JPH06118860A - Color stereoscopic image display device - Google Patents

Abstract

PURPOSE:To enable the adequate reproduction and display of color stereoscopic images even with a low-speed space light modulation element. CONSTITUTION:The space light modulation element as a hologram recording means optically writes interference fringes by dividing these fringes to regions 162-1 to 162-n, 164-1 to 164-n, 166-1 to 166-n for each of R, G, B by controlling a liquid crystal shutter, selects the wavelengths of reproducing light by reflection regions having reflection peak wavelengths at the R, G, B corresponding to the recording regions of R, G, B after the writing and synthesizes and displays the color stereoscopic images of R, G, B with simultaneous irradiation with the reconstructing light from the R, G, B light sources.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color stereoscopic image display device for displaying a stereoscopic image in color by recording hologram interference fringes (phase distribution) for each color data obtained by a computer on a medium. The stereoscopic display is a means for making it easier to visually understand the structure such as depth and thickness of a three-dimensional object, and there is a strong demand for displaying designed structures and displaying medical images. The stereoscopic image is more powerful than the two-dimensional display and is also used for amusement parks, movies, and other entertainment displays.

[0002]

2. Description of the Related Art Various methods have already been proposed for stereoscopic display. There is a hologram that allows you to see a stereoscopic image without wearing special glasses. This is a recording of an object image by utilizing the interference effect of light, and a stationary object having a sufficient color and depth feeling is manufactured.

A hologram of a fictitious object cannot be produced by a usual hologram producing method in which an object wave and a reference wave are interfered with each other. Therefore, two-dimensional images when viewed from various directions are calculated from three-dimensional shape data, and by hologram interference exposure, a stripe-shaped area having a small width in the horizontal direction and a screen width in the vertical direction is formed. There is a holographic stereogram system in which hologram interference fringes are sequentially recorded.

However, in the holographic stereogram system, a two-dimensional image is basically viewed, and the surface on which the eyes are in focus does not match the position of the image visually recognized by binocular parallax. Therefore, it is difficult to see and causes fatigue. Especially when displaying an image in front of the screen,
The burden on the eyes becomes large, and it cannot be said that the stereoscopic display is preferable.

In order to create a natural three-dimensional image (hologram) of an imaginary object, interference fringes (phase distribution) of the hologram are calculated from the three-dimensional shape data, and the phase distribution calculated using a laser drawing device or the like. There is a method of recording by changing the exposure amount spatially. Massachusetts Institute of Technology (MIT)
Professor Benton et al. Divides a hologram into stripe-shaped areas that have the width of the screen in the horizontal direction and a small width in the vertical direction, and record a hologram that stores only the horizontal parallax in each area. Is proposed.

The calculation amount of the phase distribution of a huge hologram is
It can be significantly reduced by eliminating parallax in the vertical direction. The hologram recording / reproducing apparatus employs a system in which a modulated surface acoustic wave, that is, moving interference fringes are generated in an acousto-optic device, and an image of the interference fringes is stopped by tracking with a scanning mirror.

[0007]

[Problems to be Solved by the Invention] However, Ben
Ton et al.'s hologram creation method records only the horizontal parallax in the divided stripe areas,
Although it is advantageous in calculating interference fringes, it is a method of directly looking at the hologram reproduced image, and it is possible to record the hologram interference fringes on the medium as a hard copy or reproduce and display the hologram from the interference fringes recorded on the medium. There was a problem that I could not.

[0008] Further, conventionally, mainly for monochrome stereoscopic display, it is strongly desired to display a color stereoscopic image as a still image and a moving image. An object of the present invention is to provide a computer hologram creation and display device for reproducing and displaying a color stereoscopic image from hologram interference fringes (phase distribution) for each color data calculated by a computer.

The present invention provides a color stereoscopic image display device capable of appropriately reproducing and displaying a color stereoscopic image even with a low speed spatial light modulator.

[0010]

To achieve this object, the present invention is constructed as follows. First, according to the present invention, the hologram creation area (Lx × Ly) is divided into striped areas each having a width (Lx) in the horizontal direction and a minute width (ΔLy) in the vertical direction, and a three-dimensional image of an arbitrary three-dimensional image is obtained. Interference fringes that depend only on the horizontal parallax for each stripe area for each of the three-dimensional color data are developed into Fourier series, and hologram interference fringes with horizontal light intensity distribution according to the phase distribution of this Fourier series are generated. The present invention is intended for a color stereoscopic image display device that sequentially records in a stripe area divided for each color data on a recording medium and reproduces a color hologram stereoscopic image from the recording medium.

