JP3556306B2 - Video display device - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to a video display device, and more particularly to a head or face-mounted video display device that is mounted on the head or face of an observer and that allows an image displayed on a video display element to be observed.
[0002]
[Prior art]
As an optical system of a conventional eyeball projection type head mounted image display device, for example, those shown in FIG. 17 and FIG. 18 shown in JP-A-2-136818 are known. In the optical system shown in FIG. 17, a liquid crystal display (LCD) 1 is illuminated by a backlight 2, and an image of the LCD 1 is placed on a retina 6 of the eye 4 through an eyepiece 3 and a crystalline lens 5 of an eye 4 of an observer. It is imaged.
[0003]
In the optical system shown in FIG. 18, the LCD 12 is illuminated using the point light source 11, and the image of the LCD 12 is projected on the retina 16 of the eyeball 14 via the eyepiece 13 and the crystalline lens 15 of the eyeball 14 of the observer. In this case, since the point light source 11 forms an image on the pupil of the eyeball 14, the image on the LCD 12 can be observed regardless of visual acuity. Therefore, diopter correction is unnecessary, and no correction is required even in the case of astigmatism.
[0004]
However, in the optical system as shown in FIG. 17, if the exit pupil of the projection optical system (eyepiece) is small, the interpupillary distance needs to be adjusted, or the pupil deviates from the light beam when the line of sight looks at the edge of the screen. There is a phenomenon that the image cannot be seen.
[0005]
In order to solve this, it is effective to increase the diameter a of the exit pupil P of the projection optical system, as shown in FIGS. That is, in the case of FIG. 19 (a), even if the position of the eyeball E deviates from the center of the light beam, the pupil does not become out of the light beam, and no particular adjustment of the interpupillary distance is required. In the case of FIG. Even if E rotates, the pupil does not go out of the light flux, and the image does not disappear when the line of sight looks at the edge of the screen.
[0006]
However, if the diameter of the exit pupil of the projection optical system is to be increased in this way, it becomes difficult to correct the aberration of the projection optical system, so that the configuration is complicated and must be increased.
Furthermore, since the diopter differs for each observer, a diopter correction mechanism is required in the projection optical system.
[0007]
Also, in the optical system as shown in FIG. 18, since the light beam must be made to coincide with the pupil, an adjustment for that is necessary. When the line of sight looks at the edge of the screen, the pupil deviates from the light beam and the image is not displayed. The problem of becoming invisible occurs.
[0008]
As means for solving the above two problems, as disclosed in Japanese Patent Application No. 6-100959, a pupil position of an eyeball is detected, and a point light source for illuminating a two-dimensional image display element is adjusted in accordance with the position. There is a way to move. As shown in FIGS. 20A and 20B, a point light source (not shown) is moved so that the conjugate position S 'of the point light source by the projection optical system matches the pupil position of the eyeball. FIG. 1A shows the case where the position of the eyeball E deviates laterally from the center of the light beam, and FIG. 2B shows the case where the eyeball E rotates.
[Problems to be solved by the invention]
However, the method disclosed in Japanese Patent Application No. 6-100959 requires mechanical driving means such as a motor, which complicates the apparatus, and when the eyeball moves quickly, the movement of the point light source cannot keep up with the movement. The problem is that the image becomes invisible.
[0010]
The present invention has been made in view of the above-described problems of the prior art, and its object is to use an observer's eyeball without using mechanical driving means, regardless of the position, orientation, or diopter of the eyeball. It is an object of the present invention to provide an image display device capable of satisfactorily observing an image by allowing a luminous flux from an image display element projected onto a pupil to always pass through the pupil.
[0011]
[Means for Solving the Problems]
In order to achieve the above object, an image display device according to the present invention includes a two-dimensional image display element, a projection optical system for projecting an image of the two-dimensional image display element onto an eyeball of an observer, and the two-dimensional image display element. A light source for illuminating, and an illumination optical system for guiding a light beam emitted from the light source to the two-dimensional image display element, wherein the light source is configured by arranging a plurality of point light sources on a plane; The illumination optical system and the projection optical system are arranged at substantially conjugate positions with respect to a pupil position of an eyeball.
