JP3483274B2 - Image display device - Google Patents

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, and in particular, a light beam having information of an image generated by an image generator is projected through an optical system to an observer's eye to produce the image. The present invention relates to an image display device that displays an image as a virtual image to the viewer.

[0002]

2. Description of the Related Art Conventionally, an image of a large screen with a sense of presence has been displayed using a large CRT display device, a projection TV, or the like.

However, these devices have problems that they require a large space and that it is difficult to see the image unless the surroundings are darkened, and the usage conditions are limited. For this reason, recently, there has been a device in which a light beam from an image displayed on an image display element is directly projected onto an eye by an optical system arranged very close to the face, and an observer visually recognizes an equivalently large image as a virtual image. Proposed.

FIG. 6 illustrates a main part of an image display device proposed in Japanese Patent Laid-Open No. 4-34512. The image is displayed on the liquid crystal display 101 by the data sent by the signal line 116. 101 is transilluminated by a backlight light source 104, and the light transmitted through the liquid crystal display 101 becomes a luminous flux having information of a displayed image.

After passing through the magnifying lens 151, this light flux is reflected by the mirror 150, becomes a light flux 109, and reaches the pupil 107 of the observer. The observer visually recognizes the display image by observing the light flux 109. The power of the magnifying lens 151 is set so that the image on the liquid crystal display element 101 is displayed as a virtual image at a position a predetermined distance, for example, 5 m ahead.

[0006]

However, in the above-mentioned conventional example, since the surface on which the virtual image is displayed is a flat surface, the displayed image is perceived as a flat plate by the observer, and it is not possible to display a realistic image. Further, when the image display device of the conventional example is applied to the image display of the virtual reality system, the image is still projected on a flat screen, and sufficient reality cannot be obtained.

[0007]

According to another aspect of the present invention, an image display device projects an image generator and a light flux having image information from the image generator onto an observer to form a virtual image of the image . An image display device is provided with a projection optical system for observing each of the left and right eyes of an observer, wherein the projection optical system is a virtual image of the left and right eyes.
The virtual image surface on which the image is formed is formed on the same curved surface such as a spherical surface or a cylindrical surface.
The image display device according to the invention of claim 2 observes an image generator and a light projecting optical system for projecting a light flux having image information from the image generator to an observer to observe a virtual image of the image. a respective image display device provided on the left and right eyes of the user,-projecting optical system
Is such that the virtual image planes observed by the left and right eyes of the observer are on the same curved surface such as a spherical surface or a cylindrical surface ,
The image information displayed by the image generator is of the observer.
The virtual images observed by the left and right eyes become parallax images of each other .
The feature is that it is set as follows . The invention of claim 3 is characterized in that, in the invention of claim 1 or 2, the curved surface is symmetrical with respect to a plane of symmetry of an observer's face.

[0008]

EXAMPLE 1 FIG. 1 is a layout view of an optical system showing Example 1 of the present invention. In an actual device, images are projected on both the left and right eyes, and the device configuration is bilaterally symmetrical with respect to the plane of symmetry of the observer's face.

FIG. 1 is a view of the apparatus as seen from above the head, showing a portion corresponding to the left eye. The portion corresponding to the right eye is symmetrical with FIG. 1, but is omitted because the figure becomes complicated.

In FIG. 1, reference numeral 1 denotes a liquid crystal display element (hereinafter referred to as LCD), which displays an image in accordance with an image signal sent by a signal line (not shown). The LCD 1 is also illuminated from the left side by an illuminator (not shown).

Signal lines and illuminators (not shown) may be the same as those in the conventional example shown in FIG. The light flux that has passed through the LCD 1 is converted into a light flux having information on the displayed image and enters the lens system 2. The light flux that has passed through the lens system 2 is subjected to the image forming action of the lens system 2 to become an outgoing light flux 6,
The light is reflected by the half mirror 3 and reaches the left eye 4 of the observer as a light beam 8. The function of the lens system 2 is to cause the virtual light flux 7 obtained by extending the reflected light flux 8 in the direction opposite to the actual traveling direction of the light to form an image on the virtual image plane 5.

