 39, Japanese Patent Application No. 7-158897.
2 is a cross-sectional view of the eyepiece optical system 10 according to No. Among these, Figure 3
The eyepiece optical system 10 of No. 7 is a decentered prism body which is composed of four optical surfaces 1 to 5 and is filled with a medium having a refractive index larger than 1, and is arranged facing the image display element 9. Display light from the image display element 9 that has entered the eyepiece optical system 10 via the first surface 1 of the transmission surface is incident on and reflected by the fifth surface 5 of the reflection surface, and the reflected light is The light incident on the fourth surface of the reflecting surface which also serves as the reflecting surface is incident on and reflected by the second surface 2 of the reflecting surface which is eccentrically arranged on the observer's visual axis 8 so as to face the pupil 7 of the observer. The reflected light is emitted from the eyepiece optical system 10 through the third surface 3 which is the transmission surface arranged between the second surface 2 and the observer's pupil 7 on the observer's visual axis 8 and The light travels along the visual axis 8, enters the observer's pupil 7 without forming an intermediate image, and forms an image on the observer's retina.

The eyepiece optical system 10 of FIG. 38 is a decentered prism body composed of four optical surfaces 1 to 4, and a space between them is filled with a medium having a refractive index larger than 1, and is arranged so as to face the image display element 9. Eyepiece optical system 1 through the first surface 1 of the formed transparent surface
The display light from the image display element 9 incident on 0 is the fifth surface 5 of the reflecting surface which is also eccentrically arranged facing the pupil 7 of the observer on the observer's visual axis 8 and which also serves as the second surface 2 of the reflecting surface. The reflected light is incident on the fourth surface of the reflecting surface, and the light reflected there is reflected eccentrically on the observer's visual axis 8 so as to face the pupil 7 of the observer. The reflected light is incident on the second surface 2 of the surfaces and reflected by the third surface 3 of the transmission surface disposed between the second surface 2 and the observer's pupil 7 on the observer's visual axis 8. After that, the light exits from the eyepiece optical system 10, advances along the observer's visual axis 8, enters the observer's pupil 7 without forming an intermediate image, and forms an image on the observer's retina.

The eyepiece optical system 10 shown in FIG. 39 is a decentered prism body composed of four optical surfaces 2 to 5, and a space between them is filled with a medium having a refractive index larger than 1. Second surface 2 of the reflecting surface eccentrically arranged facing the pupil 7 of
Also, the display light from the image display element 9 that has entered the eyepiece optical system 10 through the first surface 1 that is the transmission surface that is arranged so as to face the image display element 9 is incident on the fifth surface 5 that is the reflection surface. And the reflected light is reflected by the sixth surface 6 of the reflecting surface which the second surface 2 also serves.
The reflected light is incident on the fourth surface of the reflecting surface, and the light reflected there is reflected eccentrically on the observer's visual axis 8 so as to face the pupil 7 of the observer. The reflected light is incident on the second surface 2 of the surfaces, and the reflected light is reflected by the third surface of the transmission surface disposed between the second surface 2 and the observer's pupil 7 on the observer's visual axis 8.
The light exits from the eyepiece optical system 10 through the surface 3, travels along the observer's visual axis 8, enters the observer's pupil 7 without forming an intermediate image, and forms an image on the observer's retina.

FIG. 40 shows a sectional view of an eyepiece optical system 10 according to Japanese Patent Application No. 7-178657. This eyepiece optical system 10
Consists of three optical surfaces 2 to 4, with a refractive index of 1 between them.
It is a decentered prism body filled with a larger medium, and also serves as the second surface 2 of the reflecting surface, which is eccentrically arranged on the observer's visual axis 8 so as to face the pupil 7 of the observer and faces the image display element 9. The display light from the image display element 9 that has entered the eyepiece optical system 10 through the first surface 1 of the transparent surfaces arranged as shown in FIG. 1 is between the second surface 2 and the pupil 7 of the observer on the observer's visual axis 8. The light incident on the fifth surface 5 of the reflecting surface which doubles as the third surface 3 arranged in the, the light reflected there enters the fourth surface 4 of the reflecting surface and is reflected, and the reflected light is observed by the observer. The light is incident on the second surface 2 of the reflecting surface, which is eccentrically arranged so as to face the pupil 7 of the observer on the axis 8, and is reflected, and the reflected light intersects with the light reflected by the fifth surface 5. , Exits from the eyepiece optical system 10 through the third surface 3 which is the transmission surface arranged between the second surface 2 and the observer's pupil 7 on the observer's visual axis 8, and along the observer's visual axis 8. Advances, the intermediate image on the pupil 7 of the observer enters without being imaged, is imaged on the retina of the observer.

FIG. 41 shows a sectional view of an eyepiece optical system 10 according to Japanese Patent Application No. 7-212594. This eyepiece optical system 10
Consists of three optical surfaces 2 to 4, with a refractive index of 1 between them.
It is a decentered prism body filled with a larger medium, and also serves as the second surface 2 of the reflecting surface, which is eccentrically arranged on the observer's visual axis 8 so as to face the pupil 7 of the observer and faces the image display element 9. The display light from the image display element 9 that has entered the eyepiece optical system 10 via the first surface 1 of the transmission surface arranged as a unit is the fourth surface 4 of the reflection surface.
Is reflected by the second surface 2 of the reflecting surface which is eccentrically arranged on the observer's visual axis 8 so as to face the pupil 7 of the observer. The light exits from the eyepiece optical system 10 through the third surface 3 which is the transmission surface arranged between the second surface 2 and the observer's pupil 7 on the observer's visual axis 8 and is incident on the observer's visual axis 8. Along with this, an intermediate image is incident on the observer's pupil 7 without being imaged, and is imaged on the observer's retina.

The first to sixth surfaces described above are flat surfaces, spherical surfaces, aspherical surfaces, anamorphic surfaces and anamorphic aspherical surfaces, and at least one surface has a positive power. In addition, when the reflection on the surface which also serves as the transmission surface and the reflection surface, for example, the surface which constitutes the third surface and the fourth surface in FIG. 36 is caused by total reflection, or when the transmission area and the reflection area are separated from each other. Is from the back mirror.

[0016]

By the way, in recent years, the density of image display devices has been increasing, and the amount of aberration generated in the eyepiece optical system
In particular, the pixel density of the image display device has increased so that chromatic aberration cannot be ignored. However, FIG. 33 according to the applicant's proposal
In an image display device using an eyepiece optical system 10 as shown in FIG. 41, which is composed of a single decentered prism composed of three or four optical surfaces, and a space between them is filled with a medium having a refractive index larger than 1, Since the first surface 1 which is an entrance surface to the eyepiece optical system 10 and the third surface 3 which is an exit surface from the first surface 1 are refracting surfaces (only the first surface 1 and the third surface 3 are refracting surfaces), Even if the aberration is corrected by the decentered reflecting second surface or the like, the chromatic aberration cannot be completely corrected and remains.

