JP2001235705A - Picture display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize weight saving and low power consumption of a picture display device observable with both eyes, by integrating two illumination systems for illuminating right and left image display elements uniformly into a single and common illumination system. SOLUTION: In the picture display device equipped with a picture display element 2R for right eye and a picture display element 2L for left eye which project separately the display pictures of a picture display element 3R for right eye and a picture display element 3L for left eye to observer's right and left eye, respectively, the picture display elements for right eye and for left eye are composed of transmission type picture display elements which display a picture by passing illuminating light, and beam which illuminates the picture display element 3R for right eye and the picture display element 3L for left eye is luminous flux which divergent light from a common single light source 6 are divided to right and left by a illuminating light dividing optical system 1.

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 Conventionally, in a head mounted image display apparatus, a pair of eccentric prisms are arranged as eyepiece optical systems for the left and right eyes of an observer, and an LCD (liquid crystal display element) is provided on the object surface of each of the eccentric prisms. ), And illumination systems (backlights, light sources, etc.) for illuminating the image display elements must be provided separately on the left and right sides (for example, JP-A-7-333551).

On the other hand, Japanese Patent Application Laid-Open No. 10-330342 proposes using an eccentric prism for an illumination optical system for uniformly illuminating an image display element such as an LCD.

[0004]

In the conventional image display apparatus which can be observed with both eyes as described above, an illumination system for illuminating each of a pair of image display elements arranged for the right and left eyes has a left and right side. Two are required, and particularly in a head-mounted image display device, weight reduction and low power consumption of the illumination system have been major issues.

The present invention has been made in view of such problems of the prior art, and an object of the present invention is to provide an illumination system for uniformly illuminating left and right image display elements in an image display device that can be observed with both eyes. By using a single common device, the image display device is reduced in weight and power consumption is reduced.

[0006]

The image display apparatus of the present invention that achieves the above object separately projects the display images of the right-eye image display element and the left-eye image display element onto the right and left eyes of the observer. An image display device comprising a right-eye eyepiece optical system and a left-eye eyepiece optical system, wherein the right-eye and left-eye image display elements display an image by transmitting illumination light. And the luminous flux illuminating the right-eye image display element and the left-eye image display element is divergent light from a common single light source is a luminous flux distributed to the right and left by the illumination light distribution optical system. It is a feature.

In this case, the illumination light distribution optical system has a mirror surface which is disposed to face the light source and reflects the illumination light flux emitted from the light source to the right eye image display element and the left eye image display element. However, the mirror surface may be configured to have a rotationally asymmetric curved surface shape for correcting eccentric aberration.

The illumination light distribution optical system has an illumination light distribution prism for distributing an illumination light beam emitted from a light source to a right-eye image display element and a left-eye image display element, and the illumination light distribution prism. Are arranged opposite to the light source, the first surface for allowing the illumination light beam emitted from the light source to enter the inside of the prism, the twenty-first surface for reflecting the optical path for the right eye incident from the first surface, and the first surface. At least a 22nd surface that reflects the light path for the left eye, a 31st surface that emits the light beam of the optical path for the right eye to the outside of the prism, and a 32nd surface that emits the light beam for the optical path for the left eye to the outside of the prism In order to illuminate the image display element for the right eye and the image display element for the left eye with the illumination light flux emitted from the light source,
At least the twenty-first surface, the twenty-second surface, the thirty-first surface, and the thirty-second surface are configured in a curved shape that gives power to a light beam, and the twenty-first surface and the twenty-second surface have the same surface shape, Third
The one surface and the thirty-second surface may be configured to have the same surface shape.

In the present invention, since the above-mentioned configuration is used, the left and right image display elements can be uniformly illuminated by a single illumination light source common to the left and right, and the number of optical components of the image display device can be reduced. It is possible to reduce the weight, size, and power consumption.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an image display device according to the present invention will be described based on embodiments. 1 to 10 show optical path diagrams of the image display devices of Examples 1 to 10 according to the present invention, respectively.

In the first embodiment of FIG. 1, the right eye of the observer is ER, the left eye is EL, the image display element for the right eye of the image display device is 3R, and the image display element for the left eye is 3L. so,
The exit pupil for the right eye is indicated by 4R, the exit pupil for the left eye is indicated by 4L, the decentered prism placed in front of the right eye ER in the eyepiece optical system for the right eye is 2R, and the eyepiece optical system for the left eye is indicated by 4R. An eccentric prism body arranged in front of the left eye EL is indicated by 2L. Further, an illumination light distribution mirror used in an illumination light distribution optical system arranged at the center of both eyes is denoted by 1, and a negative lens is denoted by 5. A single light source common to the right eye and the left eye is indicated by 6. Here, it is assumed that the image display elements 3R and 3L are composed of transmissive liquid crystal display elements. The eccentric prisms 2R and 2L are made of a transparent medium having a refractive index larger than 1. In the following description, a surface described as a reflection surface is a mirror surface obtained by applying a mirror coat to a surface to be subjected to an eccentric prism body except for a total reflection surface.

In the first embodiment, a horizontal section (YZ) is shown in FIG.
The illumination light distribution mirror 1 at the center is located at the center of a line segment connecting the centers of the symmetry planes of both eyes (the center of the exit pupil 4R for the right eye and the exit pupil 4L for the left eye). And a left optical path reflecting surface 1L and a left optical path reflecting surface 1L, which are plane-symmetric with respect to a plane passing through the line segment and perpendicular to the line segment.

The decentered prism 2R constituting the right eyepiece optical system and the decentered prism 2L constituting the left eyepiece optical system have the same shape and are plane-symmetric with respect to the plane of symmetry of both eyes. And the first surface 2
1R (21L), second surface 22R (22L), third surface 23
R (23L) and the fourth surface 24R (24L), and the second surface 22R (22L) and the fourth surface 24R (24
L) is composed of the same surface, and the same surface serves as both a total reflection surface and a transmission surface.

The image display elements 3R and 3L are provided on the first surfaces 21R and 21R of the decentered prisms 2R and 2L of the eyepiece optical system, respectively.
It is arranged on both sides of the symmetry plane of both eyes facing L. The light source 6 is arranged on the observer side facing the illumination light distribution mirror 1. A negative lens 5 is inserted between the illumination light distribution mirror 1 and the light source 6 at a position on the symmetry plane of both eyes. The exit pupils 4R and 4L are located on substantially the same surface facing the fourth surfaces 24R and 24L of the eccentric prism bodies 2R and 2L. And each eccentric prism body 2R, 2L, each surface 21R-24R, 21L-24L of the illumination light distribution mirror 1,
Each of 1R and 1L is composed of a free-form surface represented by the following equation (a). Further, each free-form surface can be replaced with a spherical surface including a plane, an aspherical surface, an anamorphic surface, or an anamorphic aspherical surface.

