JP2001013450A - Video display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To miniaturize a video display device that projected light is recursively reflected and guided to an observer's eye by providing a 1st recursive reflection surface receiving one part of light from a projection optical system and a 2nd recursive reflection surface receiving the light from the projection optical system before reaching the extension of the 1st recursive reflection surface. SOLUTION: The light made incident on the 1st recursive reflection surface 33 is reflected and goes toward the projection optical system 32, and the light made incident on the 2nd recursive reflection surface 34 is also reflected and goes toward the system 32. The reflected light projects the entire displayed video. The light reflected by the surfaces 33 and 34 is mostly made incident on the system 32 again but the surfaces 33 and 34 have some diffusivity, so that the light is also made incident on the observer's eye E positioned near the system 32. Therefore, the observer can observe the video on an image- formation surface M1. The video display device 1 can provide field wider than the size of the surface 33.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image display device for displaying an image with a wide field of view, and is used in the field of providing images such as virtual reality.

[0002]

2. Description of the Related Art In recent years, virtual reality that provides virtual reality with a sense of realism has been remarkably spreading.
In order to provide a wide-field image, various types of image display devices have been developed. Above all, a device that enlarges an image displayed on a display by an eyepiece optical system and guides the image to an observer's eye and a device that enlarges an image displayed on the display by a projection optical system and projects the image on a screen are common.

[0003] The former is easy to reduce the size as a whole, and is suitable for a form that is used by an observer by holding it by hand or wearing it on the head. However, there is an upper limit to the field of view, and it is difficult to set the field of view to more than 180 °, for example. The latter can also be hand-held or head-mounted,
Larger than the former. On the other hand, by using a spherical screen, an image with an extremely wide field of view can be provided.

In an apparatus for projecting and displaying an image on a screen, it is necessary to supply light from all parts of the screen to an observer. For this purpose, a screen having a light diffusing property is used. However, since the degree of light diffusion depends on the angle of incidence of light on the screen, there is a difference in the amount of light traveling from each part of the screen to the viewer, resulting in uneven brightness of the provided image. easy. Further, the projected light travels in all directions from the screen, so that the light given to the observer decreases, and it is inevitable that the brightness of the observed image decreases.

In order to avoid such inconvenience, it has been proposed to use a screen having a retroreflective property for reflecting most of the light in the direction of arrival and to project light from near the observer. For example, US Pat.
No. 0702 discloses a device having a fixedly installed screen having a retroreflective property, and a combiner that reflects light from a projection optical system to guide the screen and transmits the reflected light to an observer's eye. Is disclosed. Also, U
SP5606458 and USP5621572 include:
There is disclosed a head-mounted device that includes an eyepiece optical system in addition to a retroreflective screen and a combiner so that an image projected on the screen is further enlarged and provided by the eyepiece optical system.

[0006]

However, the conventional image display device having a retroreflective screen is designed to direct all the light from the projection optical system or the light from the projection optical system via the combiner directly to the screen. I have to. For this reason, a screen having a size corresponding to the wide field of view of an image to be provided is indispensable, and an increase in the size of the apparatus has been inevitable. This impairs the advantages of its use form in the case of a hand-held or head-mounted device, and causes a significant inconvenience in that a large space is required for installation in the case of a fixed installation device.

The present invention has been made in view of such a problem, and aims at miniaturizing an image display device that projects light of a displayed image and retroreflects the projected light to guide the light to an observer's eyes. The purpose is to:

[0008]

According to the present invention, there is provided a video display for displaying an image, a projection optical system for projecting light of the video displayed on the video display, and a projection optical system. A first retroreflective surface for receiving a portion of light from the system;
The second retroreflective surface receives the light from the projection optical system that goes outside the first retroreflective surface before reaching the extension of the first retroreflective surface.

This image display device projects the light of the image displayed on the image display device and retroreflects the projection light to the observer's eye. The entire projection light is reflected by a single retroreflection. Instead of reflecting at the surface, the light is reflected at the first retroreflective surface and the second retroreflective surface. The observer can observe all parts of the image by looking at the range including the first and second retroreflective surfaces from the direction of the projection light or a direction close thereto.

