JP2000352695A - Video display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To miniaturize a video display device guiding projected light to an observer's eye by projecting the light of a displayed video and recursively reflecting the projected light. SOLUTION: This video display device is constituted of a video display device 31 displaying the video, a retroreflection surface 33, a projection optical system 32 projecting the light of the video displayed on the display device 31 to a range partially including the surface 33, a mirror 34 reflecting the light going toward the surface 33 out of the light projected by the optical system 32 and guiding it to the surface 33. By viewing the surface 33 and the mirror 34 from the direction of the projected light going toward the surface 33, an observer observes the video having wide field equal to or above 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 concave screen or a plurality of screens, the width of the field of view can be freely set. There is also a large-scale device in which the entire wall surface of the room, as well as the floor or ceiling, is used as a screen so that the observer is surrounded by the screen. Such an apparatus can provide an image with a very wide field of view, and can have a theoretical maximum viewing angle of 360 °.

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]

In order to achieve the above object, according to the present invention, there is provided an image display for displaying an image, a retroreflective surface for strongly reflecting light in an incident direction, and an image displayed on the image display. A projection optical system for projecting the light of the image onto a range partially including the retroreflective surface, and a mirror for reflecting light going out of the retroreflective surface out of the light projected by the projection optical system to guide the light to the retroreflective surface Thus, a video display device is configured.

In this image display device, not all of the light of the image displayed on the image display device is directly projected on the retroreflective surface, but only a part of the light is directly projected on the retroreflective surface, and the remaining mirrors are mirrored. Through to the retroreflective surface. On the retroreflective surface, light from different parts of the video display overlap. The mirror is arranged in a space between the projection optical system and the retroreflective surface in a direction intersecting the retroreflective surface.

[0010] The light reflected by the retroreflective surface follows the incident optical path in reverse, and the light incident on the retroreflective surface from the mirror is re-incident on the mirror and reflected. This light
If there is no mirror and the retroreflective surface is extended to its periphery, the light is the same as the light reflected at the extended portion. Since both the light from the retroreflective surface re-reflected by the mirror and the light directly incident on the retroreflective surface and reflected are directed toward the projection optical system, the retroreflective surface is formed from the direction of the projected light or a direction close thereto. By looking at the area including the mirror, all parts of the image can be observed.

Therefore, the image display device provides an image with a wide visual field larger than the actual size of the retroreflective surface. In addition, since the mirror is disposed in the space between the projection optical system and the retroreflective surface, a space for arranging the mirror is not newly required, and a compact device can be obtained. The reflecting surface of the mirror may be flat or curved, and may include a plurality of mirrors.

The projection optical system may be one that forms an image of the projection light on the retroreflection surface, or one that does not form an image on the retroreflection surface with the projection light 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.

[0013] The above-mentioned image display device may be provided with a combiner for guiding light from the projection optical system to the retroreflective surface and the mirror, and for guiding light from the retroreflective surface and light from the mirror to the eyes of the observer. Good. 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 size of the projection optical system can be reduced. 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.

An eyepiece optical system may be provided which guides the light from the retroreflective surface and the light from the mirror to the eyes of the observer and gives the observer a virtual image of the image represented by the light projected by the projection optical system. Good. 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.

[0016] The mirror may be an elliptical surface having one focal point located near the retroreflective surface and the other focal point located near the observer's eye. Due to the characteristic of the elliptical reflecting surface that light from one focal point always passes through the other focal point, the retroreflective surface can be made extremely small, and the device can be further miniaturized.

[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, a retroreflective surface 33 and a mirror 34 are 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 1 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 retroreflective surface 33 is formed by providing extremely small glass beads or corner cubes of about 10 μm or less on the surface of a plate-like member or a film-like member. The retroreflective surface 33 is a flat surface and is disposed on the image forming surface M1, 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 retroreflectivity of the retroreflective surface 33 is not set particularly high, and the retroreflective surface 33 has a slight diffuse reflectivity.

