JP5540353B2 - Electronic holography reproduction apparatus and electronic holography reproduction method - Google Patents

Description

  The present invention relates to an electronic holography reproduction device and an electronic holography reproduction method for reproducing a stereoscopic video by enlarging a viewing zone.

In recent years, display technology capable of stereoscopic viewing by electronic holography has been actively developed. This electronic holography displays interference fringes formed by interference between reference light having the same phase and object light produced by the same light being scattered by an object on a hologram display panel such as a liquid crystal display. This is a stereoscopic video reproduction method of reproducing original object light as reproduction light by using a diffraction effect generated by irradiating illumination light having the same wavelength as that of reference light.
In this electronic holography, the spread angle θ of the reproduction light is limited by the following equation (1) from the pixel interval p of the hologram display panel and the wavelength λ of the reproduction light.

For this reason, a currently available hologram display panel cannot obtain a large divergence angle and can only obtain a viewing area of about 2 ° (degrees), making it difficult to view a reproduced image with both eyes.
Therefore, conventionally, a technique for expanding the viewing area of the reproduced video has been proposed (see Patent Document 1).

  In the invention described in Patent Document 1 (prior invention), a plurality of interference fringes having different spread ranges of reproduction light are obtained, and these are displayed on different hologram display panels (interference fringe display surfaces) to provide illumination light. Irradiate. The prior invention expands the viewing zone by taking out reproduction light (hologram reproduction light) obtained as high-order diffracted light from the hologram display panel with a lens or a spatial filter and superimposing it with a half mirror.

Japanese Patent No. 3914650 (paragraph 0027, FIG. 6)

  However, the above-described prior invention is an optical system including a lens, a spatial filter, a half mirror, and the like for extracting desired diffracted light from reproduction light reproduced by a plurality of hologram display panels in order to enlarge the viewing zone. There are problems that a plurality of systems are required, the electronic holography reproducing apparatus is large, and the configuration is complicated.

  The present invention has been made in view of such problems, and it is an object of the present invention to provide an electronic holography reproduction device and an electronic holography reproduction method capable of enlarging the viewing zone with a simple optical system configuration. To do.

  The present invention has been made to solve the above-mentioned problems. First, an electronic holographic reproducing device according to claim 1 is an electronic holographic reproducing device that generates a reproduced image from an electronically generated hologram. The hologram storage unit, the light source, the diffraction unit, the illumination light selection unit, the hologram display unit, the optical path changing unit, and the reproduction light selection unit are provided.

  In such a configuration, the electronic holography reproducing device stores the electronically generated hologram in the hologram storage means. This hologram is different for each viewing zone in the horizontal direction (left-right direction). Then, the electronic holography reproducing device generates a plurality of diffracted lights having different diffraction angles in the horizontal direction (left-right direction) from the parallel light generated by the light source by the diffraction unit.

  Then, the electronic holography reproducing apparatus selects the illumination light by switching the plurality of diffracted lights generated by the diffracting means to be time-division switched by the illumination light selecting means. As described above, by selecting diffracted light diffracted at a plurality of angles in a time division manner, illumination lights at a plurality of angles are generated in a time division manner.

In addition, the electronic holography reproducing apparatus is configured such that the hologram display unit disposed at a position irradiated with the illumination light passing through the illumination light selection unit synchronizes with the illumination light switching timing in the illumination light selection unit and tilts the illumination light. A hologram in the viewing zone corresponding to the angle is read from the hologram storage means and displayed. In this way, illumination light with different angles in time division is irradiated onto the hologram display means, and in synchronization with it, the hologram display means displays a hologram in the viewing zone corresponding to the angle, so that the viewing zone in time division is displayed. Different reproduction light is generated. In the electronic holography reproducing apparatus, the optical path changing means changes the optical path of the reproducing light generated when the hologram display means is irradiated with the illumination light to an optical path in a direction different from the optical path of the illumination light .

  The electronic holography reproduction apparatus corresponds to each viewing area among the reproduction lights generated from the hologram display means by the reproduction light selection means arranged at the position irradiated with the reproduction light whose optical path is changed by the optical path changing means. The angle reproduction light is switched in synchronization with the switching timing of the illumination light and allowed to pass therethrough. In this way, by selecting only the reproduction light having an angle corresponding to the viewing zone, higher-order reproduction light included in the reproduction light generated from the hologram display unit is blocked. Then, the reproduction light having different viewing zones is time-division multiplexed and output, so that the viewer can visually recognize the reproduction light (hologram reproduction light) having a wide viewing zone.

  The electronic holography reproducing device according to claim 2 is an electronic holographic reproducing device for generating a reproduced image from an electronically generated hologram, comprising a hologram storage means, a light source, a diffraction means, a multiplexing means, The illumination light selection means, the hologram display means, the separation / multiplexing means, the optical path changing means, and the reproduction light selection means are provided.

  In such a configuration, the electronic holography reproducing device stores the electronically generated hologram in the hologram storage means. This hologram is a hologram that is different for each horizontal (horizontal) viewing area and is different for each of the three primary colors of light. The electronic holography reproducing device generates a plurality of diffracted lights having different diffraction angles in the horizontal direction (left and right direction) from the parallel light generated by the light sources of the three primary colors by the diffracting means for each color. The electronic holography reproducing device multiplexes a plurality of diffracted lights generated by the diffractive means corresponding to each light source by the multiplexing means.

  Then, the electronic holography reproducing apparatus selects the illumination light by passing the plurality of diffracted lights multiplexed by the multiplexing means switched in a time division manner by the illumination light selecting means. As described above, by selecting diffracted light diffracted at a plurality of angles in a time division manner, illumination lights at a plurality of angles are generated in a time division manner.

  Further, the electronic holography reproducing device is arranged at a position irradiated with illumination light passing through the illumination light selection means, and is synchronized with the illumination light switching timing in the illumination light selection means by the respective hologram display means corresponding to the three primary colors. Then, a hologram in the viewing zone corresponding to the tilt angle of the illumination light is read from the hologram storage means and displayed.

Then, the electronic holography reproducing device uses a separation / multiplexing unit installed between the illumination light selecting unit and the hologram display unit to convert the illumination light having different inclination angles selected by the illumination light selecting unit into a hologram corresponding to the three primary colors. The display means is irradiated separately for each color. In this way, illumination light with different angles in time division is irradiated onto the hologram display means, and in synchronization with it, the hologram display means displays a hologram in the viewing zone corresponding to the angle, so that the viewing zone in time division is displayed. Different reproduction light is generated for each color.
Further, the electronic holography reproducing device multiplexes the reproduction light generated from each hologram display means by the separating / multiplexing means. The electronic holography reproducing apparatus, the optical path changing means, for changing the optical path of the direction different from the optical path of the illumination light selecting the optical path of the multiplexed separation and multiplexing means reproducing light illuminating light selecting means.

  Then, the electronic holography reproduction device is configured to reproduce each of the reproduction lights multiplexed by the separation / multiplexing means by the reproduction light selecting means arranged at the position irradiated with the reproduction light whose optical path has been changed by the optical path changing means. The reproduction light having an angle corresponding to the area is switched in synchronization with the switching timing of the illumination light and allowed to pass therethrough. In this way, by selecting only the reproduction light having an angle corresponding to the viewing zone, higher-order reproduction light included in the reproduction light generated from the hologram display unit is blocked. Then, reproduction light having different viewing zones is time-division multiplexed and output, so that the viewer can visually recognize color reproduction light (hologram reproduction light) with a wide viewing zone.

  The electronic holography reproducing device according to claim 3 is the electronic holographic reproducing device according to claim 1 or 2, wherein the illumination light selecting means is located at a position separated from the diffraction means by a focal length on the optical path. The plurality of diffracted lights are arranged by switching the apertures in a time-sharing manner by arranging the first lens and the first lens away from the first lens by a focal length of the first lens in the light traveling direction. And a second lens having the same focal length as the first lens disposed at a position spaced from the first shutter by a focal length in the light traveling direction. And the hologram display means is arranged to be separated from the second lens by the focal length on the optical path.