The second retroreflective surface is arranged not on the extension of the first retroreflective surface but on the side closer to the projection optical system on the optical path of the projection light. Therefore, the range in which the second retroreflective surface can receive the projection light is wide, and the device can provide an image with a wide field of view, but can be configured to be small in the direction perpendicular to the projection light. In addition, it is possible to arrange the second retroreflective surface at an angle to the first retroreflective surface,
Thereby, the device can be further downsized.

The first and second retroreflective surfaces may be flat or curved. It is also possible to provide a plurality of second retroreflective surfaces. The projection optical system may be one that forms the projection light on the first and second retroreflection surfaces, or one that does not form the projection light on the first and second retroreflection surfaces as parallel light. The observer observes the image on the retroreflective surface in the former case, and observes the image on the image display in the latter case.

In the above-mentioned image display device, a combiner for guiding light from the projection optical system to the first and second retroreflective surfaces and guiding light from the first and second retroreflective surfaces to the eyes of the observer is provided. It may be provided. Either the optical path of the projected light from the projection optical system or the optical path of the reflected light from the retroreflective surface will be turned back, and the eye of the observer will be located at a position equivalent to or very close to the projection optical system. it can.

Thus, even if the exit pupil of the projection optical system is small, an image can be observed, and the projection optical system can be downsized. In addition, the depth of the image is increased by reducing the diameter of the exit pupil, and the degree of freedom of the position and direction of the retroreflective surface with respect to the light from the projection optical system is increased. Also, an extremely bright image can be provided by using a retroreflective surface having extremely high recursiveness, that is, almost no scattering.

In order to achieve the above object, the present invention also provides an image display for displaying an image, a projection optical system for projecting light of the image displayed on the image display, and a curved surface shape having different vertical and horizontal curvatures. Having a retroreflective surface that receives light from the projection optical system, and a combiner that guides light from the projection optical system to the retroreflective surface and guides light from the retroreflective surface to the eyes of the observer.
An image display device is configured.

This image display device projects the light of the image displayed on the image display onto a curved retroreflective surface via a combiner, and guides the reflected light to the observer's eyes via the combiner. . By providing the combiner, as described above, the size of the projection optical system can be reduced, the degree of freedom of the position and orientation of the retroreflective surface can be improved, and the brightness of the provided image can be increased. Is a curved surface, the retroreflective surface can be reduced, and the device can be further miniaturized. In addition, since the curvature of the retroreflective surface differs in the vertical and horizontal directions, it is easy to arrange the combiner close to the retroreflective surface that is a curved surface, and further downsizing of the device can be achieved.

Each of the above image display devices may be provided with an eyepiece optical system for giving the observer a virtual image of the image represented by the light projected by the projection optical system. The displayed image can be further enlarged by the eyepiece optical system, so that the field of view of the provided image can be further widened and the device can be made smaller.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the video display device of the present invention will be described with reference to the drawings. FIG. 1 shows the configuration of a video display device 1 according to the first embodiment and the principle of video provision.
Shown in FIG. 1 is a perspective view of the image display device 1 from the side. The image display device 1 includes a liquid crystal display 31, a projection optical system 3,
2, the first retroreflective surface 33, and the second retroreflective surface 3
4 is provided.

The liquid crystal display 31 is of a transmission type, displays a two-dimensional image on a display panel, and modulates and emits light from a backlight light source according to the displayed image. The projection optical system 32 projects the light emitted from the liquid crystal display 31 toward the surface M1. The projection optical system 32 is set to form an image of the projection light on the surface M1, and the surface M1 is an imaging surface. The imaging plane M1 is a plane perpendicular to the optical axis of the projection optical system 32. The image formed on the image plane M1 is an enlarged image of the image displayed on the liquid crystal display 31, and covers a wide range.

The first and second retroreflective surfaces 33, 34
It is manufactured by providing very small glass beads or corner cubes of about 0 μm or less on the surface of a plate-like member or a film-like member. The retroreflectivity of the first and second retroreflective surfaces 33 and 34 is not set particularly high.
Each of the retroreflective surfaces 33 and 34 has a slight diffuse reflectivity.

