JPH06186500A - Stereoscopic picture device - Google Patents

Abstract

PURPOSE:To perform color display without having a mechanically movable part by setting as optical element obtained by cutting an anisotropic optical medium with a parallel plane including two main axes whose refractive indexes are different on the front surface of a picture display unit or on an optical path. CONSTITUTION:An anisotropic optical element 13 is obtained by cutting the anisotropic optical medium with the parallel plane including two main axes whose refractive indexes are different, and an x-y plane is set in parallel with the projection surface of a polariscope 12 while making two main axes directions an (x)-axis direction and (y)-axis direction. The polariscope 12 makes picture light emitted from the picture element of the picture display unit 11 linearly polarized light having the axis of polarization in either the (x)-axis direction or the (y)-axis direction by each picture element. That is, in this case, the light emitted from the picture element displaying a short range view out of the picture elements displayed on the unit 11 is made to be the linearly polarized light in the (x)-axis direction and the light emitted from the picture element displaying a distant view out of them is made to be the linearly polarized light in the (y)-axis direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stereoscopic image device for forming a three-dimensional image from a two-dimensional image.

[0002]

2. Description of the Related Art Conventionally, a stereoscopic image device of this type has a structure in which a plurality of liquid crystal display panels are laminated, and a method of forming a stereoscopic image by scanning bright spots in a plane and vertical scanning by selecting the panel. A method of crossing a laser beam from a direction in the crystal and using light emission by optical excitation at the intersection, a method of changing the optical path length by moving an image display or a mirror on the optical path, a half mirror for multiple images with different optical path lengths There is a method of combining. (For example, JP-A-62-122494, JP-A-62-122494
194233, see JP-A-63-100898)

[0003]

In the prior art of the above-mentioned stereoscopic image device, the TN for the liquid crystal panel type is used.
When a liquid crystal panel of the GH type is used, there is a difficulty in colorization, and when a liquid crystal panel of the GH type is used, it is difficult in terms of response speed. The laser beam method is difficult to colorize, and the method of moving the mirror has a problem in operating speed and stability because there are mechanically movable parts. In addition, the method of combining with a half mirror has problems such as an increase in size of the apparatus and elimination of misalignment when superimposing images.

It is an object of the present invention to realize a stereoscopic image device which does not have a mechanically movable part and can display in color.

[0005]

In order to achieve the above object, in the stereoscopic image device of the present invention, a different image is formed on the front surface of the image display or on the optical path of the image display capable of controlling the polarization state of the emitted light for each pixel. An optical element, in which an isotropic optical medium is cut by a parallel plane including two principal axes (hereinafter, referred to as x axis and y axis) having different refractive indexes, hereinafter referred to simply as an anisotropic optical element, is provided. To do.

Here, the direction perpendicular to the x-axis and the y-axis is z
The axis.

In the above anisotropic optical element, the refractive index η (x) for linearly polarized light having a z-axis traveling direction and an electric field vibrating plane in the x-axis direction, and the traveling direction is the z-axis direction and the y-axis direction. The refractive index η (y) for linearly polarized light having a vibration plane of the electric field is different.

Therefore, through this anisotropic optical element, even if the light emitted from the point light source at the same position is x
The image position differs in the z-axis direction between the case of the linearly polarized light in the axial direction and the case of the linearly polarized light in the y-axis direction.

The present invention is characterized in that the pixels of the image display are moved in the direction of the line of sight using this principle to form a perspective image. That is, a perspective image is formed by moving the position of the bright spot in the line-of-sight direction depending on whether the light emitted from each pixel of the image display device is linearly polarized light in the x-axis direction or linearly polarized light in the y-axis direction. .

As an image display device capable of controlling the polarization state of emitted light for each pixel, an image light from each pixel of the image display device is provided on the front surface of the screen of the image display device such as a CRT or a liquid crystal image display device. Is a linearly polarized light, and a polarizer (hereinafter, simply referred to as a polarizer) that switches the polarization axes thereof in two directions perpendicular to each other is installed.

A polarizer using a TN type liquid crystal plate can be considered. At this time, a polarizing plate is installed between the screen and the liquid crystal cell as needed. Further, by appropriately taking the electrode structure of the TN liquid crystal plate and controlling the rotation angle of the emitted light from each pixel of the image display for each pixel, the characteristics required for the present invention are obtained.
An image display capable of controlling the polarization state of emitted light is configured for each pixel. A ferroelectric liquid crystal plate, an electro-optical element, a Faraday element, or the like can be used instead of the TN liquid crystal plate.

The present invention has the drawback that the amount of movement of the image is small. As a method to improve this, by installing a magnifying optical system consisting of two lenses installed with their focal points aligned or an optical system equivalent to this between the anisotropic optical element and the observer, The amount of movement of the position can be expanded.