  In such a configuration, the electronic holography reproducing device separates the diffractive means, the first lens, the first shutter, the second lens, and the hologram display means on the optical path by the focal point of the first lens (second lens). By arranging, the diffracted light generated by the diffracting means is condensed at different positions of the first shutter serving as the focal plane of the first lens for each diffracted light corresponding to the diffraction angle. In addition, the second lens can sequentially irradiate the light diffused from the first shutter as the focal plane as illumination light on the display surface of the hologram display means as original parallel light.

  Furthermore, the electronic holography reproducing device according to claim 4 is the electronic holographic reproducing device according to any one of claims 1 to 3, wherein the reproduction light selecting means is connected to the focal point on the optical path from the hologram display means. A third lens disposed at a position separated by a distance, and a position separated from the third lens by a focal distance of the third lens in the light traveling direction, and condensed by the third lens. Of the reconstructed light, a reconstructed light having an angle corresponding to the viewing zone is passed through the second shutter while switching the opening in a time-sharing manner, and is separated from the second shutter by a focal length in the light traveling direction. A fourth lens having the same focal length as that of the third lens disposed at the position.

  In such a configuration, in the electronic holography reproducing apparatus, the hologram display means, the third lens, the second shutter, and the fourth lens are arranged on the optical path at a distance of the focal length of the third lens (fourth lens). Thus, the reproduction light emitted from the hologram display means is condensed at different positions of the second shutter serving as the focal plane of the third lens for each reproduction light having an angle corresponding to the viewing zone. In addition, the fourth lens generates an image reproduced from the light diffused from the second shutter, which is the focal plane, at the position separated by the focal length as the original parallel light.

  The electronic holography reproducing device according to claim 5 is the electronic holographic reproducing device according to claim 4, wherein the opening of the second shutter is arranged so that light having the maximum diffraction angle of the hologram display means is emitted from the second shutter. It has an opening width corresponding to the irradiation width irradiated to.

  In such a configuration, the electronic holography reproducing device sets the opening width of the opening of the second shutter to a width at which the light with the maximum diffraction angle of the hologram display unit is irradiated to the second shutter, thereby Of the reproduction light, high-order reproduction light that is larger than the maximum diffraction angle is blocked by the second shutter, and unnecessary light can be removed.

  An electronic holography reproduction method according to claim 6 is an electronic holography reproduction method for generating a reproduction image from an electronically generated hologram, comprising a diffracted light generation step, a reproduction light generation step, and an optical path changing step. And a reproduction light selection step.

  In this procedure, the electronic holography reproducing method generates a plurality of diffracted lights having different diffraction angles in the horizontal direction from the parallel light generated by the light source by the diffracting means in the diffracted light generating step. The electronic holography reproduction method irradiates the hologram display means as illumination light by passing the plurality of diffracted lights generated in the diffracted light generation step in a time division manner by the illumination light selection means in the reproduction light generation step. At the same time, in synchronization with the switching timing of the illumination light in the illumination light selection means, the hologram in the viewing zone corresponding to the tilt angle of the illumination light is read out from the previously stored hologram storage means and displayed on the hologram display means. Is generated.

In the electronic holography reproduction method, the optical path of the reproduction light generated in the reproduction light generation step is changed to an optical path in a direction different from the optical path of the illumination light by the optical path changing means installed at the irradiation position of the reproduction light. In the electronic holography reproduction method, in the reproduction light selection step, among the reproduction lights whose optical paths are changed in the optical path change step, the reproduction light having an angle corresponding to the viewing zone is used as the illumination light switching timing by the reproduction light selection means. Switch in sync and pass.

  Furthermore, the electronic holography reproduction method according to claim 7 is an electronic holography reproduction method for generating a reproduction image from an electronically generated hologram, comprising a diffracted light generation multiplexing step, a reproduction light generation multiplexing step, The procedure includes an optical path changing step and a reproduction light selecting step.

  In such a procedure, the electronic holography reproducing method generates a plurality of diffracted lights having different diffraction angles in the horizontal direction from the parallel light generated by the light sources of the three primary colors of light by the diffracting means corresponding to the light source in the diffracted light generation multiplexing step. And multiplexed by the multiplexing means.

The lighting, electronic holography reproducing method, the reproduction light generated multiplexing step, a plurality of diffracted light are multiplexed to generate the diffraction light generation multiplexing step, by switching Rukoto time division by the illumination light selection means, the selected The light is transmitted as light, and is separated and irradiated for each color on the hologram display means corresponding to the three primary colors by the separation / multiplexing means. Further, in the electronic holography reproduction method, in synchronization with the illumination light switching timing in the illumination light selection means, the hologram in the viewing zone corresponding to the tilt angle of the illumination light is read out from the hologram storage means stored in advance. Reproduction light is generated by displaying on the hologram display means, and the reproduction light for each hologram display means corresponding to the three primary colors is multiplexed by the separation / multiplexing means.

The electronic holography reproducing method, the optical path of reproduction light obtained by multiplexing the reproduction light generated multiplexing step, the optical path changing means installed at the irradiation position of the reproduction light, the illumination light selected by the illuminating light selecting means The optical path is changed to a direction different from the optical path. Then, the electronic holography reproduction method uses the reproduction light selection means to convert the reproduction light having an angle corresponding to each viewing zone out of the reproduction light whose optical path is changed in the optical path change step in the reproduction light selection step. Synchronize with and pass through.

The present invention has the following excellent effects.
According to the first and sixth aspects of the invention, after extracting the diffracted light from the light from the light source, each light is switched in a time division manner as illumination light, and the reproduction light corresponding to the angle of the illumination light is time-multiplexed. Therefore, it is not necessary to provide a plurality of configurations for individually generating illumination light having different angles and generating each reproduction light individually, and the optical system can be easily configured. As a result, the present invention can expand the viewing area of the hologram while reducing the size of the apparatus itself to about 1/3 or less of the conventional apparatus.

  According to the second and seventh aspects of the present invention, even when a stereoscopic image is reproduced from a color hologram, after extracting diffracted light from the light from the light source, the respective lights are switched in a time division manner as illumination light. Since the reproduction light corresponding to the angle of the illumination light is time-multiplexed, it is not necessary to provide a plurality of configurations for individually generating the illumination light having different angles or individually generating the respective reproduction lights. The system can be configured easily. Thereby, the present invention can enlarge the viewing area of the hologram while downsizing the apparatus itself.

  According to the third aspect of the present invention, since illumination light with different angles can be generated in a time-sharing manner, the optical system can be configured simply as compared with the case where illumination light with different angles are individually generated. it can.

  According to the fourth and fifth aspects of the present invention, when generating hologram reproduction light in different viewing zones in a time-sharing manner, unnecessary light such as higher-order reproduction light can be removed from the reproduction light. Therefore, clear hologram reproduction light can be generated.

It is a block diagram which shows the structure of the electronic holography reproducing | regenerating apparatus concerning 1st Embodiment of this invention. It is explanatory drawing for demonstrating the lattice fringe space | interval of a diffraction means. It is explanatory drawing for demonstrating the mechanism of the separation / multiplexing of the colored light in a multiplexing means and a demultiplexing means. It is explanatory drawing for demonstrating the mechanism of the illumination light switching in an illumination light selection means. It is explanatory drawing for demonstrating the mechanism of switching of the reproduction | regeneration light in the reproduction | regeneration light selection means. It is a timing chart figure which shows an example of the timing signal which a switching control means produces | generates. It is a block diagram which shows the structure of the electronic holography reproducing | regenerating apparatus which concerns on 2nd Embodiment of this invention.

Embodiments of the present invention will be described below with reference to the drawings.
[First Embodiment]
[Configuration of electronic holography playback device]
First, with reference to FIG. 1, the structure of the electronic holography reproducing | regenerating apparatus concerning 1st Embodiment of this invention is demonstrated. The electronic holography reproducing device 1 generates a reproduction image from an electronically generated hologram of a color image.