[0012]
In this case, a light source may be arranged near the rear focal position of the illumination optical system. Also, a pair of left and right two-dimensional video display elements, a pair of left and right projection optical systems for projecting images of the pair of left and right two-dimensional video display elements onto an eyeball of an observer, and light of the pair of left and right projection optical systems A light source for illuminating the pair of left and right two-dimensional video display elements disposed on an axis equidistant from the axis, and a light source for guiding a light beam emitted from the light source to the pair of left and right two-dimensional video display elements. A configuration including an illumination optical system is also possible.
[0013]
In addition, the pupil position detecting means of the observer eyeball is provided, and among the light sources having a plurality of point light sources arranged on a plane, only the point light source near the position conjugate with the pupil of the observer eyeball is turned on. Is desirable.
[0014]
[Action]
In the present invention, the light source for illuminating the two-dimensional image display element is configured by arranging a plurality of point light sources on a plane. Since it is arranged at a substantially conjugate position, a point light source which is conjugate with the pupil of the observer's eyeball is selected and turned on from among the point light sources, so that the light flux emitted from the two-dimensional image display element is pupil of the observer's eyeball. Since the light is focused at one point, a good image can be observed regardless of the diopter (myopia, hyperopia, astigmatism) of the observer's eyeball. Further, by turning on a light source conjugate with the pupil position according to the pupil position, it is not necessary to move the point light source, so that the apparatus does not become complicated.
[0015]
【Example】
Hereinafter, some embodiments of the video display device of the present invention will be described in detail with reference to the drawings. In the following, unless otherwise specified, the front side means the eyeball side, and the rear side means the light source side.
First Embodiment FIG. 1 is an optical path diagram showing a configuration of a video display device according to a first embodiment. As shown in the figure, the image display device includes a two-dimensional image display element (a liquid crystal display element (LCD) in this example) 21 and a projection optical system (this is a projection optical system) for projecting an image of the LCD 21 onto an eyeball E of an observer. In the example, an eyepiece lens 22, a light source 23 for illuminating the LCD 21, and an illumination optical system (a condensing lens in this example) 24 for guiding a light beam emitted from the light source 23 to the LCD 21 The lens 24 is placed near the rear side of the LCD 21, and arranges the pupil of the observer eyeball E near the front focal position of the eyepiece 22.
[0016]
The light source 23 is disposed so as to be approximately conjugate with the pupil of the observer's eyeball E with respect to the condenser lens 24 and the eyepiece 22.
The light source 23 has a configuration in which a large number of point light sources are arranged on a plane. When one of the point light source groups or a part of the point light source group is turned on, the illumination light from the light source 23 is transmitted to the LCD 21. , And is incident on the pupil of the observer's eyeball E by the eyepiece lens 22.
[0017]
In this case, one or a part of the point light sources substantially conjugate to the position of the pupil of the eyeball E are turned on, so that the light beam passes through the pupil at substantially one point, so that the observer's eyeball A good image can be observed without being affected by the diopter of E.
[0018]
When the pupil of the observer's eyeball E is displaced from the optical axis, or when the eyeball E is rotated and the pupil is displaced from the optical axis, one of the point light sources existing at a position conjugate to the pupil position. By selecting and lighting a unit or a part of the point light source group, it is not necessary to adjust the axis of the optical system or the position of the light source.
[0019]
As the light source 23, a light source having a liquid crystal spatial modulation element arranged on the surface of a panel-shaped illumination source may be used instead of the light source in which many point light sources are arranged on a plane as described above. In this case, the same effect as in the case where the point light source is turned on can be obtained by setting the liquid crystal modulation element at the position to be turned on to the transmissive state and setting the other parts to the light blocking state.
The degree of freedom may be increased as the number of point light sources arranged on the plane increases to three or more, and more to six or more.
[0020]
Second Embodiment FIG. 2 is an optical path diagram showing a configuration of a video display device according to a second embodiment. In this embodiment, in the arrangement of the first embodiment, the light source 23 is arranged near the rear focal position of the condenser lens 24, and the eyepiece 22 is arranged so that the LCD 21 comes to the rear focal position.
[0021]
With such an arrangement, the light source 23 is substantially conjugate with the pupil of the observer's eyeball E. When one of the point light source groups or a part of the point light source group is turned on in this way, the illumination light is collimated by the condenser lens 24, illuminates the LCD 21 with parallel light, and the eyepiece E is turned on by the eyepiece 22. Into the pupil of Thereby, the influence of the angle characteristics of the LCD 21 can be reduced.