The first retroreflective surface 33 is a flat surface, and the image forming surface M
1 and thus functions as a screen. The retroreflective surface 33 has a size that receives only a part of the light beam from the projection optical system 32, and corresponds to a partial range of an image formed on the image forming surface M1.

The second retroreflective surface 34 includes two upper and lower pieces shown in FIG. 1 and two left and right pieces (not shown). The retroreflective surface 34 is also a plane. The second retroreflective surface 34 is provided between the projection optical system 32 and the first retroreflective surface 33.
The two optical axes are arranged parallel to each other, and thus perpendicular to the retroreflective surface 33. The end of the second retroreflective surface 34 reaches the edge of the first retroreflective surface 33, and the first retroreflective surface 33 is sandwiched by the second retroreflective surface 34 from above, below, left, and right. I have.

The observer positions the eye E near the projection optical system 32 and looks at the image forming surface M1 including the first retroreflective surface 33.

A part of the light projected by the projection optical system 32 enters the first retroreflective surface 33 and forms a part of the image displayed on the liquid crystal display 31 on the retroreflective surface 33. The rest of the light projected by the projection optics 32 is the first
Proceeds toward the outside of the retroreflective surface 33, enters the second retroreflective surface 34 before the image forming surface M1, and converts the remaining portion of the image displayed on the liquid crystal display 31 to the retroreflective surface 34. Form on top.

Light incident on the first retroreflective surface 33 is reflected and proceeds toward the projection optical system 32, and light incident on the second retroreflective surface 34 is also reflected and proceeds toward the projection optical system 32. . These reflected lights represent the entire displayed image.
Most of the light reflected by the retroreflective surfaces 33 and 34 re-enters the projection optical system 32. However, since the retroreflective surfaces 33 and 34 have some diffusion properties, Is also incident on the eye E of the observer located at. Therefore, the observer can observe the image on the imaging plane M1.

As described above, the image display device 1 can provide an image having a field of view wider than the size of the first retroreflective surface 33. Further, since the second retroreflective surface 34 is disposed in the space between the projection optical system 32 and the first retroreflective surface 33, the size of the video display device 1 does not increase.
Therefore, the video display device 1 is, like a conventional device,
The first retroreflective surface 33 without the second retroreflective surface 34
Is smaller than the case where is set to a size capable of receiving the entire luminous flux projected on the imaging plane M1.

The light incident on the second retroreflective surface 34 forms a clear image only at a portion near the image forming surface M1, and forms a slightly blurred image at a portion far from the image forming surface M1. However, blurring of the image on the retroreflective surface 34 can be suppressed by reducing the exit pupil of the projection optical system 32 to increase the F value and increasing the depth of the image represented by the projection light.
Further, the image formed at a portion of the retroreflective surface 34 far from the image forming surface M1 is a peripheral portion of the image displayed on the liquid crystal display 31 and is not a main observation target. Even if the blur occurs, it is not clearly recognized by the observer, and the sense of reality is not impaired.

The liquid crystal display 31, the projection optical system 32, and the first and second retroreflective surfaces 33 and 34 can be integrated, and the image display device 1 is a hand-held type or a head-mounted type. It can be a device or a fixed installation device. In the case of a hand-held type or a head-mounted type, a direction detector 37 for detecting the direction of the observer's head may be provided, and an image corresponding to the detected direction of the head may be displayed on the liquid crystal display 31. The provided image follows the direction of the observer, and a high sense of reality is obtained. Also, the visual field of the image is further expanded. Note that the projection optical system 32 only needs to face any part of the first retroreflective surface 33, and does not need to be disposed facing the center of the retroreflective surface 33.

Hereinafter, other embodiments of the present invention will be described. The same or similar components as those described above are denoted by the same reference numerals, and redundant description will be omitted. In addition, a configuration in which the same element is provided in a pair of right and left is also shown.

FIG. 2 shows the configuration of the video display device 2 of the second embodiment and the principle of providing video. FIG. 2 is a perspective view of the image display device 2 from above. The image display device 2 includes two liquid crystal displays 31L, 31R, two projection optical systems 32L, 3L.
2R, a first retroreflective surface 33, a second retroreflective surface 34,
And two eyepiece optical systems 35L and 35R.