In the above configuration, the left and right optical paths indicated by broken lines are plane-symmetric with respect to the symmetry plane of both eyes, and thus the optical path for the right eye will be representatively described. The illuminating light emitted from the common single light source 6 first enters the negative lens 5 and has a higher divergence, and the luminous flux diverged to the left side of the symmetry plane of both eyes is applied to the illumination light distribution mirror 1. The light is incident on and reflected by the reflection surface 1R, is incident on the back surface of the image display element 3R, and illuminates uniformly and brightly. The luminous flux of the display image displayed on the image display element 3R passes through the first surface 21R of the eccentric prism body 2R and enters the prism, enters the second surface 22R at an angle of incidence equal to or greater than the critical angle, and is totally reflected. , Is incident on the third surface 23R, is reflected on the back surface, is incident on the fourth surface 24R at an incident angle equal to or less than the critical angle, is refracted, exits from the eccentric prism body 2R, is guided to the exit pupil 4R for the right eye, An enlarged image of the image display element 3R is projected on the right eye of the observer. In the above optical system, the light source 6 and the exit pupil 4R are configured to be optically conjugate (an image of the light source 6 is formed at the position of the exit pupil 4R when the image display element 3R is removed). . Note that no intermediate image is formed on the optical path from the image display element 3R to the exit pupil 4R. The optical path for the left eye has a plane-symmetric relationship with the optical path for the right eye with respect to the symmetry plane of both eyes, similarly to the arrangement of the optical system for the right eye.

With the above configuration, the illumination light from the single light source 6 is distributed to the illumination light distribution mirror 1 and the negative lens 5.
Can be distributed to the two image display elements 3R and 3L for both eyes by using the illumination light distribution optical system consisting of: The size can be reduced. Further, since no prism is used for the illumination system, the weight of the entire image display device can be reduced. Further, since the light source 6 is located on the observer side, the entire display device does not protrude largely forward.

Further, although the eccentric prisms 2R and 2L are arranged at plane-symmetric positions, two eccentric prisms 2R and 2L having the same shape and the same shape are prepared, and the central illumination light is provided. What is necessary is just to arrange | position at the position which is plane-symmetric with respect to the distribution mirror 1. FIG.

It should be noted that a diffractive optical element or a lenticular lens may be used instead of or in addition to the negative lens 5. By inserting the negative lens 5 and the like between the light source 6 and the illumination light distribution mirror 1, the distribution of the illumination light becomes more uniform. Further, by using a diffractive optical element or a lenticular lens, it becomes easier to split the left and right illumination light.

In the second embodiment, as shown in a horizontal section (YZ section) in FIG. 2, instead of the illumination light distribution mirror 1 and the negative lens 5 arranged at the center of both eyes in the first embodiment, five surfaces are used. The illumination light distributing prism 10 made of the eccentric prism body is used. Eccentric prism body 2L for left and right eyes,
2R and image display elements 3L and 3R are the same as in the first embodiment.

The central illumination light distribution prism 10 has a shape that is plane-symmetric with respect to the symmetry plane of both eyes, and a first surface 11 located on the observer side of the light source 6 is a transmission surface, and the first surface 11 is Second surface 12 of the right optical path reflecting surface located on both sides on the observer side
R and the second surface 12L of the reflection surface for the left optical path,
There are five transmission surfaces 13R for the left optical path and 13R for the right optical path, which are located on the observer side of the surfaces 12R and 12L. The first surface 11 has a shape symmetrical with respect to the symmetry plane of both eyes, and the second surface 12
R and 12L are plane-symmetrical with respect to the plane of symmetry of both eyes.
The surfaces 13L and 13R have shapes that are plane-symmetric with respect to the symmetry plane of both eyes. The light source 6 faces the first surface 11 of the illumination light distribution prism 10 and is arranged on the opposite side of the illumination light distribution prism 10 from the observer.

In the above configuration, the left and right optical paths indicated by broken lines are plane-symmetric with respect to the symmetry plane of both eyes, so the optical path for the right eye will be representatively described. The illumination light diverging from the common single light source 6 first emits the illumination light distribution prism 10
And the second surface 1 of the reflection surface for the right optical path.
The light is incident on and reflected by 2R, passes through the transmission surface 13R for the right optical path, enters the back surface of the image display element 3R, and illuminates uniformly and brightly. The luminous flux of the display image displayed on the image display element 3R passes through the first surface 21R of the eccentric prism body 2R and enters the prism, enters the second surface 22R at an angle of incidence equal to or greater than the critical angle, and is totally reflected. , Is incident on the third surface 23R, is reflected on the back surface, is incident on the fourth surface 24R at an incident angle equal to or less than the critical angle, is refracted, exits from the eccentric prism body 2R, is guided to the exit pupil 4R for the right eye, An enlarged image of the image display element 3R is projected on the right eye of the observer. In the above optical system, the light source 6 and the exit pupil 4R are configured to be optically conjugate (an image of the light source 6 is formed at the position of the exit pupil 4R when the image display element 3R is removed). . Note that no intermediate image is formed on the optical path from the image display element 3R to the exit pupil 4R. The optical path for the left eye has a plane-symmetric relationship with the optical path for the right eye with respect to the symmetry plane of both eyes, similarly to the arrangement of the optical system for the right eye.

With the above configuration, the illumination light from the single light source 6 is applied to the two image display elements 3R and 3L for both eyes by using the illumination light distribution optical system including the illumination light distribution prism 10. Irradiation can be performed separately, and by sharing the left and right illumination systems, it is possible to reduce the number of optical components, reduce the weight, and reduce the size. Further, since the illumination light distribution prism 10 used for the illumination system has five surfaces, the eccentric aberration of the illumination optical system can be corrected, and the image display element 3R,
The entire 3L can be uniformly illuminated. Light source 6
Is located away from the observer, so that it does not interfere with the nose of the observer. The illumination light distribution prism 1
Within 0, the central principal ray of one illumination light beam intersects the central principal ray of the other illumination light beam once.

Further, an eccentric prism body 1 in which the left and right optical paths are mostly filled with a transparent medium having a refractive index larger than 1
0, 2R, and 2L, and the optical path is bent therein, so that the entire eyepiece optical system can be made compact. The eccentric prisms 2R and 2L are arranged at plane-symmetric positions, but have the same shape. Two eccentric prisms 2R and 2L having the same shape are prepared. What is necessary is just to arrange | position in the position symmetrical with respect to a plane.

In the third embodiment, as shown in a horizontal section (YZ section) in FIG. 3, instead of the illumination light distribution mirror 1 and the negative lens 5 arranged at the center of both eyes in the first embodiment, five surfaces are used. The illumination light distributing prism 10 made of the eccentric prism body is used. Eccentric prism body 2L for left and right eyes,
2R and image display elements 3L and 3R are the same as in the first embodiment. The major difference from the second embodiment is that the light source 6 is arranged on the observer side of the illumination light distribution prism 10.

The central illumination light distribution prism 10 has a plane-symmetrical shape with respect to the plane of symmetry of both eyes, and the first surface 11 located on the side opposite to the observer of the light source 6 is a transmission surface, and the first surface thereof. The third surface 13R of the transmission surface for the right optical path, the third surface 13L of the transmission surface for the left optical path, and the third surfaces 13R, 13L located on the opposite sides of the observer on both sides of the third optical path 11 And a second surface 12L of the reflecting surface for the right optical path and a second surface 12R of the reflecting surface for the right optical path. The first surface 11 has a shape symmetrical with respect to the symmetry plane of both eyes, the third surfaces 13R and 13L,
The surfaces 12L and 12R have shapes that are plane-symmetric with respect to the plane of symmetry of both eyes. The light source 6 is a first light source of the illumination light distribution prism 10.
It is arranged on the observer side of the illumination light distribution prism 10 facing the surface 11.