[0022]
Third Embodiment FIG. 3 is an optical path diagram showing a configuration of an image display device according to a third embodiment. In this embodiment, in the arrangement of the second embodiment, the LCD 21 and the condenser lens 24 are arranged such that the LCD 21 is located at the front focal position of the condenser lens 24. Thereby, even when the brightness of the light beam emitted from the light source 23 has an angular distribution, the emission angle of the light irradiating one point of the LCD 21 is the same for all the point light sources, and even if the lit point light source changes. , The brightness does not change.
[0023]
Fourth Embodiment FIG. 4 is an optical path diagram showing a configuration of an image display device according to a fourth embodiment. In this embodiment, the light source and the illumination optical system are shared on the left and right when the optical system of FIG. 2 or FIG. In FIG. 4, a pair of left and right LCDs 21L and 21R, a pair of left and right eyepieces 22L and 22R for projecting images of the LCDs 21L and 21R to left and right eyeballs EL and ER of the observer, and left and right LCDs 21L and 21R and an eyepiece. A left and right common light source 23 and a left and right common condenser lens 24 are disposed at the center of the optical axis of the lenses 22L and 22R. The pupils of the observer's eyes EL and ER are arranged at the front focal positions of 22L and 22R. Further, the light source 23 has a configuration in which many point light sources are arranged on a plane as described above. With such an arrangement, the light source 23 is substantially conjugate with the pupils of the observer's eyes EL and ER.
[0024]
In the first to third embodiments, a light source and an illumination optical system are required for each of the right and left. In the present embodiment, the number of parts is reduced and the weight is reduced because the left and right light sources and the illumination optical system are commonly used. Can be achieved. Also, once the interpupillary distance is adjusted, the left and right eyeballs EL and ER rotate in the same direction, so that the illuminated point light sources may always be common to the left and right as shown in FIG. When the interpupillary distance is not adjusted, as shown in FIG. 5B, at least two point light sources conjugate with the pupils of the left and right eyeballs EL and ER are turned on, and the left and right eyes EL and ER are turned on. In this case, it is sufficient that the respective luminous fluxes reach.
[0025]
Fifth Embodiment FIG. 6 is an optical path diagram showing a configuration of an image display device according to a fifth embodiment. In this embodiment, the illumination optical system of the fourth embodiment is replaced with a common condenser mirror 24 '. Since the illumination optical system is the condenser mirror 24 ', the size of the optical system can be reduced.
[0026]
Also, as shown in the perspective view of FIG. 7, the light is condensed and reflected such that the optical axis of the light source 23 is formed above (or below) the plane including the optical axes of the left and right eyepieces 22L and 22R. By decentering the mirror 24 ', the layout of the optical system can be given a degree of freedom.
[0027]
Sixth Embodiment FIG. 8 is an optical path diagram showing a configuration of an image display device according to a sixth embodiment. In this embodiment, the condenser mirror 24 'in the fifth embodiment is miniaturized by using a Fresnel condenser mirror or a diffractive condenser optical element 24 ". When 24 'is formed as a spherical surface, the pupil position shifts in each direction of the observation screen due to the aberration of the illumination light such as spherical aberration. In this case, it is difficult to fabricate the reflecting mirror, whereas the Fresnel focusing mirror or the diffractive focusing optical element 24 ″ needs to have a refractive power and an aspherical effect in a planar shape. And easy to manufacture. Further, since the device can be configured as a flat surface, it is useful for downsizing the device.
[0028]
Seventh Embodiment FIG. 9 is an optical path diagram showing a configuration of an image display device according to a seventh embodiment. This embodiment is different from the above-described first to sixth embodiments in that the eyeball illumination device 25 including an infrared light emitting element and the like arranged outside the light beam of the eyepiece lens 22 (22L, 22R) and the imaging element 26 as a pupil detection element And a circuit for determining one or a part of the point light source group conjugate with the detected pupil position based on the information from the image sensor 26. Thereby, the point light source to be turned on can be automatically selected.
[0029]
For example, as shown in FIG. 10, the eyeball illumination device 25 and the image sensor 26 are arranged outside the light flux near the eyepiece lens 22 (22L, 22R), and an image of the eyeball E is taken. The obtained eyeball image is input to the image processing circuit 27, and the position of the pupil is detected. A light emitting position calculation circuit 28 that calculates a direction of a line of sight from the obtained pupil position information and calculates a point light source corresponding to the line of sight is selected, and a point light source to be turned on is selected. The selected point light source (light emitting element) is turned on.
