JPH0627864A - Method and device for creating computer generated hologram - Google Patents

Abstract

(57) [Abstract] [Objective] A method and apparatus for creating a hologram for displaying a stereoscopic image, and more particularly, a method and apparatus for creating a computer hologram for recording hologram interference fringes (phase distribution) obtained by a computer on a medium. Based on the three-dimensional shape data, the one-dimensional phase distribution (interference fringes) of the holomgram divided into stripe regions is calculated based on the assumption that the wavefront is reproduced in a predetermined wavefront, and it is developed into a Fourier series. For the phase distribution of one spatial frequency, the first term is bias light of uniform intensity, and after the second term, two plane wave light fluxes are generated at the crossing angle determined by each term, and the light of each term is generated in the stripe area of the hologram creation space. A light intensity distribution that is the same as or similar to the calculated phase distribution is generated by collecting and adding, and recording is performed while shifting the position vertically adjacent to each other on a medium having photosensitivity. To create a one screen of the hologram interference fringes.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for producing a hologram for displaying a stereoscopic image, and more particularly to a method and apparatus for producing a computer generated hologram for recording hologram interference fringes (phase distribution) 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, a two-dimensional image when viewed from various directions is calculated from three-dimensional shape data, and by hologram interference exposure, a striped area having a minute width in the horizontal direction and a screen width in the vertical direction. There is a holographic stereogram system that sequentially records hologram interference fringes.

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 (SP
IE PROC. , No. 1461-37, PP254
-261, (1991)).

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. The present invention has been made in view of such conventional problems, and a method and apparatus for creating a computer generated hologram capable of fixedly recording the interference fringes (phase distribution) of the computer calculated hologram on a medium. The purpose is to provide.

Another object of the present invention is to provide a computer-generated hologram display device for reproducing and displaying a hologram from hologram interference fringes recorded on a medium. An object of the present invention is to provide a computer-generated hologram display device for recording and reproducing interference fringes of a color hologram on a medium.

[0009]

To achieve this object, the present invention is constructed as follows. [Computer Hologram Creating Method; Claims 1 and 2] First, the computer hologram creating method of the present invention will be described below.
Composed of processes.

The hologram creation area (Lx × Ly)
Divided into a plurality of stripe-shaped regions having a width (Lx) in the horizontal direction and a minute width (ΔLy) in the vertical direction,
First step of calculating phase distribution {F (x)} which is interference fringes of a hologram depending on only horizontal parallax for each stripe area from three-dimensional shape data of an arbitrary stereoscopic image ;, calculated in the first step Secondly sequentially generating plane waves having a light intensity distribution having a correlation with the phase distribution of each stripe region
Process: Irradiating the plane wave light flux generated in each stripe region in the second process onto one stripe region of the hologram creation region; Third process; Light intensity distribution irradiated in the third process as phase distribution of hologram interference fringes Fourth step of recording on a medium having photosensitivity while sequentially shifting the position by the stripe width; here, in the first step, a phase distribution which is a hologram interference fringe for each stripe area is developed by Fourier series,

[0011]

[Equation 1]

It is represented by. In the second step, a plane wave having a constant light intensity distribution is generated over the entire stripe region corresponding to the first term (A _0/2 ) of the Fourier series in this equation, and the Fourier series Second term {A1 cos (2
After πx / Lx−θ ₁ ), the amplitude of each term (A
n) and the phase (θn), two plane wave light fluxes having a constant light intensity distribution are generated at an angle (αn) where the crossing angle increases as the order increases, and the period of each term (Lx / n)
Interference fringes having a light intensity distribution of a cosine function with are formed separately for each stripe area in the hologram creation area. [Computer Hologram Creating Device; Claims 3 to 14] First, in the computer hologram creating device of the present invention, the hologram creating region (Lx × Ly) has a width (Lx) in the horizontal direction and a minute width in the vertical direction. Divide into stripe regions having (ΔLy), and develop the hologram interference fringes depending on only the parallax in the horizontal direction for each stripe region from the three-dimensional shape data of an arbitrary stereoscopic image into the Fourier series of equation (1). ,
A hologram having a horizontal light intensity distribution according to the phase distribution of the Fourier series is recorded on the recording medium for each stripe area.

In the present invention as such a computer hologram creating apparatus, plane wave generating means for generating a coherent plane wave is provided, and the plane wave luminous flux from the plane wave generating means is made incident on the two luminous flux generating means. A plane wave having a constant light intensity distribution (constant amplitude) is generated over the entire stripe region corresponding to the first term (A _0/2 ) of the Fourier series of the equation.

The two-beam generating means is composed of the second term {A1 cos (2πx / Lx-θ ₁ ) of the Fourier series of the equation ( ₁ ).
After that, the amplitude (An) and phase (θn) of each term
Two plane waves with a constant light intensity distribution (amplitude) determined by are generated at an angle at which the crossing angle α increases as the series increases, and the light intensity distribution of the cosine function with the period (Lx / n) of each term An interference fringe consisting of a cosine function of a single spatial frequency is formed in the hologram forming area for each stripe area.

The two plane wave light fluxes generated by the two-flux generating means for each stripe area are collected by the deflecting means in one stripe area on the recording medium and optically added. The light intensity distribution in the horizontal direction depending on the Fourier series obtained by the addition by the deflecting means is sequentially scanned and recorded for each stripe area on the recording medium. The two light flux generating means include an amplitude modulating means for modulating the light intensity of the plane wave light flux incident from the light flux generating means to a light intensity corresponding to the amplitude (An) of each term of the Fourier series, and a plane wave light flux incident from the light flux generating means. Phase modulation means for modulating the phase of each phase to the phase (θn) of each term of the Fourier series, and the plane wave light flux obtained through the amplitude modulation means and the phase modulation means are incident to form an interference fringe of a single frequency in the hologram creation space. And a diffracting means for generating two plane-wave light fluxes with a crossing angle α determined by each term of the Fourier series.

As the amplitude modulating means and the phase modulating means, it is possible to use a liquid crystal display device in which a plurality of stripe-shaped regions whose transmittances can be independently controlled are arranged in parallel. Further, the diffracting means may be composed of a hologram plate in which a plurality of stripe holograms are arranged in parallel to deflect an incident light flux with a crossing angle α determined by each term of the Fourier series. This hologram plate can simultaneously have a function as a deflection means. [Computer hologram creation and display device;
2] In addition to the plane wave generating means and the two light flux generating means used in the computer hologram production apparatus, two plane wave light fluxes generated by the two light flux generating means for each stripe area are distributed over the entire hologram forming area on the recording medium. Deflection means for irradiating and optically adding, hologram recording means for sequentially recording the light intensity distribution in the horizontal direction depending on the Fourier series obtained by the deflection addition by this deflection means for each stripe area, and hologram recording And a hologram reading means for reproducing and visually displaying a hologram stereoscopic image from the hologram interference fringes recorded in the means.

Reproduction of the hologram recorder can also be performed for color data such as RGB. [Computer Hologram Making Method and Apparatus, Part 2; Claims 23 to 33] When two light beams having a crossing angle α determined by each term of the Fourier series are generated by hologram diffraction, a low-order spatial frequency with which the crossing angle becomes small. Then, the diffraction effect of light does not sufficiently appear at a distance of several tens of centimeters from a hologram that can be realized as a device.