The present invention has been made in view of the above problems, and an object thereof is to be composed of three or four optical surfaces as proposed by the applicant of the present invention. In an image display device using an eyepiece optical system consisting of a single decentered prism filled with a medium having a refractive index larger than 1, residual size, especially chromatic aberration, is corrected to achieve a compact size and a wide angle of view, which is clear over the entire screen. To display an image.

[0018]

An image display device of the present invention that achieves the above object is an image display device for displaying an image and an image displayed on the image display device without forming an intermediate real image. In the image display device having an eyepiece optical system that guides the eyeball, and a holding unit that holds the image display element and the eyepiece optical system on the head or face of the observer, the eyepiece optical system faces the image display element. Disposed on the observer's visual axis so as to be opposed to the observer's pupil, and on the observer's visual axis between the second surface and the observer's pupil. A second surface is a reflecting surface, and a light beam emitted from the image display element passes through the first surface and enters the inside of the optical member. Is reflected by the second surface, transmitted through the third surface, and guided to the observer's eyeball. And correcting optical element is arranged in any position between the pupil of the observer from the image display device,
It is characterized in that the aberrations generated on the transmitting surface of the optical member and the correction optical element have opposite signs.

In this case, it is desirable that the region surrounded by the first surface, the second surface, and the third surface of the optical member is filled with a transparent medium having a refractive index of more than 1.

Further, it is provided with a fourth surface arranged so that the light beam emitted from the image display element passes through the first surface and the light incident on the optical member is reflected before being reflected by the second surface. Is desirable. In that case, the fourth surface and the third surface can be formed by the same surface.

Further, it is desirable that the correction optical element is composed of a diffractive optical element or a gradient index lens.

Hereinafter, the reason and operation of the above configuration in the present invention will be described. In the present invention, the Fresnel zone plate is representative of chromatic aberration, field curvature, etc. remaining in a single decentered prism which is composed of three or four optical surfaces and is filled with a medium having a refractive index larger than 1 between them. The correction is performed using a diffractive optical element (hereinafter, DOE) or a gradient index lens. Hereinafter, the correction capabilities of the DOE and the gradient index lens will be described.

The DOE represented by the zone plate has a large inverse dispersion characteristic of Abbe number ν _d = −3.45 and has a large ability of correcting chromatic aberration. Therefore, as described above, it is possible to effectively correct the residual chromatic aberration of the decentering prism alone due to the high density of the image display element.

Further, since the manufacturing method of the DOE having the aspherical surface effect is the same as the manufacturing method of the DOE having the spherical surface effect, the DOE
It is possible to positively have an aspherical surface action, and it is possible to effectively correct an increase in off-axis aberration that accompanies a wide angle of view.
In this case, if the DOE has an aspherical action (pitch distribution) such that the power becomes weaker than the power of the paraxial spherical system as the distance from the optical axis increases, the aberration correction capability increases. Further, since such a pitch arrangement increases the pitch around the effective diameter of the DOE, its manufacturability is also improved.
Further, unlike the refracting lens, the DOE only processes a diffractive surface on the surface of the substrate, and therefore, the DOE is not substantially accompanied by an increase in volume and weight, and is preferable as an optical system of a head-mounted image display device.

Further, in the present invention, paying attention to the fact that the gradient index lens has a correcting function for Petzval sum and chromatic aberration, in combination with the decentering prism alone, the chromatic aberration remaining in the decentering prism alone. , Field curvature and the like are corrected. Hereinafter, correction of Petzval sum and chromatic aberration of the gradient index lens will be described.

The gradient index lens used in the present invention is of a so-called radial type having a gradient index in the direction perpendicular to the optical axis, and the gradient index of its reference wavelength is
It is represented by the following equation (1). n (r) = N ₀ + N ₁ r ² + N ₂ r ⁴ + N ₃ r ⁶ + (1) where N ₀ is the refractive index of the reference wavelength on the optical axis of the lens,
r is the radial distance from the optical axis, n (r) is the refractive index of the reference wavelength at the distance r from the optical axis, N ₁ , N ₂ , N ₂ , N
₃ , ... are 2nd, 4th, 6 o'clock of the reference wavelength,
··· is the coefficient.

First, the correction of the Petzval sum will be described. One of the quantities that must be paid special attention at the initial design stage of the lens system is the Petzval sum determined by the power distribution. The Petzval sum of a homogeneous system can be expressed as follows, where the surface refractive power is φ _S and the refractive index of the lens on the optical axis is N ₀ . φ _S / N ₀ (2) Further, the Petzval sum of the gradient index lens unit can be expressed as follows, where the surface refractive power is φ _S 'and the medium refractive power is φ _M. it can. φ _S '/ N ₀ + φ _M / N ₀ ² (3) As is clear from this equation (3), the gradient index lens has a refractive power in its medium, and thus the Petzval sum. Can be corrected.

Next, the correction of chromatic aberration will be described.
The gradient index lens has the ability to correct chromatic aberration even in its medium, and the conditions for correcting axial chromatic aberration by the gradient index lens alone are as follows. φ _S '/ ν _od + φ _M / ν _1d = 0 (4) Here, ν _od is the refractive index on the lens optical axis due to the d-line, F-line, and C-line, which is N _0d and N _0F , respectively. , N _0C , they are expressed by the following equation (5). ν _od = (N _0d −1) / (N _0F −N _0C ) ... (5) Further, ν _1d is the second-order coefficient of the refractive index distribution formula (1) based on the d-line, F-line, and C-line. From N _1d , N _1F and N _1C , it is obtained by the following equation (6). ν _1d = N _1d / (N _1F −N _1C ) ... (6) That is, chromatic aberration can be corrected by changing the distribution shape of the medium of the gradient index lens for each wavelength.

In the present invention, aberrations such as chromatic aberration and field curvature remaining in the decentered prism having three or four optical surfaces as shown in FIGS. 33 to 41 are corrected by the above-mentioned diffractive optical element or refraction. The correction optical element composed of a rate distribution type lens is used to generate and correct aberrations of opposite signs.
These correction optical elements can be arranged on the observer's eye side or the image display element side of the decentered prism (optical member).