In the above configuration, the left and right optical paths indicated by broken lines are plane-symmetric with respect to the symmetry plane of both eyes, so the optical path for the right eye will be representatively described. The illumination light diverging from the common single light source 6 first emits the illumination light distribution prism 10
And the second surface 1 of the reflection surface for the right optical path.
The light is incident on and reflected by 2R, passes through the transmission surface 13R for the right optical path, enters the back surface of the image display element 3R, and illuminates uniformly and brightly. The luminous flux of the display image displayed on the image display element 3R passes through the first surface 21R of the eccentric prism body 2R and enters the prism, enters the second surface 22R at an angle of incidence equal to or greater than the critical angle, and is totally reflected. , Is incident on the third surface 23R, is reflected on the back surface, is incident on the fourth surface 24R at an incident angle equal to or less than the critical angle, is refracted, exits from the eccentric prism body 2R, is guided to the exit pupil 4R for the right eye, An enlarged image of the image display element 3R is projected on the right eye of the observer. In the above optical system, the light source 6 and the exit pupil 4R are configured to be optically conjugate (an image of the light source 6 is formed at the position of the exit pupil 4R when the image display element 3R is removed). . Note that no intermediate image is formed on the optical path from the image display element 3R to the exit pupil 4R. The optical path for the left eye has a plane-symmetric relationship with the optical path for the right eye with respect to the symmetry plane of both eyes, similarly to the arrangement of the optical system for the right eye.

With the above configuration, the illumination light from the single light source 6 is transmitted to the two image display elements 3R and 3L for both eyes by using the illumination light distribution optical system including the illumination light distribution prism 10. Irradiation can be performed separately, and by sharing the left and right illumination systems, it is possible to reduce the number of optical components, reduce the weight, and reduce the size. Further, since the illumination light distribution prism 10 used for the illumination system has five surfaces, the eccentric aberration of the illumination optical system can be corrected, and the image display element 3R,
The entire 3L can be uniformly illuminated. Light source 6
Is located on the observer side, so that the entire display device does not protrude greatly forward. In the illumination light distribution prism 10, the central principal ray of one illumination light beam crosses the central principal ray of the other illumination light beam three times.

Further, an eccentric prism body 1 in which the left and right optical paths are mostly filled with a transparent medium having a refractive index larger than 1
0, 2R, and 2L, and the optical path is bent therein, so that the entire eyepiece optical system can be made compact. The eccentric prisms 2R and 2L are arranged at plane-symmetric positions, but have the same shape. Two eccentric prisms 2R and 2L having the same shape are prepared. What is necessary is just to arrange | position in the position symmetrical with respect to a plane.

In the fourth embodiment, as shown in a horizontal section (YZ section) in FIG. 4, the illuminating light distribution prism 10 having five eccentric prisms of the second and third embodiments is replaced with three decentered prisms. Illuminating light distribution prism 10 composed of a prism body
Is used. Eccentric prism body 2 for left and right eyes
L, 2R, and image display elements 3L, 3R are the same as in Examples 1 to 3.

The central illumination light distribution prism 10 has a plane-symmetrical shape with respect to the plane of symmetry of both eyes, and the first surface 11 located on the viewer side of the light source 6 is a transmission surface, and the first surface 11 The second surface 12R of the right optical path reflecting surface and the second surface 1 of the left optical path reflecting surface acting as a total reflection surface located on both sides on the observer side.
2L, a transmission surface 13L for the left optical path which is the same as the second surface 12R of the reflection surface for the right optical path, and a transmission surface 13R for the right optical path which is the same as the second surface 12L of the reflection surface for the left optical path. First surface 11
Is a shape symmetrical with respect to the symmetry plane of the eyes, the second surface 12R
(13L) and 12L (13R) have shapes that are plane-symmetric with respect to the symmetry plane of both eyes. The light source 6 faces the first surface 11 of the illumination light distribution prism 10 and is disposed on the opposite side of the illumination light distribution prism 10 to the observer.

In the above configuration, the left and right optical paths indicated by broken lines are plane-symmetric with respect to the symmetry plane of both eyes, and thus the optical path for the right eye will be representatively described. The illumination light diverging from the common single light source 6 first emits the illumination light distribution prism 10
And the second surface 1 of the reflection surface for the right optical path.
2R, is totally reflected and transmitted through the right optical path transmission surface 13R (1
2L), enters the back surface of the image display element 3R, and illuminates uniformly and brightly. The luminous flux of the display image displayed on the image display element 3R passes through the first surface 21R of the eccentric prism body 2R and enters the prism, enters the second surface 22R at an angle of incidence equal to or greater than the critical angle, and is totally reflected. , Is incident on the third surface 23R, is reflected on the back surface, is incident on the fourth surface 24R at an incident angle equal to or less than the critical angle, is refracted, exits from the eccentric prism body 2R, is guided to the exit pupil 4R for the right eye, An enlarged image of the image display element 3R is projected on the right eye of the observer. In the above optical system, the light source 6 and the exit pupil 4R are optically conjugate (the image display element 3R
Is removed, the image of the light source 6 is formed at the position of the exit pupil 4R. ). The image display element 3
No intermediate image is formed in the optical path from R to the exit pupil 4R. The optical path for the left eye has a plane-symmetric relationship with the optical path for the right eye with respect to the symmetry plane of both eyes, similarly to the arrangement of the optical system for the right eye.

With the above configuration, the illumination light from the single light source 6 is applied to the two image display elements 3R and 3L for both eyes by using the illumination light distribution optical system including the illumination light distribution prism 10. Irradiation can be performed separately, and by sharing the left and right illumination systems, it is possible to reduce the number of optical components, reduce the weight, and reduce the size. In addition, since the illumination light distribution prism 10 used in the illumination system has only three surfaces, manufacture is very easy. Further, since the light source 6 is located at a position distant from the observer, it does not interfere with the nose of the observer.
Note that, in the illumination light distribution prism 10, the central principal ray of one illumination light flux is 1 to the central principal ray of the other illumination light flux.
It is a configuration that crosses twice.

Further, an eccentric prism 1 in which the left and right optical paths are mostly filled with a transparent medium having a refractive index larger than 1
0, 2R, and 2L, and the optical path is bent therein, so that the entire eyepiece optical system can be made compact. The eccentric prisms 2R and 2L are arranged at plane-symmetric positions, but have the same shape. Two eccentric prisms 2R and 2L having the same shape are prepared. What is necessary is just to arrange | position in the position symmetrical with respect to a plane.

In the fifth embodiment, as shown in the horizontal section (YZ section) in FIG. 5, the illumination light distribution prism 10 composed of the five-sided eccentric prisms of the second and third embodiments is replaced with a six-sided eccentricity prism. Illuminating light distribution prism 10 composed of a prism body
Is used. Eccentric prism body 2 for left and right eyes
L, 2R, and image display elements 3L, 3R are the same as in Examples 1 to 4.

The central illumination light distribution prism 10 has a shape that is plane-symmetric with respect to the symmetry plane of both eyes, and the first surface 11 located on the viewer side of the light source 6 is a transmission surface, and the first surface 11 is The second surface 12 of the reflecting surface facing and facing the observer, and the third of the right optical path reflecting surfaces disposed on both sides of the first surface 11 on the observer side.
Surface 13R and third surface 13L and third surface 13 of the left optical path reflection surface
Fourth surface 14L of the transmission surface for the left optical path and fourth surface 14 of the transmission surface for the right optical path disposed on both sides between R, 13L and the second surface 12
R consists of 6 surfaces. The first surface 11 and the second surface 12 are shapes symmetric with respect to the symmetry plane of both eyes, the third surfaces 13R and 13L, and the fourth surfaces 14L and 14R are shapes symmetric with respect to the symmetry plane of both eyes. is there. The light source 6 faces the first surface 11 of the illumination light distribution prism 10 and is disposed on the opposite side of the illumination light distribution prism 10 to the observer.

