JP2002169124A - Stereoscopic picture display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stereoscopic image display device for displaying a stereoscopic images which hardly gives visual fatigue an whose image quality is high using with a simple constitution. SOLUTION: This stereoscopic image display device to display the stereoscopic image is provided with a two-dimensional image display device 1 to output light having a different wavelengths from plural pixels constituting a displayed two-dimensional image and a wavelength, depending type focus variable optical system 6 to carry out image formation with the light at a different point, according to the wavelength of the light.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a three-dimensional image display device for displaying a three-dimensional image.

[0002]

2. Description of the Related Art Conventionally, a number of stereoscopic image display methods have been proposed. Among them, as a general stereoscopic image display method, there is a binocular stereoscopic display method as shown in FIG.

As shown in FIG. 1, this binocular stereoscopic display method uses a left eye image 48 corresponding to the left eye 46 and a right eye 4
Using two parallax images of the right-eye image 49 corresponding to 7, the observer can use polarized glasses or a polarization switching shutter 50.
Is a method of presenting only the image corresponding to each eye by wearing the image and allowing the observer to recognize the reproduced stereoscopic image 51.

This method has a feature that a stereoscopic image can be easily displayed with a relatively small amount of information.
When the reproduced stereoscopic image 51 is observed by a human, there is a problem that a difference between the convergence distance 52 and the focal length 53 causes visual fatigue to the observer. This is a problem common to a method of displaying a stereoscopic image only by a method of presenting a parallax image.

Here, in order to display a three-dimensional image which does not cause visual fatigue, a method of reproducing the three-dimensional image in space is effective. Such methods include a hologram display method and a depth sampling method.
Although this hologram display method has the possibility of realizing a natural three-dimensional display, it requires interference fringe information of the subject and the amount of information is enormous, so an ultra-high-definition display device is required, and a moving image stereoscopic image can be formed. There are many problems to display.

On the other hand, in the depth sampling method, a two-dimensional sampled image at each depth position of an object is displayed volumetrically in space. In this method, since a stereoscopic image having a depth is reproduced in a three-dimensional space, the convergence distance and the focal length match, so that the visual fatigue given to the observer is reduced, and even when the observer moves, the image becomes natural. A three-dimensional image can be provided.

In this depth sampling method, a varifocal mirror system for displaying a stereoscopic image by displaying an image on a vibrating mirror, a moving screen system in which a screen moves mechanically at high speed, or a rotating spiral screen is used. Although there are methods to be used, it is difficult to put them into practical use due to mechanical driving parts.

As a method of displaying a three-dimensional image by a device having no mechanical driving part, there is a half mirror combining method. In this method, a television monitor currently in practical use can be used, a relatively high-quality image can be displayed, and a special device is not required and the entire device configuration is simplified. A large number of display devices corresponding to the gray scales are required, and it is difficult to increase the number of depth gray scales, and there are problems such as light loss due to a half mirror and an increase in the size of the apparatus.

In recent years, there has been proposed a method of displaying a depth-sampled stereoscopic image using one two-dimensional image display device having no mechanical drive unit. FIG. 2 is a diagram for explaining a conventional depth sampling method using a liquid crystal focus variable lens. As shown in FIG. 2, this conventional depth sampling method displays images 55 and 56 on a two-dimensional image display device 54.
Are sequentially displayed, and the focal length of a liquid crystal focus variable lens 57 having a diameter of several centimeters or more disposed behind the lens is changed in synchronization with the display of the display image, and the reproduced images 58 and 5 are displayed in space.
9 is displayed at different depth positions, and a stereoscopic image is presented to the observer 60. The feature of this method is that a three-dimensional image display device does not require a mechanical driving part, and the observer does not need to wear special glasses, and can display a natural three-dimensional image.

However, the depth sampling display by the time division method in which the depth images are sequentially switched and displayed at high speed is as follows.
If the display of the stereoscopic image is not completed within the afterimage time of the human eye, flicker will be perceived by the observer. On the other hand, if the display time of one depth image is reduced, the brightness of the image is reduced. In addition, a special display device that displays a large number of images corresponding to the number of depth gradations at high speed within the time required to display one image with a conventional video signal, that is, for example, within 1/60 second, is required.

Here, the space division display method for reproducing the depth in pixel units solves the problem of the depth sampling display in the above-described time division method, and enables a natural moving image three-dimensional image display with little visual fatigue. . As an example of the space division method, there is a method in which a minute focus variable optical element is provided for each pixel to individually change a focal position and express depth.

However, this method requires a very high degree of technology for manufacturing a large number of variable focus lenses equivalent to the number of pixels and for driving the same. It is also conceivable to use a liquid crystal lens as an electrically controllable element with a large refractive index change as a focus variable element, but the currently proposed liquid crystal lens structure has a high driving voltage and a low response speed. Is a problem.

Further, since the viewing angle depends on the relationship between the focal length and the lens diameter of the variable focus lens provided for each pixel, a very small size variable focus element corresponding to a pixel requires a depth of a stereoscopic image. It is considered that it is difficult to realize a stereoscopic image display with a sense of depth because the reproduction range or the viewing angle is limited.

[0014]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and an object of the present invention is to provide a three-dimensional image display device which displays a high-quality three-dimensional image with a simple structure without causing visual fatigue. The purpose is to provide.