Therefore, for the phase term of the low-order Fourier series, a separate optical system independent from the high-order optical system is used, and the amplitude and phase of the plane-wave light beam are modulated, and then the wavefront conversion is performed to obtain the period of each Fourier series term. An interference fringe having a light intensity distribution of a cosine function having (Lx / n) is formed in the hologram creation area. The wavefront converting means includes a cylindrical lens that expands two stripe-shaped light fluxes in a longitudinal direction after compressing the stripe-shaped areas, and each element in the longitudinal direction of the stripe-shaped light flux area that is arranged at the light flux converging position by the cylindrical lens. By forming a phase imparting means such as surface unevenness having a phase difference of 2π according to the period of, a wavefront whose phase changes periodically on the divergence side of the light flux, that is, a wavefront equivalent to the wavefront due to the cross interference of two light fluxes is generated. To do.

[0019]

According to the method and apparatus for producing a computer generated hologram of the present invention having such a configuration, the phase distribution of the hologram in a striped area having a minute width in the vertical direction and a screen width in the horizontal direction ( (Interference fringe) is calculated from the three-dimensional shape data and expanded into a Fourier series, and the phase distribution of the single spatial frequency shown by each term of the Fourier series is individually generated for each stripe region, and on the medium having photosensitivity. By recording the light intensity distribution obtained by adding in, a stripe-shaped phase distribution that is the same as or similar to the calculated hologram phase distribution is realized, and this phase distribution is positioned next to each other in the vertical direction on the medium. By shifting and forming
Create a hologram that enables three-dimensional display that reproduces only the horizontal parallax.

When the hologram interference fringes are two-dimensionally formed as an array of one-dimensional phase distributions in an arbitrary stripe state in this way, the stripe-shaped one-dimensional phase distributions are light intensity distributions, as in ordinary hologram interference exposure. As a result, the hologram interference fringes as a hard copy can be recorded on the medium, and the hologram can be reproduced and displayed from the recording medium.

[0021]

【Example】

Table of contents 1. Computer hologram creation principle 2. Optical structure for hologram production 3. 3. First embodiment of computer generated hologram apparatus Hologram creation procedure 5. Second embodiment of computer generated hologram apparatus 6. 6. Example of computer generated hologram display device 7. Example of computer color hologram creation display device Embodiment of another method and apparatus for creating computer generated hologram [1. Computer Hologram Creation Principle] FIG. 1 is an explanatory diagram of a hologram screen created by the hologram creation method of the present invention.

In FIG. 1, the hologram screen 10 is a rectangular screen of horizontal Lx × longitudinal Ly as a screen size, and this hologram screen 10 has stripe regions 12-0, 12-1, ... Lx × vertical ΔLy. • Divide into 12- (n-1). Here, the stripe regions 12-0 to 12- (n-
The width ΔLy in 1) corresponds to the width of the scanning line in the CRT display and is set to several hundred μm to several mm depending on the observation distance of the hologram. Therefore, the hologram screen 10 is
In inches, stripe areas 12-0 to 12-
The number of (n-1) is about several hundreds to one thousand.

Stripe area 12 of hologram screen 10
For each of −0 to 12− (n−1), the phase distribution, which is the interference fringe of the hologram depending only on the parallax in the horizontal direction, is calculated for each stripe region from the three-dimensional shape data of an arbitrary stereoscopic image. The phase distribution given by the calculation result is recorded as an interference fringe consisting of a light intensity distribution. FIG. 2A is an explanatory view showing an arbitrary one of the stripe areas in the hologram screen 10 shown in FIG. Figure 2
Interference fringes having a one-dimensional phase distribution in the Lx direction calculated from three-dimensional shape data are formed in the stripe area 12 of (a), and such a one-dimensional phase distribution is formed on a recording medium having photosensitivity. In order to record, the light intensity distribution F (x) shown corresponding to the stripe region 12 is required.

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

[0025]

[Equation 2]

Here, the first term of the equation (1) corresponds to the average of the light intensity distribution, and the second term and the following terms are the amplitude (An) and the phase (θ).
n) and the period (Lx / n) are represented by different cosine functions. Here, the light intensity distribution F (x) of FIG. 2A is expressed as follows, for example, up to the third term.

[0027]

[Equation 3]

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

The second term of FIG. 2 (c) is given by a cosine function having different amplitude A ₁ , phase θ ₁ and period (Lx / x) of the light intensity distribution F ₁ . 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. 2D 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 that gives such a light intensity distribution F (x) is strictly an infinite series, but in reality, it is limited to an arbitrary finite term and the one-dimensional phase distribution of each term is individually created. Approximately by combining (integrating)
The one-dimensional phase distribution that gives the light intensity distribution F (x) shown in (a) can be synthesized. [2. Optical Structure for Creating Hologram] FIG. 3 shows the concept of an optical system for coherently adding the Fourier components shown in FIG.

In FIG. 3, 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 a hologram of an arbitrary stripe region in the hologram screen shown in FIG. 1 can be created. it can.

FIG. 4 shows the configuration 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. 4 has the stripe regions 12-0 to 12- of the hologram screen 10 shown in FIG.
An optical system for adding (2n-1) plane waves illustrated in FIG. 3 can be realized by arranging a plurality of lines in the Ly direction corresponding to n.

Actually, as shown in FIG. 5, 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 stripes corresponding to the second and subsequent terms of the Fourier series. Hologram 1
The entire hologram plate 26 in which 8-1 to 18- (n-1) are arranged is illuminated at an incident angle β. Here, the hologram plate 2
Stripe holograms 18-0 to 18-
(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 stripe 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. 6 shows the amplitude modulator 30 of FIG. 5 taken out, 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-1)
The transmittance of can be set independently. FIG. 7 shows the phase modulator 32 of FIG. 4, in which stripe-shaped liquid crystal segments 36-0 to 36-3 corresponding to the number of Fourier series terms are included.
6- (n-1) are arranged, and each liquid crystal segment 36
The phase of −0 to 36− (n−1) can be independently changed in the range of 0 to 2π.

The amplitude modulator 30 shown in FIG. 6 and the phase modulator 32 shown in FIG. 7 are arranged in the optical path of the plane wave 20 for irradiating the hologram plate 26 as shown in FIG. The liquid crystal segments forming the device 30 and the phase modulator 32 are aligned so as to correspond to the striped holograms 18-0 to (n-1) on the hologram plate 26. Here, the width t of the liquid crystal segments 34-0 to (n-1) and 36-0 to (n-1) provided in the amplitude modulator 30 and the phase modulator 32 is the angle of incidence of the plane wave 20 on the hologram plate 26. Since it is incident at β, the stripe hologram 18-0 on the hologram plate 26
To the width ΔLy of (n−1), t = ΔLycosβ must be set. [3. First Embodiment of Computer Generated Hologram Device] FIG. 8 is a block diagram of an embodiment showing a first embodiment of a hologram preparation device according to the present invention.

In FIG. 8, the plane wave 2 shown in FIG. 5 is formed by the laser light source 38, the shutter 40, the mirror 42, the objective lens 44, the pinhole 46 and the collimator lens 48.
A plane wave generating means for generating 0 is configured. In this plane wave generation means, the coherent laser beam emitted from the laser light source 38 using a semiconductor laser or the like passes through the shutter 40 and is then reflected by the mirror 42.
It is converted into a divergent spherical wave using the objective lens 44 and the pinhole 46. 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 two-beam generating means and a deflecting means, and as shown in FIG. 5, stripe holograms 18-0 to 18- (n-corresponding to the respective terms of the arranged Fourier series. In order to obtain the bias light of the first term and the phase distribution of the second term and thereafter according to 1), two plane wave light fluxes are generated respectively, and at the position of the slit 50 provided on the front surface of the hologram dry plate 52 provided as an optical recording medium. Coherently added.