In the above configuration, since the left and right optical paths indicated by broken lines are plane-symmetric with respect to the symmetry plane of both eyes, the optical path for the right eye will be representatively described. The illumination light diverging from the common single light source 6 first emits the illumination light distribution prism 10
And is reflected by the second surface 12 common to the right and left, incident on and reflected by the third surface 13R of the reflection surface for the right optical path, and transmitted through the transmission surface 14R for the right optical path to display an image. Element 3
The light is incident on the back surface of R and is illuminated uniformly and brightly. The luminous flux of the display image displayed on the image display element 3R is the eccentric prism 2R.
Through the first surface 21R, enters the prism, enters the second surface 22R at an incident angle equal to or greater than the critical angle, is totally reflected, enters the third surface 23R, is reflected on the back surface, and is incident on the fourth surface 24R. Is incident at an incident angle equal to or smaller than the critical angle, is refracted, exits from the eccentric prism body 2R, is guided to the exit pupil 4R for the right eye, and projects an enlarged image of the image display element 3R to the observer's right eye. In the above optical system, the light source 6 and the exit pupil 4R are configured to be optically conjugate (an image of the light source 6 is formed at the position of the exit pupil 4R when the image display element 3R is removed). . Note that no intermediate image is formed on the optical path from the image display element 3R to the exit pupil 4R. The optical path for the left eye has a plane-symmetric relationship with the optical path for the right eye with respect to the symmetry plane of both eyes, similarly to the arrangement of the optical system for the right eye.

With the above configuration, the illumination light from the single light source 6 is transmitted to the two image display elements 3R and 3L for both eyes by using the illumination light distribution optical system including the illumination light distribution prism 10. Irradiation can be performed separately, and by sharing the left and right illumination systems, it is possible to reduce the number of optical components, reduce the weight, and reduce the size. Further, since the illumination light distribution prism 10 used for the illumination system has six surfaces and two reflection surfaces are used, the eccentric aberration of the illumination optical system can be corrected, and the entire surface of the image display elements 3R and 3L is made uniform. Can be illuminated. Further, since the light source 6 is located at a position distant from the observer, it does not interfere with the nose of the observer. In the illumination light distribution prism 10, the central principal ray of one illumination light beam crosses itself once.

Further, an eccentric prism body 1 whose left and right optical paths are mostly filled with a transparent medium having a refractive index larger than 1
0, 2R, and 2L, and the optical path is bent therein, so that the entire eyepiece optical system can be made compact. The eccentric prisms 2R and 2L are arranged at plane-symmetric positions, but have the same shape. Two eccentric prisms 2R and 2L having the same shape are prepared. What is necessary is just to arrange | position in the position symmetrical with respect to a plane.

In the sixth embodiment, as shown in a horizontal section (YZ section) in FIG. 6, an eccentric prism 2R constituting an optical system for the right eye and an eccentric prism constituting an optical system for the left eye 2L has the same shape and is arranged symmetrically with respect to the symmetry plane of both eyes, and the first surface 21 is arranged in the order in which light rays pass.
R (21L), second surface 22R (22L), third surface 23R
(23L), fourth surface 24R (24L), fifth surface 25R
(25L), and the third surface 23R (23L).
L) and the fifth surface 25R (25L) are the same surface, and the same surface serves as both a total reflection surface and a transmission surface.

As in the third embodiment (FIG. 3), the central illumination light distribution prism 10 has a plane-symmetric shape with respect to the symmetry plane of both eyes, and the first surface located on the observer side of the light source 6. 11
Is the transmission surface, the third surface 13R of the transmission surface for the right optical path located on both sides of the first surface 11 on the observer side, and the third surface 13R of the transmission surface for the left optical path.
The surface 13L includes five surfaces, that is, a second surface 12L of the left optical path reflection surface and a second surface 12R of the right optical path reflection surface located on the observer side of the third surfaces 13R and 13L. The first surface 11 has a shape symmetrical with respect to the symmetry plane of both eyes, and the third surfaces 13R and 13R.
L, and the second surfaces 12L and 12R have shapes that are plane-symmetric with respect to the symmetry plane of both eyes. The light source 6 is an illumination light distribution prism 1
0, the illumination light distribution prism 10 facing the first surface 11.
Is located on the opposite side of the observer.

In the above configuration, the left and right optical paths indicated by broken lines are plane-symmetric with respect to the symmetry plane of both eyes, and thus the optical path for the right eye will be representatively described. The illumination light diverging from the common single light source 6 first emits the illumination light distribution prism 10
And the second surface 1 of the reflection surface for the right optical path.
The light is incident on and reflected by 2R, passes through the transmission surface 13R for the right optical path, enters the back surface of the image display element 3R, and illuminates uniformly and brightly. The luminous flux of the display image displayed on the image display element 3R passes through the first surface 21R of the eccentric prism body 2R, enters the prism, is reflected by the second surface 22R, and the reflected light is critical to the third surface 23R. Incident on the fourth surface 24R, is reflected on the back surface, and is incident on the fourth surface 24R.
R enters at an incident angle less than the critical angle, is refracted, exits from the eccentric prism body 2R, is guided to the exit pupil 4R for the right eye,
An enlarged image of the image display element 3R is projected on the right eye of the observer.
In the above optical system, the light source 6 and the exit pupil 4R are configured to be optically conjugate (an image of the light source 6 is formed at the position of the exit pupil 4R when the image display element 3R is removed). . Note that no intermediate image is formed on the optical path from the image display element 3R to the exit pupil 4R. The optical path for the left eye has a plane-symmetric relationship with the optical path for the right eye with respect to the symmetry plane of both eyes, similarly to the arrangement of the optical system for the right eye.

With the above configuration, the illumination light from the single light source 6 is transmitted to the two image display elements 3R and 3L for both eyes by using the illumination light distribution optical system including the illumination light distribution prism 10. Irradiation can be performed separately, and by sharing the left and right illumination systems, it is possible to reduce the number of optical components, reduce the weight, and reduce the size. Further, since the illumination light distribution prism 10 used for the illumination system has five surfaces, the eccentric aberration of the illumination optical system can be corrected, and the image display element 3R,
The entire 3L can be uniformly illuminated. Light source 6
Is located away from the observer, so that it does not interfere with the nose of the observer. The illumination light distribution prism 1
Within 0, the central principal ray of one illumination light beam crosses the central principal ray of the other illumination light beam three times.

Further, an eccentric prism body 1 whose left and right optical paths are mostly filled with a transparent medium having a refractive index larger than 1
0, 2R, and 2L, and the optical path is bent therein, so that the entire eyepiece optical system can be made compact. The eccentric prisms 2R and 2L are arranged at plane-symmetric positions, but have the same shape. Two eccentric prisms 2R and 2L having the same shape are prepared. What is necessary is just to arrange | position in the position symmetrical with respect to a plane.

As shown in the horizontal section (YZ section) in FIG. 7, the seventh embodiment is different from the fourth embodiment (see FIG. 7) in place of the illumination light distribution prism 10 having five decentered prisms of the sixth embodiment. An illumination light distribution prism 10 composed of the same three-sided eccentric prism body as in 4) is used. Left and right eye eccentric prisms 2L, 2R, image display elements 3L, 3
R is the same as in the sixth embodiment.