According to the present invention for such a color stereoscopic image display device, a plane wave generating means for generating a coherent plane wave and one stripe area corresponding to the first term of the Fourier series are provided for each color data. A plane wave having a constant light intensity distribution over the entire area is generated, and for the second and subsequent terms of the Fourier series, two plane waves having a constant light intensity distribution determined by the amplitude (An) and phase (θn) of each term are It occurs at an angle where the crossing angle increases as the order increases, and the period (Lx
/ N), a two-beam generating means for forming interference fringes having a light intensity distribution of a cosine function in each hologram area in the hologram forming area, and two plane-wave light fluxes generated by the two-beam generating means for each stripe area. Deflection means that irradiates the entire hologram formation area on the recording medium and optically adds, and the light intensity distribution in the horizontal direction that depends on the Fourier series obtained by the deflection addition by the deflection means is divided for each color data. The hologram recording means for recording the hologram interference fringes for one screen by recording the hologram interference fringes for one screen, and the hologram recording means for simultaneously recording the light from each light source of each color data after recording the hologram interference fringes of the color data by the hologram recording means. 3D image that is color-synthesized by irradiating the object with a hologram and reproducing a hologram 3D image from the hologram interference fringes of the recorded color data. A hologram reading means for visual display, characterized by comprising a.

Here, a spatial light modulator is used as the hologram recording means. This spatial light modulator has an optical storage structure capable of optically writing interference fringes divided into regions for each color data and a wavelength of reproduction light when reading the interference fringes of each color data stored and held in the optical storage structure. And a dielectric mirror that can be spatially different. The dielectric mirror of the spatial light modulator has a reflection peak wavelength in the wavelength region of each color data, and one reflection region is a stripe region having a small width in the vertical direction and a screen width in the horizontal direction. In this case, a liquid crystal shutter is provided as a means for spatially selecting the writing position of the optical storage structure of the spatial light modulation element, and the size of one slit of the liquid crystal shutter is different in reflection wavelength by the dielectric mirror. The size is equal to the reflective stripe area.

Further, one reflection area in the dielectric mirror of the spatial light modulator may be a minute area having a minute width in the vertical and horizontal directions, and the writing position of the optical storage structure of the spatial light modulator is spatially arranged. The size of one slit of the selectable liquid crystal shutter is also set to be equal to the minute area of the dielectric mirror.

[0014]

According to the color stereoscopic image display device of the present invention having the above structure, the following effects can be obtained. First, in order to perform colorization using the hologram phase distribution obtained by calculation, for example, a method in which different holograms are reproduced with respective lights of RGB and optically synthesized is considered. However, this method has a problem of increasing the size of the device.

To solve this problem, R, G,
The hologram interference fringes obtained at the respective wavelengths of B are sequentially recorded on a medium such as a spatial light modulator, and the wavelength of the reproduction light is changed to the corresponding wavelength for each recording of the R, G, or B components and reproduced in time division. A color stereoscopic image display device is conceivable. Such an apparatus is disclosed in Japanese Patent Application No. 4-18328 filed by the present inventors.
Proposed in No. 7.

However, in an apparatus for recording R, G, B hologram interference fringes and reproducing them in a time-division manner, a device used for recording and reproducing needs to have a high response speed, and the response speed is high. Color display using slow devices is not possible. On the other hand, in the present invention, one screen is divided into R, G, and B regions (stripe regions or minute regions), and one-dimensional hologram interference fringes calculated by R, G, and B are handled. Sequential recording is performed on the areas to be recorded to create a recording state of the R, G, B phase distribution for one screen, and after recording, the R, G, B reproducing lights are irradiated to the corresponding areas all at once. Simultaneously reproduce and combine the color stereoscopic images of.

Therefore, the afterimage phenomenon due to the switching of R, G and B is not used, and the switching operation is not necessary for the reproduction after writing as long as it is a still image. Also for moving image display, sequential writing on one screen of R, G, B and R, G,
Readout by simultaneous irradiation of each reproduction light having the wavelength component of B may be repeated, for example, in a cycle of 1/30 seconds, and such a switching speed can be easily realized even with a device having a slow response speed.

[0018]

FIG. 1 is a block diagram of an embodiment showing an embodiment of a color stereoscopic display device of the present invention. In FIG. 1, a laser light source 38, a shutter 40, a mirror 42, an objective lens 4
4, the pinhole 46 and the collimator lens 48 constitute a plane wave generating means for generating the plane wave 20.