As described above, the two plane wave luminous fluxes corresponding to the respective terms of the Fourier series that are coherently added at the position of the slit 50 are applied to the hologram plate 26 by the amplitude modulator 30 and the phase modulator 32, respectively. Since the amplitude and phase are given, (1) at the slit 50 position.
The addition (integration) of the Fourier series shown in the equation is optically realized. Then, the hologram dry plate 52 installed behind the slit 50 is exposed with the reproduced slit-shaped hologram interference fringes.

The hologram dry plate 52 is fixed on a stage 54 movable in a direction orthogonal to the slit 50, and the stage 54 can be moved in parallel with the slit 50 by the slit width by a scanning mechanism 56. The controller 58 controls the laser light source 38, the amplitude modulator 30, the phase modulator 32, and the scanning mechanism 56.

That is, the amplitude and the phase of each term of the Fourier series for each stripe area of the three-dimensional shape data to be created are given to the controller 58. Based on the Fourier series expansion data for each stripe area, the controller 58 sets the transmittance to the amplitude modulator 30 so as to obtain the set amplitude, and the range from 0 to 2π so that the phase modulator obtains the set phase. Set the phase of.

In this state, the shutter 46 of the laser light source 38 is
To open the plane wave 20 to the amplitude modulator 30 and the phase modulator 3
The hologram plate 26 is irradiated via the
In order to obtain the bias light of the first term and the phase distribution of the second and subsequent terms from the stripe hologram corresponding to each term of the Fourier series of 6, two plane wave light fluxes are applied to the position of the slit 50 to optically integrate the Fourier series. To do it.

In the initial state, the scanning mechanism 54 positions the uppermost stripe region of the hologram dry plate 52 behind the slit 50, and closes the shutter 40 when the hologram dry plate 52 is exposed. Subsequently, by driving the stage 54 by the scanning mechanism 56, the hologram dry plate 52 is moved upward by the same distance as the width of the slit 50, and the unexposed portion of the hologram dry plate 52 is moved to the position of the slit 50.

In this state, the controller 58 sets the amplitude and phase of the Fourier series obtained for the next stripe area in the amplitude modulator 30 and the phase modulator 32, opens the shutter 40, and opens the hologram interference fringes in the second stripe area. Is exposed to the hologram dry plate 52. Similarly, the exposure of the hologram interference fringes on the hologram dry plate 52 is repeated until the final stripe region.

In FIG. 8, the hologram dry plate 52 is used.
A hologram for one screen is created by moving and scanning the roll film. A roll film is used instead of the hologram dry plate 52, and a film feeding mechanism for sequentially feeding the roll film is provided to record hologram interference fringes on the roll film. It is also possible to make a hologram film for movies. [4. Hologram Creating Procedure] FIG. 9 is a flowchart showing the procedure of the computer hologram creating process according to the present invention.

In FIG. 9, first, in step 1, any 3
The hologram interference fringes in each of the stripe regions 12-0 to 12- (n-1) of the hologram screen shown in FIG. 1 are calculated from the dimensional shape data, and in step S2, the hologram interference fringes are developed into Fourier series showing the light intensity distribution. Then step S
Amplitude An and phase θ of each term of the Fourier series expanded in 3.
Control data of the amplitude modulator 30 and the phase modulator 32 is created by n.

Then, in step S4, the condition of the transmittance of the amplitude modulator 30 and the condition of the control phase of the phase modulator 32 are set. In step S5, the plane wave light flux coherent from the laser light source is modulated by the amplitude modulator 30 and the phase modulator. The hologram plate 26 is irradiated through the device 32, and in order to obtain the bias light of the first term of the Fourier series from the hologram plate 26 and the phase distribution of the second and subsequent terms, two plane wave light fluxes corresponding to the respective terms at the same position. The addition is performed and exposure recording is performed on a hologram dry plate or the like.

Then, in step S6, it is checked whether or not the exposure of all stripe areas on the hologram dry plate has been completed.
If the exposure has not ended, the process proceeds to step S7, the recording medium is moved to the next unexposed region, the amplitude and phase conditions in the next stripe region are set, and the integral exposure of the Fourier series is repeated. When the exposure of the stripe area is finished, a series of hologram forming processing is finished. [5. Second Embodiment of Computer-generated Hologram Making Apparatus] FIG.
FIG. 3 is a block diagram of an embodiment showing a second embodiment of a computer generated hologram apparatus according to the present invention. In this embodiment, the one-dimensional phase distribution of sequentially created holograms is a hologram by mechanical optical scanning. It is characterized in that the recording is performed on a medium such as a dry plate.

In FIG. 10, a laser light source 38, a shutter 40, a mirror 42, an objective lens 44, and a pinhole 46.
The plane wave generating means including the collimator lens 48, the amplitude modulator 30, the phase modulator 32, and the hologram plate 26 are the same as those in the first embodiment of FIG. 8, but the hologram dry plate 52 is arranged in the direction orthogonal to the hologram plate 26. Is fixedly arranged, and a galvanometer mirror 60 rotated and scanned by a drive coil 62 is provided as an optical deflecting means therebetween.

The drive coil 62 of the galvanometer mirror 60 is controlled by the controller 58 in synchronization with the exposure operation of the hologram interference fringes in the stripe area of the hologram screen.
That is, in the initial state, the controller 58 causes the drive coil 62 to transmit the light flux from the galvano mirror 60 to the hologram dry plate 5.
2 toward the right corner of the recording surface, and each time the exposure recording of the hologram interference fringes of one hologram region progresses, the galvanometer mirror 60 is rotated clockwise by a minute angle by the width of the hologram interference fringes, and the next Set in the unrecorded stripe area.

When optical scanning is performed by the galvanometer mirror 60 shown in FIG. 10, the image surface 66 draws an arc with respect to the recording medium surface 64 which is a flat surface as shown in FIG.
Therefore, the position of the image plane 66 formed by the galvanometer mirror 60 with respect to the flat recording medium surface 64 differs depending on the location. Usually, in image-forming rotary scanning using a lens, the image surface 66 is curved with respect to the recording medium surface 64, which causes image blurring and becomes a problem. However, in the exposure of the hologram interference fringes of the present invention, the curvature of the image plane does not pose a problem. The reason will be described below with reference to FIG.

FIG. 12 shows how two plane waves 68 and 70 are incident on the image plane 72 at the same angle with respect to the Z axis and form interference fringes 74. Here, the pitch of the interference fringes 74 on the image plane 72 is d0. Now, the image plane 72 for observing the interference fringes 74 is displaced in the Z-axis direction by an arbitrary distance l,
Further, assume an image plane 76 tilted from the xy plane by an arbitrary angle θ. If the pitch of the interference fringes 78 on the image plane 76 is d, then d ₀ = d.

This is the Y-direction propagation vector component of the plane waves 68 and 70 in which the pitch of the interference fringes 74 interferes, and depending on the eccentricity of the image plane in the Z-axis direction and the rotation around the y-axis, the Y-direction propagation vector component. Does not change, d ₀ = d even if the image surface 72 is decentered from the image surface 76. For this reason, the phase distribution generated on the recording medium surface 64 does not change even if the distance from the recording medium surface 64 changes due to scanning by the galvano mirror 60 as shown in FIG. Holographic interference fringes in the stripe area can be recorded.

As shown in FIG. 10, the galvanometer mirror 60 is used.
If the scanning mechanism for the recording surface is provided, the device configuration can be simplified as compared with the mechanical scanning of FIG. [6. Embodiment of computer generated hologram display device] FIG.
Is a first computer-generated hologram display device according to the present invention.
It is an Example lineblock diagram showing an example.