As in the case of the fourth embodiment (FIG. 4), the central illumination light distribution prism 10 has a plane-symmetrical shape with respect to the symmetry plane of both eyes, and is located on the opposite side of the light source 6 from the observer. 1
The surface 11 is a transmission surface, the second surface 12R of the reflection surface for the right optical path and the second surface 12L of the reflection surface for the left optical path, which functions as a total reflection surface located on both sides of the first surface 11 on the observer side, and the right optical path. The left transmission path 13L is the same as the second reflection surface 12R, and the right transmission path 13R is the same as the second reflection surface 12L. The first surface 11 has a shape symmetrical with respect to the symmetry plane of both eyes, and the second surfaces 12R (13L) and 12L
(13R) is a shape symmetric with respect to the symmetry plane of both eyes. The image display element 3 is arranged on the viewer side of the illumination light distribution prism 10 facing the first surface 11 of the illumination light distribution prism 10.

In the above configuration, the left and right optical paths indicated by broken lines are plane-symmetric with respect to the symmetry plane of both eyes, and therefore, the optical path for the right eye will be representatively described. The illumination light diverging from the common single light source 6 first emits the illumination light distribution prism 10
And the second surface 1 of the reflection surface for the right optical path.
2R, is totally reflected and transmitted through the right optical path transmission surface 13R (1
2L), enters the back surface of the image display element 3R, and illuminates uniformly and brightly. The luminous flux of the display image displayed on the image display element 3R passes through the first surface 21R of the eccentric prism body 2R, enters the prism, is reflected by the second surface 22R,
The reflected light is incident on the third surface 23R at an incident angle equal to or greater than the critical angle, is totally reflected, is incident on the fourth surface 24R, is reflected on the back surface, and is incident on the fifth surface 25R at an incident angle less than the critical angle. The light is refracted and exits from the eccentric prism body 2R, is guided to the exit pupil 4R for the right eye, and projects an enlarged image of the image display element 3R to the observer's right eye. In the above optical system, the light source 6 and the exit pupil 4R are configured to be optically conjugate (an image of the light source 6 is formed at the position of the exit pupil 4R when the image display element 3R is removed). . Note that no intermediate image is formed on the optical path from the image display element 3R to the exit pupil 4R. The optical path for the left eye has a plane-symmetric relationship with the optical path for the right eye with respect to the symmetry plane of both eyes, similarly to the arrangement of the optical system for the right eye.

With the above configuration, the illumination light from the single light source 6 is applied to the two image display elements 3R and 3L for both eyes by using the illumination light distribution optical system including the illumination light distribution prism 10. Irradiation can be performed separately, and by sharing the left and right illumination systems, it is possible to reduce the number of optical components, reduce the weight, and reduce the size. In addition, since the illumination light distribution prism 10 used in the illumination system has only three surfaces, manufacture is very easy. Further, since the light source 6 is located on the observer side, the entire display device does not protrude largely forward. In addition,
In the illumination light distribution prism 10, the central principal ray of one illumination light beam crosses the central principal ray of the other illumination light beam once.

Further, an eccentric prism 1 in which the left and right optical paths are mostly filled with a transparent medium having a refractive index larger than 1
0, 2R, and 2L, and the optical path is bent therein, so that the entire eyepiece optical system can be made compact. The eccentric prisms 2R and 2L are arranged at plane-symmetric positions, but have the same shape. Two eccentric prisms 2R and 2L having the same shape are prepared. What is necessary is just to arrange | position in the position symmetrical with respect to a plane.

As shown in a horizontal section (YZ section) in FIG. 8, the eighth embodiment is different from the fifth embodiment (see FIG. 8) in place of the illumination light distribution prism 10 having five decentered prisms of the sixth embodiment. An illumination light distribution prism 10 composed of six eccentric prism bodies similar to 5) is used. Left and right eye eccentric prisms 2L, 2R, image display elements 3L, 3
R is the same as in Examples 6 and 7.

As in the fifth embodiment (FIG. 5), the central illumination light distribution prism 10 has a plane-symmetrical shape with respect to the symmetry plane of both eyes, and is located on the opposite side of the light source 6 from the observer. 1
The surface 11 is a transmission surface, the second surface 12 of the reflection surface facing the first surface 11 and opposite to the observer, and the reflection surface for the right optical path disposed on both sides of the first surface 11 opposite to the observer. 13R and the third surface 13L of the reflection surface for the left optical path, and the third surfaces 13R and 13L.
The fourth surface 14L of the transmission surface for the left optical path and the fourth surface 14R of the transmission surface for the right optical path are disposed on both sides between the first and second surfaces 12 and 12. The first surface 11 and the second surface 12 are symmetrical with respect to the symmetry plane of the eyes, the third surfaces 13R and 13L, and the fourth surface 14L.
And 14R have shapes that are plane-symmetric with respect to the symmetry plane of both eyes.
The light source 6 faces the first surface 11 of the illumination light distribution prism 10 and is arranged on the observer side of the illumination light distribution prism 10.

In the above configuration, since the left and right optical paths indicated by broken lines are plane-symmetric with respect to the symmetry plane of both eyes, the optical path for the right eye will be representatively described. The illumination light diverging from the common single light source 6 first emits the illumination light distribution prism 10
And is reflected by the second surface 12 common to the right and left, incident on and reflected by the third surface 13R of the reflection surface for the right optical path, and transmitted through the transmission surface 14R for the right optical path to display an image. Element 3
The light is incident on the back surface of R and is illuminated uniformly and brightly. The luminous flux of the display image displayed on the image display element 3R is the eccentric prism 2R.
Is incident on the prism through the first surface 21R, is reflected on the second surface 22R, and the reflected light is incident on the third surface 23R at an angle of incidence equal to or greater than the critical angle, is totally reflected, and is reflected on the fourth surface 24R. And is reflected on the back surface, enters the fifth surface 25R at an incident angle smaller than the critical angle, is refracted, emerges from the eccentric prism body 2R, is guided to the exit pupil 4R for the right eye, and is observed by the observer's right eye. Project an enlarged image of the image display element 3R. In the above optical system, the light source 6 and the exit pupil 4R are configured to be optically conjugate (an image of the light source 6 is formed at the position of the exit pupil 4R when the image display element 3R is removed). . Note that no intermediate image is formed on the optical path from the image display element 3R to the exit pupil 4R. The optical path for the left eye has a plane-symmetric relationship with the optical path for the right eye with respect to the symmetry plane of both eyes, similarly to the arrangement of the optical system for the right eye.

With the above configuration, the illumination light from the single light source 6 is transmitted to the two image display elements 3R and 3L for both eyes by using the illumination light distribution optical system including the illumination light distribution prism 10. Irradiation can be performed separately, and by sharing the left and right illumination systems, it is possible to reduce the number of optical components, reduce the weight, and reduce the size. Further, since the illumination light distribution prism 10 used for the illumination system has six surfaces and two reflection surfaces are used, the eccentric aberration of the illumination optical system can be corrected, and the entire surface of the image display elements 3R and 3L is made uniform. Can be illuminated. Further, since the light source 6 is located on the observer side, the entire display device does not protrude largely forward. In the illumination light distribution prism 10, the central principal ray of one illumination light beam crosses itself once.