In this plane wave generating means, a coherent laser beam emitted from a laser light source 38 using a semiconductor laser or the like passes through a shutter 40, is then reflected by a mirror 42, and uses an objective lens 44 and a pinhole 46. Converted to a divergent spherical wave. The light converted into the divergent spherical wave by the objective lens 44 and the pinhole 46 is converted into parallel light by the collimator lens 48, becomes a plane wave 20, and enters the hologram plate 26 through the amplitude modulator 30 and the phase modulator 32. .

The hologram plate 26 has a function as a means for generating two light beams, and a striped hologram corresponding to each term of the Fourier series representing a one-dimensional hologram phase distribution, which will be made clear later, is used to form the first term of the Fourier series. 2 to obtain the one-dimensional phase distribution after the bias term and the second term
Produces two plane wave bundles. Following the hologram plate 26, a computer-generated
A hologram (hereinafter referred to as “CGH”) 80 is provided. The CGH 80 irradiates the whole area of the hologram recording area using the spatial light modulation element 92 with plane wave light fluxes from the respective stripe holograms corresponding to the respective terms of the Fourier series provided on the hologram plate 26.

A liquid crystal shutter 82 and a spatial light modulator 92 are provided at a hologram forming position subsequent to the CGH 80.
In this embodiment, the liquid crystal shutter 82 and the spatial light modulator 92 are integrated. The liquid crystal shutter 82 has a structure in which a liquid crystal 86 is sandwiched between transparent electrodes 84 and 88. The spatial light modulator also serves as the liquid crystal shutter 82 and the transparent electrode 88, and the photoconductive film 94, the dielectric mirror 96 and the liquid crystal 98 are sandwiched between the transparent electrode 100 on the opposite side. The liquid crystal shutter 82 has a driving power supply 90 and is controlled to be opened / closed by a driving voltage according to a control signal from the controller 58.

In the present invention, the liquid crystal shutter 82 has a function of opening and closing slits in units of horizontal stripe regions corresponding to the hologram recording surface 160 of FIG. The hologram recording surface 160 shown in FIG.
Assuming that the correspondence relationship with the six stripe-shaped areas is one-to-one, it is divided into stripe areas having a screen width Lx in the horizontal direction and a minute width ΔLy in the vertical direction.
Moreover, the stripe region is arranged in order from the top with the R stripe region 162-1, the G stripe region 164-1 and the B stripe region 166-1, and this is arranged in the vertical width L.
It repeats sequentially over y.

Corresponding to the stripe areas divided into RGB for each of the hologram recording surface 160 shown in FIG. 2, the liquid crystal shutter 82 has R stripe areas 162-1 to 162-for writing the R hologram phase distribution. The liquid crystal segment corresponding to the stripe region is transmission-controlled so as to open the slit of n. Further, at the time of writing the hologram phase distribution for G, the transmission control of the corresponding liquid crystal segment is performed so as to open the slits corresponding to the G stripe regions 164-1 to 164-n.

Further, at the time of writing the hologram phase distribution for B, the corresponding liquid crystal segment is controlled so as to open the slits of the B stripe regions 166-1 to 166-n.
Referring again to FIG. 1, when the spatial light modulator 92 receives the light incident through the liquid crystal shutter 82 by the photoconductive film 94, the resistance value of the photoconductive film 94 decreases according to the light intensity.
When the resistance value of the photoconductive film 94 decreases, the driving voltage by the driving power supply 95 is constant, but when the resistance value of the photoconductive film 94 decreases, the voltage applied to both ends of the liquid crystal 98 via the dielectric mirror 96 changes the resistance. It increases by the amount that the value is lowered.

When the driving voltage applied to both ends of the liquid crystal 98 increases, the refractive index (optical distance) of the liquid crystal 98 with respect to the read light incident from the right side also changes, and the liquid crystal 98 enters the liquid crystal 98 and is reflected by the dielectric mirror 96 to return. The incoming light undergoes phase modulation.
Here, the dielectric mirror 96 provided in the spatial light modulator 98.
As shown on the dielectric mirror surface 170 of FIG. 3, the stripe area is divided into one-to-one correspondence with the stripe area for recording for RGB by the liquid crystal shutter shown in FIG. Reflection area 172-1, G reflection area 1
74-1 and B reflection areas 176-1 are arranged side by side, and are repeatedly arranged in the vertical direction.