In FIG. 13, laser light source 38, shutter 40, mirror 42, objective lens 44, pinhole 4
6, the configuration up to the collimator lens 48, the amplitude modulator 30, the phase modulator 32, and the hologram plate 26 is the same as that of the hologram creating apparatus of FIG. In this hologram creation display device, as a deflection means for irradiating a plane wave light beam from a stripe hologram corresponding to each term of the Fourier series provided on the hologram plate 26 over the entire hologram creation area subsequent to the hologram plate 26. Computer-generated hologram (hereinafter referred to as "CGH") 80
Is provided.

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. First, the liquid crystal shutter 8
2 has a structure in which a liquid crystal 86 is sandwiched between transparent electrodes 84 and 88. The spatial light modulator 92 also serves as the transparent electrode 88 of the liquid crystal shutter 82, and the transparent electrode 100 on the opposite side.
Between the photoconductive film 94, the dielectric mirror 96 and the liquid crystal 98.
Sandwiched between.

The liquid crystal shutter 82 has a driving power source 90,
Opening / closing is controlled by a drive voltage based on a control signal from the controller 58. Specifically, the liquid crystal shutter 82 is shown in FIG.
Stripe region 12-0 shown in the hologram screen 10 of FIG.
.. 12- (n-1), a plurality of independently controllable liquid crystal segments are arranged, and under the control of the controller 58, the liquid crystal segments are sequentially transmitted and controlled,
A so-called shutter function is realized.

On the other hand, 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 the resistance value of the photoconductive film 94 decreases, so that the voltage applied across the liquid crystal 98 via the dielectric mirror 96 is changed. 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 of the liquid crystal 98 with respect to the read light 110 also changes,
The light enters the liquid crystal 98, is reflected by the dielectric mirror 96 and returns, but undergoes phase modulation. Such a liquid crystal shutter 8
2 and the spatial light modulation element 92 perform an optical operation by driving the liquid crystal shutter 82 for each stripe region in the hologram forming space, so that the refractive index of the liquid crystal 98 depends on the hologram interference fringes formed for each stripe region. It will be recorded as the refractive index distribution. The information on the hologram interference fringes recorded as the change in the refractive index on the liquid crystal 98 of the spatial light modulator 92 is the laser light source 102 and the shutter 1.
04, the mirror 106, and the half mirror 108 can be read by a reading means to reproduce the hologram.

That is, the laser light source 108 generates laser light or read light 110 having a nearly monochromatic color by a semiconductor laser or the like, and makes it enter the spatial light modulator 92 through the shutter 104, the mirror 106, and the half mirror 108. Upon receipt of the read light 110, the hologram interference fringes are recorded as changes in the refractive index for each stripe region of the liquid crystal 98 at that time. Therefore, read light having a phase distribution corresponding to the distribution of the refractive index is obtained. Generated by reflection, half mirror 10
A stereoscopic image can be displayed via 8.

The liquid crystal 98 may be reset by reversing the polarity of the driving voltage from the driving power supply 95, which is the operation of erasing the recorded hologram information. FIG. 14 is a block diagram of an embodiment showing a second embodiment of the hologram creation / display apparatus according to the present invention. In this embodiment, two holograms from each stripe-shaped hologram are provided over the entire hologram creation area provided subsequent to the hologram plate 26. A lenticular lens 112 is used as a deflecting unit that irradiates a plane wave light beam to perform integral addition of Fourier series. The other structure is the same as that of the embodiment shown in FIG. [7. Example of Computer Color Hologram Creation / Display Device]
FIG. 15 is a block diagram of an embodiment showing a first embodiment of a color hologram producing / displaying device according to the present invention.

In FIG. 15, laser light source 38, shutter 40, mirror 42, objective lens 44, pinhole 4
6, the collimator lens 48, the amplitude modulator 30, the phase modulator 32, and the hologram plate 26 are the same as those in the hologram creating apparatus of FIG. The optical scanning mechanism using the galvano mirror 60 provided after the hologram plate 26 is the same as that of the embodiment shown in FIG. At the position of the hologram forming space divided into stripes by the galvano mirror 60, the same spatial light modulator 9 as shown in FIGS.
Two are provided. Since the liquid crystal shutter 82 is integrally provided in FIGS. 13 and 14, the liquid crystal shutter 82 is removed in FIG. That is, the transparent electrode 84, the liquid crystal 98, and the driving power source 90 which form the liquid crystal shutter 82 in FIGS.

The controller 58 controls the amplitude modulator 30, the phase modulator 32, the spatial light modulation element 92, and the drive coil of the galvano mirror 60 (not shown) to cause the spatial light modulation element 92 to calculate each stripe area of the hologram screen by a computer. The hologram interference fringes for each of the obtained RGB color data are recorded. That is, the controller 58 calculates the hologram phase distribution of RGB for each stripe area of the hologram creation surface for each RGB data obtained from the three-dimensional shape data, and the RGB modulators are used for the amplitude modulator 30 and the phase modulator 32.
The bias light and the two plane wave light beams from each stripe hologram of the hologram plate 26 are set to the galvano mirror 60 while setting the amplitude and phase of each term of the Fourier series for each.
Then, the data are collected in a specific stripe region of the spatial light modulator 92 and are subjected to integral addition of Fourier series for writing.

On the other hand, as a reproduction type for the spatial light modulator 92, a laser light source 114 for R and a laser light source 1 for G are used.
A 16 and B laser light source 118 is provided and outputs read light of R, G and B wavelengths via shutters 120, 122 and 124, respectively. The shutters 120, 122 and 124 are controlled by the controller 58. The read light of the wavelength R from the shutter 120 is reflected by the half mirror 126, and is reflected from the mirrors 132 and 134.
The read light is applied to the spatial light modulator 92 through the beam line 8. Similarly, the read light having the G wavelength from the shutter 122 is also reflected by the half mirror 128, passes through the half mirror 126, and then passes through the mirrors 132 and 134.
The spatial light modulation element 92 is irradiated with light from 08.

Further, the read-out light of B wavelength from the shutter 124 is reflected by the mirror 130, and the half mirrors 128, 12 are read.
After passing through 6, the half mirror 108 irradiates the spatial light modulator 92 via the mirrors 132 and 134. The read light having the wavelength of R, G, or B with which the spatial light modulation element 92 is irradiated is the reflected light of the light intensity distribution according to the hologram interference fringe of each stripe area written in the spatial light modulation element 92 at this time. Is generated and reflected by the half mirror 108 to sequentially display the R, G, or B hologram images.

FIG. 16 is a timing chart showing the hologram writing operation for the shutters 120, 122, 124 and the spatial light modulator 92 in the color hologram producing and displaying apparatus of FIG. As shown in FIG. 16, the controller 58 first opens the shutter 120 at time t1 for a certain period of time, irradiates the spatial light modulation element 92 with read light having a wavelength of R, and writes R into the spatial light modulation element 92 by that time.
The hologram image of the R component is written and displayed from the hologram interference fringes of the data.

Subsequently, with the shutter 120 closed, the controller 58 obtains the hologram phase distribution in the stripe region based on the G data, so that each stripe region of the amplitude modulator 30 and the phase modulator 32 is determined by each term of the Fourier series. Amplitude and phase are set, bias light and two plane wave light fluxes are generated for each area by the hologram plate 26, and the area on the same spatial light modulation element 92 is subjected to integral exposure. When the writing of the G component is completed, the controller 58 opens the shutter 122 at time t2 to irradiate the spatial light modulator 92 with the read light having the wavelength of the G component, and the G component written in the spatial light modulator 92. The hologram of G component is reproduced and displayed by the hologram interference fringes.