When a diffractive optical element is used as the correction optical element, when the focal length of the diffractive optical element is f (mm), the condition of -1 <1 / f <1 (a) should be satisfied. Is desirable. Furthermore, it is more desirable to satisfy the condition of −0.1 <1 / f <0.1 (a ′). More preferably, it is desirable to satisfy the condition of 0 <1 / f <0.01 (a ”).

When a gradient index lens is used as the correction optical element, 0.5 <N0 / N1 <when the refractive index at the center of the gradient index lens is N0 and the refractive index at the periphery is N1. It is desirable to satisfy the condition of 1.5 (b). Furthermore, it is more desirable to satisfy the condition of 0.8 <N0 / N1 <1.2 (b ').

These conditions (a), (a '), (a "),
(B) and (b ') are eye points of the entire eyepiece optical system,
It is desirable that the diffractive optical element and the gradient index lens have substantially no power in order to perform desired aberration correction without substantially changing the focal length, the magnification, etc. is there.

[0033]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Some embodiments of the image display device of the present invention will be described below with reference to the drawings.
First, a method of designing an optical system including a DOE used in the present invention will be described first. The principle of the optical element DOE based on the diffraction phenomenon is described in detail in Chapters 6 and 7 of "Small optical element for optical designer" (Opttronics Co., Ltd.), but will be briefly described below.

In the optical element based on the refraction phenomenon, the light beam is bent according to Snell's law, as shown in FIG.

N · sin θ = n ′ · sin θ ′ (7) where n: refractive index of the incident side medium n ′: refractive index of the exit side medium θ: incident angle of light ray θ ′: of light ray Exit Angle On the other hand, in the case of DOE, as shown in FIG.
The light beam is bent by the diffraction phenomenon expressed by equation (8).

N · sin θ−n ′ · sin θ ′ = mλ / d (8) where n: refractive index of the incident side medium n ′: refractive index of the exit side medium θ: incident angle θ of the light beam ′: Emission angle of light ray m: Diffraction order λ: Wavelength d: Pitch of DOE At this time, if blazing or blazing approximation is performed, high diffraction efficiency can be maintained.

The Sweat model is known as a method for designing an optical system including a DOE. For this,
"WCSweatt," NEW METHODS OF DESIGNING HOLOGRAPHI
C OPTCALELEMENTS ", SPIE, Vol.126, pp.46-53 (1977)
], But will be briefly described below with reference to FIG.

In FIG. 31, n >> 1 is a refraction system lens (ultra-high index lens),
Is the normal line, z is the coordinate along the optical axis, and h is the coordinate along the substrate. According to the above paper, equation (9) holds.

(N _u −1) dz / dh = n · sin θ−n ′ · sin θ ′ (9) where n _u : the refractive index of the ultra-high index lens (in the design described below, , N _u = 1001.) Z: Coordinate in the optical axis direction of the ultra-high index lens h: Coordinate along the medium of the ultra-high index lens n: Refractive index of the incident side medium n ′: Of the exit side medium Refractive index θ: incident angle of light ray θ ′: exit angle of light ray Therefore, the following equation (6) is established from the equations (8) and (9).

(N _u −1) dz / dh = mλ / d (10) That is, “the surface shape of the refraction lens with n >> 1” and “D
Since the equivalence relation expressed by the equation (10) is established between the “OE pitch”, ul designed by the Sweat model
The DOE pitch distribution can be obtained from the surface shape of the tra-high index lens.

Specifically, assuming that the ultra-high index lens is designed as an aspherical lens defined by the equation (11), z = ch ² / {1+ [1-c ² (k + 1) h ² ] ^{1 / 2} } + Ah ⁴ + Bh ⁶ + Ch ⁸ + Dh ¹⁰ (11) where, z: deviation from the tangent plane contacting the lens on the optical axis (sag value) c: curvature h: distance from the optical axis k: conical constant A: 4th-order aspherical coefficient B: 6th-order aspherical coefficient C: 8th-order aspherical coefficient D: 10th-order aspherical coefficient Here, in order to simplify the description, ultra-high index l
If one side of ens is a plane, then from equations (10) and (11), d = mλ / [(n−1) dz / dh] = [mλ / (n−1)] × [ch / [1-c ² (k + 1) h ² ] ^1/2 + 4Ah ³ + 6Bh ⁵ + 8Ch ⁷ + 10Dh ⁹ ] ^-1 (12) is obtained. It suffices to provide the pitch distribution defined by the equation (12).

Further, the expression (10) needs to be established at an arbitrary wavelength.

∴n (λ) -1 = Kλ (13) However, K = m / [d · dz / dh] Since this time, n _d = 1001, K = 1.702
0.

Therefore, according to the equation (13), n _C = 1
118.0, n _e = 93.39, n _F = 828.3.
If 7, n _g = 742.78, the dispersion characteristics of DOE can be expressed.

In the embodiments described below, only the 10th order is used as the aspherical term, but of course 12
Next, 14th-order aspherical terms may be used. Further, in the examples using the DOE shown below, only one surface of the DOE is used, but two or more surfaces may be used.

Next, Examples 1 to 1 of the image display device of the present invention will be described.
6 and Comparative Example will be described with reference to FIGS. 1 to 7, which are cross-sectional views of an optical system of a monocular image display device. These image display devices are all eyepiece optical systems 1 of FIG.
Although 0 is basically used, the same applies to the case where the eyepiece optical system 10 shown in FIGS. 33 to 35 and 37 to 41 is used.

The constituent parameters of each Example and Comparative Example will be described later, but in the following description, the surface number is shown as the surface number of the reverse tracking from the pupil position 7 of the observer to the image display element 9. Then, as shown in FIG. 1, the coordinate is taken with the observer's iris position 7 as the origin, and the observer's visual axis 8 as the Z axis in which the direction from the origin to the eyepiece optical system 10 is positive. Y axis orthogonal to the axis 8 and positive from the bottom to the top in the vertical direction when viewed from the observer's eye, X orthogonal to the observer visual axis 8 and positive from the right to the left in the horizontal direction when viewed from the observer's eye Define as an axis. That is, the inside of the paper is taken as the YZ plane, and the surface perpendicular to the paper is taken as the XZ plane. It is assumed that the optical axis is bent in the YZ plane of the drawing.

Then, in the constituent parameters described later, regarding the surface on which the eccentricity amounts Y and Z and the tilt angle θ are described, the Y of the apex of the surface from the one surface (pupil position 7) which is the reference surface. It means the amount of eccentricity in the axial direction, the Z-axis direction, and the angle of inclination of the central axis of the surface from the Z-axis, and in this case, θ means counterclockwise. It should be noted that a surface on which the eccentricity amounts Y and Z and the tilt angle θ are not described means that it is coaxial with the surface before it.