  Here, the electronic holography reproducing apparatus 1 includes a light source 2, a diffraction unit 3, a multiplexing unit 4, an illumination light selection unit 5, a hologram display unit 6, a separation / multiplexing unit 7, and an optical path changing unit 8. A reproduction light selection means 9, a hologram storage means 10, a switching control means 11, and a readout switching means 12.

The light source 2 generates parallel light. Here, the light source 2 corresponds to a color, and a R (red) light source _{2 1} and G (green) light source _{2 2} and B (blue) light source _{2 3} for generating a parallel beam of RGB are three primary colors of light I have. The light source 2 (2 ₁ , 2 ₂ , 2 ₃ ) emits parallel light from one side of the diffractive means 3 (3 ₁ , 3 ₂ , 3 ₃ ), and diffracted light is multiplexed from the other side of the diffractive means 3. It is arranged at a position where the means 4 is irradiated.
As the light source 2 (2 ₁ , 2 ₂ , 2 ₃ ), a laser or a light emitting diode (LED) that emits each color can be used.
In addition, R light source 2 ₁ irradiates parallel beams generated in the diffraction means 3 _1. Also, G light source 2 ₂ irradiates parallel beams generated in the diffraction unit 3 _2. Further, B light source 2 ₃ irradiates parallel beams generated in the diffraction unit 3 _3.

The diffracting means 3 generates a plurality of diffracted lights having different diffraction angles in the horizontal direction (left-right direction) from the parallel light generated by the light source 2. The diffraction means 3 can be a diffraction grating (gratings) having grating fringes at predetermined intervals.
Here, the diffracting means 3 includes three diffracting means 3 ₁ , 3 ₂ , and 3 ₃ corresponding to the R light source 2 ₁ , the G light source 2 ₂ , and the B light source 2 ₃ , respectively. That is, the diffraction means _{3 1} diffracts parallel light R light source _{2 1,} the diffraction means _{3 2} diffracts parallel light G light source _{2 2,} the diffraction means _{3 3} is the B light source _{2 3} parallel light Diffraction.

This diffractive means 3 (3 ₁ , 3 ₂ , 3 ₃ ) is arranged at a position where parallel light is irradiated from the light source 2 (2 ₁ , 2 ₂ , 2 ₃ ), and further, each diffractive means 3 ₁ , 3 Reference numerals ₂ and 3 ₃ are arranged at positions facing the incident surfaces for the respective colors of the multiplexing means 4 when the multiplexing means 4 multiplexes the light. Thus, the diffracted light diffracted by the respective diffraction means 3 ₁ , 3 ₂ , 3 ₃ is incident on the multiplexing means 4.

Further, it is assumed that the diffraction means 3 ₁ , 3 ₂ , 3 ₃ all have the same angle of diffraction light (diffraction angle). That is, if the lattice fringe spacing is the same, the diffraction angle is different for each color. Therefore, the diffraction means 3 ₁ , 3 ₂ , 3 ₃ are arranged so that the diffraction angles of the n-th order beams are the same. It is assumed that the lattice fringe spacing is different for each color. Thereby, in the multiplexing means 4, the diffracted light incident from the diffracting means 3 ₁ , 3 ₂ , 3 ₃ can be multiplexed with lights having the same diffraction angle.

  Further, the diffracted light diffracted by the diffracting means 3 acts as illumination light for irradiating a hologram display means 6 described later. This diffracted light is used in the hologram display means 6 to expand the viewing zone by using ± 1st-order diffracted light as illumination light in addition to 0th-order diffracted light that is straight light.

Here, the configuration of the diffraction means 3 (3 ₁ , 3 ₂ , 3 ₃ ) will be described more specifically with reference to FIG. 2 (refer to FIG. 1 as appropriate).
As shown in FIG. 2A, the diffracting means 3 generates 0th-order diffracted light C that is straight light and ± 1st-order diffracted lights R and L that are diffracted in the left-right direction by diffracting the parallel light by lattice fringes. The diffracting means 3 also generates higher-order diffracted light larger than the first order, but is not shown here. Here, the diffraction angle θ is given by the following equation (2), where λ is the wavelength of light and p is the interval between lattice fringes.

Further, as shown in FIG. 2B, this equation (2) is an electronically generated hologram (interference fringe: minimum) displayed by the hologram display means 6 when the pixel interval of the hologram display means 6 is p. This also holds as the spread angle θ of the reproduction light that can be diffracted at an interval of 2 pixels.
In the diffracting means 3, this is the interval between adjacent lattice fringes (interval between black lines, or interval between portions where white light passes between the black lines), and the diffraction angle θ is determined and fixed by the equation (2). However, in the hologram display means 6, in order to obtain a free diffraction angle, it is necessary to create a checkered pattern with a pair of white and black pixels. If at least two pixels are not used, a checkered pattern with an arbitrary interval cannot be drawn, and the maximum diffraction angle. This is because one side θ / 2.

  Therefore, by using the same pattern as the pixel spacing of the hologram display means 6, the ± 1st order diffracted light (± 1st order diffracted light R, L) generated by the diffracting means 3 is used. The viewing zone in the hologram display means 6 can be enlarged by the angle 2θ (= θ + θ) formed by the next diffracted beams.

For example, when the pixel interval p of the hologram display means 6 is 4.8 μm, the wavelength λ _{R of} red light is 660 nm, the wavelength λ _{G of} green light is 532 nm, and the wavelength λ _{B of} blue light is 475 nm, the equation (2) The diffraction angle of blue light is the smallest, and θ≈λ _B /p=0.475/4.8=5.68 (degrees).

Therefore, the lattice fringes spacing _{p R} of the diffraction means _{3 1} for diffracting the red light, from the equation (2), and _{p R} = _{λ R /sinθ=0.660/sin(5.68} degrees) = 6.67Myuemu . Further, the lattice fringes spacing _{p G} of the diffraction means _{3 2} which diffracts green light, from the equation (2), and _{p G} = _{λ G /sinθ=0.532/sin(5.68} degrees) = 5.38Myuemu . Further, the lattice fringes spacing p _B of the diffraction means 3 ₂ for diffracting blue light, the same 4.8μm as the pixel spacing p of the hologram display means 6. As a result, red, green, and blue (RGB) light is all diffracted at 5.68 degrees.
Returning to FIG. 1, the description of the configuration of the electronic holography reproducing device 1 will be continued.

The multiplexing means 4 multiplexes red light, green light and blue light. Here, the multiplexing means 4 multiplexes the RGB diffracted lights diffracted by the diffraction means 3 ₁ , 3 ₂ , 3 ₃ . That is, since the multiplexing means 4 multiplexes the light incident from the three directions in one direction and outputs the multiplexed light, the diffracted light exit surfaces of the diffracting means 3 ₁ , 3 ₂ , 3 ₃ are Each color light is installed so as to face the incident surface, and the light emitting surface of the multiplexing unit 4 is installed so as to face the illumination light selecting unit 5.

  The multiplexing means 4 can be constituted by a prism, for example. As shown in FIG. 3A, this prism is formed by combining four triangular prisms (triangular prism P) into a rectangular parallelepiped. A red reflection film that reflects only red light and a blue reflection film that reflects only blue light are attached to the surfaces to which the prisms of each triangular prism are joined.

Thus, as shown in FIG. 3 (b), multiplexing means 4, the red (R) light diffracted by the diffraction means 3 ₁ is reflected at a right angle with red reflective film, which is diffracted by the diffraction means 3 ₂ blue (B) light is reflected at a right angle in blue reflective film, the diffraction means 3 ₂ diffracted green (G) is a light that is as straight multiplexes RGB light.

The multiplexing means 4 may be one in which half mirrors that reflect and transmit half of the amount of light instead of prisms are orthogonal to each other. Or you may use what made the dichroic mirror which stuck the film | membrane which reflects only red light and blue light orthogonally crossed.
The multiplexed RGB light is incident on the lens 51 of the illumination light selection unit 5.