The liquid crystal displays 31L and 31R display images provided to the left eye EL and the right eye ER of the observer, respectively, and the projection optical systems 32L and 32R display the liquid crystal displays 31L and 31R, respectively.
The light emitted from the 1R is projected to form an image on the surface M1. The projection optical systems 32L and 32R are provided for the left and right eyes EL and ER of the observer.
Are arranged so that they can be located in the vicinity of, and the optical axes of both are parallel. The settings of the first and second retroreflective surfaces 33 and 34 are the same as those of the image display device 1 of the first embodiment. Since the liquid crystal displays 31L and 31R display images with parallax, stereoscopic images can be provided to the observer.

The eyepiece optical systems 35L and 35R are respectively a projection optical system 32 reflected by the retroreflective surfaces 33 and 34.
The light from L, 32R is guided to the left and right eyes EL, ER. With the positive power of the eyepiece optical systems 35L and 35R, the eyes EL and E
The light guided to R becomes equivalent to the light coming from the surface M2 farther than the imaging surface M1, and the observer observes the virtual image located on the surface M2.

In the image display device 2, the eyepiece optical system 35L,
By providing the 35R and enlarging the image formed on the image plane M1, the field of view of the provided image can be made wider than that of the image display device 1. When the visual field of an image is the same as that of the image display device 1, the projection optical system 3
Since the distance from the 2L, 32R to the first retroreflective surface 33 can be shortened, the device becomes smaller. In this case, the incident position of the light on the second retroreflective surface 34 approaches the image forming surface M1, and the blur on the image on the retroreflective surface 34 is reduced.

The light of the left and right images projected by the projection optical systems 32L and 32R overlaps on the retroreflective surface 33, but the light of the left and right images reflected by the retroreflective surface 33 is separated. The retroreflective surface 33 is provided so that light is incident on the observer's eyes EL and ER near the projection optical systems 32L and 32R.
Is set to have a slight diffuse reflectance, but the degree of the diffusivity is not so high, and the light of the image for the left eye is incident on the right eye ER, and the light of the image for the right eye is It does not enter the eye EL. Here, the projection optical system 3
Although the optical axes of 2L and 32R are parallel, the optical axes of both may be non-parallel.

FIG. 3 shows the configuration of the video display device 3 of the third embodiment and the principle of providing video. FIG. 3 is a perspective view of the image display device 3 from the side. The image display device 3 includes a liquid crystal display 31, a projection optical system 32, a first retroreflective surface 33, a second
And a half mirror 36 as a combiner.

The projection optical system 32 is disposed so as to project the light from the liquid crystal display 31 downward, and the half mirror 36 emits the light projected by the projection optical system 32.
It is arranged so as to reflect toward the image forming plane M1. Part of the light from the projection optical system 32 reflected by the half mirror 36 is incident on the first retroreflective surface 33, and the rest is incident on the second retroreflective surface 34. Retroreflective surfaces 33, 34
Is reflected by the half mirror 36, passes through the half mirror 36, and enters the eye E of the observer.

The projection optical system 32 is arranged at a position optically equivalent to the eye E of the observer. Therefore, of the light reflected by the retroreflective surfaces 33 and 34, a portion having a high intensity is guided to the eye E, and a bright image can be provided. It is also possible to increase the retroreflectivity of the retroreflective surfaces 33 and 34 and suppress the diffusivity low.
This can also increase the brightness of the provided image.

The diameter of the light beam at the position of the eye E of the observer is equal to the diameter of the exit pupil of the projection optical system 32 at an equivalent position. Therefore, if the exit pupil of the projection optical system 32 is increased,
The degree of freedom of the position of the eye E of the observer is increased, and the image is easily observed. This setting is particularly effective when increasing the retroreflectivity of the retroreflective surfaces 33 and 34.