The surface spacing is shown only for the coaxial system portion, and is the axial spacing from that surface to the next surface.
The surface spacing is shown as positive in the direction of reverse tracking along the optical axis.

Further, in each surface, an aspherical shape which is non-rotationally symmetric has coordinates R _y and R _{x which} are paraxial curvature radii in the YZ plane (paper surface) and X- Paraxial radii of curvature in the Z plane, K _x and K _y are the X-Z plane and Y-, respectively.
The conic coefficients AR, BR, CR, and DR in the Z plane are the fourth-order, sixth-order, eighth-order, and tenth-order aspherical coefficients that are rotationally symmetric with respect to the Z-axis, and AP, BP, CP, and DP are each Z. Assuming fourth-order, sixth-order, eighth-order, and tenth-order aspherical coefficients that are rotationally asymmetric with respect to the axis, the aspherical surface equation is as follows.

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 + B
R [(1-BP) X 2 + (1 + BP) Y 2] 3 + CR [(1-C
^{P) X 2 + (1 +} CP) Y 2] 4 + DR [(1-DP) X 2 + (1
+ DP) Y ² ] ⁵ The refractive index of the medium between the surfaces is represented by the refractive index of the d-line. The unit of the length is mm.

The following examples are all image display devices for the right eye, and all the optical elements for the left eye are Y-type.
It can be realized by symmetrically arranging in the Z plane. Further, it goes without saying that in an actual device, the direction in which the optical axis is bent by the eyepiece optical system may be above, below, or lateral to the observer.

In each of the sectional views, 7 is the observer's pupil position, 8 is the observer's visual axis, and 1 is the first eyepiece optical system.
Surface 2, 2 is the second surface of the eyepiece optical system, 3 is the third surface of the eyepiece optical system
Surface 4, 4 is the fourth surface of the eyepiece optical system, 9 is an image display device, 10
Is an eyepiece optical system, 11 is a decentered prism, 12 is a DOE, 1
Reference numeral 3 denotes a gradient index lens (hereinafter, GRIN).

The actual light ray paths in the respective examples are as follows. Taking the comparative example as an example, the light ray bundle emitted from the image display element 9 is
The light is refracted by the first surface 1 of the eyepiece optical system 10 to enter the eyepiece optical system 10, and is internally reflected by the fourth surface (which also serves as the third surface 3) 4,
The light is reflected by the second surface 4, is incident on the third surface 3 again, is refracted, and is projected into the observer's eyeball by using the iris position of the observer's pupil or the center of rotation of the eyeball as the exit pupil 7.

Comparative Example This comparative example, whose cross section is shown in FIG. 7, relates to the basic decentering prism 11 of Examples 1 to 6. The eyepiece optical system 10 has a horizontal angle of view of 45.4 ° and a vertical angle of view of 34.4.
°, pupil diameter 4 mm. In the constituent parameters described below, the second, third, and fourth surfaces are anamorphic aspherical surfaces, and the fifth surface is a flat surface.

Spot diagrams showing the aberration correction state of this comparative example are shown in FIGS. In these figures, among the four numbers on the left side of the spot diagram,
The two numbers in the upper row are the coordinates (X,
Y) is (0.00, 0.00), the center coordinate of the right end is (0.00, -1.00), and the coordinate of the upper right corner is (1.0).
0, -1.00), and the coordinates of the center of the upper end are (1.00,0.
00) indicates relative coordinates (X, Y), and the lower two numbers are the X component of the angle formed by the coordinate (X, Y) direction with respect to the visual axis (center of the screen). The Y component (in degrees) is shown.

Example 1 This example, whose cross section is shown in FIG. 1, has a horizontal angle of view of 45.4.
°, vertical angle of view 34.4 °, and pupil diameter 4 mm. This example is an example in which a substantially non-power DOE 12 is arranged between the exit pupil 7 and the decentering prism 11 of Comparative Example 1. In the constituent parameters described below, the surfaces 5, 6, and 7 are anamorphic aspherical surfaces, and the surface 8 is a flat surface. Spot diagrams similar to FIGS. 26 to 28 showing the aberration correction state of this embodiment are shown in FIGS.

Example 2 This example shows a cross section in FIG. 2 and has a horizontal angle of view of 45.4.
°, vertical angle of view 34.4 °, and pupil diameter 4 mm. This example is an example in which a substantially non-power DOE 12 is arranged between the decentering prism 11 and the image display element 9 of Comparative Example 1. In the constituent parameters described below, the second, third, and fourth surfaces are anamorphic aspherical surfaces, and the fifth surface is a flat surface. 11 to 13 show spot diagrams similar to FIGS. 26 to 28 showing the aberration correction state of this embodiment.

Example 3 This example shows a cross section in FIG. 3, with a horizontal angle of view of 45.4.
°, vertical angle of view 34.4 °, and pupil diameter 4 mm. This example is an example in which the GRIN 13 having a two-sided plane is arranged between the decentering prism 11 and the image display element 9 of Comparative Example 1 with substantially no power. In the configuration parameters described below, 2, 3,
The fourth surface is an anamorphic aspherical surface, and the fifth surface is a flat surface. 14 to 16 show spot diagrams similar to FIGS. 26 to 28 showing the aberration correction state of this embodiment.

Example 4 In this example, a cross section is shown in FIG.
°, vertical angle of view 34.4 °, and pupil diameter 4 mm. This example is an example in which the GRIN 13 having a double-sided plane is arranged between the exit pupil 7 and the decentering prism 11 of Comparative Example 1 with substantially no power. In the constituent parameters described below, the fourth, fifth and sixth surfaces are anamorphic aspherical surfaces, and the seventh surface is a flat surface. 17 to 19 show spot diagrams similar to FIGS. 26 to 28 showing the aberration correction state of this embodiment.

Example 5 This example shows a cross section in FIG. 5, with a horizontal angle of view of 45.4.
°, vertical angle of view 34.4 °, and pupil diameter 4 mm. This example is an example in which a meniscus-shaped GRIN 13 having a concave surface facing the image display element 9 is disposed between the decentering prism 11 and the image display element 9 of Comparative Example 1 with substantially no power. In the constituent parameters described below, the second, third, and fourth surfaces are anamorphic aspherical surfaces, and the fifth surface is a flat surface. 20 to 22 show spot diagrams similar to FIGS. 26 to 28 showing the aberration correction state of this example.