[0015]

SUMMARY OF THE INVENTION An object of the present invention is to provide a stereoscopic image display device for displaying a stereoscopic image, in which light having different wavelengths is output from a plurality of pixels constituting a displayed two-dimensional image. This is attained by providing a three-dimensional image display device comprising: a three-dimensional image display unit; and an imaging unit that forms the light at different points according to the wavelength of the light.

According to such a means, a three-dimensional image is displayed by forming light having different wavelengths output from the two-dimensional image displayed on the two-dimensional image display means at different points in a three-dimensional space. can do.

Another object of the present invention is to provide a three-dimensional image display device for displaying a three-dimensional image, wherein light having different wavelengths is output at an arbitrary intensity from a plurality of pixels constituting a displayed two-dimensional image. A plurality of two-dimensional image display means, a plurality of image forming means provided corresponding to each of the two-dimensional image display means, and a plurality of image forming means for forming the light at different points according to the wavelength of light; and a plurality of image forming means And an image synthesizing means for synthesizing the images respectively obtained by the above methods.

According to such a means, a stereoscopic image having an arbitrary color can be easily displayed by controlling the luminance ratio between a plurality of images synthesized by the image synthesizing means.

Another object of the present invention is a three-dimensional image display device for displaying a three-dimensional image, wherein a plurality of two-dimensional images are switched and displayed at predetermined time intervals, and a plurality of two-dimensional images constituting the displayed two-dimensional image are displayed. A two-dimensional image display means for outputting light having different wavelengths from the pixels of the pixels, and forming the light at different image points according to the wavelength of the light, and forming an image in synchronization with the switching display of the two-dimensional image. This is attained by providing a stereoscopic image display device comprising: an image forming means for changing a position of a point.

According to such a means, the two-dimensional image displayed on the two-dimensional image display means and the position of the image forming point are changed at a predetermined time interval. A stereoscopic image having an arbitrary color can be easily displayed.

[0021]

Embodiments of the present invention will be described below in detail with reference to the drawings. In the drawings, the same reference numerals indicate the same or corresponding parts.

A three-dimensional image display device according to an embodiment of the present invention employs a new space division display method, and displays a three-dimensional image based on depth information of a display object. That is, the three-dimensional image display device is a two-dimensional image display device that outputs and displays light of an arbitrary wavelength for each pixel according to the depth distance information of the display object, and a wavelength-dependent display device in which the focal length differs greatly depending on the wavelength of the light. And a stereoscopic image with a depth in space.

That is, the wavelength of the image display output light is determined according to the depth distance information of the display object, and the image displayed by the light having the wavelength is converted using an optical system having a different focal length depending on the wavelength of the light. By creating an image, a three-dimensional image can be displayed in the depth direction. In addition, a color stereoscopic image reproducing the color of the surface of the subject is created by using a plurality of the devices to form an image of the display object, combining light of different wavelengths at each depth and changing the intensity ratio of each light. Can be displayed.

According to the three-dimensional image display device according to the embodiment of the present invention, a special high-speed image display device is unnecessary because a space division method of controlling the wavelength of output light for each pixel and reproducing the depth is adopted. Thus, the problem of flicker and brightness caused by the time division method can be solved.

Further, according to the stereoscopic image display device according to the embodiment of the present invention, since a large number of display devices equivalent to the number of depth gradations are not required, the size of the device can be reduced. Further, by continuously changing the wavelength, an image can be reproduced at an arbitrary position in the depth direction.

Since the visual field depends on the numerical aperture of a wavelength-dependent variable focus lens, the use of a lens having a large numerical aperture or a lens having a large diameter or an array of microlenses increases the depth distance reproduction range. Both viewing zones can be enlarged.

Further, according to the three-dimensional image display device according to the embodiment of the present invention, it is possible to use a conventional high-definition two-dimensional image display device and to provide a filter function element capable of electrically selecting a wavelength. By combining with a wavelength-dependent variable focus optical system having large chromatic aberration, a natural three-dimensional moving image can be displayed.

Hereinafter, the stereoscopic image display device according to the embodiment of the present invention will be described more specifically. [First Embodiment] FIG. 3 is a diagram showing a stereoscopic image display apparatus according to a first embodiment of the present invention. As shown in FIG. 1, the three-dimensional image display device according to the first embodiment includes a filter control device 12, a two-dimensional image display device 1, and a wavelength-dependent focus variable optical system 6. Here, the two-dimensional image display device 1 is connected to the filter control device 12.

The two-dimensional image display apparatus 1 outputs light having an arbitrary wavelength. For example, the two-dimensional image display device 1 is illuminated by a white light backlight and selectively transmits only an arbitrary wavelength for each pixel. Be composed. Then, the two-dimensional image display device 1 determines, for example, the wavelength of the light 3 output from the pixel 2 and the
By appropriately selecting the wavelength of the light 5 output from the illuminator, each light 3, 5 transmitted through the wavelength-dependent variable focus optical system 6 disposed after the two-dimensional image display device 1 is viewed from the observer 9. An image is formed at each of imaging points 7 and 8 having different depths. According to such a principle, a stereoscopic image 10 having a depth can be displayed (presented) to the observer 9.