In this case, the projection light from the projection optical system 32 is reflected by the half mirror 36 and is reflected by the retroreflective surfaces 33, 3
4, the reflected light from the retroreflective surfaces 33 and 34 is transmitted through the half mirror 36 and guided to the eye E.
By changing the arrangement, the half mirror 36 may transmit the projection light and guide it to the retroreflective surfaces 33 and 34, and may reflect the reflected light to the eye E. Further, the projection optical system 32 is set to project light downward, but the direction of the projection optical system 32 may be set freely.

FIG. 4 shows the structure of the image display device 4 of the fourth embodiment and the principle of providing images. FIG. 4 is a perspective view of the image display device 4 from the side. The image display device 4 includes a portion 34 of the second retroreflective surface 34 on the first retroreflective surface 33 side.
b is made non-parallel to the optical axis of the projection optical system 32 and the first retroreflective surface 33 is made smaller. Other configurations are the same as those of the video display device 3 of the third embodiment.
The portion 34 a of the retroreflective surface 34 on the half mirror 36 side is parallel to the optical axis of the projection optical system 32. Thus, the second
It is also possible to change the inclination with respect to the first retroreflective surface 33 between a portion of the retroreflective surface 34 and the other portion, thereby further reducing the size of the device.

FIG. 5 shows the configuration of the video display device 5 of the fifth embodiment and the principle of providing video. FIG. 5 is a perspective view of the image display device 5 from the side. The image display device 5 includes a liquid crystal display 31, a projection optical system 32, a first retroreflective surface 33,
The second retroreflective surface 34 and the half mirror 36 are all integrated, and the whole is held by the observer by hand or worn on the head.

The liquid crystal display 31 displays an image corresponding to the direction of the head detected by the direction detector 37,
An image with an extremely wide field of view can be provided. Further, there is no restriction on the posture of the observer, and it is possible to observe a video image in any posture regardless of the direction.

FIGS. 6 to 8 show the structure of the image display device 6 according to the sixth embodiment and the principle of providing images. These figures are perspective views from the side, above, and front of the image display device 6, respectively. This video display device 6 is provided with the eyepiece optical system 35 (35L, 35R) in the video display device 5 of the fifth embodiment. Due to the positive power of the eyepiece optical system 35, light guided to the eye E is converted to a surface M2 farther than the image forming surface M1.
And the observer observes a virtual image located on the surface M2.

In the image display device 6, the image formed on the image plane M1 is enlarged by the eyepiece optical system 35, so that the field of view of the image to be provided can be made wider than that of the image display device 5. When the visual field of an image is the same as that of the image display device 5, the distance from the projection optical system 32 (32L, 32R) to the retroreflective surface 33 can be shortened, so that the device becomes smaller.

FIG. 9 shows the configuration of the video display device 7 of the seventh embodiment and the principle of providing video. FIG. 9 is a perspective view of the image display device 7 from the side. The image display device 7 includes a liquid crystal display 31, a projection optical system 32, a first retroreflective surface 33,
A second retroreflective surface 34, an eyepiece optical system 35, and a half mirror 36 are provided.

The first retroreflective surface 33 is a concave surface. Therefore, the same range of light can be reflected with an area smaller than the plane, and the field curvature can be easily corrected. Projection optical system 32
Is set so that the projected light is imaged on the retroreflective surface 33, that is, on the concave surface.

The second retroreflective surface 34 is a flat surface, and is located near the middle between the half mirror 36 and the first retroreflective surface 33.
The projection mirror 32 is disposed in a direction nearly perpendicular to the optical axis of the projection optical system 32 turned back by the half mirror 36. The second retroreflective surface 34 is fixed to the first retroreflective surface 33 by a support member 38 provided so as not to receive light from the half mirror 36. Further, the half mirror 36 is directly fixed to the first retroreflective surface 33, and the distance from the retroreflective surface 33 to the eyepiece optical system 35 is set slightly shorter than that of the image display device 6 of the sixth embodiment. ing.

The F value of the projection optical system 32 is set large, and the depth of the image represented by the projection light is deep. This suppresses blurring of the image formed on the second retroreflective surface 34, which is at a distance from the first retroreflective surface 33, which is the image forming surface.