Example 6 This example shows a cross section in FIG. 6 and has a horizontal angle of view of 45.4.
°, vertical angle of view 34.4 °, and pupil diameter 4 mm. This example is an example in which a meniscus-shaped GRIN 13 having a convex surface facing the image display element 9 is disposed between the decentering prism 11 and the image display element 9 of Comparative Example 1 with substantially no power. In the constituent parameters described below, the second, third, and fourth surfaces are anamorphic aspherical surfaces, and the fifth surface is a flat surface. 23 to 25 show spot diagrams similar to FIGS. 26 to 28 showing the aberration correction state of this embodiment.

Next, constituent parameters of Examples 1 to 6 and Comparative Example will be shown. Regarding GRIN 13, the above N _1d , N _1F and N _1C are also shown.

Example 1 Surface number Curvature radius Spacing Refractive index Abbe number (Eccentricity) (Tilt angle) 1 ∞ (pupil) 2 ∞ 1.58875 64.1 Y 0.000 θ 0.00 ° Z 27.000 3 ∞ (DOE) 1001.00000 -3.45 Y 0.000 θ 0.00 ° Z 28.000 4 -2.2939 × 10 ⁺⁶ Y 0.000 θ 0.00 ° Z 28.000 5 R _y -209.268 1.49216 57.5 R _x -95.115 Y 18.335 θ 12.00 ° K _y 0.000000 Z 27.921 K _x 0.000000 AR 0.783868 × 10 ^-6 BR 0.299472 × 10 ^-12 CR 0.152974 × 10 ^-13 DR -0.502892 × 10 ^-16 AP -0.449899 BP -0.794713 × 10 ⁺¹ CP 0.654541 DP -0.138730 6 R _y -67.801 1.49216 57.5 R _x -58.220 Y -9.356 θ -27.44 ° K _y 0.000000 Z 38.348 K _x 0.000000 AR 0.427047 × 10 ^-6 BR -0.770285 × 10 ^-10 CR 0.407932 × 10 ^-21 DR 0.105909 × 10 ^-16 AP 0.107024 BP 0.496744 CP 0.119380 × 10 ⁺³ DP -0.923056 × 10 ^-2 7 R _y -209.268 1.49216 57.5 R _x -95.115 Y 18.335 θ 12.00 ° K _y 0.000000 Z 27.921 K _x 0.000000 AR 0.7 83868 × 10 ^-6 BR 0.299472 × 10 ^-12 CR 0.152974 × 10 ^-13 DR -0.502892 × 10 ^-16 AP -0.449899 BP -0.794713 × 10 ⁺¹ CP 0.654541 DP -0.138730 8 ∞ Y 27.164 θ 62.56 ° Z 27.921 9 ( Image display device) Y 27.796 θ 46.89 ° Z 39.073.

Example 2 Surface Number Curvature Radius Spacing Refractive Index Abbe Number (Eccentricity) (Tilt Angle) 1 ∞ (Pupil) 2 R _y -209.268 1.49216 57.5 R _x -95.115 Y 18.335 θ 12.00 ° K _y 0.000000 Z 27.921 K _x 0.000000 AR 0.783868 × 10 ^-6 BR 0.299472 × 10 ^-12 CR 0.152974 × 10 ^-13 DR -0.502892 × 10 ^-16 AP -0.449899 BP -0.794713 × 10 ⁺¹ CP 0.654541 DP -0.138730 3 R _y -67.801 1.49216 57.5 R _x -58.220 Y -9.356 θ -27.44 ° K _y 0.000000 Z 38.348 K _x 0.000000 AR 0.427047 × 10 ^-6 BR -0.770285 × 10 ^-10 CR 0.407932 × 10 ^-21 DR 0.105909 × 10 ^-16 AP 0.107024 BP 0.496744 CP 0.119380 × 10 ⁺³ DP -0.923056 × 10 ^-2 4 R _y -209.268 1.49216 57.5 R _x -95.115 Y 18.335 θ 12.00 ° K _y 0.000000 Z 27.921 K _x 0.000000 AR 0.783868 × 10 ^-6 BR 0.299472 × 10 ^-12 CR 0.152974 × 10 ^{-13 DR -0.502892 × 10 -16 AP -0.449899} BP -0.794713 × 10 +1 CP 0.654541 DP -0.138730 5 ∞ 27.164 θ 62.56 ° Z 27.921 6 ∞ 1.000 1.58875 64.1 Y 25.000 θ 60.00 ° Z 36.000 7 ∞ (DOE) 0.000 1001.00000 -3.45 8 -0.344807 × 10 +6 9 ( image display device) Y 28.388 θ 46.88 ° Z 39.413 .

Example 3 Surface number Curvature radius Spacing Refractive index Abbe number (Eccentricity) (Inclination angle) 1 ∞ (Pupil) 2 R _y -209.268 1.49216 57.5 R _x -95.115 Y 18.335 θ 12.00 ° K _y 0.000000 Z 27.921 K _x 0.000000 AR 0.783868 × 10 ^-6 BR 0.299472 × 10 ^-12 CR 0.152974 × 10 ^-13 DR -0.502892 × 10 ^-16 AP -0.449899 BP -0.794713 × 10 ⁺¹ CP 0.654541 DP -0.138730 3 R _y -67.801 1.49216 57.5 R _x -58.220 Y -9.356 θ -27.44 ° K _y 0.000000 Z 38.348 K _x 0.000000 AR 0.427047 × 10 ^-6 BR -0.770285 × 10 ^-10 CR 0.407932 × 10 ^-21 DR 0.105909 × 10 ^-16 AP 0.107024 BP 0.496744 CP 0.119380 × 10 ⁺³ DP -0.923056 × 10 ^-2 4 R _y -209.268 1.49216 57.5 R _x -95.115 Y 18.335 θ 12.00 ° K _y 0.000000 Z 27.921 K _x 0.000000 AR 0.783868 × 10 ^-6 BR 0.299472 × 10 ^-12 CR 0.152974 × 10 ^{-13 DR -0.502892 × 10 -16 AP -0.449899} BP -0.794713 × 10 +1 CP 0.654541 DP -0.138730 5 ∞ 25.000 θ 62.56 ° Z 27.921 6 ∞ (GRIN) 5.000 1.49216 57.5 N 1d -0.1005 × 10 -3 N 1F -0.1068 × 10 -3 N 1C -0.9399 × 10 -4 Y 21.500 θ 62.56 ° Z 35.222 7 ∞ 8 ( image Display element) Y 29.022 θ 46.89 ° Z 39.742.