The reflection regions 172-1 to 172-n for R are R
The component has a reflection peak wavelength, and the reflection region for G 174
-1 to 174-n have a reflection peak wavelength in the G component, and the reflection areas for B 176-1 to 176-n have a reflection peak wavelength in the B component. Therefore, the dielectric mirror surface 170 has wavelength selectivity that reflects only the R, G, or B wavelength component due to the stripe region.

As a reproducing system for the spatial light modulator 92, an R laser light source 114 and a G laser light source 116 are provided.
And a laser light source 118 for B are provided for each of R, G, B
The wavelength of light of the mirror 130, the dichroic mirror 12
After being combined by 8, 126, the light is passed through the shutter 132 and further reflected by the half mirror 108 to irradiate the spatial light modulation element 92 with the reading light. Therefore, the read light for the spatial light modulator 92 simultaneously contains the R component, the G component, and the B component.

Next, the display operation of the color static stereoscopic image in the embodiment of FIG. 1 will be described. First, the controller 58 controls the amplitude modulator 30, the phase modulator 32, the liquid crystal shutter 82, and the spatial light modulator 92, for each R, G, B color data calculated by the computer for each stripe-shaped area of the hologram screen. Record the hologram interference fringes. That is, the controller 58 calculates the hologram phase distribution for each R, G, B of each stripe area on the hologram creation surface for each color data of R, G, B obtained from the three-dimensional shape data, and the amplitude modulator 30 and While setting the amplitude and phase of each term of the Fourier series for each of R, G, and B in the phase modulator 32, the bias light and the two plane wave light fluxes from each stripe hologram of the hologram plate 26 are collected in a specific stripe area. Then, the integral addition of the Fourier series is performed and the result is written.

For example, taking the writing to the uppermost R stripe area 162-1 of the hologram recording surface 160 of FIG. 2 as an example, the one-dimensional phase distribution recorded in the R stripe area 162-1 on the hologram plate 26. The component of each term of the Fourier series of is generated by the control of the amplitude modulator 30 and the phase modulator 32, and the light according to the phase distribution from the first term of the Fourier series arranged from the top to the bottom of the hologram plate 26 to the predetermined light is generated. The front surface of the liquid crystal shutter 82 is illuminated by the CGH 80 to perform additive synthesis, and in this state, the R stripe region 1 at the top of FIG.
By controlling the transmission of the liquid crystal segment corresponding to 62-1, the one-dimensional phase distribution of the R component is recorded as a change in the resistance value of the photoconductive film 94.

Similarly, the one-dimensional phase distributions for the second and subsequent R stripe regions 162-2 to 162-n in FIG. 2 are recorded, and the one-dimensional phase distributions for the G component and B component stripe regions are recorded. Record. When the writing of the one-dimensional phase distribution of RGB components for one screen to the spatial modulation element 92 is completed in this way, the controller 58 causes the laser light sources 114, 116, 1 for R, G, B lasers.
18 is activated, and the read light obtained by combining the wavelengths of the R component, the G component, and the B component is controlled by the shutter 132 to open, and the half mirror 1
The spatial light modulator 92 is irradiated with light from 08.

At this time, the dielectric mirror 96 of the spatial light modulator 92 has the R reflection area 172-1 as shown in FIG.
.About.172-n, the reflection regions 174-1 to 174-n for G and the reflection regions 176-1 to 176-n for B have different wavelength reflection characteristics, and therefore only R, B, and R components correspond. The light reflected by the stripe region undergoes wavefront conversion in accordance with the recording state of the corresponding one-dimensional R, G, and B phase distributions shown in FIG. A three-component composite color stereoscopic image can be displayed to the observer.

FIG. 4 is a time chart showing the timing of opening / closing the shutter 132 and displaying a hologram for displaying a moving image in the embodiment of FIG. As is apparent from the time chart of FIG. 4, in order to display a moving image of a color stereoscopic image, writing of R, G, and B hologram phase distributions to the spatial light modulator 92 and reading by opening the shutter 132 are performed. Repeat this RGB
The light and shutter opening cycle may be repeated at a cycle of, for example, 1/30 second in order to obtain a smooth motion of a moving image.

FIG. 5 is an explanatory view showing a second embodiment of the spatial color distribution on the hologram recording surface of the present invention realized by the liquid crystal shutter 82 and the spatial light modulator 92 of FIG. One of the features is that one recording area is a minute area in both the vertical and horizontal directions. That is, in FIG. 5, R is set as one recording area.
A minute area 182 for G, a minute area 184 for G and a minute area 186 for B are set, and each minute area 182, 18 is set.
4, 186 have the same minute width .DELTA.Ly in the vertical direction as the stripe region and have a minute width .DELTA.Lx in the horizontal direction which is sufficiently smaller than the wavefront width Lx, as shown in FIG.