In the ninth embodiment, as shown in the horizontal section (YZ section) in FIG. 9, the right-eye eccentric prism 2R composed of the four eccentric prisms of the seventh embodiment (FIG. 7) and the left eccentric prism 2R are used. Instead of the eccentric prism body 2L for the eye, the eccentric prism body 2R for the right eye and the eccentric prism body 2L for the left eye, each having three eccentric prism bodies having the same shape, are formed with respect to the symmetry plane of both eyes. The illumination light distribution prism 10 is arranged in a plane symmetrical manner, and is the same. Image display element 3R to eccentric prism 2R
Is transmitted through the first surface 21R and enters the prism.
The reflected light is reflected by the second surface 22R, and the reflected light is refracted by the third surface 23R, exits from the eccentric prism body 2R, is guided to the exit pupil 4R for the right eye, and is applied to the image display element 3R by the right eye of the observer. Project an enlarged image. In such an optical system, the light source 6
And the exit pupil 4R are configured to be optically conjugate (an image of the light source 6 is formed at the position of the exit pupil 4R when the image display element 3R is removed). The image display element 3
No intermediate image is formed in the optical path from R to the exit pupil 4R. The optical path for the left eye has a plane-symmetric relationship with the optical path for the right eye with respect to the symmetry plane of both eyes, similarly to the arrangement of the optical system for the right eye. Others are the same as the seventh embodiment.

In the tenth embodiment, a horizontal section (YZ) is shown in FIG.
As shown in the cross-section, instead of the right-eye eccentric prism 2R and the left-eye eccentric prism 2L, each of which has four eccentric prisms according to the sixth embodiment (FIG. 6), three surfaces having the same shape are used. An eccentric prism 2R for the right eye and an eccentric prism 2L for the left eye, which are formed of eccentric prisms, are arranged symmetrically with respect to the symmetry plane of both eyes.
Is similar. Image display element 3R to eccentric prism 2
Light transmitted through the first surface 21R of R and entering the prism is reflected by the second surface 22R, and the reflected light is reflected by the third surface 23R.
The light is refracted by R, exits from the eccentric prism body 2R, is guided to the exit pupil 4R for the right eye, and is displayed on the image display element 3 for the right eye of the observer.
Is projected. In such an optical system, the light source 6 and the exit pupil 4R are configured to be optically conjugate (an image of the light source 6 is formed at the position of the exit pupil 4R when the image display element 3R is removed). You. The image display element 3
No intermediate image is formed in the optical path from R to the exit pupil 4R. The optical path for the left eye has a plane-symmetric relationship with the optical path for the right eye with respect to the symmetry plane of both eyes, similarly to the arrangement of the optical system for the right eye. Others are the same as the sixth embodiment.

As described above, in the optical system for an image display apparatus of the present invention as described above, the reflecting surfaces 1R and 1L of the illumination light distribution mirror 1, the surfaces 11, 12 of the illumination light distribution prism 10, and 12R, 12L, 13R,
13L, 14R, 14L, the surfaces 21R to 25R of the decentered prism 2R of the eyepiece optical system for the right eye, and the surfaces 21L to 25L of the decentered prism 2L of the eyepiece optical system for the right eye correct eccentric aberration. It is desirable to form such a rotationally asymmetric curved surface shape.

Here, the right eyepiece prism 2R, the left eyepiece prism 2L, the illumination light distribution prism 10, and the illumination light distribution mirror 1 of the present invention are basically eccentric optical systems, and correct eccentric aberrations. It is preferable to include at least one optical surface having a rotationally asymmetric curved surface.

When the eccentric optical system is used as an observation optical system of a head-mounted image display device, in order to eliminate dead space and reduce the size of the entire device, the position of the light source, the image display element, and the eccentricity It is necessary to arrange the optical surface constituting the optical system at a position where the optical surface is as compact as possible inside the apparatus. In such a case, the optical system is inevitably three-dimensionally eccentrically arranged, and rotationally asymmetric aberration occurs. It is impossible to correct the aberration only with the rotationally symmetric optical system. The best surface shape for correcting rotationally asymmetric aberrations caused by dimensional eccentricity is a rotationally asymmetric surface. Therefore, in the image display device of the present invention, the reflection surfaces 1R, 1L,
Each surface 11, 12, 12 of the illumination light distribution prism 10
R, 12L, 13R, 13L, 14R, 14L, surfaces 21R to 25R of the decentered prism body 2R of the eyepiece optical system for the right eye,
Surfaces 21L to 2L of decentered prism body 2L of eyepiece optical system for right eye
In 5L, it is desirable that at least one surface, preferably the shape of the reflecting surface, is formed to have a rotationally asymmetric curved surface shape for correcting eccentric aberration.

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

[0059] Here, the first term of the equation (a) is a spherical term, and the second term is a free-form surface term.

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

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

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

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

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

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

The free-form surface of the illumination light distribution mirror 1, the illumination light distribution prism 10, the right eyepiece prism 2R, and the right eyepiece prism 2L forms a light beam connecting the center of the light source and the pupil center. When the optical axis is used, it is desirable that a plane (YZ plane) including the optical axis in the folded optical path in the prism is configured as the only symmetric plane.

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

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

Z = C ₂ + C ₃ Y + C ₄ | X | + C ₅ Y ² + C ₆ Y | X | + C ₇ X ² + C ₈ Y ³ + C ₉ Y ² | X | + C ₁₀ YX ² + C ₁₁ | X ³ | + C ₁₂ Y ⁴ + C ₁₃ Y ³ | X | + C ₁₄ Y ² X ² + C ₁₅ Y | X ³ | + C ₁₆ X ⁴ + C ₁₇ Y ⁵ + C ₁₈ Y ⁴ | X | + C ₁₉ Y ³ X ² + C ₂₀ Y ² | X ^{_{3 | + C 21 YX 4 +}} C 22 | X 5 | + C 23 Y 6 + C 24 Y 5 | X | + C 25 Y 4 X 2 + C 26 Y 3 | X 3 | + C 27 Y 2 X 4 + C 28 Y | X 5 | ^{_{+ C 29 X 6 + C 30}} Y 7 + C 31 Y 6 | X | + C 32 Y 5 X 2 + C 33 Y 4 | X 3 | + C 34 Y 3 X 4 + C 35 Y 2 | X 5 | + C 36 YX 6 + C 37 | X ⁷ | (c) Note that the refracting surfaces closest to the exit pupil side of the eyepiece prisms 2L and 2R for the left and right eyes (the surfaces 24L and 24R in Examples 1 to 5 and the surfaces 25L and 25R in Examples 6 to 8). Examples 9 to 10 Face 23
L, 23R) may be constituted by a rotationally symmetric aspherical surface. In this case, the manufacturability is improved, and positioning of another surface with the rotationally symmetric aspheric surface as a reference surface is facilitated.

Further, as the eccentric prism bodies 2L and 2R constituting the optical system for the left and right eyes in the above embodiments, other known types of eccentric prism bodies may be used.

As the light source 6, not only a single light source but also a plurality of light sources may be used.

By providing and supporting one set of the image display devices as described above, it is possible to configure a stationary or portable image display device. This is shown in FIG. In FIG. 11, reference numeral 31 denotes a display device main body, and a supporting member is fixed via a head so as to be held in front of both eyes of the observer's face. One end of the support member is joined to the display device main body 31, the left and right front frames 32 extending from the temple of the observer to the upper part of the ear, and the other end of the front frame 32 is joined to the side of the observer. From the left and right rear frames 33 extending across the head, or further, one end of each is joined one by one so as to be sandwiched by the other ends of the left and right rear frames 33, supporting the top of the observer's head And a top frame 34.