By arranging the second retroreflective surface 34 substantially perpendicular to the optical axis of the projection optical system 32, the second retroreflective surface 34 is reduced by a fraction With the size, it is possible to reflect the same range of light. Although the retroreflection efficiency of the retroreflection surface depends on the incident angle of light, the above arrangement can keep the reflection efficiency high at any part of the retroreflection surface.

FIG. 16 schematically shows the relationship between the incident angle of light on the retroreflective surface and the intensity of the reflected light. In FIG. 16, the horizontal axis represents the incident angle of light, and the vertical axis represents the ratio of the intensity of the reflected light in the incident direction to the intensity of the incident light. The intensity of the light retroreflected by the retroreflective surface is 1 from an incident angle of 0 ° to a certain angle θ1, gradually decreases when the incident angle exceeds θ1, and becomes extremely small when the angle of incidence exceeds θ2. In the case of a normal retroreflective surface having no directivity, that is, a retroreflective surface having exactly the same retroreflectivity for light incident from any direction, the angle θ1 is about 40 ° and the angle θ2 is
Is about 60 °.

Therefore, in order to provide a bright image on a normal retroreflective surface, it is preferable to set the angle of incidence of light on the retroreflective surface 34 so as not to greatly exceed 40 °. This setting is very easy. Even if the incident angle is 50 °, the intensity of the reflected light is 0.5 or more, and the incident angle is about 55 °, which is within a range that can be practically used.

If the retroreflective surface is provided with directivity, the angle θ1 at which the reflection intensity starts to decrease can be increased in one direction and reduced in the opposite direction. As in the image display device of the present invention, the position of the retroreflective surface 34 with respect to the projected light is fixed, and if there is no possibility that the projected light is incident on the retroreflective surface 34 from the opposite direction, the light is directed toward the retroreflective surface 34. There is no inconvenience even if it has the property. Therefore, for example, in the configuration in which the second retroreflective surface 34 is arranged parallel to the optical axis of the projection optical system 32 as in the video display device 5 of the fifth embodiment, the directivity is given and the reflection intensity is increased. An increased angle θ1 at which the decrease starts may be used as the second retroreflective surface 34.

FIG. 10 shows the configuration of the video display device 8 of the eighth embodiment and the principle of providing video. FIG. 10 is a perspective view of the image display device 8 from the side. This video display device 8
The second retroreflective surface 34 is constituted by a plurality of pieces arranged in a direction almost perpendicular to the optical axis of the projection optical system 32 turned back by the half mirror 36. The pieces forming the retroreflective surface 34 are fixed to each other or to the first retroreflective surface 33 by a support member 38. Other configurations are the same as those of the video display device 5 of the fifth embodiment.

FIG. 11 shows the configuration of the video display device 9 of the ninth embodiment and the principle of providing video. FIG. 11 is a perspective view of the image display device 9 from the side. This video display device 9
The liquid crystal display 31 includes a projection optical system 32 ′ that emits light from each part on the liquid crystal display 31 as parallel light. Therefore, the first
No image is formed on the surface M1 'including the retroreflective surface 33, and the first retroreflective surface 33 does not function as a screen. The observer observes a virtual image on a plane M2 'farther than the plane M1'. Other configurations are the same as those of the video display device 5.

By making the light projected from the projection optical system 32 'parallel light, the distance from the projection optical system 32' to the retroreflective surface 33 can be shortened.
The device becomes even smaller than that. By increasing the exit pupil of the projection optical system 32 ', it is easy to secure the degree of freedom of the position of the eye E.

FIGS. 12 and 13 show the configuration of the video display apparatus 10 according to the tenth embodiment and the principle of providing video. These figures are perspective views of the image display device 10 from the side and from above, respectively. The image display device 10 includes a liquid crystal display 31, a projection optical system 32 (32L, 32R), a retroreflective surface 33, an eyepiece optical system 35 (35L, 35R), and a half mirror 36. The retroreflective surface 33 is a curved surface having a radius of curvature in the horizontal (horizontal) direction larger than the radius of curvature in the vertical (vertical) direction.
It is fixed to.