Therefore, the observer recognizes the reflected light beam 8 as if it were the light emitted from each point on the virtual image plane 5. The image on the LCD 1 is magnified in this way and is visually recognized as an image formed on the virtual image plane 5.

The present invention is characterized by utilizing the ergonomic fact that the sense of realism is increased by making the observed virtual image plane 5 a curved surface. In this embodiment, the virtual image plane 5 is a spherical surface having the left eye 4 as the center and a radius set to a preset distance, for example, 1 m.

When the virtual image plane 5 is set in this manner, the observer can project the image on the LCD 1 in an enlarged form as if it were projected on a spherical screen centered on the left eye 4 and having a radius of 1 m. Can be observed. As a result,
The observer uses the image visually recognized on the virtual image plane 5 having a radius of 1 m.
You can enjoy a much more realistic image than when the virtual image plane is flat.

As described above, in the actual device, there is a right eye portion corresponding to the left eye in FIG. 1 with respect to the plane of symmetry of the observer's face. The virtual image planes formed are two spherical surfaces centered on the left eye and the right eye, respectively, with a gap between the eyes, for example, 60 mm. It is preferable that the two virtual image planes originally have the same shape and position.

In the numerical example of this embodiment, the virtual image planes for the right eye and the left eye each have a radius of 10 mm which is 1000 mm away from the corresponding eye.
It is a spherical surface of 00 mm. Therefore, the deviation of 60 mm does not become a major obstacle to image recognition by both eyes.

Next, in the system shown in FIG. 1, means for making the virtual image plane 5 a spherical surface centered on the left eye 4 and having a radius of 1000 mm will be described. It is the lens system 2 that shares the imaging action. The lens system 2 is composed of three lenses 2-1 to 2-3.

Here, the image formation of the center point A of the LCD 1 will be considered. The distance from the right side surface of the third lens 2-3 of the lens system 2 to the half mirror 3 is 60 mm,
If the distance from to the left eye 4 is 50 mm, the position of the left eye is 110 mm apart from the surface on the right side of 2-3, that is, the surface closer to the eye. The lens system 2 has a function of drawing 890 mm, that is, 1000 mm to 110 mm from the right surface of the lens 2-3 closest to the eye and forming the center point A as a virtual image at the left position.

Further, the Petzval sum of the lens system 2 is almost 1
It is designed to be / 1000 mm ^-1 . By setting the lens system 2 as described above, the virtual image plane 5 can be a spherical surface centered on the left eye 4 and having a radius of 1000 mm.

As described above, in this embodiment, there is a portion corresponding to the right eye, which is completely symmetrical to the system of FIG. Also in this case, if the system is constructed in the same manner as in the case of the left eye, a spherical virtual image plane having a radius of 1000 mm centering on the position of the right eye can be formed for the right eye.

When the half mirror 3 is used as shown in FIG. 1, it is necessary to avoid crosstalk between the left and right systems. If the light 6 from the image 1 for the left eye passes through 3 and illuminates the LCD 1 for the right eye, the light becomes flare light and reduces the contrast of the image observed by the right eye. is there. The same applies to the light of the image for the right eye.

Therefore, in order to prevent the light of the image displayed on the left side from going to the right eye and the light showing the image on the right side from entering the left eye, a light blocking member is provided between the optical systems of the left and right eyes. It is necessary to provide it. However, when a mirror is used as 3, crosstalk does not occur, so a light shielding member is not necessary. Further, the configuration of the optical system may be arranged such that crosstalk does not occur as shown in FIG. 6 of the conventional example.

In the present embodiment, it is not always necessary to display the same image on both the left and right eyes, and it is also possible for the observer to visually recognize a stereoscopic image by displaying images with parallax on the left and right LCDs. Also in this case, since the virtual image surface is a spherical surface with a finite distance surrounding the observer, it is possible to display a stereoscopic image having a greater sense of reality.

In the first embodiment of FIG. 1, an example in which the virtual image surface is a spherical surface having a radius of 1000 mm centered on the left and right eyes is shown.
However, when the display image is a horizontally long image, for example, an HD size image or a panoramic size image, the virtual image surface is preferably a cylindrical surface surrounding the observer rather than a spherical surface. In order to further emphasize the capturing effect, it is preferable that the virtual image plane is not too far from the observer.