In the vicinity of the joint of the front frame 32 with the rear frame 33, a rear plate 35 made of an elastic body and made of, for example, a metal plate spring is joined. The rear plate 35 is joined so that a rear cover 36, which carries one wing of the support member, is supported behind the ear at a portion where the back of the observer's head is attached to the neck of the viewer. Rear plate 35 or rear cover 36
A speaker 39 is mounted at a position corresponding to the ear of the observer inside.

A cable 41 for transmitting video / audio signals and the like from the outside is connected to the rear plate 35 or the rear cover 35 via the top frame 34, the rear frame 33, the front frame 32 and the rear plate 35 from the display device main body 31. 36 protrudes outside from the rear end. The cable 41 is connected to the video playback device 40. In the figure, reference numeral 40a denotes a switch and a volume adjusting unit of the video reproducing device 40.

It is to be noted that the cable 41 may be jacked at the end so that it can be attached to an existing video deck or the like. Furthermore, it is connected to a tuner for TV radio wave reception,
It may be used for viewing, or may be connected to a computer to receive computer graphics images, message images from the computer, and the like. In addition, an antenna may be connected to receive an external signal by radio wave in order to reject an obstructive code.

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

[1] A right-eye eyepiece optical system and a left-eye eyepiece optical system for separately projecting the display images of the right-eye image display element and the left-eye image display element to the right and left eyes of the observer, respectively. In the image display device, the image display element for the right eye, the image display element for the left eye is configured by a transmission type image display element that displays an image by transmitting the illumination light, the image display element for the right eye and the image display element for the left eye An image display device, wherein a light beam illuminating the image display element is divergent light from a single light source shared by the illumination light sorting optical system.

[2] The light source is in the front-rear direction (Z direction)
And disposed between the illumination light distribution optical system and the observer, and disposed between the right eyepiece optical system and the left eyepiece optical system in the left-right direction (Y direction). 2. The image display device according to the above item 1, wherein

[3] The light source is in the front-rear direction (Z direction)
The illumination light distribution optical system is arranged on the opposite side to the observer, and is arranged between the right eyepiece optical system and the left eyepiece optical system in the left-right direction (Y direction). 2. The image display device according to the above item 1, wherein

[4] The illumination light distribution optical system is arranged to face the light source and reflect the illumination light flux emitted from the light source to the right eye image display element and the left eye image display element. 4. The image display device according to any one of claims 1 to 3, wherein the image display device has a mirror surface having a curved surface, and has a rotationally asymmetric curved surface shape for correcting eccentric aberration.

[5] The image display apparatus as described in [4], wherein the rotationally asymmetric curved surface of the illumination light distribution mirror is a free-form surface having only one symmetric surface.

[6] The image display apparatus according to the above item 4 or 5, wherein a negative lens for giving a negative power to the light beam is arranged between the light source and the illumination light distribution mirror.

[7] The illumination light distribution optical system has an illumination light distribution prism that distributes the illumination light beam emitted from the light source to the right-eye image display element and the left-eye image display element. A first surface on which the illumination light distribution prism is arranged to face the light source and allows an illumination light flux emitted from the light source to enter the inside of the prism;
A twenty-first surface that reflects the optical path for the right eye incident from a surface;
A second reflecting the optical path for the left eye incident from the first surface;
The illumination light distribution prism having at least two surfaces, a thirty-first surface for emitting the light beam in the optical path for the right eye to the outside of the prism, and a 32nd surface for emitting the light beam in the optical path for the left eye to the outside of the prism. In order to illuminate the image display element for the right eye and the image display element for the left eye with the illumination light flux emitted from the light source, at least the 21st surface, the 22nd surface, the 31st surface, and the The thirty-second surface has the same surface shape as the twenty-first surface and the twenty-second surface, and the thirty-first surface and the thirty-second surface have the same shape. The image display device according to any one of claims 1 to 3, wherein the image display device is configured to have the following surface shape.

[8] The first surface, the twenty-first surface, the twenty-second surface, the thirty-first surface, and the thirty-second surface of the illumination light distribution prism form optical surfaces of the prism as independent surfaces, respectively. 8. The image according to the above item 7, wherein the curved shape of the twenty-first surface, the twenty-second surface, the thirty-first surface, and the thirty-second surface of the sorting prism is a rotationally asymmetric curved surface shape for correcting eccentric aberration. Display device.

[0085]

[9] The light source and the illumination light distribution prism are disposed to face each other, and as the illumination light distribution prism moves away from the light source in the front-rear direction (Z direction), the first surface is disposed, and left and right across a medium. The twenty-first surface and the twenty-second surface are arranged at the position, and further, the thirty-first surface and the thirty-second surface are arranged so as to sandwich the air gap with the right-eye image display element. The 31st surface is disposed at a position facing the third image display device, and the third surface is disposed at a position facing the left-eye image display element with an air gap therebetween.
9. The image display device according to the item 8, wherein the image display device is configured so that two surfaces are arranged.

[10] The light source and the illumination light distribution prism are disposed to face each other, and as the illumination light distribution prism moves away from the light source in the front-rear direction (Z direction), the first surface is disposed and the medium is disposed. The 31st surface and the 32nd surface are arranged at left and right positions sandwiched therebetween, and further, the 21st surface and the 22nd surface are arranged, and the right eye image display element and the air are arranged. The thirty-first surface is arranged at a position facing the image display element for the left eye at a position facing the image display element for the left eye with the air gap therebetween.
9. The image display device according to the item 8, wherein the image display device is configured so that two surfaces are arranged.

[11] The illumination light distribution prism is configured such that the twenty-first surface and the thirty-second surface are shared by one surface, and the twenty-second surface and the thirty-first surface are one. The optical path for the right eye is incident on the combined surface of the 21st and 32nd surfaces at an angle larger than the critical angle for total reflection, so that the right path in the prism is formed by the total reflection action. The luminous flux in the optical path for the right eye is reflected by reflecting the luminous flux in the optical path for the right eye, and the luminous flux in the optical path for the right eye is prism-incident by making the optical path for the right eye incident on the combined surface of the 22nd surface and the 31st surface at an angle smaller than the critical angle for total reflection. The light flux of the optical path for the left eye is emitted inside the prism by the total reflection by emitting the light to the outside and causing the optical path for the left eye to enter the combined surface of the 22nd and 31st surfaces at an angle larger than the critical angle for total reflection. Reflected, total reflection of the optical path for the left eye 21st at an angle smaller than the critical angle
The luminous flux in the optical path for the left eye is emitted out of the prism by being incident on the dual-purpose surface of the surface and the 32nd surface, and the curved shape of the dual-purpose surface of the 21st and 32nd surfaces corrects the eccentric aberration. It is characterized by being constituted by a rotationally asymmetric curved surface shape, and being constituted by a rotationally asymmetric curved surface shape such that the curved surface shape of the combined surface of the 22nd and 31st surfaces corrects eccentric aberration. 8. The image display device according to the above item 7, wherein

[12] The fourth surface having a curved surface shape, in which the illumination light distribution prism reflects the illumination light flux emitted from the light source incident on the first surface toward the twenty-first surface and the twenty-second surface. And the first surface, the twenty-first surface, the twenty-second surface, the thirty-first surface, the thirty-second surface, and the fourth surface of the illumination light distribution prism form optical surfaces of the prism as independent surfaces, The curved surface shape of the 21st surface, the 22nd surface, the 31st surface, the 32nd surface, and the 4th surface of the illumination light distribution prism is constituted by a rotationally asymmetric curved surface shape for correcting eccentric aberration. 8. The image display device according to the above item 7, wherein

[13] The light source and the illumination light distribution prism are arranged to face each other, and the first surface is arranged as the illumination light distribution prism moves away from the light source in the front-rear direction (Z direction). The twenty-first surface and the twenty-second surface are arranged at left and right positions sandwiching the medium, the thirty-first surface and the thirty-second surface are arranged at left and right positions sandwiching the medium, and further, the first surface and the medium The fourth surface is arranged at a position facing the image display element for the right eye, and the third surface is arranged at a position facing the image display element for the right eye with an air gap therebetween.
13. The image display according to the above item 12, wherein one surface is arranged and the 32nd surface is arranged at a position facing the image display element for the left eye with an air gap therebetween. apparatus.