[0030]
Eighth Embodiment FIG. 11 is an optical path diagram showing a configuration of an image display device according to an eighth embodiment. In this embodiment, the half mirror 30 is arranged between the light source 23 and the illumination optical system 24 (24 ', 24 ") in the first to sixth embodiments, and the light returning from the eyeball E is reflected by the half mirror 30. The imaging device 26 is disposed at a conjugate position on the surface of the eyeball E formed by the eyepiece lens 22 and the illumination optical system 24 in the direction reflected by the eyepiece 22 to detect the pupil position. A similar circuit for determining one or a part of a group of point light sources that is conjugate to the pupil position thus set is installed, and a point light source to be turned on is automatically selected.
[0031]
Ninth Embodiment FIG. 12 is an optical path diagram showing a configuration of a video display device according to a ninth embodiment. This embodiment is different from the first to sixth embodiments in that, instead of the light source 23, as shown in a front view in FIG. It is arranged at the light source position. Since the position of the light source 23 coincides with the conjugate position of the surface of the eyeball E formed by the eyepiece lens 22 and the illumination optical system 24, the pupil position can be detected by the light source / imaging element 31. Moreover. In this case, one or a part of the point light sources to be turned on is in the vicinity of the light receiving element that has detected the pupil position, so that the determination circuit can be easily configured. With such an arrangement, the number of parts can be reduced as compared with the seventh and eighth embodiments.
[0032]
In the above first to ninth embodiments, the example in which the eyepiece lens is used for the projection optical system 22 has been described, but the projection optical system may have any configuration. For example, as shown in FIG. 14, a beam splitter 32 arranged at an angle to the image display element 21 and a concave mirror 33 arranged at a transmission side of a light beam by the beam splitter 32 are integrally formed by a prism 34 to form an image display. Using an eyepiece optical system that first passes the light beam from the element 21 through the beam splitter 32, then reflects and focuses the light with the concave mirror 33, and then reflects the converged light with the beam splitter 32 and condenses the pupil of the eyeball E. Can be.
[0033]
Further, as shown in FIGS. 15A to 15E, the eyepiece optical system may be constituted by an eccentric mirror 22 '(FIG. 15A), and this eccentric mirror 22' uses a rotationally asymmetric aspheric surface. It is desirable. Further, a refracting optical element (eccentric lens) 221 may be disposed between the LCD 21 and the eccentric mirror 22 '(FIG. (B)), and it is desirable to use a rotationally asymmetric aspherical surface for the refracting optical element 221. . Further, the illumination optical system can be constituted by an eccentric focusing mirror 241 (FIG. 3C). Further, the eccentric mirror of the eyepiece optical system can be constituted by the eccentric back mirror 222 (FIG. 4D). Further, a prism 223 may be joined to the eccentric back mirror 222 for chromatic aberration correction (FIG. 7E). Of course, other optical elements can be used. Further, for example, in a configuration as shown in FIGS. 14 and 15, the mirror constituting the eyepiece optical system is a semi-transmissive mirror so that the see-through type external world can be selectively or superimposed on an electronic image. You can also.
[0034]
Further, the two-dimensional image display element 21 is not limited to a liquid crystal display element (LCD), but may be any type of a type that displays an image by illuminating a display surface with illumination light from an illumination light source.
[0035]
By the way, a pair of left and right video display devices of any of the above embodiments is prepared (as is in the case of FIGS. 4 and 6 to 8), and they are supported by being separated by the interpupillary distance, so that they can be observed with both eyes. It can be configured as a head-mounted image display device that can be used. FIG. 16 shows the overall configuration of an example of such a video display device. The display device body 50 is provided with a pair of left and right display devices of any of the above-described embodiments, and a two-dimensional video display element composed of an LCD is arranged on the image plane corresponding to them. A temporal frame 51 as shown in the figure is provided on the main body 50 continuously on the left and right sides. The temporal frames 51 on both sides are connected by a parietal frame 52, and a leaf spring 53 is provided between the temporal frames 51 on both sides. A rear frame 54 is provided through the display device main body. The rear frame 54 is applied to the rear portions of both ears of the observer like vines of glasses, and the parietal frame 52 is placed on the vertex of the observer. Can be held in front of the observer's eyes. A top pad 55 made of an elastic body such as a sponge is attached inside the top frame 52, and a similar pad is attached inside the rear frame 54 in the same manner. It is designed so that it does not feel uncomfortable when attached to
[0036]
Further, a speaker 56 is attached to the rear frame 54 so that stereophonic sound can be heard together with image observation. As described above, the playback device 58 such as a portable video cassette is connected to the display device main body 50 having the speaker 56 via the video / audio transmission cord 57, so that the viewer can attach the playback device 58 as shown in the figure. Video and sound can be enjoyed by holding the belt at an arbitrary position such as a belt position. Reference numeral 59 in the drawing denotes an adjustment unit for the switch, volume and the like of the playback device 58. It should be noted that electronic components such as a circuit for determining one or a part of a group of point light sources conjugate to the detected pupil position as shown in FIG. It is built in.