As for the arrangement of the minute areas, for example, as shown in the uppermost row, the minute areas for R 182, the minute areas 184 for G and the minute areas 186 for B are repeatedly arranged in this order. Further, also in the vertical direction, as shown in the first column on the right side, the R micro area 182, the G micro area 184, and the B micro area 18
Arrange so that the sequence of 6 is repeated. Corresponding to the hologram recording surface 180 shown in FIG. 5, the liquid crystal shutter 82 shown in FIG. 1 forms a liquid crystal segment so that a slit corresponding to each minute area can be opened and closed.

FIG. 6 shows the arrangement of reflection areas in the dielectric mirror 96 of the spatial light modulator 92 of FIG. 1 corresponding to the hologram recording surface 180 of FIG. In FIG. 6, the reflection area is an R reflection area 192 and a G reflection area 19
4 and B reflection areas 196, and each reflection area 19
2, 194 and 196 are the minute regions 182 of FIG.
Corresponding to 184 and 186, it has a minute width ΔLy in the vertical direction and ΔLx in the horizontal direction. In addition, the reflection area 1 for R, G, B
The array of 92, 194, 196 is the minute regions 182, 184 for R, G, B on the hologram forming surface 180 of FIG.
There is a one-to-one correspondence with 186.

The writing operation when divided into minute recording areas in the horizontal and vertical directions shown in FIGS. 5 and 6 is as shown in FIG.
Of the R, G, and B components of the stripe region having the screen width Lx with the minute width ΔLy in the vertical direction of R, G, and B for the same region, and when writing the R component, for example, the uppermost minute width Taking the horizontal arrangement of ΔLy as an example, the segment of the liquid crystal shutter 82 corresponding to the minute region for R 182 is controlled to be transmitted, and the hologram phase distribution for R is written.

Similarly, for each of the horizontally arranged regions from the second to the bottom of the hologram forming surface, the writing light having the hologram phase distribution of the corresponding R component is irradiated to the liquid crystal corresponding to the R minute region 182. Writing is performed by transparent control of only the segment. When the writing of the R hologram phase distribution is completed in this manner, next, the G hologram phase distribution is written, and further the B hologram phase distribution is written.

The reading for writing is similar to the case of the first embodiment, and the laser light sources 114, 116 and 11 for R, G and B are used.
8 are driven all at once, and the read light combined by the shutter 132 is incident on the spatial light modulation element 92, R, shown in FIG.
Since selective wavelength reflection is performed according to the G, B reflection areas 192, 194, 196, and the wavelength reflection area corresponds to the minute area of the hologram recording surface 180 shown in FIG. , R, G, B three-dimensional one-dimensional phase distribution wavefront conversion is simultaneously performed, and RGB color stereoscopic images can be combined and displayed.

According to the second embodiment shown in FIGS. 5 and 6, the dispersion state of the R, G and B components is denser as compared with the first embodiment in which the stripe regions of FIGS. 2 and 3 are divided. Because,
The resolution of the reproduced color stereoscopic image can be increased.
In the above embodiment, the laser light sources for RGB are simultaneously driven to reproduce the read light.
You may make it use the single light source which irradiates the light containing the wavelength component of G, B.

Next, the principle of creating the one-dimensional hologram phase distribution in the present invention will be described. First, the hologram recording surface (hologram forming surface) 160 of FIG.
This is a rectangular screen of x vertical Ly, and this hologram recording surface 16
0 is divided into R, G, and B stripe regions 162-1 to 162-n, 164-1 to 164-of horizontal Lx × vertical ΔLy.
n, 166-1 to 166-n.

Here, the width ΔLy of each stripe region is CR
It corresponds to the width of the scanning line in the T display and is set to several hundred μm to several mm depending on the observation distance of the hologram. Therefore,
When the hologram recording surface 160 is, for example, 10 inches, the number of stripe regions is several hundreds to one thousand.
In each of the stripe areas of the hologram recording surface 160, phase distributions, which are interference fringes of holograms that depend only on the parallax in the horizontal direction for each stripe area, are calculated for each stripe area from three-dimensional shape data of an arbitrary stereoscopic image for each of R, B, and B. The calculation is performed and the phase distribution given by this calculation result is recorded as an interference fringe consisting of the distribution of light intensity.