[14] The above-mentioned items 7 to 13, wherein the rotationally asymmetric curved surface of the illumination light distribution prism is a free-form surface having only one symmetric surface.
The image display device according to any one of the claims.

[15] The free-form surface of the illumination light distribution prism is characterized in that a plane (YZ plane) connecting the center of the light source and the center of the pupil is used as the only plane of symmetry. 15. The image display device according to 14 above.

[16] The eyepiece optical system for the right eye has a first surface on which the display light of the image display element for the right eye enters the prism, and a second surface for reflecting the light beam in the optical path for the right eye in the prism. Surface and the third that emits the light beam of the optical path for the right eye outside the prism
A first surface for causing the display light of the left-eye image display device to enter the prism, and a left-side optical path within the prism. And a third surface for emitting a light beam in the optical path for the left eye outside the prism, and is at least a reflecting surface of the eyepiece prism for the right eye. Any one of the above items 1 to 15, wherein the second surface and the second surface, which is the reflecting surface of the eyepiece prism for the left eye, are formed in a rotationally asymmetric curved surface shape for correcting eccentric aberration. 2. The image display device according to claim 1.

[17] The eyepiece prism for the right eye causes a light beam transmitted through the first surface and incident on the prism to enter the third surface at an angle larger than the critical angle for total reflection, thereby performing a total reflection operation. Is reflected toward the second surface in the prism, and the light beam reflected by the second surface is incident on the third surface at an angle smaller than the critical angle for total reflection, thereby transmitting the light beam through the third surface. Out of the prism, and the eyepiece prism for the left eye causes the light beam transmitted through the first surface and incident on the prism to enter the third surface at an angle larger than the critical angle for total reflection. Accordingly, the light is reflected toward the second surface in the prism by the total reflection action, and the light beam reflected on the second surface is incident on the third surface at an angle smaller than the critical angle for total reflection. Through 17. The image display device according to the above item 16, wherein the light beam is emitted outside the prism.

[18] The eyepiece prism for the right eye has a fourth surface for reflecting a light beam in the prism, and reflects a light beam transmitted through the first surface and incident on the prism on the fourth surface. The light reflected from the fourth surface is incident on the third surface at an angle larger than the critical angle for total reflection, whereby the light is reflected toward the second surface within the prism by a total reflection effect, and the second surface is reflected. The light beam reflected by the third surface is incident on the third surface at an angle smaller than the critical angle for total reflection, so that the light beam is transmitted through the third surface and emitted out of the prism. A fourth surface for reflecting a light beam in the prism, and reflecting a light beam transmitted through the first surface and incident on the prism on the fourth surface;
The luminous flux reflected from the surface is incident on the third surface at an angle larger than the critical angle for total reflection, whereby the light is reflected toward the second surface in the prism by a total reflection effect, and
The luminous flux reflected by the surface is incident on the third surface at an angle smaller than the critical angle for total reflection, so that the luminous flux is transmitted through the third surface and emitted out of the prism. 17. The image display device according to the above item 16.

[0095]

As is clear from the above description, according to the present invention, the divergent light from a common single light source is distributed right and left by the illumination light distribution optical system to illuminate the left and right image display elements. It is possible to reduce the number of optical components, reduce the weight, reduce the size, and reduce the power consumption of the display device.

[Brief description of the drawings]

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

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

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

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

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

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

FIG. 7 is an optical path diagram of an image display device according to a seventh embodiment of the present invention.

FIG. 8 is an optical path diagram of an image display device according to an eighth embodiment of the present invention.

FIG. 9 is an optical path diagram of an image display device according to a ninth embodiment of the present invention.

FIG. 10 is an optical path diagram of an image display device according to a tenth embodiment of the present invention.

FIG. 11 is a diagram showing a state in which the image display device of the present invention is mounted on the observer's head.

[Explanation of symbols]

 ER: Right eye EL: Left eye 1: Illumination light distribution mirror 1R: Reflective surface for right optical path 1L ... Reflective surface for left optical path 2R: Eyepiece prism for right eye 2L ... Eyepiece prism for left eye 3R: Image display element for right eye 3L: Left-eye image display element 4R: Right-eye exit pupil 4L: Left-eye exit pupil 5: Negative lens 6: Illumination light source 10: Illumination light distribution prism 11: First surface 12, 12R, 12L: Second surface 13R, 13L: Third surface 14R, 14L: Fourth surface 21R, 21L: First surface 22R, 22L: Second surface 23R, 23L: Third surface 24R, 24L: Fourth surface 25R, 25L: Fifth surface 31 ... display device main body 32 ... front frame 33 ... rear frame 34 ... crown frame 35 ... rear plate 36 ... rear cover 39 ... speaker 40 ... video playback device 40a ... volume adjustment unit 41 ... cable

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H059 AA24 AA35 5C061 AB14 AB18 AB24 5G435 AA00 AA18 BB12 BB15 DD02 DD03 DD09 FF02 GG01 GG03 GG06 GG08 GG22

Claims (3)

[Claims] 1. An eyepiece optical system for a right eye and an eyepiece optical system for a left eye for separately projecting display images of an image display element for a right eye and an image display element for a left eye to right and left eyes of an observer, respectively. In the image display device, the right-eye image display element and the left-eye image display element each include a transmission-type image display element that displays an image by transmitting illumination light, and the right-eye image display element and the left-eye image. An image display apparatus, wherein a light beam illuminating a display element is divergent light from a single light source shared by the illumination light sorting optical system. 2. The illumination light distributing optical system distributes and reflects an illumination light flux emitted from the light source disposed opposite to the light source to the right eye image display element and the left eye image display element. 2. The image display device according to claim 1, further comprising a mirror surface, wherein the mirror surface has a rotationally asymmetric curved surface shape for correcting eccentric aberration. 3. The illumination light distribution optical system includes an illumination light distribution prism that distributes an illumination light beam emitted from the light source to the right-eye image display element and the left-eye image display element. A first surface on which an illumination light distribution prism is arranged to face the light source and which receives an illumination light beam emitted from the light source inside the prism; and a twenty-first surface which reflects the optical path for the right eye incident from the first surface. , The first
A 22nd surface that reflects the optical path for the left eye incident from a surface,
No. 31 for emitting the light beam of the optical path for the right eye to the outside of the prism
Surface, and at least a thirty-second surface that emits a light beam in the light path for the left eye to the outside of the prism, and the illumination light distribution prism includes an illumination light beam emitted from the light source and the image display element for the right eye. In order to illuminate the left-eye image display element, at least the twenty-first surface, the twenty-second surface, the thirty-first surface, and the thirty-second surface are configured with a curved surface shape that gives power to a light flux, 2. The device according to claim 1, wherein the 21st surface and the 22nd surface have the same surface shape, and the 31st surface and the 32nd surface have the same surface shape. 3. The image display device as described in the above.