The filter control device 12 selects the wavelength of light output from each pixel by controlling the output light wavelength filter of the two-dimensional image display device 1 according to the supplied depth distance information. Here, the depth distance information 11 is a distance value obtained by actually photographing a subject by an imaging device having a distance detection function, or a distance value artificially obtained by computer graphics or the like.

Hereinafter, the two-dimensional image display device 1 will be described.
Is specifically described.

In general, as an optical bandpass filter, there is a lyo-filter that obtains a sharp transmission spectrum of a specific wavelength by stacking a large number of birefringent plates sandwiched between two polarizers. A wavelength-variable bandpass filter can be configured by using a medium whose electrical birefringence changes electrically as a birefringent plate used in this filter. Here, for example, by using a liquid crystal whose electric birefringence effect changes as a medium, a wavelength tunable bandpass filter capable of electrically selecting a wavelength can be formed.

Then, such a liquid crystal variable lyo filter is arranged in an array corresponding to each pixel of the two-dimensional image display device, and a control device for individually controlling the pixels is provided, so that an arbitrary wavelength can be obtained. It is possible to output the reflected light for each pixel.

FIG. 4 is a diagram showing a configuration example of the two-dimensional image display device 1 shown in FIG. As shown in FIG.
The two-dimensional image display device 1 includes a light emitter 22 and an image display unit 2.
4 and a wavelength tunable filter element 25, and the wavelength tunable filter element 25 includes a plurality of polarizing plates 26 arranged in parallel.

Here, the image display section 24 is provided so as to face the light emitter 22, and the wavelength variable filter element 25 is provided on the output side of the image display section 24. In the two-dimensional image display device 1 having such a configuration, the white light 23 having a wavelength in the visible light region output from the light emitter 22 is input to the image display unit 24 that displays a luminance image and intensity-modulated. .

The above-mentioned "intensity modulation" means that a portion where the brightness of the subject image is high is bright and a portion where the brightness is low is dark. Therefore, by the intensity modulation, the same modulation as when a black and white television image is created is performed. In the "intensity modulation", the intensity of the transmitted light is controlled by changing the transmittance of the incident white light. For example, as in a liquid crystal panel sandwiched between polarizing plates,
The amount of transmitted light of light incident from the outside is controlled by electrical control.

Here, the image display section 24 shown in FIG. 4 can be constituted by a transmissive liquid crystal panel. Then, the white light whose intensity has been modulated as described above in the image display unit 24 is input to the wavelength variable filter element 25 for selecting an arbitrary wavelength. Here, the tunable filter element 25 has a structure in which a plurality of electrically driven liquid crystal display devices 27 sandwiched between two flat polarizing plates 26 are stacked.

The arrangement, number, and size of the pixels of the image display unit 24 and the pixels of the plurality of electrically driven liquid crystal display devices 27 are the same, and the wavelength of the transmitted light is independently selected for each pixel. It can be done. That is, the white light incident on the wavelength tunable filter element 25 is
Is transmitted at a transmittance depending on the wavelength in each of the electrically driven liquid crystal display devices 27. By setting the wavelength dependence of the transmittance to be different in each of the electrically driven liquid crystal display devices 27, the Independently, only light 28 having a desired wavelength can be selectively transmitted.

When the electrically driven liquid crystal display device 27 sandwiched between the polarizing plates 26 is laminated, the thickness increases, so that the luminous flux output from the image display section 24 spreads and passes through the tunable filter 25. In such a case, crosstalk occurs between pixels.
By connecting the corresponding pixels between seven with a fiber, a micro lens, or the like, it is possible to prevent light from spreading in the horizontal direction.

FIG. 5 is a diagram showing another configuration of the two-dimensional image display device 1 shown in FIG. As shown in FIG. 5, the two-dimensional image display device 1 a has the same configuration as the two-dimensional image display device 1 shown in FIG. 4, but includes a tunable filter element 29 instead of the tunable filter element 25. They differ in the point.

Here, the image display unit 24 shown in FIG. 5 displays a grayscale image similarly to the image display unit 24 shown in FIG. 4, and light output from the image display unit 24 is arbitrary. The wavelength is input to a wavelength variable filter element 29 for selecting a wavelength.

On the other hand, this tunable filter element 29
The medium 30 in which the birefringence effect changes electrically is provided with an electrode 2
It has a configuration of being sandwiched between two parallel flat substrates 31 having a high reflectance, and constitutes a multi-beam interference system. Here, for example, liquid crystal can be used as the medium, and selectively outputting light 28 having an arbitrary wavelength by changing the birefringence effect by an electric means such as changing an applied voltage. Can be.

The substrate 31 is, for example, a glass substrate having high surface accuracy on which a metal film of silver or aluminum is deposited, or a dielectric having multiple layers deposited thereon to have high reflection characteristics (so-called etalon). Can be used.

FIG. 6 is a diagram showing still another configuration of the two-dimensional image display device 1 shown in FIG. As shown in FIG. 6, the two-dimensional image display device 1b includes a light emitting body 22, a spectral optical system 32, a lens array 34, and a filter device 36, and the filter device 36 includes a plurality of sub-pixels corresponding to each pixel. Includes pixel 37.