  The illumination light selection means 5 selects illumination light by switching a plurality of diffracted lights generated by the diffraction means 3 to pass through in a time division manner. The illumination light selection means 5 is installed so as to face the exit surface that emits the multiplexed diffracted light of the multiplexing means 4. Here, the illumination light selection means 5 time-divides the 0th-order diffracted light, which is straight-ahead light, and the diffracted light (± 1st-order diffracted light) diffracted in the horizontal (left-right) direction from the diffracted light diffracted by the diffracting means 3. Select to switch the output.

The illumination light selection unit 5 includes a lens 51, a shutter 52, and a lens 53. The lens 51 is disposed on the optical path from the diffractive means 3 (3 ₁ , 3 ₂ , 3 ₃ ) at a position separated by the focal length of the lens 51, and a shutter 52 is disposed at a position separated by the focal distance. Has been. Further, the lens 53 is disposed on the opposite side of the lens 51 from the shutter 52 on the optical path at a position separated by the focal length of the lens 53.

  Here, the lens 51 and the lens 53 are lenses having the same focal length, but lenses having different focal lengths may be used. In this case, when the ratio of the focal lengths of the lens 51 and the lens 53 is f1: f2, when the diffraction angle of the diffraction means 3 is θ1, and the diffraction angle of the hologram display means 6 is θ2, θ2 = θ1 × f1 / f2. What is necessary is just to have a relationship.

The lens 51 collects the diffracted light (0th-order diffracted light C, ± 1st-order diffracted light R, L; see FIG. 2) emitted from the diffracting means 3 (3 ₁ , 3 ₂ , 3 ₃ ) on the shutter 52. It is. The lens 51 can be constituted by a convex lens, for example.
The lens 51 receives the diffracted light from the diffractive means 3 (3 ₁ , 3 ₂ , 3 ₃ ) separated by the focal length and collects it on the shutter 52 arranged on the rear focal plane. The folded light C and the ± first-order diffracted lights R and L are collected at different positions of the shutter 52. That is, the 0th-order diffracted light C is condensed on the central region (region S _C ) of the shutter 52, and the ± 1st-order diffracted lights R and L are condensed on the left and right regions (regions S _R and S _L ) of the shutter 52. .

The shutter 52 allows the diffracted light collected by the lens 51 to be switched in a time-sharing manner for each type of diffracted light (0th order diffracted light C, ± 1st order diffracted light R, L). That is, the shutter 52 has openings that can open and close the regions S _R , S _C , and S _L , respectively, and sequentially opens the openings to sequentially switch the emitted diffracted light. For example, the shutter 52 can be composed of a liquid crystal panel or a rotating disk provided with slits at different positions in the radial direction.

The region _{S R,} S C, aperture size of _{S L} is sized to only 0-order diffracted light passes through the central area _{S C.} Specifically, when the focal length of the lens 51 is f and the diffraction angle of the diffracting means 3 is θ (see FIG. 2A), the aperture size W can be determined by the following equation (3).

In addition, the shutter 52 switches which region is opened in synchronization with a timing signal output from the switching control unit 11 described later. Here, the shutter 52 receives timing signals (T _L , T _C , T _R ) as shown in FIG. 6A, and −1 next time in a time interval in which the timing signal T _L is “Low (L)”. and exposing the region _{S L} where diffracted light L is converged, the timing signal _{T C} is "Low (L)" of the zero-order diffracted light C is opened the area _{S C} of condensing in a time interval, the timing signal _{T R} is "Low (L) is 1-order diffracted light R at the time interval of "opening the area S _R to condense.
Thus, the light that sequentially passes through the shutter 52 enters the lens 53.

The lens 53 returns the light passing through the shutter 52 to the original straight light and the parallel light diffracted left and right. The lens 53 can be constituted by a convex lens, for example.
The lens 53 is arranged at a position away from the shutter 52 by the focal length, and further, as will be described later, the hologram display means 6 is arranged at a position away from the shutter by the focal length on the optical path. As a result, the lens 51 converts the light diffused from the shutter 52, which is the focal plane, into parallel light diffracted left and right with the original straight light, and sequentially irradiates the display surface of the hologram display means 6 as illumination light. Can do.

Here, with reference to FIGS. 4 and 6 (refer to FIG. 1 as appropriate), a mechanism for switching the illumination light in the illumination light selection means 5 will be described in detail.
As shown in FIG. 4A, the diffracting means 3, the lens 51, and the shutter 52 are spaced apart from each other by the focal length f of the lens 51, and therefore the 0th-order diffracted light C diffracted by the diffracting means 3 is used. through the lens 51, it is focused on the area _{S C} of the shutter 52.

On the other hand, the shutter 52 is, for example, the timing signal _{T C} as shown in FIG. 6 (a) to open the area _{S C} a time interval of "Low (L)". Thereby irradiation, in the time interval of the timing signal T _C is "Low (L)", as only the light passing through the area S _C of the shutter 52 is, the original parallel straight light on the hologram display means 6 through the lens 53 Is done. At this time, the shutter 52 and the lens 53 and the hologram display unit 6, because of the spaced apart by the focal length f of each lens 53, light passing through the area S _C of the shutter 52, the original parallel straight Light (illumination light) is applied to the hologram display means 6.

Further, as shown in FIG. 4 (b), 1-order diffracted light R which is diffracted by the diffraction means 3, through the lens 51, is focused on the area S _R of the shutter 52. On the other hand, the shutter 52 is, for example, the timing signal _{T R} as shown in FIG. 6 (a) to open the area _{S R} in the time interval of the "Low (L)". Thereby, in the time interval of the timing signal T _R is "Low (L)", only the light passing through the area S _R of the shutter 52 through the lens 53 hologram display means 6 into the original parallel diffracted light (illumination Light). The diffracted light is incident as −1st order diffracted light L having a diffraction direction different from that of the 1st order diffracted light R. However, when reflected by the hologram display means 6, it acts as the first order diffracted light R in the original diffraction direction. become.

Further, as shown in FIG. 4 (c), -1-order diffracted light L is diffracted by the diffraction means 3, through the lens 51, is focused on the area S _L of the shutter 52. On the other hand, the shutter 52 is, for example, the timing signal _{T L} as shown in FIG. 6 (a) to open the area _{S L} in a time interval of "Low (L)". Thereby, in the time interval of the timing signal T _L is "Low (L)", only the light passing through the area S _L of the shutter 52, through a lens 53 hologram display means 6 into the original parallel diffracted light (illumination Light). This diffracted light is incident as a first-order diffracted light R having a diffraction direction different from that of the −1st-order diffracted light L, but acts as a −1st-order diffracted light L in the original diffraction direction when reflected by the hologram display means 6. It will be.

As described above, the illumination light selection means 5 can switch the illumination light applied to the hologram display means 6 to the 0th-order diffracted light C and the ± 1st-order diffracted lights R and L based on the timing signal output from the switching control means 11. .
Returning to FIG. 1, the description of the configuration of the electronic holography reproducing device 1 will be continued.

The hologram display means 6 displays hologram data (hologram pattern). For example, the hologram display means 6 can be composed of a liquid crystal panel. Alternatively, a micro mirror (digital micromirror device) in which minute mirrors capable of electrically changing the light reflection direction are arranged in units of pixels may be used. Here, the hologram display means 6 includes a hologram display means ₆₁ for red display for displaying the RGB respective hologram data, the hologram display means 6 ₂ for green display, and a hologram display means 6 ₃ for blue display I have.

The hologram display means 6 ₁ , 6 ₂ , 6 ₃ are arranged at positions separated from the lens 53 by the focal length of the lens 53 on the optical path. Further, here, the hologram display means 6 ₁ , 6 ₂ , 6 ₃ are rotated by 90 degrees in order to receive the reflected light (illumination light) separated for each color by the separating / multiplexing means 7 described later. Placed in position.

In this hologram display means 6 (6 ₁ , 6 ₂ , 6 ₃ ), hologram data with different viewing zones stored in the hologram storage means 10 switched via the read switching means 12 described later are sequentially switched and read out. Thus, the hologram data is displayed.
It should be noted that reproduction light (hologram light) is generated by irradiating illumination light from the lens 53 with the hologram data displayed.