By making the retroreflective surface 33 a curved surface,
It is easy to reduce the size of the device while ensuring a wide field of view. Here, it is possible to reduce the size of the device even if the retroreflective surface 33 is a spherical surface. It becomes much narrower than that. In order to widen the vertical field of view at both left and right ends, as shown by a broken line in FIG.
It is necessary to increase the distance to the device 6, which leads to an increase in the size of the device in the front-rear direction. As in this embodiment,
If the radius of curvature of the retroreflective surface 33 is made greater in the horizontal direction than in the vertical direction, the field of view in the vertical direction can be made smaller in the front-rear direction without making the left and right ends too narrow.

The center of curvature of the retroreflective surface 33 in the horizontal direction is located behind the eyes EL and ER of the observer.
The optical axes of the left and right projection optical systems 32L, 32R and the left and right eyepiece optical systems 35L, 35R are all set so as to pass through the center of curvature. Thereby, it is easy to suppress the generation of asymmetric distortion in the image on the retroreflective surface 33, and it is also easy to arrange the left and right eyepiece optical systems 35L and 35R so as not to collide with each other.

The half mirror 36 is connected to the retroreflective surface 33.
It is not necessary to directly fix to both, and it is good also as composition which both adjoin. In addition, the image display device 10 can provide an image with a very wide field of view with the single retroreflective surface 33, and thus does not include the second retroreflective surface. Two retroreflective surfaces 34 may be added to further widen the field of view.

FIG. 14 shows the configuration of the image display device 11 of the eleventh embodiment and the principle of providing images. FIG. 14 is a perspective view from above of the video display device 11. The image display device 11 has a configuration similar to that of the image display device 10, but uses a spheroidal surface as the retroreflective surface 33. The retroreflective surface 33 is set so that the direction connecting the two focal points is parallel to the direction connecting the left and right eyes EL and ER of the observer. The optical axes of the left and right projection optical systems 32L and 32R are non-parallel, and the optical axes of the left and right eyepiece optical systems 35L and 35R are also non-parallel.

In FIG. 14, the broken line represents a spherical surface having the same curvature as the central portion of the retroreflective surface 33 which is an elliptical surface. From this, it can be seen that the image display device 11 having the retroreflective surface 33 as an elliptical surface is smaller than the image display device 10 having a constant horizontal curvature. The occurrence of blurring in the image around the retroreflective surface 33 can be easily suppressed by reducing the exit pupil of the projection optical system 32 to increase the F value and increasing the depth of the image.

FIG. 15 shows the structure of the image display device 12 of the twelfth embodiment and the principle of providing images. FIG. 15 is a perspective view of the image display device 12 from above. This image display device 12 has a configuration similar to that of the projection display device 10 of the tenth embodiment, with the addition of a flat plate 34c having both surfaces as retroreflective surfaces. Both surfaces of the flat plate 34c are the second retroreflective surfaces 34
Becomes The flat plate 34c is arranged in the vertical direction, and the image display device 12 is symmetric with respect to the flat plate 34c.

Of the light projected by the left projection optical system 32L, the light traveling toward the right half of the first retroreflective surface 33 is reflected on one side of the second retroreflective surface 34, and is reflected by the right projection optical system. Of the light projected by the system 32R, light traveling toward the left half of the first retroreflective surface 33 is reflected by the other of the second retroreflective surfaces 34. Therefore, the light of the image for the left eye does not enter the right eye ER or the light of the image for the right eye enters the left eye EL, and crosstalk can be completely prevented.

Although the crosstalk can be prevented by simply arranging a light shielding plate at the position of the flat plate 34c, the field of view of the image is reduced to about half in this configuration. Since the image display device 12 includes the flat plate 34c having retroreflective properties on both surfaces, a wide field of view can be secured.

[0064]

According to the present invention, there is provided an image display apparatus having a second retroreflective surface which reflects projection light directed outside of the first retroreflective surface before the first retroreflective surface is extended. It is possible to provide a configuration that is small in the direction perpendicular to the projection light while providing a visual field image. Therefore, the device is suitable for use by the observer while holding it by hand or wearing it on the head, and does not require a large space for installation even when used in a fixed installation.