In the two-dimensional image display device 1 b having the above-described configuration, white light 23 having a wavelength in the visible light region is output from the light emitting body 22. Spatially separated for each different light of
A spectrum 33 is formed.

The spectroscopic optical system 32 may be a prism that makes use of the wavelength dependence of the refractive index, a diffraction grating that makes use of the wavelength dependence of the diffraction angle, or a transmittance characteristic that spatially depends on the wavelength. An interference filter or the like having a distribution can be used.

Further, based on the spectrum 33 spatially dispersed, the lens array 34 has at least one pixel for each pixel.
The images 35 are created at the ratio of the number of the images 35. Then, this image 35 is also an image that is spatially spectrally similar to the light that is spectrally separated by the spectral optical system 32, that is, an image in which light spreads in a rainbow color from red to blue. Here, in order to extract light 28 having a specific wavelength from such an image 35, only a part of the light forming the image 35 may be selectively transmitted.

That is, in the filter device 36, of the plurality of sub-pixels 37 constituting one pixel, only a part of the sub-pixels 37 for each pixel is in a transmitting state, and the other sub-pixels 37 do not transmit light. And Thus, by selecting the position of the sub-pixel 37 transmitting light for each pixel, it is possible to output the light 28 having a desired wavelength for each pixel.

Hereinafter, the wavelength-dependent variable focus optical system 6 shown in FIG. 3 will be described in detail. As the wavelength-dependent focus variable optical system 6 according to the first embodiment, a refractive lens having a large wavelength dependency can be used. Here, the wavelength dependence of the focal length can be increased by selecting a material having a large change in the refractive index depending on the wavelength as the refractive lens.

As the material constituting the refraction type lens, a material having a small Abbe number, that is, a material having a high dispersion characteristic with a large change in the refractive index with respect to wavelength is suitable. For example, heavy titanium flint, heavy flint, Optical glass materials such as heavy lanthanum flint and lanthanum flint correspond.

In a reflection or transmission type diffraction lens utilizing the diffraction phenomenon of light, the wavelength dependence of the focal length is proportional to the reciprocal of the wavelength, so that the wavelength dependence of the relatively large focal length can be easily reduced. Can be realized.

Here, a trial calculation on how much the focal length dependency can be obtained by the diffractive lens will be shown. First, the relationship between the focal length f of the diffractive lens and the wavelength λ is expressed by the following equation (1). Note that a is a constant. f = a / λ (1) At this time, for example, when a lens having a wavelength of 632.8 nm and a focal length of 0.8 m is used, the focal length f _{400 at} a short wavelength of 400 nm in the visible wavelength region is represented by the following equation (2). Is calculated by f ₄₀₀ = 632.8 × 10 ^-9 × 800 × 10 ^-3 / 400 × 10 ^-9 = 1.26 m (2) Further, the focal length f at a long wavelength of 700 nm in the visible wavelength range.
₇₀₀ is similarly calculated by the following equation (3). f ₇₀₀ = 632.8 × 10 ⁻⁹ × 800 × 10 ⁻³ / 700 × 10 ⁻⁹ = 0.72 m (3) Accordingly, the change Δf in the focal length in the visible wavelength range is calculated by the following equation (4). . Δf = f ₄₀₀ −f ₇₀₀ = 1.26−0.72 = 0.54 m (4) From this, it can be seen that a very large change in the focal length can be obtained.

As the diffractive optical element, a holographic optical element or the like in which interference fringes are recorded by a laser beam, an electron beam drawing apparatus, or the like can be used. The lens as the holographic element can be easily formed only by interfering a laser beam and recording on a hologram dry plate or film, and a large lens having a size of several tens cm or more can be manufactured. In order to avoid the influence of the 0th-order or higher-order diffracted light when using the holographic element lens, it is also effective to shift the optical axes of the reference light and the object light.

Further, binary optics formed with a binary phase pattern by a lithography technique can also be used for the wavelength-dependent focus variable optical system. The binary optical element is a stepped lens formed by a series of steps such as mask alignment and exposure, development, etching, and resist removal, similar to an electronic integrated circuit, and can be manufactured relatively easily. The diffraction efficiency can be increased by repeating the manufacturing process a plurality of times and increasing the number of steps of the phase.

In particular, a phase-type zone plate (quinoform) lens can obtain high diffraction efficiency.
A bright image can be displayed, and the influence of 0-order or higher-order diffracted light can be suppressed.

Further, by providing a lens having a large wavelength dependence in multiple stages, a large focal length wavelength dependence can be obtained.
Of course, a hybrid lens combining a refraction lens and a diffraction lens can be used as the wavelength-dependent lens.

FIG. 7 is a diagram showing an example of the wavelength-dependent focus variable optical system 6 shown in FIG. The wavelength-dependent variable focus optical system 6 needs to be large enough to form an image on the screen of the two-dimensional image display device 1, that is, a lens having a large diameter is required. In addition, such a lens has a problem that it is expensive and difficult to manufacture. Therefore, in order to display a large image, the image forming optical system 6a may be configured using the lens arrays 39 and 40 in which minute wavelength-dependent focal length variable lenses are arranged in an array as shown in FIG. .