When the virtual image planes are close to each other as described above, it is desirable that the virtual image planes for the right eye and the left eye are not displaced and that they have the same shape and position.

FIG. 2 shows a second embodiment of the present invention, in which the virtual image plane is a cylindrical surface in consideration of the above matters. In the figure, the same components as those in the first embodiment are designated by the same numbers as in FIG. Hereinafter, description of elements having the same operations as in the first embodiment will be omitted, and items unique to the present embodiment will be described.

FIG. 2 shows an optical system corresponding to the left eye of the device which is constructed symmetrically. As in the case of FIG. 1, the figure is drawn with the observer looking down from above the head, and 9 is the plane of symmetry of the observer's face. 9 is also the plane of symmetry showing the right side of the device. B is the midpoint between the right and left eyes.

In this embodiment, the virtual image plane 5 for the left eye 4 has no curvature in the direction perpendicular to the plane of the drawing, and in the direction of the plane of the drawing, it is a circle of radius BC centered on the midpoint B, and is a cylindrical surface as a whole. Is formed.

In the case of this embodiment, BC = 300 mm. The part for the right eye (not shown) is symmetrical with respect to the plane of symmetry 9. Since the center B is on the plane of symmetry 9, the virtual image plane for the right eye does not have a curvature in the direction perpendicular to the paper surface of FIG. 2 like the virtual image surface 5 for the left eye, and B is the center within the paper surface. It becomes a cylindrical surface which is a circle with a radius BC.

The lens system 2 is for making the virtual image plane 5 for the left eye a cylindrical surface. In this embodiment, the lens system 2 is 2-
It is composed of four lenses 11 to 14. The first lens 2-11 is a lens having spherical surfaces on both sides, and the second lens 2-11.
Reference numeral 12 is a lens whose left side surface has no curvature in the direction perpendicular to the paper surface, and has a curvature in the direction inside the paper surface, and whose right side surface is a spherical surface.

On the contrary, the third lens 2-13 is a lens whose left side surface is a spherical surface, and whose right side surface is a cylindrical surface having no curvature in the direction perpendicular to the paper surface and having a curvature in the paper surface direction.
The fourth lens 2-14 is a double-sided spherical lens. The lens system 2 as a whole has no astigmatism, and is set so that a point on the LCD 1 is imaged in the same state in two directions of a cross section perpendicular to the paper surface and a cross section lying in the paper surface.

In order to form a virtual image plane which is a cylindrical surface, the Petzval sum is approximately 0 for the image formation of the cross section perpendicular to the paper surface, and the Petzval sum is approximately 1/300 mm ^-1 for the image formation of the cross section in the paper surface. Then, the glass material and the curvature of the lens system 2 are set. The second lens 2-12, the third lens 2-13, and the fourth lens 2-14 are arranged with different amounts of eccentricity in the vertical direction within the plane of FIG. 2, and as a result, the virtual image plane 5 is a cross section within the plane of the plane of FIG. The circle is centered on the point B.

In FIG. 2, the right part not shown is also
In exactly the same manner, the virtual image plane can be a cylindrical plane that has no curvature in the direction of the plane of FIG. 2 and has a radius BC centered on the point B in the plane of paper. Therefore, the virtual image plane for the right eye and the virtual image plane 5 for the left eye completely match. By setting the virtual image plane as described above, it is possible to display a highly realistic image to the observer due to the surrounding effect.

In this embodiment, the virtual image plane of the cross section in the plane of the drawing is a cylindrical surface having a circle centered on the midpoint B of the right and left eyes. However, the center of the circle can be a point other than B on the symmetry plane 9 of the observer's face, for example, the center of the observer's head or the center of rotation of the neck. In that case, the position of the image forming point of the lens system 2 including the cylindrical surface, and the Petzval sum and decentering amount of the image forming system of the in-plane section of the paper may be set so as to meet the conditions.