Subsequently, after closing the shutter 122, similarly, the hologram interference fringes of the B component are written in the spatial light modulator 92, and the shutter 124 is opened at time t3 to spatially modulate the read light having the wavelength of B. Illuminate element 92,
Reproduce and display the B component hologram. Similarly, R,
Reproduction and display of RGB holograms by writing and reading to and from the spatial light modulation element 92 of G and B components are repeated.

If the processing for reproducing such an RGB hologram is performed by high-speed switching, the color hologram can be viewed as an image due to the afterimage effect. FIG. 17
FIG. 14 is a configuration diagram of an embodiment showing a second embodiment of a color hologram producing display device, which is characterized in that the hologram producing display device shown in FIG. 13 is colorized.

That is, the configuration from the laser light source 38 to the spatial light modulator 92 is the same as that of the embodiment of FIG. 13, and in addition to this, as a reading means for the spatial light modulator 92, FIG.
The configuration of the half mirror 108 is added from the laser light sources 114, 116 and 118 shown in FIG. 5, and even in this embodiment, writing and reading of the color hologram interference fringes to the spatial light modulator 92 are performed similarly to FIG. Done. [8. Other Embodiments of Computer Hologram Creating Method and Apparatus] FIG. 18 is an embodiment configuration diagram showing another embodiment of the computer hologram creating method and apparatus according to the present invention, which is obtained from the phase distribution for hologram creation. Regarding the formation of interference fringes by the one-dimensional striped hologram after the second term of the Fourier series of the light intensity, the optical system for hologram production is divided into a low-order Fourier series term and a high-order Fourier series term. And

First, in the hologram producing method of the present invention, as shown in FIG. 3, for the lower-order terms of the Fourier series, two plane wave light fluxes are intersected with each other at a minute crossing angle so that the hologram formation surface is formed. Interference fringes are formed in the stripe region 12. However, it is difficult to use the stripe hologram 18 as shown in FIG. 4 to generate a stripe-shaped plane wave light flux group that intersects at a minute crossing angle because the distance to the hologram creation surface is restricted.

That is, in the method of generating two plane wave light fluxes from a single wave front, that is, a plane wave by a hologram, when the spatial frequency is as small as 1 to 0.01 [1 / mm], that is, the second term of the Fourier series. In the case of the spatial frequency of the subsequent low-order terms, the diffraction effect of light does not appear remarkably at a distance of several tens of centimeters from the hologram, and two intersecting plane wave light fluxes cannot be generated.

Therefore, in the embodiment of FIG. 18, the phase distribution is optically determined for the stripe region that realizes the second and lower terms of the Fourier series in which the diffraction effect cannot be obtained by the hologram plate 26. I try to magnify and project.
In FIG. 18, the plane wave generating means is composed of a laser light source 38, a shutter 40, a mirror 42, an objective lens 44, a pinhole 46 and a collimator lens 48. The plane wave 20 from the collimator sensor 48 is reflected by the beam splitter 36.
Are divided into plane waves 20-1 and 20-2.

On the side of the plane wave 20-2, the amplitude modulator 30, the phase modulator 32, and the hologram plate 26-1 are arranged as in the first embodiment shown in FIG. This hologram plate 26-1
In (1), a plurality of stripe holograms for generating two plane-wave light fluxes are arranged with a crossing angle αi determined by higher-order Fourier series terms after the second term of the Fourier series of equation (1).

On the other hand, the plane wave 20-1 from the beam splitter 136 is reflected by the mirror 138 and the amplitude modulator 30
-1, Phase modulator 32-1, Cylindrical lens 14
The deflection hologram 144 is irradiated via the 0 and the phase plate 142. FIG. 19 is an explanatory diagram showing an optical system for extracting hologram interference fringes in the stripe region of the second and subsequent terms of the Fourier series shown in FIG.

In FIG. 19, the second of the Fourier series is
The case where the hologram interference fringes in the stripe region are generated is described as an example with respect to the three terms, the third term, and the fourth term. In FIG. 19, the plane wave 20-1 is the liquid crystal segment 34-
Amplitude is determined by the setting of the transmittance through three of 1, 2, and 3. The phase modulator 32 also has liquid crystal segments 36-1, 2, and 3, and controls the phase passing through each segment to be the set phase.

The plane wave light beam 20-1 having passed through the amplitude modulator 30 and the phase modulator 32 converges the plane waves of the three stripe regions by the cylindrical lens 140. A phase plate 142 is provided at the converging position of the cylindrical lens 140.
Is provided. The phase plate 142 is provided with a phase imparting unit 146-1 for imparting wavefronts corresponding to the respective single spatial frequencies of the second term, the third term, and the fourth term of the Fourier series, corresponding to the three stripe regions. 2 and 3 are provided.

For this reason, the plane wave light flux of each stripe region that has passed through the phase plate 142 is optically created with a wave front, and a plurality of single spatial frequencies are generated on one stripe region 12 of the hologram forming space via the deflection hologram 144. Add and combine the light intensity distributions that it has. FIG. 20 shows FIG. 19 in a plan view. By providing unevenness 148 on the surface of the phase plate 142 as enlargedly shown in FIG. 21, the phase of the wavefront can be periodically changed on the diverging side.

Here, the surface unevenness 1 provided on the phase plate 142
When the refractive index of 48 is n, the height of the surface unevenness 148 is h, and the wavelength of the light flux to be transmitted is λ, the height h of the surface unevenness 148 is determined so that (n-1) h = λ.

When the phase plate 142 is converged by the cylindrical lens 140 as shown in FIG. 20 and irradiated with a plane wave light flux, the wave front 15 having an arc shape on the incident side is obtained.
Reference numeral 0 indicates the surface unevenness 148 shown in FIG.
Can be converted into a wavefront 152 whose phase changes periodically. Therefore, the surface unevenness 148 shown in FIG. 21 is formed to have unevenness numbers corresponding to, for example, the second term, the third term, and the fourth term of the Fourier series.
9 of the phase plate 142, the phase imparting parts 146-1, 142-1,
By arranging them as 3, it is possible to optically add low-order phase terms of the Fourier series.

In FIG. 21, a surface unevenness 142 for obtaining a wavefront whose phase changes periodically on the phase plate 142.
However, as the phase plate 142, an optical element having a phase distribution recorded by refractive index modulation, for example, a volume hologram may be used. Further, in the embodiment of FIG. 18, the hologram interference fringes are exposed while moving the hologram dry plate 52 installed on the stage 54 of the scanning mechanism 56 with respect to the slit 50 by the width of the stripes. Optical scanning by the illustrated galvanometer mirror 60 may be used.

Further, it is needless to say that the hologram creating apparatus of FIG. 18 may be used to realize the hologram creating and displaying apparatus of FIGS. 13, 14, 15, and 17. Furthermore, although the above embodiment has been described as a method and a configuration for fixedly writing a hologram on a medium, a moving image can be realized by rewriting the hologram at a high speed.

[0086]

As described above, according to the present invention, the hologram phase distribution (interference fringes) in a striped area having a small width in the vertical direction and a width of the screen in the horizontal direction.
Is calculated from the three-dimensional shape data and expanded into a Fourier series, and the phase distribution of the single spatial frequency indicated by each term of the Fourier series is individually generated for each stripe region and added and synthesized on a medium having photosensitivity. By recording the hologram, it is possible to fixedly create a hologram having a stripe-like phase distribution that is the same as or similar to the calculated hologram phase distribution.

Further, the hologram can be easily reproduced from the stripe interference fringes of the recorded hologram. In addition, RGB
Color recording and reproduction of holograms can be performed by sequentially creating and reading holograms for the components. Furthermore, a moving image of a hologram can be realized by sequentially creating and reading holograms in which different stereoscopic images are recorded.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a hologram screen created by the present invention.