Here, as shown in FIG. 7, the light output from the two-dimensional image display device 1 is
The stereoscopic image 1 having a depth by being imaged by 0
0 is generated. At this time, as shown in FIG. 8, the distance between the image 63 displayed on the two-dimensional image display device 1 and the lens array 39 is set to twice the center focal length f of the focal length variable range, and the two lenses By making the distance between the arrays 39 and 40 four times the central focal length f,
At a position separated from the lens array 40 by twice the center focal length f, a reproduced image 61 having substantially the same size as the image 63 is provided.
Can be obtained.

In the above description, “center focal length” means a focal length near the center of a variable range in which the focal length changes. For example, when visible light having a wavelength of 400 nm to 700 nm is used for image display, if the focal length for a wavelength of 400 nm is f1 and the focal length for a wavelength of 700 nm is f2, the "center focal length f" is (f1 + f2) / 2. Means the value of Then, as shown in FIG.
By arranging 9, 40, the imaging optical system in which the original image and the reproduced image have a one-to-one relationship even when the focal length changes does not break down significantly.

As the minute wavelength-dependent focus variable lens constituting the lens arrays 39 and 40, not only the above-mentioned refractive or diffractive lens but also a distributed refractive index lens can be used. Here, the ordinary lens has a constant refractive index of the medium and produces an imaging effect by a change in the thickness of the lens, whereas the distributed refractive index lens has a constant thickness of the medium and is located at a distance from the optical axis of the center of the medium. By having a refractive index distribution corresponding to the distance in the radial direction, an imaging effect is brought about.

FIG. 9 is a diagram showing an example of such a distributed index lens. As shown in FIG. 9, the gradient index lens is made of a relatively short rod-shaped plastic or glass, and the refractive index becomes lower as the distance from the center of the rod (optical axis 66) becomes larger. You. Therefore, the central portion 65 near the optical axis 66 has a higher refractive index than the outer peripheral portion 64. As shown in FIG. 9, an image 63b is obtained from the image 63 by the distributed index lens having the above-described configuration.

As described above, by configuring the wavelength-dependent variable focus optical system 6 with the lens arrays 39 and 40, an optical system capable of displaying a large image can be easily configured.

FIG. 10 is a view showing another example of the wavelength-dependent variable focus optical system 6 shown in FIG. When a three-dimensional image is formed by one wavelength-dependent focal length variable lens,
The imaging magnification varies greatly depending on the depth position,
Image distortion around the image also increases. Therefore, even when the depths are different, the imaging magnification is made uniform, and a variable wavelength focal length lens and a plurality of lenses are combined as shown in FIG. Should be configured.

That is, as shown in FIG. 10, the wavelength-dependent variable focal length optical system 6b is a combination of the first lens system 41 and a wavelength-dependent variable focal length lens or a combination of a wavelength-dependent variable focal length lens and another lens. And a third lens system 43.

The light output from the pixel 2 of the two-dimensional image display device 1 is incident on the first lens system 41 which has a focal length of f1 and is arranged at a position separated from the two-dimensional image display device 1 by the distance f1. Then, the light is supplied to a second lens system 42 disposed at a position away from the first lens system 41 by a distance f1. Further, the light output from the second lens system 42 is incident on a third lens system 43 disposed at a position having a focal length of f2 and being separated from the second lens system 42 by a distance f2 to form an image. Thereby, the sizes of the images 44 and 45 formed at different depths as viewed from the observer 9 according to the wavelength can be made substantially uniform, and the distortion of the images 44 and 45 can be reduced.

As described above, according to the three-dimensional image display device according to the first embodiment of the present invention, light having different wavelengths selected in the two-dimensional image display device 1 is transmitted to the wavelength-dependent focus variable optical system 6. By using this, a stereoscopic image is displayed by forming an image at a point at a different depth when viewed from the observer, so that it gives less visual fatigue than stereoscopic display by a parallax image and enables natural stereoscopic vision. A stereoscopic image can be displayed with a simple configuration.

Further, according to the stereoscopic image display apparatus according to Embodiment 1 of the present invention, the observer can view the stereoscopic image without wearing special glasses, and can observe the stereoscopic image in both the horizontal and vertical directions. It can be stereoscopically viewed.

According to the three-dimensional image display device according to the first embodiment of the present invention, various two-dimensional image display devices can be used. Further, since the present three-dimensional image display device spatially divides light and performs depth sampling, it is not necessary to display a large number of images corresponding to the number of depth gradations required for time-division display at high speed. Images can be displayed.

Further, according to the three-dimensional image display device according to the first embodiment of the present invention, it is possible to display a three-dimensional image which has a large viewing angle and can be observed by a plurality of observers. Further, since the information required in the stereoscopic image display according to the first embodiment is two-dimensional image information and depth distance information, even when the display target (subject) is moving, the display target is displayed. A stereoscopic image can be displayed. Further, since the amount of the information required for displaying the stereoscopic image is small, the transmission of the information in the display can be easily performed. [Embodiment 2] A stereoscopic image display apparatus according to Embodiment 2 of the present invention displays an image by light having different wavelengths by time division, and changes the transmittance of the image display apparatus in accordance with the display timing. Thus, a stereoscopic image is displayed. Hereinafter, the stereoscopic image display device according to Embodiment 2 will be specifically described.