FIG. 7A is an explanatory view showing an arbitrary one of the stripe areas on the hologram recording surface 160 shown in FIG. In the stripe area of FIG. 2A, interference fringes having a one-dimensional phase distribution in the Lx direction calculated from three-dimensional shape data are formed, and such a one-dimensional phase distribution is applied to a recording medium having optical sensitivity. In order to record the light intensity distribution F (x) shown corresponding to the stripe region.
is necessary.

The light intensity distribution F (x) in the Lx direction can be expanded by Fourier series as follows.

[0044]

[Equation 1]

Here, the first term of the equation (1) corresponds to the average of the light intensity distribution, and the second term and below are the amplitude (An) and phase (θ).
n) and the period (Lx / n) are represented by different cosine functions. Here, the light intensity distribution F (x) of FIG. 7A is expressed as follows, for example, up to the third term.

[0046]

[Equation 2]

FIGS. 7B, 7C and 7D show the light intensity distributions F ₀ , F ₁ and F _{2 at the} single spatial frequencies of the first, second and third terms in the equation (2). Is shown. Figure 7
The first term in (b) corresponds to the average of the amplitudes in the light intensity distribution F (x) in FIG. 7 (a), and the one-dimensional phase distribution Φ ₀ has a uniform light intensity distribution over the entire stripe region.

The second term of FIG. 7C is given by a cosine function of which the amplitude A ₁ , the phase θ ₁ , and the period (Lx / x) of the light intensity distribution F ₁ are different. Such one-dimensional phase distribution [Phi ₁ having a light intensity distribution F ₁ of the cosine function is two plane wave light beam having a single frequency (n / Lx) given by the second term 14
-1 and 14-2 can be generated by interfering at different angles as shown.

Similarly, the third term shown in FIG. 7D is a cosine function of amplitude A ₂ , phase θ ₂ , and period (Lx / n), and the light intensity distribution of such a cosine function is followed. 1
The dimensional phase distribution Φ ₂ has two plane wave luminous fluxes 16-1 and 16− having a single spatial frequency (n / Lx) given by the third term.
2 can be generated by interfering with the first term at a larger angle.

The Fourier series which gives such a light intensity distribution F (x) is strictly an infinite series, but in reality, it is limited to an arbitrary finite term to make a one-dimensional phase distribution of each term individually. Approximately by combining (integrating)
The one-dimensional phase distribution that gives the light intensity distribution F (x) shown in (a) can be synthesized. FIG. 8 shows the concept of an optical system for coherently adding the Fourier components shown in FIG.

In FIG. 8, the first term is bias exposure of the stripe region 12 by a single plane wave light beam, and the second term is
The term below is the exposure of the interference wave obtained by combining two plane waves having different crossing angles, and if the Fourier components are combined up to n terms, (2n-1) coherent plane wave light fluxes are generated in the same stripe region 12. The summed and calculated desired light intensity distribution F (x) can be generated.

Further, when coherently adding the second and subsequent terms of the Fourier component, it is necessary to properly set the amplitude Ai and the phase θi (where i = 1, 2, ... N) of each Fourier component. is there. The first in such a Fourier series
The light intensity distribution in the stripe region 12 is almost linearly converted into a phase distribution by the additive synthesis of the finite Fourier components of the second term and the second term, and the hologram recording surface 16 shown in FIG.
Holograms of any stripe area at 0 can be created.

FIG. 9 shows the structure of an optical system for causing two plane wave light beams to interfere with each other in order to obtain a phase distribution of a single spatial frequency corresponding to one Fourier component. In FIG.
Reference numeral 18 denotes a stripe hologram, which forms interference fringes so as to reproduce two plane waves 22 and 24 having an angle αi when the plane wave 20 is irradiated. Two plane waves 2
Since the crossing angle αi of 2, 24 is small when the second and subsequent orders of the Fourier series are low, the plane wave 20 as the carrier spatial frequency is given by the incident angle β in the direction orthogonal to the crossing angle αi.

By setting the incident angle β to be several tens of times the intersection angle αi of the two plane waves 22 and 24, it is possible to separate the high-order diffracted light and the first-order diffracted light necessary for forming interference fringes. . The configuration of the optical system shown in FIG. 9 is changed to L corresponding to the stripe area of the hologram recording surface 160 shown in FIG.
By arranging a plurality of elements in the y direction, as shown in FIG.
It is possible to realize an optical system that adds -1) plane waves.