FIG. 2 is an explanatory diagram showing the one-dimensional phase distribution and light intensity distribution of the first to third terms by the stripe region of FIG. 2 and its Fourier series expansion.

FIG. 3 is an explanatory diagram showing a concept for optically realizing each term of Fourier series and Fourier series integration according to the present invention.

FIG. 4 is an explanatory diagram of a stripe hologram that generates two plane wave light fluxes and generates a phase distribution for each single spatial frequency after the second term of the Fourier series in the present invention.

FIG. 5 is an explanatory diagram showing a basic configuration of an optical system for forming 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.

6 is an explanatory diagram of the amplitude modulator of FIG. 5 in which a plurality of stripe-shaped liquid crystal segments are arranged.

7 is an explanatory view of the phase modulator of FIG. 5 in which a plurality of stripe-shaped liquid crystal segments are arranged.

FIG. 8 is a configuration diagram of an embodiment showing a first embodiment of the hologram creating apparatus according to the present invention.

FIG. 9 is a flowchart showing a hologram creating process according to the present invention.

FIG. 10 is a configuration diagram of an embodiment showing a second embodiment of the hologram creating apparatus according to the present invention using a galvano mirror.

FIG. 11 is an explanatory diagram showing curved scanning by the galvanometer mirror of FIG.

12 is an explanatory diagram showing the reason why the interference fringes on the image plane are not affected by the curved scanning in FIG.

FIG. 13 shows a first hologram creation / display apparatus according to the present invention.
Example configuration diagram showing an example

FIG. 14 is a second hologram creating and displaying apparatus according to the present invention.
Example configuration diagram showing an example

FIG. 15 is a structural diagram of an embodiment showing a first embodiment of a color hologram producing / displaying device according to the present invention.

16 is a timing chart showing the control of the RGB shutter and the writing operation of the RGB hologram of FIG.

FIG. 17 is a structural diagram of an embodiment showing a second embodiment of the color hologram producing / displaying device according to the present invention.

FIG. 18 is a configuration diagram of an embodiment showing a third embodiment of the hologram creating apparatus of the present invention which creates a hologram by dividing the second and subsequent terms of the Fourier series into low-order and high-order optical systems and then synthesizing them.

FIG. 19 is an explanatory diagram showing an optical system on the lower order side of FIG.

20 is an explanatory view showing generation of an interference fringe wavefront of a single spatial frequency by the optical system of FIG.

FIG. 21 is an enlarged explanatory view of the phase plate shown in FIG.

[Explanation of symbols]

10: Hologram screen 12, 12-0 to 12- (n-1): Stripe region 18, 18-0 to 18- (n-1): Striped hologram 20, 22, 24: Plane wave 26: Hologram plate 28: Medium surface 30: Amplitude modulator 32: Phase modulator 34-0 to 34- (n-1), 36-0 to 36- (n-
1): Liquid crystal segment 38: Laser light source 40: Shutter 42: Mirror 44: Objective lens 46: Pinhole 48: Collimator lens 50: Slit 52: Hologram dry plate 54: Stage 56: Scanning mechanism 58: Controller 60: Galvano mirror 62: Drive coil 80: Computer generated hologram (CGH) 82: Liquid crystal shutters 84, 88, 100: Transparent electrode 86: Liquid crystal (transmittance control type) 90, 95: Drive power supply 92: Spatial light modulator 94: Photoconductive Film 96: Dielectric mirror 98: Liquid crystal (refractive index control type) 102: Laser light source (for reading) 104: Shutter 106, 130, 132, 134, 138: Mirror 108, 126, 128: Half mirror 110: Read light 112 : Lenticular lens 114,116,1 8: a laser light source (for RGB) 120, 122, 124: shutters (for RGB) 136: beam splitter 140: cylindrical lens 142: phase plate 144: deflection hologram 146-1～3: phase deposition unit 148: surface roughness

Claims (33)