The mirror 34 includes the upper and lower two pieces shown in FIG. 1 and the left and right two pieces (not shown). Mirror 34 is totally reflective and planar. The mirror 34 is arranged between the projection optical system 32 and the retroreflective surface 33 in parallel with the optical axis of the projection optical system 32, and thus perpendicular to the retroreflective surface 33. The end of the mirror 34 reaches the edge of the retroreflective surface 33, and the retroreflective surface 33 is sandwiched by the mirror 34 from above, below, right and left.

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

A part of the light projected by the projection optical system 32 directly enters the 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 optical system 32 travels outside the retroreflective surface 33, is reflected by the mirror 34, and is guided to the retroreflective surface 33. This light forms the remaining portion of the image displayed on the liquid crystal display 31 on the retroreflective surface 33. Therefore, different portions of the image displayed on the liquid crystal display 31 are overlapped on the retroreflective surface 33. The image formed on the retroreflective surface 33 by the light reflected by the mirror 34 is obtained by folding the image formed around the retroreflective surface 33 when the mirror 34 does not exist by the mirror 34.

Light directly incident on the retroreflective surface 33 from the projection optical system 32 is reflected by the retroreflective surface 33 and travels in the direction of the projection optical system 32. Light that has entered the retroreflective surface 33 from the mirror 34 is reflected by the retroreflective surface 33 and
4 again, is reflected again and proceeds in the direction of the projection optical system 32. This light is equivalent to light from an image formed around the retroreflective surface 33 if the mirror 34 is not present,
Together with the light that goes directly from the retroreflective surface 33 to the projection optical system 32, it represents the entire displayed image.

The light reflected by the retroreflective surface 33 is
Many of them will re-enter the projection optical system 32,
Since the retroreflective surface 33 has a slight diffusivity, the light also enters the eye E of the observer located near the projection optical system 32. 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 retroreflective surface 33. Further, since the mirror 34 is disposed in the space between the projection optical system 32 and the retroreflective surface 33, the size of the image display device 1 is not increased. Therefore, the image display apparatus 1 is smaller than the conventional apparatus without the mirror 34 and the retroreflective surface 33 is made large enough to receive the entire luminous flux projected on the imaging surface M1. .

The liquid crystal display 31, the projection optical system 32, the retroreflective surface 33 and the mirror 34 can be integrated, and the image display device 1 can be a hand-held or head-mounted device. It can also be 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 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 image display device 2 of the second embodiment and the principle of providing images. 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 retroreflective surface 33, a mirror 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 respectively display the liquid crystal displays 31L and 31R.
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 retroreflective surface 33 and the mirror 34 are the first
The settings are the same as those of the video display device 1 of the 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 projection optical systems 32L and 3R reflected by the retroreflective surface 33, respectively.
The light from the 2R is guided to the left and right eyes EL and ER. Due to the positive power of the eyepiece optical systems 35L and 35R, the light guided to the eyes EL and ER becomes equivalent to the light coming from the surface M2 farther than the imaging surface M1, and the observer can see the virtual image located on the surface M2. Will be observed.

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 retroreflective surface 33 can be shortened, a more compact device can be obtained.

The left and right image lights projected by the projection optical systems 32L and 32R overlap on the retroreflective surface 33, but the left and right image light reflected by the retroreflective surface 33 are 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 retroreflective surface 33, and a mirror 3.
4 and a half mirror 36 as a combiner.

The projection optical system 32 is arranged 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 directly enters the retroreflective surface 33, and the rest is reflected by the mirror 34 and guided to the retroreflective surface 33. The light reflected by the retroreflective surface 33 is directly or mirror 34
The light is re-reflected and enters 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 surface 33, a portion having high intensity is guided to the eye E, and a bright image can be provided. In addition, it is possible to increase the retroreflectivity of the retroreflective surface 33 and suppress the diffusivity, thereby also increasing the brightness of the image to be provided.

The light beam diameter 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 surface 33.