  The separation / multiplexing means 7 separates the light in which the RGB color lights are multiplexed into the R, G, B color lights or multiplexes the R, G, B color lights. is there. The separating / multiplexing means 7 is installed so that the surface for inputting / outputting the multiplexed light is opposed to the illumination light selecting means 5, and the surface for inputting / outputting the colored light in a state of being separated is a hologram display corresponding to each color light. It is installed so as to face the means 6. The demultiplexing / multiplexing means 7 can be constituted by a prism as in the multiplexing means 4 (see FIG. 3). Or you may use what made the dichroic mirror which stuck the film | membrane which reflects only red light and blue light orthogonally crossed.

Here, the separation and multiplexing means 7, the light selected by the illuminating light selecting means 5 (illumination light), R, G, is separated into color light of B, the hologram display means ₆₁ corresponding to the respective colors , 6 ₂ , 6 ₃ . Further, the demultiplexing / multiplexing means 7 reproduces light of R, G, B colors (reproduced by illumination lights of R, G, B colors) in the hologram display means 6 ₁ , 6 ₂ , 6 ₃ ( Holographic light) is multiplexed. The multiplexed reproduction light is incident on the reproduction light selection means 9 via the optical path changing means 8.

The optical path changing means 8 changes the traveling direction of the reproduction light reproduced by the hologram display means 6 (6 ₁ , 6 ₂ , 6 ₃ ). For example, the optical path changing means 8 can be constituted by a prism. As this prism, it is possible to use a prism in which a film that performs a transmission to reflection ratio of 1: 1 is attached to the joint surface of two triangular prisms. Moreover, a half mirror may be used for the optical path changing means 8. When the hologram display means 6 is a liquid crystal panel, a polarization beam splitter (PBS) using the fact that the polarization plane of light rotates by 90 degrees in the liquid crystal panel may be used. In this case, by aligning the polarization plane of the illumination light with the transmission direction of the PBS, the illumination light passes almost without attenuation and is reflected by the liquid crystal surface, and the reflected light whose polarization plane is rotated by 90 degrees is almost attenuated. Without being reflected by the same PBS and separated from the optical path of the illumination light.

  This optical path changing means 8 is installed between the illumination light selection means 5 and the hologram display means 6, transmits the light incident from the illumination light selection means 5, and displays the hologram via the separation / multiplexing means 7. The light is irradiated on the means 6, and the direction of the light incident from the hologram display means 6 through the separation / multiplexing means 7 is changed by 90 degrees and reflected by the reproduction light selection means 9.

  The reproduction light selection means 9 is the reproduction light having an angle corresponding to each viewing area among the reproduction lights generated by sequentially irradiating the hologram display means 6 with the illumination light having different inclination angles selected by the illumination light selection means 5. Are switched in synchronization with the switching timing. The reproduction light selecting means 9 is installed at a position for receiving the reproduction light of the hologram whose optical path has been changed by the optical path changing means 8. Here, the reproduction light selection means 9 corresponds to the reproduction light in the viewing zone corresponding to the 0th-order diffracted light C and the ± 1st-order diffracted lights R and L from the reproduction light of the hologram whose optical path has been changed by the optical path changing means 8. Each reproduction light is selected in a time-sharing manner, and the output is switched.

The reproduction light selecting unit 9 includes a lens 91, a shutter 92, and a lens 93. The lens 91 is disposed on the optical path from the hologram display means 6 (6 ₁ , 6 ₂ , 6 ₃ ) at a position separated from the focal length of the lens 91, and a shutter 92 is located at a position separated by the focal distance. Has been placed. Further, the lens 93 is disposed at a position away from the shutter 92 by the focal length of the lens 93 on the opposite side of the lens 91 on the optical path.

  Here, the lens 91 and the lens 93 are lenses having the same focal length, but lenses having different focal lengths may be used. In this case, if the ratio of the focal lengths of the lens 91 and the lens 93 is f1: f2, the diffraction angle of the hologram display means 6 is θ1, and the diffraction angle emitted from the lens 93, that is, the diffraction angle of the diffraction means 3 is θ2. At this time, it is only necessary to have a relationship of θ2 = θ1 × f1 / f2.

The lens 91 condenses the reproduction light emitted from the hologram display means 6 (6 ₁ , 6 ₂ , 6 ₃ ) on the shutter 92. The lens 91 can be constituted by a convex lens, for example.

Since this lens 91 receives the reproduction light from the hologram display means 6 (6 ₁ , 6 ₂ , 6 ₃ ) separated by the focal length and collects it on the shutter 92 disposed on the rear focal plane, Of the reproduced light by the next-order diffracted light C and ± first-order diffracted lights R and L, the light corresponding to the spread angle θ of the reproduced light of the hologram display means 6 is condensed at different positions of the shutter 92, respectively. That is, the reproduction light reproduced by the first-order diffracted light R passing through the area S _R of the shutter 52, and focused on the area S _R of the shutter 92, are reproduced by the zero-order diffracted light C having passed through the area S _C of the shutter 52 reproduction light is condensed on the region S _C of the shutter 92, it reproduced light reproduced by the -1st-order diffracted light L having passed through the area S _L of the shutter 52 is focused on the area S _L of the shutter 92.

The shutter 92 allows the reproduction light collected by the lens 91 to be switched in a time division manner for each reproduction light viewing area. That is, the shutter 92 sequentially switches the reproduction light to be emitted by sequentially opening the regions S _R , S _C , and S _L. For example, the shutter 92 can be composed of a liquid crystal panel or a rotating disk provided with slits at different positions in the radial direction.

Note that the reproduction light includes higher-order diffracted light. Therefore, in order to remove the higher-order reproduction light, the shutter 92 has an opening size of each region S _R , S _C , S _L of the shutter 92 that allows only the 0th-order diffracted light of the reproduction light to pass. .
Specifically, when the focal length of the lens 91 is f and the maximum diffraction angle of the hologram light in the hologram display means 6 is ± θ / 2 (see FIG. 2B), the aperture size W is (4 ) Formula.

In addition, the shutter 92 switches which region is opened in synchronization with a timing signal output from the switching control unit 11 described later. Here, the shutter 92 receives timing signals (T _L , T _C , T _R ) as shown in FIG. 6A, and the region S _{L in} the time interval in which the timing signal T _L is “Low (L)”. the opening, the timing signal _{T C} is "Low (L)" and exposing the region _{S C} a time interval of the timing signal _{T R} is exposing the region _{S R} in the time interval of the "Low (L)".
Thus, the reproduction light that sequentially passes through the shutter 92 is incident on the lens 93.

The lens 93 returns the reproduction light passing through the shutter 92 to the original diffusion reproduction light. The lens 93 can be constituted by a convex lens, for example.
The lens 93 is arranged at a position away from the shutter 92 by the focal length, so that the reproduced image is visually recognized at a position further away from the focal distance.

Here, with reference to FIG. 5 and FIG. 6, the mechanism for switching the reproduction light in the reproduction light selection means 9 will be described in detail.
As shown in FIG. 5A, the hologram display means 6, the lens 91, and the shutter 92 are arranged apart from each other by the focal length f of the lens 91, so that the zero-order diffracted light displayed on the hologram display means 6 is displayed. reproducing light reproduced by the illumination beam (0-order illumination light) is via the lens 91, is focused on the area S _C of the shutter 92. However, at this time, since the reproduction light includes high-order reproduction light, when the maximum diffraction angle of the hologram display means 6 is θ, the shutter 92 has the region S as shown in the above equation (4). _By setting the aperture size of _C to W, higher-order light can be removed.

The shutter 92 is, for example, the timing signal _{T C} as shown in FIG. 6 (a) to open the area _{S C} a time interval of "Low".
Thus, in the time interval of the timing signal T _C is "Low", only the light passing through the area S _C of the shutter 92, a hologram reproducing light through the lens 93.