[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.
A phase distribution {F (x), which is an interference fringe of a hologram, which is divided into a plurality of stripe-shaped regions each having Ly), and which is dependent only on the horizontal parallax for each stripe region from the three-dimensional shape data of an arbitrary stereoscopic image. } And a second step of sequentially generating a plane wave having a light intensity distribution having a correlation with the phase distribution of each stripe region calculated in the first step
Step, a third step of irradiating one stripe area of the hologram creation area with the plane wave light flux generated for each stripe area in the second step, and hologram interference of the light intensity distribution irradiated in the third step. A fourth step of recording on a medium having photosensitivity while sequentially shifting the position by the stripe width as the phase distribution of the stripes, and a method for producing a computer generated hologram. 2. The method for producing a computer generated hologram according to claim 1, wherein in the first step, a phase distribution, which is a hologram interference fringe for each stripe region, is expanded by Fourier series, and in the second step, A plane wave having a constant light intensity distribution is generated over one stripe region corresponding to the first term of the Fourier series, and the amplitude (An) and the phase of each term are generated for the second and subsequent terms of the Fourier series. Two plane wave light fluxes having a constant light intensity distribution determined by (θn) are generated at an angle at which the crossing angle increases as the order increases, and the light intensity distribution of the cosine function having the period (Lx / n) of each term A method for producing a computer generated hologram, characterized in that the interference fringes are formed in the hologram production area separately for each stripe area. 3. 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 the hologram interference fringes that depend only on the horizontal parallax are expanded into Fourier series from the three-dimensional shape data of an arbitrary stereoscopic image, and the phase of the Fourier series is expanded. A computer hologram production apparatus for recording a hologram having a horizontal light intensity distribution according to a distribution on a recording medium for each stripe area. 4. 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 the hologram interference fringes that depend only on the horizontal parallax are expanded into Fourier series from the three-dimensional shape data of an arbitrary stereoscopic image, and the phase of the Fourier series is expanded. In a computer hologram creating apparatus for recording a hologram having a horizontal light intensity distribution according to a distribution on a recording medium for each stripe region, plane wave generating means for generating a coherent plane wave, and the first of the Fourier series Generates a plane wave with a constant light intensity distribution over one stripe region,
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 generated at an angle at which the crossing angle increases as the order increases. And two light flux generating means for forming interference fringes formed by a light intensity distribution of a cosine function having a period (Lx / x) of each term in the hologram forming area for each stripe area, and each stripe area by the two light flux generating means. Deflection means for collecting and optically adding two plane wave light fluxes generated for each one in one stripe area on the recording medium, and light in the horizontal direction depending on the Fourier series obtained by the addition by the deflection means. Scanning means for sequentially scanning and recording the intensity distribution for each stripe area on the recording medium;
An apparatus for creating a computer generated hologram, comprising: 5. The apparatus for creating a computer generated hologram according to claim 4, wherein the two-beam generation means determines the light intensity of the surface-wave light flux incident from the flux generation means by the amplitude (An of each term of the Fourier series. ), An amplitude modulating means for modulating the light intensity corresponding to the above, a phase modulating means for modulating the phase of the plane wave light flux incident from the light flux generating means to a phase (θn) of each term of the Fourier series, the amplitude modulating means, Two plane wave luminous fluxes are attached with a crossing angle (α) determined by each term of the Fourier series so that the plane wave luminous flux obtained through the phase modulation means is incident and interference fringes of a single frequency are formed in the hologram forming space. An apparatus for producing a computer generated hologram, comprising: a diffracting means for generating the hologram. 6. A computer-generated hologram producing apparatus according to claim 5, wherein said amplitude modulating means has a plurality of stripe-shaped regions arranged in parallel and capable of independently controlling the transmittance of a coherent plane-wave light beam. A display device,
An apparatus for producing a computer generated hologram, wherein the transmittance of each area is controlled independently so that the light intensity corresponds to the amplitude component of the Fourier series indicating the stripe area where the hologram is currently being created. 7. A liquid crystal display according to claim 5, wherein said phase modulating means has a plurality of stripe-shaped regions arranged in parallel and capable of independently controlling the phase of a coherent plane-wave light beam. An apparatus for producing a computer generated hologram, wherein each area is independently controlled so as to have a phase corresponding to a phase component of a Fourier series indicating a stripe area in which a hologram is currently being created. 8. A computer-generated hologram producing apparatus according to claim 5, wherein the diffracting means transmits the incident light beam and at the same time deflects it by providing a crossing angle (α) determined by each term of the Fourier series. 1. A computer generated hologram production apparatus comprising a hologram plate in which a plurality of stripe holograms that generate two plane wave light fluxes are arranged in parallel. 9. The computer-generated hologram producing apparatus according to claim 8, wherein two first-order diffracted light beams required for generating interference fringes are obtained by causing a plane wave light beam to enter the hologram plate at a predetermined incident angle (β). An apparatus for creating a computer generated hologram, characterized in that only the light is deflected into the hologram creation space. 10. A computer generated hologram apparatus according to claim 9, wherein the incident angle (β) of the plane wave light beam to the hologram plate is several tens of the intersection angle (α) of two light beams obtained by transmission and deflection. An apparatus for creating a computer generated hologram, which is set to double. 11. The computer generated hologram apparatus according to claim 4, wherein the plane wave generating means is a laser light source.
An objective lens that collects the laser light emitted from the laser light source, a pinhole that converts the light collected by the objective lens into a divergent spherical wave, and a spherical divergent wave from the pinhole into parallel light An apparatus for producing a computer generated hologram, comprising: a collimator lens. 12. A computer-generated hologram creating apparatus according to claim 4, wherein said scanning means includes a slit for transmitting a light beam corresponding to the stripe area and a recording medium arranged behind said slit in the stripe area. A computer generated hologram comprising: a scanning mechanism that moves in a direction orthogonal to the longitudinal direction, and the scanning mechanism moves the recording medium by the stripe width each time the exposure recording of the interference fringes of a specific stripe region is completed. Creation device. 13. A computer-generated hologram creating apparatus according to claim 4, wherein said scanning means fixedly arranges said recording medium in a hologram creating space for causing interference of two plane wave light fluxes from said two light flux generating means, In front of the recording medium, deflection scanning means for deflecting and scanning the two plane wave luminous fluxes from the two luminous flux generating means on the surface of the recording medium in a direction orthogonal to the stripe area is provided, and in synchronization with the creation of the hologram of the stripe area. An apparatus for producing a computer generated hologram, characterized in that the deflection scanning means is driven to deflect by a stripe width. 14. A computer generated hologram creating apparatus according to claim 13, wherein a galvano mirror is used as the deflection scanning means. 15. A hologram creation area (Lx × Ly)
It is divided into stripe-shaped regions having a width (Lx) in the horizontal direction and a minute width (ΔLy) in the vertical direction, and only the parallax in the horizontal direction is calculated for each stripe region from the three-dimensional shape data of an arbitrary stereoscopic image. Dependent hologram interference fringes are developed into a Fourier series, and hologram interference fringes having a horizontal light intensity distribution according to the phase distribution of the Fourier series are recorded on a recording medium for each stripe region, and hologram holograms are recorded from the recording medium. In a display device for producing a computer generated hologram for reproducing an image, a plane wave generating means for generating a coherent plane wave, and a constant light intensity distribution over one stripe region corresponding to the first term of the Fourier series Generate a plane wave,
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 generated at an angle at which the crossing angle increases as the order increases. And two light flux generating means for forming interference fringes formed by a light intensity distribution of a cosine function having a period (Lx / n) of each term in the hologram forming area for each stripe area, and each stripe area by the two light flux generating means. Deflection means for irradiating the entire area of the hologram formation area on the recording medium with two plane wave light fluxes generated for each of them and optically adding them, and a horizontal direction depending on the Fourier series obtained by the deflection addition by the deflection means. A hologram recording means for sequentially recording the light intensity distribution in each stripe area, and a hologram stereoscopic image reproduced from the hologram interference fringes recorded in the hologram recording means, and a visual display. Creating display device of a computer hologram, characterized in that it and a hologram reading means for. apparatus. 16. A hologram creation area (Lx × Ly)
It is divided into stripe-shaped areas having a width (Lx) in the horizontal direction and a minute width (ΔLy) in the vertical direction, and the three-dimensional color data of an arbitrary stereoscopic image is divided in the horizontal direction for each stripe area. Of the interference fringes depending only on the parallax of the Fourier series, and hologram interference fringes having a horizontal light intensity distribution according to the phase distribution of the Fourier series are recorded on the recording medium for each stripe region, and the recording medium is recorded. In a display device for producing a computer generated hologram for reproducing a three-dimensional image of a color hologram, a plane wave generating means for generating a coherent plane wave and a constant light beam over one stripe region corresponding to the first term of the Fourier series are provided. Generates a plane wave with an intensity distribution,
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 generated at an angle at which the crossing angle increases as the order increases. And two light flux generating means for forming interference fringes formed by a light intensity distribution of a cosine function having a period (Lx / n) of each term in the hologram forming area for each stripe area, and each stripe area by the two light flux generating means. Deflection means for irradiating the entire area of the hologram formation area on the recording medium with two plane wave light fluxes generated for each of them and optically adding them, and a horizontal direction depending on the Fourier series obtained by the deflection addition by the deflection means. A hologram recording means for recording the light intensity distribution at each stripe area and sequentially generating hologram interference fringes for one screen for each color data, and a color by the hologram recording means. The hologram recording means is irradiated with light from each light source of color data in synchronism with the recording operation of the hologram interference fringes of the data, and the hologram stereoscopic image for each color data is sequentially reproduced from the recorded hologram interference fringes for visual observation. Hologram reading means for displaying,