Here, the projection light from the projection optical system 32 is reflected by the half mirror 36 and guided to the retroreflection surface 33, and the reflection light from the retroreflection surface 33 is transmitted through the half mirror 36 to the eye E. Although the setting is to guide the light, the arrangement may be changed such that the half mirror 36 transmits the projection light and guides it to the retroreflective surface 33, and reflects the reflected light to guide 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 configuration of the video display device 4 of the fourth embodiment and the principle of providing video. FIG. 4 is a perspective view of the image display device 4 from the side. The image display device 4 integrates the liquid crystal display 31, the projection optical system 32, and the half mirror 36 of the above-described image display device 3 so that the observer can hold them by hand or wear them on the head. is there. Therefore, the positions and directions of the liquid crystal display 31, the projection optical system 32, and the half mirror 36 with respect to the retroreflection surface 33 and the mirror 34 are variable.

The image display device 4 also has a direction detector 37 for detecting the direction of the observer's head, and the liquid crystal display 31 displays an image corresponding to the direction of the head detected by the direction detector 37. I do. The light from the projection optical system 32 is
Can be observed as long as the light is incident on the retroreflective surface 33 and is guided to the retroreflective surface 33. Therefore, the image display device 4 can provide an image with an extremely wide field of view. In addition, the observer can observe the image in a free posture without being restricted so much in the posture.

The optical path length from the projection optical system 32 to the image forming plane M1 greatly changes according to the direction of the observer's head. In order to prevent the image on the retroreflective surface 33 from being blurred due to the change in the optical path length, the image display device 4 increases the F value by reducing the exit pupil of the projection optical system 32 and increases the F value. The depth of the image formed in the image 33 is increased. The retroreflective surface 33 is provided with a slight diffuse reflectivity in order to suppress a decrease in the diameter of the light beam at the position of the observer's eye E by reducing the exit pupil of the projection optical system 32. With such a setting, the observer can observe a clear and unobstructed image in any direction.

Here, the projection optical system 32 is set so as to project light over a wider area than the retroreflective surface 33, but the projection optical system 32 emits light over a narrower area than the retroreflective surface 33. You may make it project. The liquid crystal display 31 displays an image according to the direction of the observer's head, and the mirror 34 guides light from the projection optical system 32 to the retroreflective surface 33 to provide an image with a wide field of view. Is possible.

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 mirror 3
4 is arranged non-parallel to the optical axis of the projection optical system 32. Another configuration is the video display device 3 of the third embodiment.
Is the same as The distance between the mirrors 34 depends on the projection optical system 3.
The second side is narrower than the retroreflective surface 33 side, and the image display device 5 is smaller than the image display device 3.

Since the mirror 34 is not perpendicular to the image forming surface M1, the optical path length of the light reflected by the mirror 34 to the retroreflective surface 33 is equal to the optical path length to the image forming surface M1 when the mirror 34 is not present. Not equal to length. In order to prevent blurring of an image on the retroreflective surface 33 due to the difference in the optical path length, the exit pupil of the projection optical system 32 is reduced similarly to the above-described image display device 4, and the retroreflective surface 33 is The depth of the image to be formed is increased. In addition, the retroreflective surface 33 is provided with a slight diffuse reflectivity, so that the diameter of the light beam at the position of the eye E due to the reduction of the exit pupil of the projection optical system 32 is suppressed.

FIG. 6 shows the structure of the image display device 6 of the sixth embodiment and the principle of providing images. FIG. 6 is a perspective view of the image display device 6 from the side. The image display device 6 includes a mirror 3
4 is the projection optical system 3
2 is made non-parallel to the optical axis and the retroreflective surface 33 is made smaller. The other configuration is the same as that of the image display device 3 of the third embodiment.
The portion 34 a on the sixth side is parallel to the optical axis of the projection optical system 32. As described above, it is also possible to change the inclination of the mirror 34 with respect to the retroreflective surface 33 between another part and the other part.
Thereby, the device can be further miniaturized.