FIG. 11 is a diagram showing a configuration of a stereoscopic image display device according to Embodiment 2 of the present invention. As shown in FIG. 11, the three-dimensional image display device includes a two-dimensional image display device 1 and a wavelength-dependent variable focus optical system 6, a light emitter 22 and optical systems 100, 101, and 104, a reflecting mirror 102, and a spectral optical element. 38, and an aperture 103.

The second embodiment shown in FIG.
In the three-dimensional image display device according to (1), first, the luminous body 22 outputs light 23 having a wavelength in the visible light region. The light 23 is converted into parallel light by the optical system 100 and is incident on a spectral optical element 38 including a diffraction grating or a prism.

Further, the light reflected or transmitted by the spectroscopic optical element 38 is collected by the optical system 101 at different positions for each wavelength. Here, since a reflecting mirror 102 such as a galvano mirror or a polygon mirror capable of changing the inclination angle of the surface at high speed is provided between the optical system 101 and the converging point, the light is reflected by the reflecting mirror 102. Is reflected.

An aperture 103 is provided at a position where the light is condensed, and selectively transmits only light having a specific wavelength. At this time, by changing the angle of the reflecting surface of the reflecting mirror 102 with respect to the incident light at high speed, each wavelength can be sequentially transmitted in a short time.

The light transmitted through the aperture 103 is incident on the secondary image display device 1 via the optical system 104. At this time, the secondary image display device 1 displays the stereoscopic image 10 in the depth direction via the wavelength-dependent variable focus optical system 6 by switching the display image in synchronization with the change in the wavelength of the supplied light.

As described above, according to the stereoscopic image display apparatus according to Embodiment 2 of the present invention, light having an arbitrary wavelength can be selected from white light by a simple optical system, and light such as a polarizing plate can be selected in wavelength selection. Since a component having a large absorption is unnecessary, the light use efficiency can be improved. Therefore, by using a high-output light source, an image with high-luminance light can be obtained.

Further, if the rotation speed of the reflecting mirror 102 is increased, scanning of the wavelength can be easily accelerated. In the above description, while the reflecting mirror 102 is fixed,
Instead of the reflecting mirror 102, the angle of the spectral optical element 38 itself may be changed at a high speed.

Further, the three-dimensional image display device according to the second embodiment includes the spectroscopic optical element 38 and the reflecting mirror 102 as described above.
And the light is time-dispersed by the aperture 103 or the like, but these can be substituted by one variable band-pass filter that selects a transmission wavelength using a medium such as a liquid crystal that can change the birefringence effect by an electric means. it can.

In this case, since light is transmitted through the polarizing plate and the liquid crystal cell, it is difficult to make strong light incident on the two-dimensional image display device 1. Can be supplied to the two-dimensional image display device 1 while switching light at a high speed, so that a mechanical drive unit such as a rotating mirror is not required, and the size of the stereoscopic image display device is greatly reduced. can do. [Third Embodiment] FIG. 12 is a diagram showing a configuration of a stereoscopic image display apparatus according to a third embodiment of the present invention. As shown in FIG. 12, the three-dimensional image display device according to the third embodiment includes two-dimensional image display devices 13, 15, 17, a wavelength-dependent variable focus optical system 14, 16, 18, and an image combining optical system. 19 is provided. Here, the wavelength-dependent focus variable optical system 1
4, 16, and 18 are two-dimensional image display devices 13,
It is provided between 15, 15 and the image synthesizing optical system 19.

The three-dimensional image display device having such a configuration uses a plurality of the three-dimensional image display devices according to the first embodiment, and synthesizes the respective display images to form a color three-dimensional image 2.
0 is displayed.

More specifically, the two-dimensional image display device 13
Since the three-dimensional image reproduced by the optical system and the wavelength-dependent variable focus optical system 14 has different wavelengths in the depth direction, the color differs for each depth distance, and the color of the surface of the display object cannot be reproduced. . Therefore, in order to display a color stereoscopic image faithful to the display object, images and images reproduced by the other plural two-dimensional image display devices 15 and 17 and the corresponding wavelength-dependent variable focus optical systems 16 and 18 are displayed. The images are combined in the combining optical system 19 and a color stereoscopic image 20 is displayed.

In the above-described image synthesis, the wavelength-dependent focus variable optical systems 14, 16, and 18 having different focal length dependencies with respect to wavelength are used, or the two-dimensional image display devices 13, 15, and By sequentially providing an optical path difference between the optical distance between each of the three-dimensional images to be reproduced and the three-dimensional images to be reproduced, images having different wavelengths are reproduced at different depths. Then, the color of the surface of the display object can be reproduced as the color stereoscopic image 20 by controlling the luminance ratio between the images displayed by the lights having different wavelengths. Note that the image synthesis described above can be easily realized by an image synthesis optical system 19 including a plurality of half mirrors, as shown in FIG.

As described above, according to the three-dimensional image display device of the third embodiment of the present invention, it is possible to easily generate a color three-dimensional image that reproduces the display object including the surface color. [Fourth Embodiment] A three-dimensional image display device according to a fourth embodiment of the present invention uses the three-dimensional image display device according to the first embodiment to display a plurality of three-dimensional images at positions having different depth distances with time. A color stereoscopic image is displayed by high-speed display.