[0037]
The cord 57 may have a jack at the end so that it can be attached to an existing video deck or the like. Furthermore, it may be connected to a TV radio wave receiving tuner for TV viewing, or may be connected to a computer to receive computer graphics images, message images from the computer, and the like. Further, in order to reject an obstructive code, an antenna may be connected to receive an external signal by radio wave.
[0038]
As described above, the image display device of the present invention has been described based on some embodiments, but the present invention is not limited to these embodiments, and various modifications are possible.
[0039]
The above-described video display device of the present invention can be configured, for example, as follows.
[0040]
[1] A two-dimensional image display element, a projection optical system for projecting an image of the two-dimensional image display element onto an eyeball of an observer, a light source for illuminating the two-dimensional image display element, and the light source An illumination optical system for guiding the emitted light beam to the two-dimensional image display element,
The image is characterized in that the light source is configured by arranging a plurality of point light sources on a plane, and is disposed at a substantially conjugate position of the illumination optical system and the projection optical system with respect to a pupil position of an observer's eyeball. Display device.
[0041]
[2] The image display device according to [1], wherein the light source is arranged near a rear focal position of the illumination optical system.
[0042]
[3] The video display device according to [2], wherein the two-dimensional video display element is arranged near a front focal position of the illumination optical system.
[0043]
[4] A pair of left and right two-dimensional video display elements, a pair of left and right projection optical systems for projecting images of the pair of left and right two-dimensional video display elements onto an eyeball of an observer, and a pair of left and right projection optical systems A light source for illuminating the pair of left and right two-dimensional image display elements, which is arranged on an axis positioned at an equal distance from the optical axis, and guiding light emitted from the light source to the pair of left and right two-dimensional image display elements. The video display device according to the above [1], comprising: the illumination optical system according to [1].
[0044]
[5] The image display device according to [4], wherein the illumination optical system is configured by a reflection optical system.
[0045]
[6] The image display device according to [4], wherein the reflection optical system is constituted by a diffractive optical element.
[0046]
[7] The pupil position detecting means of the observer's eyeball is provided, and only a point light source in the vicinity of a position conjugate with the pupil of the observer's eyeball among the light sources having a plurality of the point light sources arranged on a plane is turned on. The video display device according to the above [1], wherein:
[0047]
【The invention's effect】
As is apparent from the above description, according to the video display device of the present invention, the light source for illuminating the two-dimensional video display element is configured by arranging a plurality of point light sources on a plane, and the pupil position of the observer's eyeball. Is arranged at a position substantially conjugate with the illumination optical system and the projection optical system, and therefore, a point light source that is conjugate with the pupil of the observer's eyeball is selected from among the point light sources and turned on, thereby providing a two-dimensional light source. Since the light beam emitted from the image display element is focused on the pupil of the observer's eyeball at one point, a good image can be observed regardless of the diopter (myopia, hyperopia, astigmatism) of the observer's eyeball. Further, by turning on a light source conjugate with the pupil position according to the pupil position, it is not necessary to move the point light source, so that the apparatus does not become complicated.
[Brief description of the drawings]
FIG. 1 is an optical path diagram showing a configuration of an image display device according to a first embodiment of the present invention.
FIG. 2 is an optical path diagram illustrating a configuration of a video display device according to a second embodiment.
FIG. 3 is an optical path diagram illustrating a configuration of a video display device according to a third embodiment.
FIG. 4 is an optical path diagram illustrating a configuration of a video display device according to a fourth embodiment.