In the second embodiment of the present invention, the virtual image surface having the shape of the cylindrical surface is realized by the decentering lens system including the cylindrical surface and the half mirror. In the third embodiment, the cylindrical virtual image surface of the second embodiment is realized by a hologram combiner.

FIG. 3 shows an optical system representing the third embodiment. The virtual image plane formed and the image visually recognized by the observer are the same as those in the second embodiment. In the figure, the same members as those in the previous embodiments are
Since the same numbers are assigned, the description of common parts will be simplified or omitted.

Also in this embodiment, the device is bilaterally symmetrical with respect to the symmetry plane of the face, as in the first and second embodiments. Therefore, only the part corresponding to the left eye is shown in the figure, and the part on the right side is omitted. First, the LCD 1 is driven by an illumination system not shown in FIG.
Illuminated from the lower left side of the light source, a light flux 11 having image information is generated. The light beam 11 is reflected by the hologram combiner 10, and becomes a reflected light beam 8 by the lens action of the hologram combiner 10 and enters the left eye 4. The lens action of the hologram combiner 10 also causes the viewer to recognize the reflected light beam 8 as if it were a light beam emitted from each point on the virtual image plane 5.

As a result, the image displayed on the LCD 1 is enlarged and visually recognized by the observer. The virtual image plane 5 does not have a curvature in the direction perpendicular to the paper surface as in the second embodiment of FIG. 2 and has a radius BC centered on the midpoint B of the left eye 4 and the unillustrated right eye in the direction of the paper surface. It has a cylindrical surface that is a circle. Figure 3
Since the virtual image plane 5 is the same as the virtual image plane of the second embodiment, it is possible to display an image with a large sense of presence to the observer due to the surrounding effect.

In this embodiment, the hologram combiner 10 is used.
Makes the virtual image plane 5 a cylindrical surface. That is, point A on LCD1
The light flux emitted from 1 is the point A2 of the hologram combiner 10.
Incident on the virtual image plane 5 due to the diffraction effect at the point A2.
3 is formed as a virtual image.

Similarly, the light beam emitted from the point B1 different from the point A1 is incident on the point B2 of the hologram combiner 10 and is imaged as a virtual image at the point B3 on the virtual image plane 5 by the diffraction effect at the point B2. Therefore, diffraction holograms are distributed on the hologram combiner 10 at positions where the light beams from the respective points on the LCD 1 are incident on the cylindrical combiner 10 so as to form virtual images at the corresponding points on the cylindrical virtual image plane 5. There is a need.

The hologram combiner 10 having such a function can be produced by causing two light flux wavefronts having a phase distribution set in accordance with a required diffraction action distribution to interfere and burn.

FIG. 4 is an explanatory diagram of a method for producing the hologram combiner 10 used in this embodiment. The hologram photosensitive material 18 is attached or coated on a substrate 17 such as glass or plastic, to which the object light beam 14 and the reference light beam 15 are incident.

Reference numerals 14 and 15 are formed by a laser beam (not shown), and interference fringes of both are recorded on the photosensitive material 18. A photopolymer is typically used as the photosensitive material, and an argon ion laser having a wavelength of 514.5 nm is typically used as the laser. Needless to say, other known materials such as dichromated gelatin, polyvinylcarbazole, and silver salt photosensitive materials can be used in addition to the above.

In the system of FIG. 4, the reference light beam 15 is a parallel light beam, and the object light beam 14 is a light beam refracted by the printing lens system 16. The lens system 16 is composed of two anamorphic lenses 12 and 13. The anamorphic lens 13 is a cylindrical lens having no curvature in the direction perpendicular to the paper surface and having a curvature only in the in-plane direction, and the anamorphic lens 12 is an anamorphic lens having a curved surface having symmetry with respect to the paper surface. The printing lens system 16 is set so as to generate the object light beam 14 having a phase distribution that realizes the diffractive action required for the hologram combiner 10.

The hologram combiner 10 is produced by applying a predetermined developing process to the photosensitive material 18 exposed by the optical system constructed as shown in FIG. FIG. 5 shows the phase distribution of the aspherical component excluding the spherical wave component from the object light beam 14 formed in FIG. 4 by contour lines. It can be seen that a saddle-shaped wavefront distribution of horses, which is unique to the anamorphic system, is formed.