Further, as shown in FIGS. 5B and 5C, the reproduction light displayed by the hologram display means 6 and reproduced by the illumination light (± first order illumination light) which is ± first order diffracted light passes through the lens 91. Then, the light is condensed on the areas S _L and S _R of the shutter 92. However, this time, the reproducing light because it contains higher order of the reproduction light, the shutter 92, the (4) regions S _L as indicated by the _formula, the aperture size of S _R by the W , Remove higher order light.

The shutter 92 is, for example, by exposing the region _{S L} at time intervals shown in FIG. 6 (a) to indicate such timing signal _{T L} is "Low (L)", the timing signal _{T R} is "Low (L)" opening the space S _R in the time interval.
Thereby, in the time interval of the timing signal _{T L} is "Low (L)", only the light passing through the area _{S L} of the shutter 92 becomes a hologram reproducing light through the lens 93, the timing signal _{T R} is "Low ( in time segment L) ", only the light passing through the area S _R of the shutter 92, a hologram reproducing light through the lens 93.

As described above, the reproduction light selection unit 9 switches the emission light reproduced by the zero-order illumination light and the ± first-order illumination light for each illumination light in accordance with the timing signal output from the switching control unit 11. To do.
Returning to FIG. 1, the description of the configuration of the electronic holography reproducing device 1 will be continued.

  The hologram storage means 10 stores hologram data (hologram pattern). The hologram storage means 10 can be composed of a general memory. This hologram data is data corresponding to the tilt angle of the illumination light, and specifically corresponds to the maximum diffraction angle θ in the horizontal (left / right) direction of the hologram display means 6, and ranges from “−θ / 2” to “+ θ / Hologram data corresponding to a viewing area of 2 ”and viewing of“ −3θ / 2 ”to“ −θ / 2 ”and“ + θ / 2 ”to“ + 3θ / 2 ”moved by θ from the viewing area to the left and right respectively. Data corresponding to the area.

  That is, the hologram data is obtained by arranging each pixel on the three-dimensional space (x, y, z) and forming the hologram surface on the three-dimensional space (u, v, 0). The pixel value h (u) of the hologram pixel, where the luminance I (x, y) of the subject existing in the viewing range of “−θ / 2” to “+ θ / 2”, the depth value is z, and the light wavelength is λ. , V) is obtained by the following equation (5).

  When the viewing zone is “−3θ / 2” to “−θ / 2” or “+ θ / 2” to “+ 3θ / 2”, the reference light is inclined by ± θ, The pixel value h (u, v) is obtained by the following equation (6).

  X is the X component of the distance from the reference point arbitrarily determined on the X axis, taking the X axis of the hologram surface in the direction of the inclination of the reference light, and the point at which the hologram is being obtained.

Thus, the hologram data obtained from the equation (5) is set as hologram data HC corresponding to the central viewing zone. Similarly, the hologram data obtained in the viewing zone of “−3θ / 2” to “−θ / 2” from the equation (6) is set as the hologram data HL corresponding to the left viewing zone, and “+ θ / 2” is obtained. The hologram data obtained in the viewing area of “+ 3θ / 2” is set as hologram data HR corresponding to the right viewing area. Note that the hologram data HL, HC, and HR are generated for each RGB.
The hologram data HL, HC, HR stored in the hologram storage means 10 are switched by the read switching means 12 and output to the hologram display means 6.

  The switching control means 11 synchronizes switching of the shutter 52 of the illumination light selecting means 5, switching of the shutter 92 of the reproduction light selecting means 9, and switching of the display of the hologram data HL, HC, HR in the hologram display means 6. It is.

For example, the switching control unit 11 generates timing signals that can identify three types of states as shown in FIG. 6A and outputs the timing signals to the shutter 52, the shutter 92, and the readout switching unit 12. As a result, the shutter 52 and the shutter 92 can open corresponding areas in the “Low (L)” time interval of each timing signal. Further, the read switching unit 12 can switch and read the corresponding hologram data HL, HC, HR in the “Low (L)” time section of each timing signal.
Note that the “Low” time interval of each timing signal is, for example, 1 / (60 × 3) seconds when displaying a hologram reproduction image of 60 frames per second.

  Based on the timing signal output from the switching control unit 11, the read switching unit 12 sequentially switches the reading source address of the hologram data HL, HC, HR stored in the hologram storage unit 10 to the hologram display unit 6. Output.

The read switching unit 12 receives the timing signal shown in FIG. 6A and sequentially switches and outputs the hologram data HL, HC, HR to the hologram display unit 6. As a result, the hologram display means 6 sequentially displays the hologram data HL, HC, and HR as shown in FIG.
The read switch means 12, for the hologram data corresponding to red light, and outputs the hologram data to the hologram display means _61, for the hologram data corresponding to green light, outputs the hologram data to the hologram display means 6 ₂ and, for the hologram data corresponding to the blue light, and outputs the hologram data to the hologram display means 6 _3.

Thereby, the hologram display means 6 can sequentially display hologram data having different viewing zones in synchronization with the switching of the shutter 52 and the shutter 92.
As described above, the electronic holography reproducing device 1 displays time-multiplexed hologram data with different viewing zones. For this reason, the reproduced image to be reproduced is an image of the viewing zone in which the spread angle of the reproduction light of the hologram display means 6 is tripled.

[Operation of electronic holography playback device]
Next, the operation of the electronic holography reproducing device 1 according to the first embodiment of the present invention will be described with reference to FIG. It is assumed that hologram data different for each viewing zone is stored in advance in the hologram storage unit 10 for each RGB.

In addition, the electronic holography reproducing device 1 generates light of each color of RGB as parallel light by the light source 2 (2 ₁ , 2 ₂ , 2 ₃ ) during hologram reproduction.
During generation of the parallel light by the light source 2, electron holography reproducing apparatus 1, R light source 2 red light generated by _a diffracted by the diffraction means 3 _1, G light source 2 _second diffraction means 3 ₂ green light generated by diffracted by, and diffracted by the diffraction means 3 ₃ blue light generated by the B light source 2 _3.

Further, the electronic holography reproducing apparatus 1 multiplexes the diffracted light diffracted by the diffracting means 3 ₁ , 3 ₂ , 3 ₃ by the multiplexing means 4. Note that the diffraction means 3 ₁ , 3 ₂ , and 3 ₃ define the lattice fringe spacing so that the respective diffraction angles are the same, and therefore, light having the same diffraction angle is multiplexed. The light multiplexed by the multiplexing unit 4 enters the illumination light selection unit 5.

The illumination light selection means 5 condenses the light multiplexed by the multiplexing means 4 on the shutter 52 by the lens 51. Since the diffracting means 3 ₁ , 3 ₂ , 3 ₃ , the lens 51, and the shutter 52 are spaced apart by the focal length of the lens 51, the multiplexed 0th-order diffracted light C, ± 1 next time The folded lights R and L (see FIG. 2) are collected at different positions of the shutter 52. That is, the 0th-order diffracted light C is condensed on the central region (region S _C ) of the shutter 52, and the ± 1st-order diffracted lights R and L are condensed on the left and right regions (regions S _R and S _L ) of the shutter 52. .

As described above, during generation of parallel light by the light source 2, the electronic holography reproducing device 1 always supplies the 0th-order diffracted light C and the ± 1st-order diffracted lights R and L to different regions S _R , S _C , and S _L of the shutter 52. It is in a state of being condensed separately.

In this state, the electronic holography reproducing device 1 performs hologram reproduction according to the following procedure.
First, the electronic holography reproducing apparatus 1 generates a timing signal indicating three states necessary for switching of the shutter 52, switching of the shutter 92, and switching of hologram data to be displayed on the hologram display unit 6 by the switching control unit 11. To do. This timing signal is, for example, the signal shown in FIG. The switching control unit 11 outputs the timing signal shown in FIG. 6A to the shutter 52, the shutter 92, and the readout switching unit 12.

Shutter 52 entering this timing signal, the timing signal _{T L} is "Low (L)" -1 order diffracted light L in a time interval of open areas _{S L} for focusing, the timing signal _{T C} is "Low (L ) "0-order diffracted light C in the time interval of open areas S _C which condenses, the timing signal T _R is" Low (L) 1-order diffracted light R at the time interval "is open areas S _R for condensing .
And the illumination light selection means 5 returns the light which passed the shutter 52 with the lens 53 to the original straight-ahead light and the parallel light diffracted right and left.