Example 4 Surface Number Curvature Radius Spacing Refractive Index Abbe Number (Eccentricity) (Tilt Angle) 1 ∞ (Pupil) 2 ∞ (GRIN) 1.49216 57.5 N _1d 0.1005 × 10 ^-3 N _1F 0.1068 × 10 ^-3 N _1C 0.9399 × 10 ^-4 Y 0.000 θ 0.00 ° Z 25.000 3 ∞ Y 0.000 θ 0.00 ° Z 29.000 4 R _y -209.268 1.49216 57.5 R _x -95.115 Y 18.335 θ 12.00 ° K _y 0.000000 Z 27.921 K _x 0.000000 AR 0.783868 × 10 ^-6 BR 0.299472 × 10 ^-12 CR 0.152974 × 10 ^-13 DR -0.502892 × 10 ^-16 AP -0.449899 BP -0.794713 × 10 ⁺¹ CP 0.654541 DP -0.138730 5 R _y -67.801 1.49216 57.5 R _x -58.220 Y -9.356 θ -27.44 ° K _y 0.000000 Z 38.348 K _x 0.000000 AR 0.427047 × 10 ^-6 BR -0.770285 × 10 ^-10 CR 0.407932 × 10 ^-21 DR 0.105909 × 10 ^-16 AP 0.107024 BP 0.496744 CP 0.119380 × 10 ⁺³ DP -0.923056 _{^{× 10 -2 6 R y -209.268 1.49216}} 57.5 R x -95.115 Y 18.335 θ 12.00 ° K y 0.000000 Z 27.921 K x 0.000000 AR 0.783 868 × 10 ^-6 BR 0.299472 × 10 ^-12 CR 0.152974 × 10 ^-13 DR -0.502892 × 10 ^-16 AP -0.449899 BP -0.794713 × 10 ⁺¹ CP 0.654541 DP -0.138730 7 ∞ Y 25.000 θ 62.56 ° Z 27.921 8 ( Image display device) Y 28.166 θ 46.89 ° Z 39.360.

Example 5 Surface number Curvature radius Spacing Refractive index Abbe number (Decentering amount) (Inclination angle) 1 ∞ (Pupil) 2 R _y -209.268 1.49216 57.5 R _x -95.115 Y 18.335 θ 12.00 ° K _y 0.000000 Z 27.921 K _x 0.000000 AR 0.783868 × 10 ^-6 BR 0.299472 × 10 ^-12 CR 0.152974 × 10 ^-13 DR -0.502892 × 10 ^-16 AP -0.449899 BP -0.794713 × 10 ⁺¹ CP 0.654541 DP -0.138730 3 R _y -67.801 1.49216 57.5 R _x -58.220 Y -9.356 θ -27.44 ° K _y 0.000000 Z 38.348 K _x 0.000000 AR 0.427047 × 10 ^-6 BR -0.770285 × 10 ^-10 CR 0.407932 × 10 ^-21 DR 0.105909 × 10 ^-16 AP 0.107024 BP 0.496744 CP 0.119380 × 10 ⁺³ DP -0.923056 × 10 ^-2 4 R _y -209.268 1.49216 57.5 R _x -95.115 Y 18.335 θ 12.00 ° K _y 0.000000 Z 27.921 K _x 0.000000 AR 0.783868 × 10 ^-6 BR 0.299472 × 10 ^-12 CR 0.152974 × 10 ^{-13 DR -0.502892 × 10 -16 AP -0.449899} BP -0.794713 × 10 +1 CP 0.654541 DP -0.138730 5 ∞ 25.000 θ 62.56 ° Z 27.921 6 54.928 (GRIN) 5.000 1.49216 57.5 N 1d -0.1005 × 10 -3 N 1F -0.1068 × 10 -3 N 1C -0.9399 × 10 -4 Y 21.500 θ 62.56 ° Z 35.222 7 84.049 8 ( image Display element) Y 28.637 θ 46.89 ° Z 39.508.

Example 6 Surface Number Curvature Radius Interval Refractive Index Abbe Number (Eccentricity) (Tilt Angle) 1 ∞ (Pupil) 2 R _y -209.268 1.49216 57.5 R _x -95.115 Y 18.335 θ 12.00 ° K _y 0.000000 Z 27.921 K _x 0.000000 AR 0.783868 × 10 ^-6 BR 0.299472 × 10 ^-12 CR 0.152974 × 10 ^-13 DR -0.502892 × 10 ^-16 AP -0.449899 BP -0.794713 × 10 ⁺¹ CP 0.654541 DP -0.138730 3 R _y -67.801 1.49216 57.5 R _x -58.220 Y -9.356 θ -27.44 ° K _y 0.000000 Z 38.348 K _x 0.000000 AR 0.427047 × 10 ^-6 BR -0.770285 × 10 ^-10 CR 0.407932 × 10 ^-21 DR 0.105909 × 10 ^-16 AP 0.107024 BP 0.496744 CP 0.119380 × 10 ⁺³ DP -0.923056 × 10 ^-2 4 R _y -209.268 1.49216 57.5 R _x -95.115 Y 18.335 θ 12.00 ° K _y 0.000000 Z 27.921 K _x 0.000000 AR 0.783868 × 10 ^-6 BR 0.299472 × 10 ^-12 CR 0.152974 × 10 ^{-13 DR -0.502892 × 10 -16 AP -0.449899} BP -0.794713 × 10 +1 CP 0.654541 DP -0.138730 5 ∞ 25.000 θ 62.56 ° Z 27.921 6 -52.463 (GRIN) 5.000 1.49216 57.5 N 1d -0.1005 × 10 -3 N 1F -0.1068 × 10 -3 N 1C -0.9399 × 10 -4 Y 24.263 θ 62.56 ° Z 34.395 7 -41.145 8 (Image display element) Y 29.137 θ 46.89 ° Z 39.882.

Comparative Example Surface Number Curvature Radius Spacing Refractive Index Abbe Number (Eccentricity) (Tilt Angle) 1 ∞ (Pupil) 2 R _y -209.268 1.49216 57.5 R _x -95.115 Y 18.335 θ 12.00 ° K _y 0.000000 Z 27.921 K _x 0.000000 AR 0.783868 × 10 ^-6 BR 0.299472 × 10 ^-12 CR 0.152974 × 10 ^-13 DR -0.502892 × 10 ^-16 AP -0.449899 BP -0.794713 × 10 ⁺¹ CP 0.654541 DP -0.138730 3 R _y -67.801 1.49216 57.5 R _x -58.220 Y -9.356 θ -27.44 ° K _y 0.000000 Z 38.348 K _x 0.000000 AR 0.427047 × 10 ^-6 BR -0.770285 × 10 ^-10 CR 0.407932 × 10 ^-21 DR 0.105909 × 10 ^-16 AP 0.107024 BP 0.496744 CP 0.119380 × 10 ^{+3 DP -0.923056 × 10 -2 4 R} y -209.268 1.49216 57.5 R x -95.115 Y 18.335 θ 12.00 ° K y 0.000000 Z 27.921 K x 0.000000 AR 0.783868 × 10 -6 BR 0.299472 × 10 -12 CR 0.152974 × 10 - ¹³ DR -0.502892 × 10 ^-16 AP -0.449899 BP -0.794713 × 10 ⁺¹ CP 0.654541 DP -0.138730 5 ∞ Y 25.000 θ 62.56 ° Z 27.921 6 (Image display element) Y 28.166 θ 46.89 ° Z 39.360.