Further, in the configuration including the combiner, since the projection optical system and the observer's eye can be in an equivalent positional relationship, the diameter of the exit pupil of the projection optical system can be reduced. This makes it easy to reduce the size of the projection optical system and increase the degree of freedom in the position and orientation of the retroreflective surface. In addition, it is possible to provide a very bright image by using a retroreflective surface having extremely high recursiveness.

In a video display device in which the projected light is guided to the retroreflective surface by the combiner, and the retroreflective surface has a curved surface shape having different vertical and horizontal curvatures, the above-described effect of the combiner is obtained, and the retroreflective surface is a curved surface. By doing
It is possible to provide a wide field of view while providing a compact configuration. In addition, since the curvature of the retroreflective surface differs depending on the direction, it is easy to arrange the combiner and the retroreflective surface close to each other, and it is possible to further reduce the size of the device.

In the configuration including the eyepiece optical system, the image represented by the projection light can be further enlarged by the eyepiece optical system, and the field of view of the provided image can be further widened. Further, the distance from the projection optical system to the retroreflective surface can be shortened, so that the device can be further downsized.

[Brief description of the drawings]

FIG. 1 is a perspective side view showing the configuration of an image display device according to a first embodiment and the principle of image provision.

FIG. 2 is a transparent top view illustrating the configuration of an image display device according to a second embodiment and the principle of providing images.

FIG. 3 is a perspective side view showing the configuration of a video display device according to a third embodiment and the principle of providing video.

FIG. 4 is a perspective side view showing the configuration of a video display device according to a fourth embodiment and the principle of providing video.

FIG. 5 is a perspective side view showing the configuration of a video display device according to a fifth embodiment and the principle of providing video.

FIG. 6 is a perspective side view showing the configuration of a video display device according to a sixth embodiment and the principle of providing video.

FIG. 7 is a transparent top view showing the configuration of a video display device according to a sixth embodiment and the principle of providing video.

FIG. 8 is a transparent front view showing the configuration of an image display device according to a sixth embodiment and the principle of image provision.

FIG. 9 is a perspective side view showing the configuration of an image display device according to a seventh embodiment and the principle of image provision.

FIG. 10 is a transparent side view showing the configuration of an image display device according to an eighth embodiment and the principle of providing an image.

FIG. 11 is a perspective side view showing the configuration of a video display device according to a ninth embodiment and the principle of providing video.

FIG. 12 is a perspective side view showing the configuration of the video display device according to the tenth embodiment and the principle of providing video.

FIG. 13 is a transparent top view showing the configuration of the video display device of the tenth embodiment and the principle of providing video.

FIG. 14 is a transparent top view showing the configuration of the video display device according to the eleventh embodiment and the principle of providing video.

FIG. 15 is a transparent top view showing the configuration of the video display device of the twelfth embodiment and the principle of providing video.

FIG. 16 is a diagram schematically showing a relationship between an incident angle of a retroreflective surface and a reflection intensity.

[Explanation of symbols]

 1-12 Image display device 31, 31L, 31R Liquid crystal display 32, 32L, 32R Projection optical system 33 First retroreflective surface 34 Second retroreflective surface 34c Flat plate 35, 35L, 35R Eyepiece optical system 36 Half mirror 37 Direction detector 38 Support member E, EL, ER Eye

Claims (4)

[Claims] An image display for displaying an image, a projection optical system for projecting light of the image displayed on the image display, and a first retroreflection receiving a part of the light from the projection optical system And a second retroreflective surface that receives light from the projection optical system going out of the first retroreflective surface before reaching an extension of the first retroreflective surface. Video display device. 2. A combiner that guides light from the projection optical system to the first and second retroreflective surfaces and guides light from the first and second retroreflective surfaces to an observer's eye. The video display device according to claim 1, wherein: 3. An image display for displaying an image, a projection optical system for projecting light of the image displayed on the image display, and a curved surface shape having different vertical and horizontal curvatures. An image display device comprising: a retroreflective surface that receives light; and a combiner that guides light from the projection optical system to the retroreflective surface and guides light from the retroreflective surface to an observer's eye. 4. The eyepiece optical system according to claim 1, further comprising an eyepiece optical system for giving a virtual image of an image represented by the light projected by the projection optical system to an observer. Video display device.