Further, in a device such as a 3D goggles used in a virtual realism system or the like, in which a right-eye image and a left-eye image having parallax are visually recognized only by their corresponding eyes, the stereoscopic image of the present invention is displayed for image display. By using a pair of left and right display devices, a 3D system that can obtain a stereoscopic image with parallax and perspective can be configured.

[0014]

The principle used in the present invention will be briefly described.

In the above anisotropic optical element, a light beam traveling in the z-axis direction has an x-polarized wave and a y-polarized wave having a vibration plane of an electric field in the x-axis direction.
It is decomposed into y-polarized light having an oscillation plane of an electric field in the axial direction, and the refractive index η (x) for the x-polarized component and the refractive index η (y) for the y-polarized component are different. From this, this anisotropic optical element approximates to the incident light in the z-axis direction, the refractive index η (x) for the linear polarized light in the x-axis direction and the refractive index η (y) for the linear polarized light in the y-axis direction. Behave as an optical medium.

When geometrical optics is used, when the refractive index of an optical medium having a thickness d and a refractive index η placed on the optical path is changed by δ, the apparent position of the image is -dδ / (η ^ 2). Only changes. Here, η ^ 2 indicates the square of η, and the following is used similarly. Further, the negative sign indicates that when the moving direction is δ> 0, it is a direction approaching the observer.

With the above two points in mind, consider the case where the linearly polarized light in the x-axis direction and the linearly polarized light in the y-axis direction emitted from the same point light source pass through the anisotropic optical element having the thickness d. Then the two images are roughly d | η (x) −η (y) | / (η (x)
^ 2) It appears to be displaced in the direction of the line of sight.

Image formation in the present invention will be described.

For the purpose of explanation, the refractive index of the anisotropic optical element is η
It is assumed that (x)> η (y). (In the opposite case, swap η (x) and η (y))

In the image displayed on the image display, the emitted light of the pixel displaying the near view is linearly polarized in the x direction, and the emitted light of the pixel displaying the distant view is linearly polarized in the y axis direction.

When this is passed through the anisotropic optical element, the anisotropic optical element causes the refractive index η for a pixel displaying a near view.
(x), a pixel displaying a distant view behaves as a refractive index η (y).
Only (x) −η (y) | / (η (x) ^ 2) looks distant. Where d
Is the thickness of the anisotropic optical element.

In this way, it is possible to display images with a sense of perspective.

As an optical medium used in the anisotropic optical element, it is effective to use a medium such as calcite having a great difference in refractive index in the two principal axis directions. In calcite η (e)
= 1.486 η (o) = 1.658, so if you use the one with a thickness of 10 mm, you can obtain the image movement of about 1 mm.

The expansion of the amount of movement of the image using the optical system will be described. In the magnifying optical system (FIG. 3) in which the lens 34 having the focal length f1 and the lens 35 having the focal length f2 are used to match the focal points of both, the amount of movement of the image position when the object is moved by the distance a is a ( f2 / f1) ^ 2 The magnification of the image is f2 / f1. In this way, the amount of movement of the image in the line-of-sight direction can be increased.

Further, by combining a plurality of magnifying optical systems composed of the above two lenses or by using a more complicated optical system, it is possible to magnify the amount of movement of the image more effectively.

[0026]

EXAMPLES Examples will be described with reference to the drawings.

FIG. 1 shows an example of the present invention comprising a general image display 11, a polarizer 12 for controlling the polarization characteristics of light emitted from each pixel of the image display, and an anisotropic optical element 13. The optical element 13 is obtained by cutting an anisotropic optical medium with a parallel plane including two principal axes having different refractive indexes. The two principal axes are defined as x-axis and y-axis, and the xy plane is a polarizer 12. Install parallel to the exit surface of.

The polarizer 12 converts the image light emitted from the pixel of the image display 11 into linearly polarized light having a polarization axis in either one of the x axis and the y axis for each pixel.

FIG. 2 shows an embodiment of the present invention in which an active matrix type color liquid crystal display is used as an image display and an active matrix type liquid crystal plate is used as a polarizer.
Is an anisotropic optical element, the x-axis and the y-axis are directions of two mutually perpendicular principal axes having different refractive indices, and the z-axis is a direction perpendicular to these. In the figure, 210 to 260 are parts constituting an active matrix type color liquid crystal display, and 270 to 290 are parts constituting a polarizer.

210 and 220 are polarizing plates. 231 to 233 and 240 are transparent electrodes. 250 is TN liquid crystal. 260 is a color filter. 270, 2
81 to 283 are transparent electrodes. 290 is TN liquid crystal.

Here, the direction of the incident side director of the TN liquid crystal 290 is taken to be parallel to the polarization axis of the polarizing plate 220.

Further, one of the x-axis and the y-axis is installed so as to be parallel to the polarization axis of the polarizing plate 220. In the following description, x
The axis is parallel to the polarization axis of the polarizing plate 220, and the polarizing element 200 has a refractive index η (x) for linearly polarized light in the x-axis direction that is larger than a refractive index η (y) for linearly polarized light in the y-axis direction. And

Image display on the color liquid crystal display is performed in exactly the same manner as in the usual case.