Now, the chromatic aberration, the field curvature, etc. remaining in the decentered prism alone, which is composed of the three or four optical surfaces of the present invention as described above and filled with a medium having a refractive index larger than 1, is defined between them. By using two sets of eyepiece optical systems corrected using DOE or GRIN, it is not necessary to close one eye and observe the observation image. If it is possible to observe with both eyes, the observer can observe without getting tired. Also, by presenting images with parallax to both eyes, it is possible to observe as a stereoscopic image. Further, by using two sets of the eyepiece optical system of the present invention and attaching a supporting mechanism for supporting the observer's head, it becomes possible to observe an observation image in a comfortable posture.

As described above, the eyepiece optical system according to the present invention is used, and a pair of the optical system and the image display element is prepared on the left and right sides, and they are supported by being separated by the eye radiation distance. It can be configured as a portable image display device such as a stationary or head-mounted image display device. FIG. 32 shows the overall configuration of an example of such a portable image display device. The display device main body 50 is provided with a pair of left and right eyepiece optical systems as described above, and an image display element composed of a liquid crystal display element is arranged on the image plane corresponding to them. A temporal frame 51 as shown in the figure is provided continuously to the left and right of the main body 50, the temporal frames 51 on both sides are connected by a crown frame 52, and a leaf spring 53 is provided between the temporal frames 51 on both sides. The rear frame 54 is provided via
The display device main body 50 can be held in front of the observer's eyes by placing the display device main body on the back of both ears of the observer like a temple of eyeglasses and placing the crown frame 52 on the observer's crown. A top pad 55 made of an elastic body such as a sponge is attached inside the top frame 52, and a similar pad is attached inside the rear frame 54 in the same manner. It does not feel uncomfortable when attached to the camera.

The rear frame 54 has a speaker 56.
Is provided so that stereophonic sound can be heard together with image observation. As described above, the display device main body 50 having the speaker 56 has a video / audio transmission code 57.
The viewer 58 holds the playback device 58 at an arbitrary position such as a belt position as shown in FIG.
You can enjoy the sound. 5 shown
Reference numeral 9 denotes an adjustment unit such as a switch and a volume of the playback device 58. Note that electronic components such as a video processing / audio processing circuit are built in the top frame 52.

The cord 57 may be attached to an existing video deck or the like by using a jack at the tip. 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. Also, in order to reject an obstructive code, an antenna may be connected to receive an external signal by radio waves.

The image display device of the present invention has been described above based on some embodiments, but the present invention is not limited to these embodiments and various modifications can be made.

The above-described image display device of the present invention can be configured as follows, for example.

[1] An image display element for displaying an image and an eyepiece optical system for guiding the image displayed on the image display element to an eyeball of an observer without forming an intermediate real image, and the image display element and the eyepiece optics. In an image display device having a holding means for holding the system on an observer's head or face, the eyepiece optical system observes on a first surface arranged facing the image display element and on the observer's visual axis. An optical member having a second surface which is arranged to face the viewer's pupil and is inclined, and a third surface which is arranged between the second surface and the viewer's pupil on the viewer's visual axis. The second surface is a reflecting surface, and the light beam emitted from the image display element passes through the first surface and enters the inside of the optical member, and is reflected by the second surface and passes through the third surface. Is guided to the observer's eyeball, and any one between the image display element and the observer's pupil. Corrective optics are placed in position,
The image display device is characterized in that the aberrations generated in the transmission surface of the optical member and the correction optical element have opposite signs.

[2] The first surface and the second surface of the optical member
The area surrounded by the surface and the third surface is filled with a transparent medium having a refractive index of more than 1, and the image display device according to the above [1].

[3] A fourth surface arranged so that the light beam emitted from the image display element passes through the first surface and the light incident on the optical member is reflected before being reflected by the second surface. The image display device according to the above [2], further comprising:

[4] The image display device according to the above [3], wherein the fourth surface is the same surface as the third surface.

[5] The image display device according to the above [4], wherein the second surface is a back surface reflecting mirror.

[6] The image display device as described in the above item [5], wherein among the above four surfaces, the transmission surface of the first surface and the reflection surface of the fourth surface are the same surface.

[7] The image display device according to the above [5], wherein among the above four surfaces, the transmitting surface of the third surface and the reflecting surface of the fourth surface are the same surface.

[8] A light ray incident on the same surface of the eyepiece optical system is incident on one optical path beyond a critical angle and reflected, and is incident on another optical path at an incident angle less than the critical angle and transmitted. The image display device according to any one of [2] to [7], wherein the image display device is arranged so as to

[0085]

[9] The image display device according to any one of [1] to [8], wherein the correction optical element is a diffractive optical element.

[10] The above [1] to [8], wherein the correction optical element is a gradient index lens.
The image display device according to claim 1.

[11] The diffractive optical element is arranged between the optical member and an observer's eyeball.

The image display device according to [9].

[12] The diffractive optical element is arranged between the optical member and the image display element.

The image display device according to [9].

[13] When the focal length of the diffractive optical element is f (mm), the condition of -1 <1 / f <1 (a) is satisfied [11] Alternatively, the image display device according to [12].

[14] When the focal length of the diffractive optical element is f (mm), the condition of −0.1 <1 / f <0.1 (a ′) is satisfied. The image display device according to [13] above.

[15] When the focal length of the diffractive optical element is f (mm), the condition 0 <1 / f <0.01 (a ") is satisfied. 14] The image display device as described above.

[16] The image display device according to the above [10], wherein the gradient index lens is arranged between the optical member and an eyeball of an observer.

[17] The image display device according to the above [10], wherein the gradient index lens is arranged between the optical member and the image display element.

[18] When the central refractive index of the gradient index lens is N0 and the peripheral refractive index is N1, the condition of 0.5 <N0 / N1 <1.5 (b) is satisfied. The image display device according to the above [16] or [17], which is satisfied.