FIG. 7 shows the configuration of the video display device 7 of the seventh embodiment and the principle of providing video. FIG. 7 is a perspective view of the video display device 7 from the side. The image display device 7 has an elliptical mirror 34. One focus of the mirror 34 is set on the retroreflective surface 33, and the other focus is set so as to be located at or near the eye E of the observer. The projection optical system 32 is located at a position equivalent to the eye E of the observer, and is substantially located at the focal point of the mirror 34.

Due to the characteristic of the elliptical reflecting surface that light from one focal point always passes through the other focal point after reflection, the projection optical system 3
The light projected by 2 enters a very narrow range on the retroreflective surface 33. For this reason, in the video display device 7, the retroreflective surface 33 can be made extremely small. Retroreflective surface 3
Numeral 3 is not in contact with the mirror 34, and is set so as to have retroreflective properties on both the front and back surfaces, and also reflects light incident on the back surface on the back surface side with respect to the half mirror 36.

In this configuration, it is also possible to make the retroreflective surface 33 smaller and closer to a point. In this case, the exit pupil of the projection optical system 32 is made smaller, but the degree of freedom of the position of the eye E can be easily secured by making the retroreflective surface 33 slightly diffuse. Further, if the exit pupil of the projection optical system 32 is made large and the size of the retroreflection surface 33 is set to be substantially the same as the exit pupil of the projection optical system 32, even if the retroreflection surface 33 does not have a diffusive property, The degree of freedom of the position of E is sufficiently ensured.

The mirror 34 may or may not be rotationally symmetric with respect to the axis connecting the two focal points.
The entire mirror 4 does not necessarily have to be an elliptical surface. For example, only the upper and lower portions may be elliptical surfaces, and the left and right may be flat surfaces.

FIG. 8 shows the configuration of the video display device 8 of the eighth embodiment and the principle of providing video. FIG. 8 is a perspective view of the image display device 8 from the side. The mirror 34 of the video display device 8 is also elliptical. The point that one focus of the mirror 34 is located on the retroreflective surface 33 and the other focus is set so as to be located at or near the eye E of the observer is the same as the above-described image display device 7. However, the difference is that the edge of the retroreflective surface 33 is in contact with the mirror 34.

FIG. 9 shows the configuration of the video display device 9 of the ninth embodiment and the principle of providing video. FIG. 9 is a perspective view of the image display device 9 from the side. The image display device 9 reduces the distance between the mirrors 34 of the image display device 3 of the third embodiment,
The retroreflective surface 33 is made smaller.

Of the light from the projection optical system 32 reflected by the half mirror 36, the light not directly incident on the retroreflective surface 33 is reflected a plurality of times by the mirror 34 and incident on the retroreflective surface 33. Further, the light incident from the mirror 34 and reflected by the retroreflective surface 33 is also reflected by the mirror 34 a plurality of times and is incident on the half mirror 34. The image provided to the observer is the same as the image display device 3, but the image display device 9 achieves further miniaturization.

FIG. 10 shows the configuration of the video display device 10 according to the tenth embodiment and the principle of providing video. FIG. 10 is a perspective view of the image display device 10 from the side. The image display device 10 has a structure in which the mirror 34 is shortened and the liquid crystal display 3
1. Projection optical system 32, mirror 34 and half mirror 3
6 are integrated so that the observer can hold them by hand or wear them on the head. The positions and orientations of the liquid crystal display 31, the projection optical system 32, the mirror 34, and the half mirror 36 with respect to the retroreflective surface 33 are variable.

The image display device 10, like the image display device 4 of the fourth embodiment, displays an image corresponding to the direction of the observer's head detected by the direction detector 37 on the liquid crystal display 31.
, It is possible to provide an image with an extremely wide field of view. Further, the observer can observe the image in a free posture.

FIG. 11 shows the configuration of an image display apparatus 11 according to the eleventh embodiment and the principle of providing an image. FIG. 11 is a perspective view of the image display device 11 from the side. In the image display device 11, the mirror 34 is divided into two parts 34a and 34b, one part 34a is integrated with the liquid crystal display 31, the projection optical system 32 and the half mirror 36, and the other part 34b is returned. It is fixed to the reflection surface 33.