Actually, as shown in FIG. 10, the plane wave 20 is made common, and the stripe hologram 18-0 for deflecting the bias light according to the first term of the Fourier series is followed by the stripe corresponding to the second term of the Fourier series. Plate 26 in which linear holograms 18-1 to 18- (n-1) are arranged
Is irradiated with the incident angle β. Here, the stripe holograms 18-0 to 18- provided on the hologram plate 26.
(N-1) is the intersection angle α1 determined by each term of the Fourier series
2 plane wave light fluxes having .about..alpha.n are reproduced, but the stripe hologram 18 is set so that the exit angle .gamma.i is set in the same plane as the incident angle .beta. So that synthetic interference can occur at the same place on the medium surface 28 of the recording medium. Holograms -1 to 18- (n-1) are formed by interference exposure.

This point also applies to the striped hologram 18-0 provided on the top of the hologram plate 26 and subjected to bias exposure of the first term of the Fourier series. In order to enable independent amplitude control and phase control for the striped holograms 18-0 to 18-n corresponding to the respective terms of the Fourier series provided on the hologram plate 26, the amplitude modulator 30 is provided in the optical path of the plane wave 20. And the phase modulator 32 are installed.

FIG. 11 shows the amplitude modulator 30 of FIG. 10 taken out and shown, in which stripe-shaped liquid crystal segments 34-0 to 34- (n-1) are arranged by the number of terms of the Fourier series. Each liquid crystal segment 34-0 to 34- (n-
The transmittance of 1) can be set independently. Figure 1
2 shows the phase modulator 32 of FIG. 10, in which stripe-shaped liquid crystal segments 36 corresponding to the number of Fourier series terms are included.
-0-36- (n-1) are arranged so that the phase of each liquid crystal segment 36-0-36- (n-1) can be independently changed within the range of 0-2π. There is.

The amplitude modulator 30 shown in FIG. 11 and FIG.
The phase modulator 32 shown in FIG. 2 is arranged in the optical path of the plane wave 20 for irradiating the hologram plate 26 as shown in FIG. 10, and each liquid crystal segment forming the two amplitude modulators 30 and the phase modulator 32 is The alignment is performed so as to correspond to the stripe holograms 18-0 to (n-1) on the hologram plate 26. Here, the liquid crystal segments 34-0 to (n-) provided in the amplitude modulator 30 and the phase modulator 32.
1) and 36-0 to (n-1) have a width t of the hologram plate 2
Since the plane wave 20 is incident at the incident angle β with respect to 6, the width ΔLy of the stripe holograms 18-0 to (n−1) on the hologram plate 26 must be t = ΔLycosβ.

In the above embodiment, the RGB color components are taken as an example, but the present invention can be applied as it is to stereoscopic display using other color components.

[0060]

As described above, according to the present invention, even if a device such as a liquid crystal shutter or a spatial light modulator having a slow response speed is used, a color display of a stereoscopic image can be appropriately performed by electronic control. It is possible to easily display not only a static color stereoscopic image but also a color stereoscopic image as a moving image.

[Brief description of drawings]

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

FIG. 2 is an explanatory diagram showing a first embodiment of a space-divided color area written in the spatial light modulator of FIG.

3 is an explanatory view showing a reflection wavelength control region of a dielectric mirror of the spatial light modulator of FIG. 1 corresponding to the space division color region of FIG.

FIG. 4 is a time chart showing the timing of opening / closing a shutter and hologram writing for displaying a moving image in the embodiment of FIG.

5 is an explanatory diagram showing a second embodiment of a space division color area written in the spatial light modulator of FIG.

6 is an explanatory diagram showing a reflection wavelength control region of a dielectric mirror of the spatial light modulator of FIG. 1 corresponding to the space division color region of FIG.

7 is an explanatory diagram showing the first-order phase distributions and light intensities of the first to third terms according to the stripe region and its Fourier series in the hologram plate of FIG.

FIG. 8 is an explanatory view showing a concept for optically generating each term of Fourier series and Fourier series integration in the present invention.

FIG. 9 is an explanatory diagram of a striped hologram that generates two plane wave light fluxes and generates a single spatial frequency phase distribution after the second term of the Fourier series in the present invention.

FIG. 10 is an explanatory diagram showing a basic configuration of an optical system for generating a computer generated hologram on a medium surface which is a stripe region based on Fourier series expansion of a light intensity distribution in the present invention.

11 is an explanatory diagram of the amplitude modulator of FIG. 1 in which a plurality of stripe-shaped liquid crystal segments are arranged.