Then, the electronic holography reproducing apparatus 1 separates the original straight light and the parallel light diffracted left and right into the R, G, and B color lights by the lens 53 by the separating / multiplexing means 7, respectively. The hologram display means 6 ₁ , 6 ₂ , 6 ₃ corresponding to the color is irradiated.

On the other hand, the read switching unit 12 that has input the timing signal from the switching control unit 11 has the address of the hologram data HL corresponding to the left viewing area in the hologram storage unit 10 in the time interval in which the timing signal _TL is “Low (L)”. outputs, and outputs the hologram data HL read from the hologram storage means 10 in the hologram display unit 6, a timing signal T _C is a time interval of "Low (L)", corresponding to the central viewing area on the holographic storage means 10 outputs an address of the hologram data HC, outputs hologram data HC read from the hologram storage means 10 in the hologram display unit 6, a timing signal T _R is the time interval "Low (L)", the right to holographic storage means 10 Output hologram data HR address corresponding to viewing area, hologram storage means The hologram data HR read from 0 to output to the hologram display means 6. The read switch means 12, for the hologram data corresponding to the red light, and outputs the hologram display unit _61, the hologram data corresponding to green light, and outputs the hologram display means 6 _2, corresponding to the blue light for the hologram data, and it outputs the hologram display means 6 _3.

  In this way, the electronic holography reproducing device 1 displays hologram data with different viewing zones on the hologram display means 6 in a time-sharing manner, and diffracted light (0th order diffracted light, ± 1st order diffracted light) corresponding to the viewing zone at the same timing. Therefore, reproduction light (hologram reproduction light) with different viewing zones is reproduced in a time-sharing manner. The reproduction light for each RGB color is multiplexed by the separation / multiplexing means 7, the traveling direction (optical path) is changed by the optical path changing means 8, and is incident on the reproduction light selecting means 9.

  Then, the reproduction light selection unit 9 condenses the reproduction light (hologram reproduction light) on the shutter 92 by the lens 91. Note that the hologram display means 6, the lens 91, and the shutter 92 are arranged apart from each other by the focal length of the lens 91. Therefore, among the reproduction lights by the 0th-order diffracted light C and the ± 1st-order diffracted lights R and L, Lights corresponding to the spread angle θ of the reproduction light of the hologram display means 6 are condensed at different positions of the shutter 92, respectively. However, this reproduction light includes higher-order reproduction light.

Therefore, the shutter 92 of the reproduction light selection unit 9 receives the timing signal from the switching control unit 11 and the region S in which the reproduction light of the hologram data HL is condensed in the time interval in which the timing signal _TL is “Low (L)”. opened _L, and the timing signal _{T C} is "Low (L)" reproduction light of the hologram data HC at time intervals of opening areas _{S C} for focusing, the timing signal _{T R} is "Low (L)" of the time reproduction light of the hologram data HR is open areas S _R for focusing in the interval. Thereby, in each region, only light corresponding to the spread angle θ of the reproduction light of the hologram display means 6 passes, so that the higher-order reproduction light is blocked.
Then, the reproduction light selection unit 9 returns the reproduction light that has passed through the shutter 92 in a time-sharing manner to the original diffusion reproduction light by the lens 93.

  As described above, the electronic holography reproducing apparatus 1 diffracts the parallel light from the light source 2 and uses the 0th-order diffracted light that is straight traveling light and the ± 1st-order diffracted light diffracted to the left and right, By reproducing by division and time multiplexing, the viewing zone can be expanded.

  The configuration and operation of the electronic holography reproducing device 1 according to the first embodiment of the present invention have been described above. However, the present invention is not limited to color hologram reproduction, and is implemented as an electronic holography reproducing device that performs monochromatic hologram reproduction. It is also possible to do. Hereinafter, as a second embodiment, an electronic holography reproducing device that reproduces a stereoscopic image from a monochromatic hologram will be described.

[Second Embodiment]
[Configuration of electronic holography playback device]
With reference to FIG. 7, the structure of the electronic holography reproducing | regenerating apparatus concerning 2nd Embodiment of this invention is demonstrated. The electronic holography reproducing device 1B generates a reproduced image from a monochromatic electronically generated hologram.

  Here, the electronic holography reproduction apparatus 1B includes a light source 2B, a diffraction unit 3B, an illumination light selection unit 5, a hologram display unit 6B, an optical path changing unit 8, a reproduction light selection unit 9, and a hologram storage unit 10B. Switching control means 11 and readout switching means 12B.

  Since this electronic holography reproducing device 1B does not need to multiplex or separate colored light as compared with the electronic holographic reproducing device 1 (see FIG. 1), the multiplexing means 4 and the separation / multiplexing means 7 are configured. Omitted. Further, the illumination light selection unit 5, the optical path changing unit 8, the reproduction light selection unit 9, and the switching control unit 11 have the same configuration as the electronic holography reproduction device 1, and thus the description thereof is omitted. In addition, since it is the same as the electronic holography reproducing | regenerating apparatus 1 about a basic function also about another structure, a different part is demonstrated.

The light source 2B, the diffraction means 3B, and the hologram display means 6B are the light source 2 (2 ₁ , 2 ₂ , 2 ₃ ) and the diffraction means 3 (3 ₁ , 3 ₂ , 3 ₃ ) of the electronic holography reproducing device 1 (see FIG. 1). Each of the hologram display means 6 (6 ₁ , 6 ₂ , 6 ₃ ) has one configuration so as to correspond to a single color. Therefore, these functions are the same in function and action.
The light source 2B and the diffracting means 3B are installed so as to face the lens 51 of the illumination light selecting means 5, and the diffracting means 3B is arranged at a position separated from the lens 51 by the focal length of the lens 51.
Further, the hologram display means 6 </ b> B is disposed at a position facing the lens 53 of the illumination light selection means 5 and separated by the focal length of the lens 53.

  The hologram storage means 10B is the same as the electronic holography reproducing device 1 in that it stores hologram data (hologram pattern). However, the hologram storage means 10B is different in that only monochrome hologram data is stored.

The read switching unit 12B reads out the hologram data HL, HC, HR stored in the hologram storage unit 10B based on the timing signal output from the switching control unit 11, and outputs it to the hologram display unit 6B. The read switching means 12 of the electronic holography reproducing apparatus 1 (see FIG. 1) outputs hologram data corresponding to RGB to the hologram display means 6 ₁ , 6 ₂ , 6 ₃ corresponding to the respective colors. The switching means 12B is different only in that monochromatic hologram data is output to the hologram display means 6B.

  Thus, by simplifying the configuration of the electronic holography reproducing device 1 (see FIG. 1), the electronic holographic reproducing device 1B can perform monochromatic hologram reproduction with an enlarged viewing zone. The operation of the electronic holography reproduction device 1B is basically the same as that of the electronic holography reproduction device 1 (see FIG. 1) except that the operation of multiplexing or separating the color light is omitted. The description is omitted.

The electronic holography reproducing devices 1 and 1B according to the embodiment of the present invention have been described above, but the present invention is not limited to this embodiment.
Here, the parallel light generated by the light source 2 is diffracted and the shutters 52 and 93 are switched in time division according to the timing signal using the 0th-order diffracted light and the ± 1st-order diffracted light. A reproduction image (stereoscopic image) of a viewing area three times the viewing area limited by the maximum diffraction angle is reproduced.

However, in the present invention, the viewing zone can be further expanded by further using ± second-order diffracted light diffracted by the diffraction means 3. In this case, the shutters 52 and 93 may be opened for each region divided into five in the left-right direction. Further, as the hologram data, zero-order, ± 1-order, ± 2 then prepares the data of the corresponding viewing zone in advance, the timing signal, T _L shown in FIG. _6, T _C, 3 one time interval T _R By changing to 5 time sections, it is possible to secure a viewing area of 5 times. Similarly, by using up to ± nth order diffracted light, a (2n + 1) times viewing zone can be secured.