Also in this configuration, since 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. The portion 34b of the mirror 34 reflects the light directly entering from the half mirror 36 or the light from the half mirror 36 reflected by the portion 34a,
The retroreflective surface 33 can be made smaller than the image display device 10, resulting in a smaller device.

FIG. 12 shows the configuration of the video display device 12 of the twelfth embodiment and the principle of providing video. FIG. 12 is a perspective view of the image display device 12 from the side. This image display device 12 integrates a liquid crystal display 31, a projection optical system 32, a retroreflective surface 33, a mirror 34, and a half mirror 36, and holds the whole by hand or mounted on a head. It was done.

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.

FIG. 13 shows the structure of a video display device 13 according to the thirteenth embodiment and the principle of video provision. FIG. 13 is a perspective view of the image display device 13 from the side. The image display device 13 includes a projection optical system 32 ′ that emits light from various parts on the liquid crystal display 31 as parallel light. Therefore, no image is formed on the surface M1 'including the retroreflective surface 33, and the retroreflective surface 33 does not function as a screen. The observer observes a virtual image on a plane M2 'farther than the plane M1'. Another configuration is the image display device 1
Same as 2.

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.
It becomes a device smaller than 2. 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. 14 to 16 show the configuration of the video display apparatus 14 according to the fourteenth embodiment and the principle of providing video. These figures are perspective views from the side, above and front of the video display device 14, respectively. This video display device 14
The eyepiece optical system 35 (3
5L, 35R). Due to the positive power of the eyepiece optical system 35, the light guided to the eye E 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. become.

In the image display device 14, since the image formed on the image plane M1 is enlarged by the eyepiece optical system 35,
The field of view of the provided image can be made wider than that of the image display device 12. When the visual field of an image is the same as that of the image display device 12, the distance from the projection optical system 32 (32L, 32R) to the retroreflective surface 33 can be shortened.
It results in a smaller device.

FIGS. 17 to 19 show the structure of the image display device 15 of the fifteenth embodiment and the principle of providing images. These figures are perspective views from the side, above, and front of the video display device 15, respectively. The image display device 15 has a spherical retroreflective surface 33. The half mirror 36 is large enough to reach the retroreflective surface 33, and the mirrors 34 are provided on the upper and side portions. Further, the projection optical system 32 is set so that the projection light is not focused on a plane but is focused on a spherical surface including the retroreflective surface 33.

The center of curvature of the retroreflective surface 33 is equidistant from the left and right eyes EL and ER of the observer, and the radius of curvature is set larger than the distance from the retroreflective surface 33 to the eyes EL and ER. The optical axes of the left and right projection optical systems 32L, 32R are both set so as to pass through the center of curvature of the retroreflective surface 33, and the projection optical systems 32L, 32R and the retroreflective surface 33 are coaxial. I have. By adopting the coaxial system in this way, an asymmetric distortion does not occur in the image formed on the retroreflective surface 33, and a sharp focus can be obtained at any part of the retroreflective surface 33.

The mirror 34 is not parallel to the optical axes of the projection optical systems 32L and 32R. Therefore, the optical path length of the light directly entering the retroreflective surface 33 from the half mirror 36 and the retroreflective surface 33 reflected by the mirror 34 There is a difference in the optical path length of the light incident on. However, by reducing the exit pupil of the projection optical system 32 and increasing the F-number, the depth of the image can be increased, and the image without blur can be displayed on the retroreflective surface 33.
Can be formed.

The optical axes of the left and right eyepiece optical systems 35L and 35R are also set to pass through the center of curvature of the retroreflective surface 33, respectively. Therefore, no distortion occurs in the image given to the observer's eyes EL and ER as a virtual image. With such a setting, the image display device 15 can provide not only a wide field of view but also an extremely high-quality image. Further, it is easy to arrange the eyepiece optical systems 35L and 35R so as not to collide with each other, so that the apparatus configuration is suitable for miniaturization.