A display device for creating and displaying a computer generated hologram. 17. A computer generated hologram display device according to claim 4, 15 or 16, wherein said hologram recording means comprises a plurality of independently controllable areas corresponding to a plurality of stripe areas on the front surface of the recording medium. A computer-generated hologram display device, wherein a shutter device having a shutter region is arranged, and the shutter region is sequentially opened and controlled in synchronization with the hologram formation of the stripe region. 18. A computer generated hologram display device according to claim 4, 15 or 16 wherein a spatial light modulator is provided as a recording medium of said hologram recording means. . 19. The computer generated hologram display device according to claim 18, wherein the spatial modulation element has a structure in which a transparent electrode, a photoconductive film, a dielectric mirror, a liquid crystal and a transparent electrode are sequentially laminated from the incident surface side. The hologram interference fringes are written as the change in the refractive index due to the change in the voltage applied to the liquid crystal by controlling the resistance value of the dielectric mirror according to the incident light intensity, and the reading light flux is incident in the written state. A computer hologram creation and display device characterized by reproducing a hologram stereoscopic image. 20. The computer generated hologram display device according to claim 19, wherein the spatial modulation element is integrally provided with a liquid crystal shutter device on the incident surface side, and the liquid crystal shutter device and the spatial light modulation element are adjacent to each other. A computer-generated hologram display device, characterized in that transparent electrodes are integrally formed. 21. The computer generated hologram display device according to claim 4, 15 or 16, wherein a computer generated hologram element for controlling a deflection direction by a control signal from a controller is used as the deflection means. A display device for creating a computer generated hologram. 22. The computer generated hologram display device according to claim 4, 15 or 16, wherein a lenticular lens is used as the deflection means. 23. A hologram creation area (Lx × Ly)
It is divided into stripe-shaped regions having a width (Lx) in the horizontal direction and a minute width (ΔLy) in the vertical direction, and only the parallax in the horizontal direction is calculated for each stripe region from the three-dimensional shape data of an arbitrary stereoscopic image. First, the phase distribution {F (x)}, which is the interference fringe of the dependent hologram, is expanded to the Fourier series.
Step, and a plane wave light flux having a constant light intensity distribution is generated over the entire stripe region corresponding to the first term of the Fourier series developed in the first step, and the low-frequency wave after the second term of the Fourier series is generated. For the next phase term, the interference fringes formed by the light intensity distribution of the cosine function having the period (Lx / n) of each term are hologramed by the wavefront conversion of the plane wave light flux having the amplitude (An) and the phase (θn) of each term. For the higher-order phase terms after the second term of the Fourier series, two plane waves having a constant light intensity distribution determined by the amplitude (An) and the phase (θn) of each term are formed in the creation area. A second step of forming interference fringes in the hologram creation region, the interference fringes having a light intensity distribution of a cosine function having a period (Lx / n) of each term, which is generated at an angle where the crossing angle increases as the order increases; For each stripe area in two steps A third step of collecting and adding the two generated plane wave light fluxes onto one stripe area of the hologram creation area, and a light intensity distribution generated by the addition of the third step are sequentially striped as a phase distribution of hologram interference fringes. A fourth step of recording on a medium having photosensitivity while shifting the position by the width, and a method of creating a computer generated hologram. 24. A hologram creation area (Lx × Ly)
It is divided into stripe-shaped regions having a width (Lx) in the horizontal direction and a minute width (ΔLy) in the vertical direction, and only the parallax in the horizontal direction is calculated for each stripe region from the three-dimensional shape data of an arbitrary stereoscopic image. A coherent computer holographic device for developing dependent hologram interference fringes into a Fourier series and recording hologram interference fringes having a horizontal light intensity distribution according to the Fourier series on a recording medium for each stripe region Plane wave generating means for generating a flat plane wave, and a plane wave light flux having a constant light intensity distribution over one stripe region corresponding to the first term of the Fourier series, For the low-order phase term phase, the cycle (Lx /
n), a first two-beam generating means for forming interference fringes having a light intensity distribution of a cosine function in the hologram creation region, and a higher-order phase term phase after the second term of the Fourier series. Two plane wave light fluxes having a constant light intensity distribution determined by the amplitude (An) and the phase (θn) are generated at an angle where the crossing angle increases as the order increases, and each term has a period (Lx / n). A second two-beam generating means for forming interference fringes having a light intensity distribution of a cosine function in the hologram forming area, and a plane-wave light beam generated for each stripe area by the first two-beam generating means on the recording medium. First deflecting means for collecting and optically adding to one stripe area, and two interfering plane wave light fluxes generated for each stripe area by the second two light flux generating means to the stripe area on the recording medium. Same area Second deflecting means for collecting and optically adding, and light intensity distribution in the horizontal direction depending on the Fourier series obtained by the addition by the first and second deflecting means, stripes on the recording medium An apparatus for creating a computer generated hologram, comprising: a scanning unit that sequentially scans and records each area. 25. An apparatus for producing a computer generated hologram according to claim 24, wherein said first two light flux generating means determines the light intensity of the coherent plane wave light flux incident from said light flux generating means in each Fourier series. Amplitude modulation means for modulating the intensity of light corresponding to the amplitude (An) of the plane wave, and phase modulation means for modulating the phase of the plane wave light flux incident from the light flux generation means so as to become the phase (θn) of each term of the Fourier series. When,
Wavefront conversion means for entering the plane wave light flux obtained through the amplitude modulation means and the phase modulation means and performing wavefront conversion so as to generate interference fringes of a single spatial frequency in the hologram creation space, and wavefront conversion of the wavefront conversion means An apparatus for producing a computer generated hologram, comprising: a deflection means for deflecting light to a stripe region of a spectrum producing space. 26. An apparatus for producing a computer generated hologram according to claim 25, wherein said wavefront conversion means compresses a plane wave light beam in the longitudinal direction of the stripe-shaped region and then expands it, and a light beam of said cylindrical lens. An apparatus for creating a computer generated hologram, which is arranged at a converging position, and which is provided with a phase applying means for performing a wavefront conversion in which the phase of the passing light flux changes in a cosine manner at a cycle corresponding to the spatial frequency of each term of the Fourier series. 27. An apparatus for producing a computer generated hologram according to claim 26, wherein the phase imparting means uses an optical element in which a phase distribution is recorded as a surface unevenness distribution in a longitudinal direction of a stripe-shaped light flux region. Characteristic computer hologram creation device. 28. The computer generated hologram apparatus according to claim 26, wherein the phase imparting means uses an optical element in which a phase distribution is recorded as a refractive index distribution in a longitudinal direction of a stripe-shaped light flux region. Characteristic computer hologram creation device. 29. An apparatus for producing a computer generated hologram according to claim 24, wherein the second two-beam generating means determines the light intensity of the coherent plane-wave light beam incident from the light-beam generating means in each of the Fourier series. Amplitude modulation means for modulating the intensity of light corresponding to the amplitude (An) of the plane wave, and phase modulation means for modulating the phase of the plane wave light flux incident from the light flux generation means so as to become the phase (θn) of each term of the Fourier series. When,
The plane wave light flux obtained through the amplitude modulation means and the phase modulation means is made incident and a crossing angle α determined by each term of the Fourier series is added so that interference fringes of a single spatial frequency are generated in the hologram creation space. An apparatus for producing a computer generated hologram, comprising: a diffracting means for generating two plane wave light fluxes. 30. An apparatus for producing a computer generated hologram according to claim 25 or 29, wherein said diffracting means transmits an incident light beam and at the same time deflects it by providing a crossing angle α determined by each term of the Fourier series. A computer generated hologram production apparatus comprising a hologram plate in which a plurality of stripe holograms for generating two plane wave light fluxes are arranged in parallel. 31. An apparatus for producing a computer generated hologram according to claim 25 or 29, wherein said amplitude modulating means has a plurality of stripe-shaped regions arranged in parallel so that the transmittance of a coherent plane-wave light beam can be independently controlled. A computer-generated hologram characterized by controlling the transmittance of each area independently so that the light intensity corresponds to the amplitude component of the Fourier series indicating the stripe area where the hologram is currently being created. apparatus. 32. An apparatus for producing a computer generated hologram according to claim 25 or 29, wherein said phase modulating means has a plurality of stripe-shaped regions arranged in parallel and capable of independently controlling the phase of a coherent plane wave light beam. An apparatus for producing a computer generated hologram, which is a liquid crystal display device, wherein the phase of each area is independently controlled so that the light intensity corresponds to the phase component of the Fourier series indicating the stripe area where the hologram is currently being created. 33. The computer generated hologram apparatus according to claim 24, wherein the plane wave generating means includes a laser light source, an objective lens for converging laser light oscillated from the laser light source, and the objective lens. A pinhole that converts the condensed light into a divergent spherical wave, a collimator lens that converts the spherical divergent wave from the pinhole into parallel light, and a light beam from the collimator lens is divided into two light beams, An apparatus for producing a computer generated hologram, comprising: a second two-beam generating means and a beam splitter which is incident on it.