That is, since the three-dimensional images reproduced by the two-dimensional image display device 1 and the wavelength-dependent variable focus optical system 6 have different wavelengths in the depth direction, the colors of the images are different for each distance and the object to be displayed is different. The color of the surface cannot be reproduced.

Therefore, in the three-dimensional image display device according to the fourth embodiment, as shown in FIG. 13, electrical control such as control of applied voltage is performed to enable color display of the display object. The variable focus optical element 21 which can adjust the focal length at high speed is used. Hereinafter, the operation of the stereoscopic image display device according to Embodiment 4 will be described with reference to FIG.

As shown in FIG. 14, for example, at time T1
Then, the applied voltage of the focus variable optical element 21 is set to a voltage V1,
By controlling the voltage V2 at time T2, the voltage V3 at time T3, and the voltage V4 at time T4, the imaging position of the image reproduced by the wavelength-dependent focus variable optical system 6 is shifted in the depth direction with time. Thereby, images with different wavelengths can be displayed at positions with different depth distances z when viewed from the observer 9.

A conventional color display in a video image is as follows.
It is realized by changing the luminance ratio of the R, G, B three primary color images to be synthesized.
The focal length of the focus variable optical element 21 is changed so that at least three or more images having the respective colors are synthesized at each depth distance. Then, by controlling the luminance ratio between the images using light having at least three or more different wavelengths, it is possible to reproduce the color of the surface of the expression target.

A specific example will be described below with reference to FIG. Here, as shown in the frame of FIG. 15D, a case where a white ball, a yellow lemon, and a red apple are displayed as three-dimensional images G1, G2, and G3, respectively, will be described as an example.

As shown in FIG. 15A, at time T1
Assuming that the voltage applied to the variable focus optical element 21 is voltage V1, the light having a long wavelength in the visible region is located at the position D1a, and the light having a short wavelength is located at the position D1a. An image is formed on D1b. FIG. 15 (b)
As shown in (2), when the voltage applied to the focus variable optical element 21 at the time T2 is set to the voltage V2, the focal length changes, so that the long wavelength light in the visible region is in the position D2a, and the short wavelength light is in the position An image is formed on D2b. And FIG.
As shown in (c), when the voltage applied to the focus variable optical element 21 at the time T3 is set to the voltage V3, the focal length changes in the same manner as described above. The short-wavelength light is imaged at the position D3b.

In order to reproduce the depth distance z and the color of the display object, the wavelength and the brightness of the output light are controlled in synchronization with the switching of the applied voltage in the focus variable optical element 21 as described above. The displayed two-dimensional image is switched and displayed on the two-dimensional image display device 1. Here, as an example of the switching display, when displaying the white ball, an image having a wavelength corresponding to the depth distance for reproducing the ball,
That is, at the time T1 when the voltage V1 is applied to the focus variable optical element 21, the time T2 when the red image G1r and the voltage V2 are applied.
, The image is displayed as a green image G1g, and at time T3 when the voltage V3 is applied, as a blue image G1b.

Then, the luminance ratio between the red image G1r, the green image G1g, and the blue image G1b is controlled and the color is added by switching at high speed, and the white color, which is the color of the ball surface, is displayed as a three-dimensional image. You. Note that, in a similar manner, a stereoscopic image G2 displaying a yellow lemon and a stereoscopic image G3 displaying a red apple can be simultaneously displayed at positions having different depth distances z.

FIG. 15 shows an example in which the voltage applied to the variable focus optical element 21 is changed in three stages at times T1, T2, and T3, and the images formed in time series are multiplexed. However, by changing the applied voltage in more steps, it is possible to reproduce the color of the surface of the display object in a wide range in the depth direction.

Here, as the variable focus optical element 21,
As described above, a variable focus liquid crystal lens whose focal length changes according to the applied voltage can be used. And
As shown in FIG. 16A, this variable focus liquid crystal lens includes a lens-shaped substrate 69 having a lens and sandwiching a liquid crystal 67 and having a curvature, or FIG.
The liquid crystal is sandwiched between substrates having a hole-shaped transparent electrode 68 shown in FIG. 16 and a ring-shaped transparent electrode 71 shown in FIG.
There is a liquid crystal having a refractive index distribution by controlling an electric field applied to the liquid crystal.

On the other hand, in the above description, the wavelength-dependent variable focal length optical system 6 and the variable focal length optical element 21 are separately independent elements. Is used, the focal length can be changed depending on the wavelength of light, and the focal length can be changed by controlling the applied voltage.

Here, for example, as the liquid crystal focal length variable element, as shown in FIG. 17, a transparent electrode 77 is provided on a diffraction lens-like substrate 73 whose wavelength dependence of the focal length is large, and a substrate 75 with a transparent electrode is further provided. As a counter substrate, a diffractive liquid crystal focus variable lens 79 having a liquid crystal 67 interposed between a diffraction lens-like substrate 73 provided with a transparent electrode 77 and a substrate 75 with a transparent electrode can be used.

As shown in FIG. 18, such a diffractive liquid crystal focus variable lens 79 has a different focal length depending on the wavelength of the incident light, and also changes the focal length by controlling the applied voltage. be able to.

As described above, the three-dimensional image display device according to the fourth embodiment of the present invention can also easily generate a color three-dimensional image that reproduces the display object including the surface color.