FIG. 20 shows the configuration of the video display device 16 of the sixteenth embodiment and the principle of providing video. FIG. 20 is a perspective view of the image display device 16 from the side. The image display device 16 is configured such that the mirror 34 is moved to a portion 34 near the half mirror 36.
The angle of the mirror 34 with respect to the retroreflective surface 33 is changed on the way, divided into a and a portion 34b close to the retroreflective surface 33. Other configurations are the same as those of the video display device 15.
Since the ends of the portions 34a and 34b of the mirror 34 overlap with each other, and the portion 34a near the half mirror 36 is located inside, there is no possibility that light is shielded at the end face of the portion 34b.

FIG. 21 shows the configuration of the video display device 17 of the seventeenth embodiment and the principle of providing video. FIG. 21 is a perspective view of the image display device 17 from the side. This image display device 17 has an elliptical mirror 34, and the other configuration is the same as that of the image display device 15. One focus of the mirror 34 is set on the retroreflective surface 33, and the other focus is set so as to be located at or near the eye E of the observer. The projection optical system 32 is located at a position equivalent to the eye E of the observer, and is substantially located at the focal point of the mirror 34.

Due to the characteristics of the elliptical reflection surface, the light reflected by the mirror 34 enters a very narrow range on the retroreflection surface 33. Therefore, in the image display device 17, the retroreflective surface 33
Can be made extremely small.

FIG. 22 shows the configuration of the video display device 18 of the eighteenth embodiment and the principle of providing video. FIG. 22 is a perspective view of the image display device 18 from the side. This image display device 18 is a modification of the above-described image display device 17 and is configured such that the retroreflective surface 33 includes a spherical portion 33a and a flat portion 33b. The flat part 33b is very small, on which one focal point of the mirror 34 is located.

Of the light from the half mirror 36, the light reflected by the mirror 34 enters the portion 33b of the retroreflective surface 33, and the rest enters the portion 33a. The portion 33b is arranged so that its normal passes substantially at the center of the mirror 34, and is close to perpendicular to the light incident from the mirror 34, and therefore has excellent reflection characteristics.

FIG. 23 shows the configuration of the video display device 19 of the nineteenth embodiment and the principle of providing video. FIG. 23 is a perspective view of the image display device 19 from above. This image display device 19 has a configuration similar to that of the projection display device 15 of the fifteenth embodiment, except that a mirror 34c having both surfaces being total reflection surfaces is added as a part of the mirror 34. The mirror 34c is arranged in the vertical direction, and the image display device 19
4c is left-right symmetric.

Of the light projected by the left projection optical system 32L, the light traveling toward the right half of the retroreflective surface 33 is
The light that is reflected by the mirror 34c and is incident on the left half of the retroreflective surface 33 and that travels toward the left half of the retroreflective surface 33 out of the light projected by the right projection optical system 32R is reflected by the mirror 34c. The light enters the right half of the retroreflective surface 33. Similarly, the light reflected by the left half and the right half of the retroreflective surface 33 is also the eyepiece optical systems 35L and 35L, respectively.
It is selectively guided to 5R.

Therefore, the light of the image for the left eye is shifted to the right eye ER.
And the light of the image for the right eye does not enter the left eye EL, and crosstalk can be completely prevented. Although crosstalk can be prevented by simply disposing a light shielding plate at the position of the mirror 34c, the field of view of the image is reduced to about half with this configuration. In the image display device 19, by providing the mirror 34c having the double-sided reflection,
A wide field of view can be secured.

FIG. 24 shows an example of the usage of the video display device of the present invention. This example uses the video display device 3 of the third embodiment. One wall surface of the rectangular box 38 is a retroreflective surface 33, and left and right wall surfaces, a ceiling surface, and a floor surface of the retroreflective surface 33 are mirrors 34. The liquid crystal display 31, the projection optical system 32, the half mirror 36, and the direction detector 37 are integrated into a mounting unit 39, and the observer U mounts the mounting unit 39 on his / her head and puts it in the box 38. Observe the incoming video. As described repeatedly, the provided image has a wide field of view, so that the observer U can enjoy an extremely high presence.