Image light from the color image display is polarized by the polarizing plate 22.
A value of 0 results in linearly polarized light in the x-axis direction. Electrode 2 here
When the potential between 81 and the electrode 270 is the same, the light passing through the electrode 281 becomes linearly polarized light in the y-axis direction due to the rotation of the liquid crystal 290, and the electrode 2
If a voltage equal to or higher than the threshold value Vt of the liquid crystal is applied between the electrode 81 and the electrode 270, the rotatory property of this region of the liquid crystal 290 disappears and the emitted light in this region becomes linearly polarized light in the x-axis direction. In this way, the light emitted from each pixel can be switched to linearly polarized light in the x-axis direction and the y-axis direction.

If the potential between the electrode 281 and the electrode 270 is equipotential, the pixel in this region looks distant when the anisotropic optical element 200 is passed, and if the voltage of Vt or more is applied between the electrode 281 and the electrode 270, the pixel is close. Looks like.

Thus, a stereoscopic image with a perspective is obtained from the plane image.

FIG. 3 schematically shows the structure of an embodiment using a magnifying optical system consisting of two lenses. 31 is an image display, 32 is a polarizing element, 33 is an anisotropic optical element, and 34 is a focal length.
f1 lens, 35 is a focal length f2 lens, and these two lenses are installed at an interval of f1 + f2. As a result, the amount of movement of the image can be expanded by (f2 / f1) ^ 2 times. Generally, the lens 34 is a concave lens (f1 <0) and the lens 35 is a convex lens (f2>).
It is effective to use one in which f1 + f2> 0 in 0).

FIG. 4 is a schematic view of the stereoscopic image device shown in FIG. 3 as viewed from above, in an embodiment having one set for the right eye and one set for the left eye.

Reference numeral 41 is a right-eye image display, 42 is a right-eye polarizing element, 43 is a right-eye anisotropic optical element, and 44 and 45 are lenses forming a right-eye magnifying optical system. Reference numeral 46 is an image display for the left eye, 47 is a polarizing element for the left eye, 48 is an anisotropic optical element for the left eye, and 49 and 50 are lenses forming a magnifying optical system for the left eye.

When this apparatus is used, the right near view is viewed in front of the right eye, and the left near view is viewed in front of the left eye. The same applies to the distant view, whereby a stereoscopic image with not only parallax but also perspective is visually recognized.

[0041]

Since the present invention is constructed as described above, it has the following effects.

In the present invention, since a single image display is used, there is no problem of overlapping the whole view and background images due to the movement of the viewpoint, which is a problem in the image combining method using the mirror, and the apparatus is small. .

Further, in the system in which the liquid crystal panels are laminated, there is no difficulty in colorization, which is a problem, and a color image can be easily handled.

By combining with an appropriate optical system,
The amount of movement of the image position in the line-of-sight direction can be expanded to a practically sufficient value.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing the structure of the present invention.

FIG. 2 is a schematic partial cross-sectional view of an embodiment of the present invention using an active matrix type color liquid crystal display as an image display and an active matrix type liquid crystal plate as a polarizer.

FIG. 3 is a schematic diagram of an embodiment of the present invention having a magnifying optical system.

FIG. 4 is a schematic diagram of an embodiment using the present invention, one for the right eye and one for the left eye.

[Explanation of symbols]

11 Image display 12 Polarizer 13 Anisotropic optical element 14 Observer 231, 232, 233 Primary electrode for active matrix type color liquid crystal display 240 Secondary electrode for active matrix type color liquid crystal display 250, 290 Liquid crystal 270 Active for polarizer Matrix type liquid crystal primary electrode 281, 282, 283 Active matrix type liquid crystal secondary electrode for polarizers 34, 35 Lens

Claims (5)

[Claims] 1. An optical system in which an anisotropic optical medium is cut in a parallel plane including two principal axes having different refractive indexes on the front surface or the optical path of an image display capable of controlling the polarization state of outgoing light for each pixel. Stereoscopic imager characterized by installing elements 2. An optical system in which an anisotropic optical medium is cut by a parallel plane including two principal axes having different refractive indexes on the front surface or the optical path of an image display capable of controlling the polarization state of outgoing light for each pixel. Stereoscopic imager characterized by installing elements and optical system 3. A stereoscopic image device having the stereoscopic image device according to claim 1 or 2 each for the right eye and the left eye. 4. An image display device capable of controlling the polarization state of emitted light for each pixel, wherein the image display device and the image light from each pixel of the image display device are linearly polarized light, and their polarization axes are mutually 2. A polarizer that switches in two vertical directions.
2 or 3 stereoscopic image device 5. A polarizer for linearly polarizing the image light from each pixel of the image display and switching the polarization axis between the two directions perpendicular to each other is composed of a TN liquid crystal plate. Stereoscopic image device