  As described above, according to the present invention, it is possible to perform optical components such as lenses and spatial filters, which have been conventionally required for enlarging the viewing zone, simply by changing the numerical aperture of the shutter and the timing signal. Therefore, the apparatus configuration can be greatly simplified and downsized. For example, the device configuration can be reduced in size and size even when the screen size is increased in the future such that the number of pixels of the liquid crystal panel is 8K × 4K.

  In addition, the present invention can enlarge the viewing zone while downsizing / compacting the apparatus configuration. Therefore, the present invention makes it possible to reproduce a hologram that can be viewed with both eyes, to suppress the occurrence of eye strain, and to view a natural stereoscopic image with the naked eye.

DESCRIPTION OF SYMBOLS 1 Electronic holography reproduction | regeneration apparatus 2 Light source 3 Diffraction means 4 Multiplexing means 5 Illumination light selection means 51 Lens (1st lens)
52 Shutter (first shutter)
53 Lens (second lens)
6 Hologram display means 7 Separation / multiplexing means 8 Optical path changing means 9 Reproducing light selection means 91 Lens (third lens)
92 Shutter (second shutter)
93 Lens (4th lens)
DESCRIPTION OF SYMBOLS 10 Hologram memory | storage means 11 Switching control means 12 Reading switching means

Claims (7)

An electronic holographic reproducing device that generates a reproduced image from an electronically generated hologram,
Hologram storage means for storing the hologram;
A light source that generates parallel light;
Diffracting means for generating a plurality of diffracted lights having different diffraction angles in the horizontal direction from the parallel light generated by the light source;
Illumination light selection means for selecting illumination light by switching a plurality of diffracted lights generated by the diffraction means to pass through time division, and
A hologram in a viewing zone corresponding to the tilt angle of the illumination light is arranged at a position where the illumination light passing through the illumination light selection means is irradiated and synchronized with the illumination light switching timing in the illumination light selection means. Hologram display means for reading out and displaying from the storage means;
An optical path changing means for changing the optical path of the reproduction light generated by irradiating the hologram display means with the illumination light to an optical path in a direction different from the optical path of the illumination light ;
Of the reproduction light generated by sequentially irradiating the hologram display means with illumination light having different inclination angles selected by the illumination light selection means, which is arranged at a position where the reproduction light whose optical path is changed by the optical path changing means is irradiated. And reproducing light selection means for switching and passing the reproducing light at an angle corresponding to the viewing zone in synchronization with the switching timing;
An electronic holography reproducing device comprising: An electronic holographic reproducing device that generates a reproduced image from an electronically generated hologram,
Hologram storage means for storing the hologram;
A light source for each of the three primary colors of light that generates parallel light;
Diffracting means corresponding to each light source for generating a plurality of diffracted lights having different diffraction angles in the horizontal direction from parallel light generated by the light sources of the three primary colors;
A multiplexing means for multiplexing a plurality of diffracted lights generated by the diffraction means corresponding to each light source;
Illumination light selection means for selecting illumination light by switching a plurality of diffracted lights multiplexed by this multiplexing means in a time-sharing manner, and
A hologram in a viewing zone corresponding to the tilt angle of the illumination light is arranged at a position where the illumination light passing through the illumination light selection means is irradiated and synchronized with the illumination light switching timing in the illumination light selection means. Hologram display means corresponding to the three primary colors read out from the storage means and displayed;
Installed between the illumination light selection means and the hologram display means, and illuminates the illumination light having different inclination angles selected by the illumination light selection means on the hologram display means corresponding to the three primary colors separately for each color. In addition, separation / multiplexing means for multiplexing the reproduction light generated from each hologram display means by irradiation of the illumination light,
An optical path changing means for changing the optical path of the reproduction light multiplexed by the separation / multiplexing means to an optical path in a direction different from the optical path of the illumination light selected by the illumination light selection means;
Among the reproduction lights that are arranged at the position where the reproduction light whose optical path has been changed by the optical path changing means is irradiated and multiplexed by the demultiplexing / multiplexing means, the reproduction light having an angle corresponding to the viewing zone is switched. Reproduction light selection means for switching and passing in synchronization with the timing;
An electronic holography reproducing device comprising: The illumination light selection means includes
A first lens disposed at a position separated from the diffractive means by a focal length on the optical path;
The plurality of diffracted lights are switched in a time-division manner by switching from the first lens to the focal length of the first lens in the light traveling direction and switching the opening in a time-division manner. A first shutter to be
A second lens having the same focal length as the first lens disposed at a position separated from the first shutter by a focal length in the light traveling direction;
The hologram display means includes
3. The electronic holography reproducing device according to claim 1, wherein the electronic holography reproducing device is arranged to be separated from the second lens by the focal length on an optical path. The reproduction light selecting means includes
A third lens disposed at a position separated from the hologram display means by a focal length on the optical path;
An angle corresponding to the viewing zone in the reproduction light that is arranged from the third lens at a position separated by the focal length of the third lens in the light traveling direction and is collected by the third lens. A second shutter that allows the reproduction light to pass through by switching the opening in a time-sharing manner,
A fourth lens having the same focal length as the third lens disposed at a position separated from the second shutter by a focal length in the light traveling direction;
The electronic holography reproducing device according to any one of claims 1 to 3, further comprising:   5. The electronic holography according to claim 4, wherein the opening of the second shutter has an opening width corresponding to an irradiation width with which light having a maximum diffraction angle of the hologram display unit is irradiated onto the second shutter. Playback device. An electronic holography reproduction method for generating a reproduction image from an electronically generated hologram,
A diffracted light generation step of generating a plurality of diffracted lights having different diffraction angles in the horizontal direction from the parallel light generated by the light source by the diffracting means;
A plurality of diffracted lights generated in this diffracted light generating step are irradiated to the hologram display means as illumination light by switching the illumination light selection means in a time-sharing manner, and the illumination light switching timing in the illumination light selection means A reproduction light generation step for generating reproduction light by reading out a hologram in a viewing zone corresponding to the tilt angle of the illumination light in advance and displaying the hologram on the hologram display means, and displaying the hologram on the hologram display means;
An optical path changing step of changing the optical path of the reproduction light generated in the reproduction light generation step to an optical path in a direction different from the optical path of the illumination light by an optical path changing unit installed at the irradiation position of the reproduction light;
Of the reproduction light whose optical path has been changed in this optical path changing step, reproduction light selection step of passing reproduction light at an angle corresponding to the viewing zone in synchronization with the switching timing by the reproduction light selection means,
An electronic holography reproducing method comprising: An electronic holography reproduction method for generating a reproduction image from an electronically generated hologram,
A diffracted light generating and multiplexing step for generating a plurality of diffracted lights having different diffraction angles in the horizontal direction from parallel light generated by light sources of three primary colors of light by a diffracting means corresponding to the light sources, and multiplexing by a multiplexing means;
A plurality of diffracted light multiplexed generated in the diffraction light generated multiplexing step, by switching Rukoto time division by illuminating light selecting means is passed through as the illumination light selected by the separation and multiplexing means, the passage The illuminating light is applied to the hologram display means corresponding to the three primary colors separately for each color, and the viewing light corresponding to the tilt angle of the illumination light is synchronized with the illumination light switching timing in the illumination light selection means. Reproduction light is generated by reading out the hologram of the area from the hologram storage means stored in advance and displaying it on the hologram display means, and the separation / multiplexing means generates reproduction light for each of the hologram display means corresponding to the three primary colors. A reproduction light generating and multiplexing step for multiplexing;
The optical path of reproduction light multiplexed by the reproduction light generated multiplexing step, the optical path changing means installed at the irradiation position of the reproduction beam, in different directions from the optical path of the illumination light selected by the illuminating light selecting means An optical path changing step for changing to an optical path;
Of the reproduction light whose optical path has been changed in this optical path changing step, reproduction light selection step of passing reproduction light at an angle corresponding to the viewing zone in synchronization with the switching timing by the reproduction light selection means,
An electronic holography reproducing method comprising:

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