FIG. 5 is a diagram illustrating positions conjugate to a pupil when eye width adjustment is performed and when eye width adjustment is not performed in a fourth embodiment.
FIG. 6 is an optical path diagram showing a configuration of a video display device according to a fifth embodiment.
FIG. 7 is a perspective view showing a modification of the fifth embodiment.
FIG. 8 is an optical path diagram showing a configuration of an image display device according to a sixth embodiment.
FIG. 9 is an optical path diagram illustrating a configuration of a video display device according to a seventh embodiment.
FIG. 10 is a diagram illustrating an example of a circuit for determining a lighting point light source.
FIG. 11 is an optical path diagram illustrating a configuration of an image display device according to an eighth embodiment.
FIG. 12 is an optical path diagram showing a configuration of a video display device according to a ninth embodiment.
FIG. 13 is a front view of a light source / image sensor used in a ninth embodiment.
FIG. 14 is an optical path diagram showing a modification of the projection optical system.
FIG. 15 is an optical path diagram showing various modifications of the entire optical system.
FIG. 16 is a diagram showing an overall configuration of an example in which the video display device of the present invention is configured as a head-mounted video display device.
FIG. 17 is a diagram illustrating an example of an optical system of a conventional eye-mounted projection type head mounted image display device.
FIG. 18 is a diagram showing an optical system of another conventional eye-mounted projection type head mounted image display device.
FIG. 19 is a diagram illustrating an operation when the diameter of the exit pupil of the projection optical system is enlarged.
FIG. 20 is a diagram illustrating an operation of a method of moving a point light source in accordance with a pupil position of an eyeball.
[Explanation of symbols]
E: observer's eyeball EL, ER: eyeball 21: two-dimensional image display device (liquid crystal display device (LCD))
21L, 21R ... LCD
22 Projection optical system (eyepiece)
22L, 22R eyepiece 23 light source 24 illumination optical system (condensing lens)
24 ': Converging / reflecting mirror 24 ": Fresnel converging / reflecting mirror or diffractive condensing optical element 25 ... Eyeball illuminator (infrared light emitting element, etc.)
26. Image sensor (pupil detector)
27 image processing circuit 28 light emission position calculation circuit 29 light emitting element driving circuit 30 half mirror 31 light source / image pickup element 32 beam splitter 33 concave mirror 34 prism 22 'eccentric mirror 50 display device body 51 side Head frame 52 ... Pain frame 53 ... Leaf spring 54 ... Rear frame 55 ... Pain pad 56 ... Speaker 57 ... Video / audio transmission code 58 ... Playback device 59 ... Adjustment unit 221 ... Refractive optical element (eccentric lens)
222: eccentric back mirror 223: prism 241: eccentric focusing mirror

Claims (7)

A two-dimensional image display element, a projection optical system for projecting an image of the two-dimensional image display element onto an eyeball of an observer, a light source for illuminating the two-dimensional image display element, and a light beam emitted from the light source And an illumination optical system for guiding the two-dimensional image display device to
The image is characterized in that the light source is configured by arranging a plurality of point light sources on a plane, and is disposed at a substantially conjugate position of the illumination optical system and the projection optical system with respect to a pupil position of an observer's eyeball. Display device. The image display device according to claim 1, wherein the light source is disposed near a rear focal position of the illumination optical system. The image display device according to claim 2, wherein the two-dimensional image display element is arranged near a front focal position of the illumination optical system. A pair of left and right two-dimensional video display elements, a pair of left and right projection optical systems for projecting images of the pair of left and right two-dimensional video display elements onto an eyeball of an observer, and an optical axis of the pair of left and right projection optical systems. A light source for illuminating the pair of left and right two-dimensional image display elements disposed on axes located at equal distances, and an illumination optic for guiding a light beam emitted from the light source to the pair of left and right two-dimensional image display elements 2. The image display device according to claim 1, comprising a system. 5. The image display device according to claim 4, wherein said illumination optical system is constituted by a reflection optical system. 5. The image display device according to claim 4, wherein said reflection optical system is constituted by a diffractive optical element. The observer's eyeball pupil position detecting means is provided, and among the light sources having a plurality of the point light sources arranged on a plane, only a point light source near a position conjugate with the pupil of the observer's eyeball is turned on. 2. The video display device according to claim 1, wherein:

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