As described above, according to the three-dimensional image display device of the present invention, light of different wavelengths output from the two-dimensional image displayed on the two-dimensional image display means is transmitted to different points in the three-dimensional space. Since a stereoscopic image can be displayed by forming an image, a high-quality stereoscopic image with little visual fatigue can be obtained with a simple configuration.

Further, according to the stereoscopic image display device of the present invention provided with the image synthesizing means, by controlling the luminance ratio among a plurality of images to be synthesized, a stereoscopic image having an arbitrary color can be easily formed. , The color of the display object can be easily reproduced as a stereoscopic image.

Further, according to the three-dimensional image display apparatus of the present invention in which the position of the imaging point is changed in synchronization with the switching display of a plurality of two-dimensional images, an arbitrary image can be obtained by utilizing the afterimage effect generated in the human eye. Since a three-dimensional image having a color can be easily displayed, various color three-dimensional images for reproducing a display object can be easily displayed.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining a conventional binocular stereoscopic display method.

FIG. 2 is a diagram illustrating a conventional time-division depth sampling stereoscopic display method using a liquid crystal focus variable lens.

FIG. 3 is a diagram showing a stereoscopic image display device according to Embodiment 1 of the present invention.

FIG. 4 is a diagram showing a configuration of the two-dimensional image display device shown in FIG.

5 is a diagram showing another configuration of the two-dimensional image display device shown in FIG.

FIG. 6 is a diagram showing still another configuration of the two-dimensional image display device shown in FIG.

FIG. 7 is a diagram illustrating an example of a wavelength-dependent focus variable optical system illustrated in FIG. 3;

FIG. 8 is a diagram illustrating a one-to-one imaging optical system using a microlens array.

FIG. 9 is a diagram illustrating an example of a distributed index lens.

FIG. 10 is a diagram showing another example of the wavelength-dependent focus variable optical system shown in FIG.

FIG. 11 is a diagram showing a configuration of a stereoscopic image display device according to Embodiment 2 of the present invention.

FIG. 12 is a diagram showing a configuration of a stereoscopic image display device according to Embodiment 3 of the present invention.

FIG. 13 is a diagram showing a configuration of a stereoscopic image display device according to Embodiment 4 of the present invention.

FIG. 14 is a diagram illustrating the operation of the stereoscopic image display device shown in FIG.

15 is a diagram illustrating a specific operation of the stereoscopic image display device shown in FIG.

FIG. 16 is a diagram illustrating an example of a liquid crystal focus variable lens.

FIG. 17 is a diagram showing another example of the liquid crystal focus variable lens.

18 is a diagram illustrating the operation of the liquid crystal variable lens shown in FIG.

[Explanation of symbols]

1, 1a, 1b, 13, 15, 17, 54 Two-dimensional image display device 6, 6b, 14, 16, 18 Wavelength-dependent focus variable optical system 6a Image imaging optical system 12 Filter control device 19 Image synthesis optical system 21 Variable focus optical element 22 Light emitter 24 Image display unit 25, 29 Variable wavelength filter element 26 Polarizer 27 Electric drive type liquid crystal display device 30 Medium 31, 69, 73, 75 Substrate 32 Spectral optical system 34, 39, 40 Lens array 36 Filter device 37 Sub-pixel 38 Spectral optical element 41 First lens system 42 Second lens system 43 Third lens system 50 Polarized glasses or polarization switching shutter 57 Liquid crystal focus variable lens 67 Liquid crystal 68, 71, 77 Transparent electrode 79 Diffractive liquid crystal focus Variable lens 100, 101, 104 Optical system 102 Reflecting mirror 103 Aperture

Continued on the front page (72) Inventor Yoshimi Iino 1-10-11 Kinuta, Setagaya-ku, Tokyo Japan Broadcasting Corporation Japan Broadcasting Research Institute F-term (reference) 2H059 AA33 5C061 AA06 AA20 AA25 AB14 5G435 AA04 CC09 CC11 DD04 DD05 DD09 FF01 GG28 HH01

Claims (3)

[Claims] 1. A three-dimensional image display device for displaying a three-dimensional image, comprising: two-dimensional image display means for outputting light having different wavelengths from a plurality of pixels constituting a displayed two-dimensional image; A three-dimensional image display device comprising: an image forming means for forming an image at a different point according to the wavelength of the light. 2. A three-dimensional image display device for displaying a three-dimensional image, wherein a plurality of pixels constituting a displayed two-dimensional image output light having different wavelengths at an arbitrary intensity from a plurality of pixels. Means, a plurality of image forming means provided corresponding to each of the two-dimensional image display means, for forming the light at different points according to the wavelength of the light, and a plurality of image forming means, respectively obtained by the plurality of image forming means. A stereoscopic image display device comprising: an image synthesizing unit that synthesizes the obtained image. 3. A three-dimensional image display device for displaying a three-dimensional image, wherein a plurality of two-dimensional images are switched and displayed at predetermined time intervals, and different wavelengths from a plurality of pixels constituting the displayed two-dimensional image. A two-dimensional image display unit that outputs light having the following: and the light is focused on different imaging points according to the wavelength of the light, and the focusing point is synchronized with the switching display of the two-dimensional image. A three-dimensional image display device comprising: an image forming means for changing a position of the three-dimensional image.