12 is an explanatory diagram of the phase modulator of FIG. 1 in which a plurality of stripe-shaped liquid crystal segments are arranged.

[Explanation of symbols]

18: Striped hologram 20: Plane wave 26: Hologram plate 28: Medium surface 30: Amplitude modulator 32: Phase modulator 38: Laser light source 40: Shutter 42: Mirror 44: Objective lens 46: Pinhole 48: Collimator lens 80: Computer generated hologram (CGH) 82: Liquid crystal shutters 84, 88, 100: Transparent electrode 86: Liquid crystal (transmittance control type) 90, 95: Driving power supply 92: Spatial light modulator 94: Photoconductive film 96: Dielectric Body mirror 98: Liquid crystal (refractive index control type) 130: Mirror 108: Half mirror 114, 116, 118: Laser light source (for RGB) 126, 128: Dichroic mirror 132: Shutter 160, 180: Hologram recording surface 162-1 to 162-n: R stripe region 164-1 to 16-16 4-n: G stripe region 166-1 to 166-n: B stripe region 170, 190: Dielectric mirror surface 172-1 to 172-n, 192: R reflection wavelength region 174-1 to 174-n , 194: G reflection wavelength region 176-1 to 176-n, 196: B reflection wavelength region 182: R minute region 184: G minute region 186: B minute region

Claims (6)

[Claims] 1. A hologram forming area (Lx × Ly) having a width (Lx) in the horizontal direction and a minute width (Δ) in the vertical direction.
Ly) is divided into striped regions, and interference fringes depending on only the parallax in the horizontal direction are developed into Fourier series for each of the striped regions for each of the three-dimensional color data of an arbitrary stereoscopic image. A color solid that sequentially records hologram interference fringes having a horizontal light intensity distribution according to the phase distribution of a series in a stripe area divided for each color data on a recording medium and reproduces a color hologram stereoscopic image from the recording medium. In the image display device, a plane wave generating means for generating a coherent plane wave, and a plane wave having a constant light intensity distribution over one stripe region corresponding to the first term of the Fourier series for each color data. For the second and subsequent terms of the Fourier series, a constant light intensity distribution determined by the amplitude (An) and phase (θn) of each term is also generated. Two plane waves are generated at an angle where the crossing angle increases as the order increases, and interference fringes formed by a light intensity distribution of a cosine function having a period (Lx / n) of each term are hologram-created for each stripe region. And a deflecting means for irradiating two plane wave luminous fluxes generated by the two luminous flux generators for each stripe area to the entire hologram forming area on the recording medium and optically adding the two plane wave luminous fluxes. A hologram for recording a light intensity distribution in the horizontal direction depending on the Fourier series obtained by the deflection addition by the deflection means in a stripe area divided for each color data to generate a hologram interference fringe for one screen Recording means, and after recording hologram interference fringes of color data by the hologram recording means, simultaneously emits light from each light source of each color data to the hologram recording means. Shines, color stereoscopic image display apparatus characterized by comprising a hologram reading means for visually displaying a stereoscopic image that is color synthesized by reproducing a hologram solid image from the hologram interference fringes of each color data recorded. 2. The color three-dimensional image display device according to claim 1, wherein the hologram recording means is an optical storage structure capable of optically writing interference fringes divided into regions for each color data, and the optical storage. Color stereoscopic image characterized by using a spatial light modulator having a dielectric mirror capable of spatially varying the wavelength of the reproduction light when reading the interference fringes of each color data stored and stored in the structure Display device. 3. The color stereoscopic image display device according to claim 2, wherein the dielectric mirror of the spatial light modulator has a reflection peak wavelength in a wavelength region of each color data, and one reflection region is in a vertical direction. A color stereoscopic image display device having a stripe area having a very small width and a screen width in the horizontal direction. 4. The color stereoscopic image display device according to claim 2, wherein the dielectric mirror of the spatial light modulator has a reflection peak wavelength in a wavelength region of each color data, and one reflection region is perpendicular to A color stereoscopic image display device characterized by having a minute region having a minute width in the horizontal direction. 5. The color stereoscopic image display device according to claim 3 or 4, wherein a liquid crystal shutter is provided as means for spatially selecting a writing position of the optical storage structure of the spatial light modulator, and the liquid crystal is provided. A color stereoscopic image display device, characterized in that the size of one slit of the shutter is equal to the size of one reflection region in which the reflection wavelength is made different by the dielectric mirror. 6. The color stereoscopic image display device according to claim 5, wherein the liquid crystal shutter is formed integrally with the spatial light modulator.