[19] When the central refractive index of the gradient index lens is N0 and the peripheral refractive index is N1, the condition of 0.8 <N0 / N1 <1.2 (b ') is satisfied. The image display device according to the above [18], characterized in that

[0096]

As is apparent from the above description, in the image display device of the present invention, a decentered prism which is composed of three or four optical surfaces and is filled with a medium having a refractive index larger than 1 between them. For chromatic aberration, field curvature, etc. that occur on a single transmission surface, a correction optical element is placed at any position between the image display element and the observer's pupil, and the correction optical element produces aberrations with opposite signs. The correction optical element has a DO effective for correcting these aberrations.
E, By using the gradient index lens, even if the pixel density of the image display element is increased, residual aberration, especially chromatic aberration is sufficiently corrected, and the size is compact, and a clear image is displayed on the entire screen with a wide angle of view. A displayable head- or face-mounted image display device can be obtained.

[Brief description of drawings]

FIG. 1 is a diagram for explaining an optical path of an image display device according to a first embodiment of the present invention.

FIG. 2 is a diagram for explaining an optical path of an image display device according to a second embodiment of the present invention.

FIG. 3 is a diagram for explaining an optical path of an image display device according to a third embodiment of the present invention.

FIG. 4 is a diagram illustrating an optical path of an image display device according to a fourth exemplary embodiment of the present invention.

FIG. 5 is a diagram for explaining an optical path of an image display device according to a fifth embodiment of the present invention.

FIG. 6 is a diagram illustrating an optical path of an image display device according to a sixth embodiment of the present invention.

FIG. 7 is a diagram for explaining an optical path of an image display device of a comparative example.

8 is a part of a spot diagram showing an aberration correction state of Example 1. FIG.

FIG. 9 is another part of the spot diagram showing the aberration correction state of Example 1.

FIG. 10 is the remaining part of the spot diagram showing the aberration correction state of the first embodiment.

FIG. 11 is a part of a spot diagram showing an aberration correction state of Example 2;

12 is another part of the spot diagram showing the aberration correction state of Example 2. FIG.

FIG. 13 is the remaining part of the spot diagram showing the aberration correction state of the second embodiment.

FIG. 14 is a part of a spot diagram showing the aberration correction state of Example 3;

FIG. 15 is another part of the spot diagram showing the aberration correction state of the third embodiment.

FIG. 16 is the remaining part of the spot diagram showing the aberration correction state of the third embodiment.

FIG. 17 is a part of a spot diagram showing an aberration correction state of Example 4.

FIG. 18 is another part of the spot diagram showing the aberration correction state of Example 4.

FIG. 19 is the remaining part of the spot diagram showing the aberration correction state of the fourth embodiment.

FIG. 20 is a part of a spot diagram showing the aberration correction state of Example 5;

FIG. 21 is another part of the spot diagram showing the aberration correction state of Example 5.

FIG. 22 is the remaining part of the spot diagram showing the aberration correction state of Example 5;

FIG. 23 is a part of a spot diagram showing the aberration correction state of Example 6;

FIG. 24 is another part of the spot diagram showing the aberration correction state of the sixth embodiment.

FIG. 25 is the remaining part of the spot diagram showing the aberration correction state of Example 6;

FIG. 26 is a part of a spot diagram showing an aberration correction state of a comparative example.

FIG. 27 is another part of the spot diagram showing the aberration correction state of the comparative example.

FIG. 28 is the remaining part of the spot diagram showing the aberration correction state of the comparative example.

FIG. 29 is a principle diagram of refraction for explaining the diffractive optical element used in the present invention.

FIG. 30 is a principle diagram of diffraction for explaining the diffractive optical element used in the present invention.

[Fig. 31] Ultra-high index lens
FIG.

FIG. 32 is a diagram showing the overall configuration of an example of a portable image display device incorporating the eyepiece optical system according to the present invention.

FIG. 33 is a diagram for explaining the optical path of the image display device according to one of the applicant's proposals.

FIG. 34 is a diagram for explaining an optical path of an image display device according to another proposal of the applicant.

FIG. 35 is a diagram for explaining an optical path of an image display device according to another proposal of the applicant.

FIG. 36 is a diagram for explaining an optical path of an image display device according to another proposal of the applicant.

FIG. 37 is a diagram for explaining an optical path of an image display device according to another proposal of the applicant.

FIG. 38 is a diagram for explaining an optical path of an image display device according to another proposal of the applicant.

FIG. 39 is a diagram for explaining an optical path of an image display device according to another proposal of the applicant.

FIG. 40 is a diagram for explaining an optical path of an image display device according to another proposal of the applicant.

FIG. 41 is a diagram for explaining an optical path of an image display device according to another proposal of the applicant.

[Explanation of symbols]

 1 ... 1st surface 2 ... 2nd surface 3 ... 3rd surface 4 ... 4th surface 5 ... 5th surface 6 ... 6th surface 7 ... Observer's pupil 8 ... Observer's visual axis 9 ... Image display element 10 ... Eyepiece Optical system 11 ... Decentered prism 12 ... Diffractive optical element (DOE) 13 ... Gradient index type lens (GRIN) 50 ... Display device body 51 ... Temporal frame 52 ... Top frame 53 ... Leaf spring 54 ... Rear frame 55 ... Top pad 56 ... Speaker 57 ... Video / audio transmission code 58 ... Playback device 59 ... Control section for switches, volume, etc.

Claims (6)

[Claims] 1. An image display element for displaying an image, an eyepiece optical system for guiding the image displayed on the image display element to an eyeball of an observer without forming an intermediate real image, and the image display element and the eyepiece optical system. In the image display device having a holding means for holding the head on the observer's head or face, the eyepiece optical system has a first surface arranged facing the image display element, and the observer on the observer's visual axis. An optical member having a second surface which is arranged so as to be opposed to the pupil and is inclined, and a third surface which is arranged between the second surface and the observer pupil on the observer's visual axis; Two surfaces are reflection surfaces, and a light beam emitted from the image display element passes through the first surface and enters the inside of the optical member, and is reflected by the second surface and passes through the third surface. Guided to the eyeball of the observer, and any position between the image display device and the pupil of the observer A correction optical element is disposed in the image display device, and the aberration generated in the transmission surface of the optical member and the aberration generated in the correction optical element have opposite signs. 2. The region surrounded by the first surface, the second surface, and the third surface of the optical member is filled with a transparent medium having a refractive index of more than 1. Image display device. 3. A fourth surface arranged so that a light beam emitted from the image display element passes through the first surface and the light incident on the optical member is reflected before being reflected by the second surface. The image display device according to claim 2, further comprising: 4. The image display device according to claim 3, wherein the fourth surface is the same surface as the third surface. 5. The image display device according to claim 1, wherein the correction optical element is a diffractive optical element. 6. The image display device according to claim 1, wherein the correction optical element is a gradient index lens.