By using the hologram combiner manufactured by the method described above, the above-mentioned cylindrical virtual image plane can be formed. In this embodiment, it is possible to easily realize a modification in which the virtual image surface is a cylindrical surface in which the center of the circle is a point other than the point B in the in-plane section of the paper, or a curved surface other than the cylindrical surface, for example, a spherical surface or an elliptic surface. You can In this case, it suffices to reset the phase distribution of the printing wavefront that creates the hologram combiner 10 to those conditions.

The hologram combiner produced in this embodiment is a Lippmann hologram printed with two opposing light beams as shown in FIG. Therefore, the photosensitive material 18
By increasing the thickness of the hologram combiner, a strong wavelength selectivity characteristic of a three-dimensional grating can be obtained.
The wavelength width having high diffraction efficiency of 0 can be extremely narrowed.

As a result, the chromatic aberration generated in the hologram combiner 10 can be suppressed to a value that can be substantially ignored. If chromatic aberration must be taken into consideration, an interference filter is arranged between the LCD 1 and the illumination system (not shown) that illuminates the LCD 1 in FIG. 3 to narrow the wavelength width of the illumination light, and the chromatic aberration in the hologram combiner 10 is reduced. It is also possible to reduce the occurrence.

[0049]

As described above, according to the present invention, the LCD is
In an image display device for projecting a light beam having image information of an image generator, etc., to an observer's eye through an optical system and displaying it to the observer as a virtual image, the virtual image plane is a curved surface surrounding the observer. By doing so, it is possible to display a more three-dimensional, realistic and realistic image for the observer.

[Brief description of drawings]

FIG. 1 is a diagram showing a first embodiment of the present invention.

FIG. 2 is a diagram showing a second embodiment of the present invention.

FIG. 3 is a diagram showing Embodiment 3 of the present invention.

FIG. 4 is an explanatory diagram of a method for producing a hologram combiner used in Example 3 of the present invention.

FIG. 5 is a diagram showing a phase distribution of a printing wavefront of the hologram combiner.

FIG. 6 is an explanatory view of JP-A-4-34512, which is a conventional example.

[Explanation of symbols] 1 Liquid crystal display (LCD) 2 lens system 3 half mirror 4 left eye 5 Virtual image plane 6 Output luminous flux 7 Virtual luminous flux 8 Reflected light flux 9 Face symmetry plane 10 Hologram combiner 12 Anamorphic lens 13 Cylindrical lens 14 object luminous flux 15 Reference luminous flux 17 board 18 Photosensitive material 101 liquid crystal display 104 Backlight light source 107 observer's eyes 116 signal line 121 Virtual image plane 150 mirror 151 magnifying lens

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tadashi Kaneko 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Toshiyuki Sudo 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Incorporated (72) Inventor ▲ Yoshi ▼ Yoko Yoko 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Tatsu Kobayashi 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. In-company (72) Inventor Susumu Matsumura 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (56) Reference JP-A-4-318809 (JP, A) JP-A-4-503440 (JP, A) US Patent 5130794 (US, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G02B 27/00, 27/02 G03B 37/00

Claims (3)

(57) [Claims] 1. An image generator and a projection optical system for projecting a light flux having image information from the image generator to an observer and observing a virtual image of the image for each of the left and right eyes of the observer. An image display device provided, wherein the projection optical system includes left and right eye images.
The image display device, wherein the virtual image surface on which the virtual image is formed is on the same curved surface such as a spherical surface or a cylindrical surface. 2. An image generator and a projection optical system for projecting a light flux having image information from the image generator to an observer and observing a virtual image of the image for the left and right eyes of the observer, respectively. an image display device provided,-projecting optical system, the virtual image plane observed in the right and left eyes of the observer, are set to be on the same curved surface forming a spherical or cylindrical surface or the like,該画
The image information displayed on the image generator is the left eye of the observer.
And the virtual images observed by the right eye become parallax images with each other.
An image display device characterized by being set . 3. The image display device according to claim 1, wherein the curved surface is symmetrical with respect to a plane of symmetry of an observer's face.