Since the space between the left and right wall surfaces of the retroreflective surface 33 only needs to allow the viewer U to enter, the box 38 can be made small. Therefore, a large installation space is not required, and it can be installed not only outdoors but also indoors of a normal size. Retroreflective surface 3 on one wall of room
3, and another wall surface, ceiling surface, and floor surface may be used as the mirror 34.

[0076]

According to the image display device of the present invention, a mirror which reflects light going out of the retroreflective surface out of the light projected by the projection optical system and guides the light to the retroreflective surface is provided. Light from the part is superimposed on the retroreflective surface,
The light can be restored and guided to the observer's eyes, and an image with a wider field of view than the actual size of the retroreflective surface can be provided. In addition, since no new space is required for disposing the mirror, the device is small. 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.

In the configuration including the combiner, the projection optical system and the observer's eye can be placed 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 the configuration having 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, and the size of the apparatus can be further reduced.

When the mirror is an elliptical surface having a focal point near the retroreflective surface and near the observer's eye, the retroreflective surface can be made extremely small, resulting in a more compact device.

[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 perspective side view showing the configuration of a video display device according to a seventh embodiment and the principle of providing video.

FIG. 8 is a perspective side view showing the configuration of an image display device according to an eighth embodiment and the principle of providing images.

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

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

FIG. 11 is a perspective side view showing the configuration of an image display device according to an eleventh embodiment and the principle of image provision.

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

FIG. 13 is a perspective side view showing the configuration of a video display device according to a thirteenth embodiment and the principle of providing video.

FIG. 14 is a perspective side view showing the configuration of an image display device according to a fourteenth embodiment and the principle of providing images.

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

FIG. 16 is a perspective front view showing the configuration of an image display device according to a fourteenth embodiment and the principle of providing images.

FIG. 17 is a transparent side view showing the configuration of the video display device of the fifteenth embodiment and the principle of providing video.

FIG. 18 is a transparent top view showing the configuration of the video display device of the fifteenth embodiment and the principle of providing video.

FIG. 19 is a transparent front view showing the configuration of the video display device of the fifteenth embodiment and the principle of providing video.

FIG. 20 is a transparent side view showing the configuration of the video display device of the sixteenth embodiment and the principle of providing video.

FIG. 21 is a perspective side view showing the configuration of an image display device according to a seventeenth embodiment and the principle of providing images.

FIG. 22 is a transparent side view showing the configuration of the video display device of the eighteenth embodiment and the principle of providing video.

FIG. 23 is a transparent top view showing the configuration of the video display device of the nineteenth embodiment and the principle of providing video.

FIG. 24 is a transparent perspective view showing one mode of use of the video display device of the present invention.

[Explanation of symbols]

 1-19 Image display device 31, 31L, 31R Liquid crystal display 32, 32L, 32R Projection optical system 33 Retroreflective surface 34, 34a, 34b, 34c Mirror 35, 35L, 35R Eyepiece optical system 36 Half mirror 37 Direction detector 38 Box 39 Mounting unit E, EL, ER Eye

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04N 5/64 511 H04N 5/64 511A

Claims (4)

[Claims] 1. An image display for displaying an image, a retroreflective surface for strongly reflecting light in an incident direction, and a range in which light of an image displayed on the image display is partially included in the retroreflective surface. An image display device comprising: a projection optical system for projecting light to the outside of the retroreflection surface out of light projected by the projection optical system; and a mirror for guiding the light to the retroreflection surface. . 2. A combiner that guides light from the projection optical system to the retroreflective surface and the mirror, and guides light from the retroreflective surface and light from the mirror to an observer's eye. The video display device according to claim 1. 3. An eyepiece optical system that guides light from the retroreflective surface and light from the mirror to an observer's eye, and provides the observer with a virtual image of an image represented by the light projected by the projection optical system. The video display device according to claim 1, further comprising: 4. The mirror according to claim 1, wherein the mirror is an ellipsoid having one focal point located near the retroreflective surface and the other focal point located near the observer's eye. Video display device.