JP6960144B2 - Hologram manufacturing method and hologram recording device - Google Patents

Description

The present invention relates to a hologram manufacturing method and a hologram recording device.

The hologram realizes a desired light wave distribution by utilizing the diffraction phenomenon of light. Specifically, in a hologram, light from an object (object light) and reference light are interfered with each other to form an interference fringe, and the interference fringe is recorded on a hologram recording medium. In the conventional hologram, since the real object is irradiated with light to generate the object light, there are various restrictions such as the need for the real object and a large-diameter lens. For example, in order to generate a holographic optical element (HOE) equivalent to a lens having a diameter of 30 cm, 100 cm, or 200 cm, a conventional hologram requires a lens having a diameter of 30 cm or more, 100 cm or more, and 200 cm or more, respectively.

Recently, DDHOE (Digitally Designed Holographic Optical Element) technology that uses digital data has been proposed. In this DDHOE technology, hologram data is displayed on a spatial light modulator (SLM) and irradiated with light to generate object light. Since this hologram data can be calculated by a computer, it is possible to obtain a light wave distribution of desired object light.

As a result, with the DDHOE technology, even if there is no real object or a large-diameter lens, a desired light wave distribution can be realized by a wave surface printer and a hologram can be easily generated as long as there is wave surface information such as CG (Computer Graphics) data. .. However, for example, when the number of pixels of the SLM is 1000, the pixel spacing of the SLM is 2 μm, and the wavelength of the laser light is 533 nm, the size of the hologram can be 2 mm in length and width, and the light emission angle from the hologram can be realized only about 7.3 °. However, it is not sufficient for practical use.

Therefore, in the DDHOE technology, the "step of exposing a part of the entire light wave distribution to the hologram recording medium as an element cell" and the "step of changing the displayed hologram data and moving the hologram recording medium" are sequentially repeated. , A method of exposing the entire light wave distribution to generate a hologram has been proposed (Non-Patent Document 1). For example, in the case of a 1000-pixel SLM, both steps can be repeated 2500 times while shifting the position of the hologram recording medium to generate a hologram having a length and width of 10 cm.

In the technique described in Non-Patent Document 1 (hereinafter, "tiling"), due to the geometric distortion due to the optical system and the positioning accuracy of the automatic stage, between the element cells between the previous process and the current process. The stripes remain. That is, in the entire hologram, the element cells are arranged in a tile shape, and grid-like stripes are formed.

K. Wakunami et al, “Wavefront printer by using cell overlappingtechnique”, 3D systems and applications (2015)

In the prior art, the hologram recording process of FIG. 8 (a) and (b), through the hologram replication process shown in FIG. 8 (c) and (d), it is often replicate master hologram 9 _{M.
First, in the hologram recording step, as shown in FIG. 8A, the master hologram 9 M} is recorded using the hologram data in which the object T is arranged in the vicinity of the hologram recording medium 9. At this time, as shown in FIG. 8B, not only the interference fringes of the object T but also the grid-like fringes due to tiling are recorded on _{the master hologram 9 M.}
In FIG. 8, the recorded stripes are shown by hatching.

Then, in the hologram duplication step, as shown in FIG. 8C _{, the master hologram 9 M} is duplicated by _{contact copying in which the master hologram 9 M} and the hologram recording medium 9 are brought into close contact with each other. Hereinafter, the hologram recording medium 9 on which the same interference fringes as the master hologram 9 _M is recorded will be referred to as a “replica hologram 9 _C ”. In this case, as shown in FIG. 8 (d), also duplicate hologram 9 _C, not only the interference pattern of the object T, lattice fringes will also be recorded.

Accordingly, as shown in FIG. 8 (e), when playing a copy hologram 9 _C, the observer 90, fringe is seen near the object T. That is, when the eyes of the observer 90 focus on the object T in order to see the object T, the fringes near the object T are also in focus, and the fringes are visible.

Therefore, it is an object of the present invention to provide a hologram manufacturing method and a hologram recording device that solve the above-mentioned problems and improve the quality of holograms.

In view of the above problems, the hologram manufacturing method according to the present invention is a hologram manufacturing method in which interference fringes between the object light and the reference light on which the hologram data is reflected are recorded on the master hologram and the master hologram is duplicated. , A procedure including a complex amplitude data generation step, a hologram data generation step, a display step, a recording step, an arrangement step, and a duplication step.

According to this procedure, in the hologram manufacturing method, in the complex amplitude data generation step, complex amplitude data which is a light wave distribution when an object is placed at a position of a preset separation distance on the front side of the first hologram recording medium is obtained. Generate. Further, in the hologram manufacturing method, in the hologram data generation step, hologram data is generated from the complex amplitude data generated in the complex amplitude data generation step. Here, the complex amplitude data generation step includes the initial position complex amplitude data generation step for generating complex amplitude data representing the light wave distribution when the object is placed at the preset initial position, and the position where the object is separated from the initial position. It comprises a complex amplitude data correction step that corrects the complex amplitude data so as to move to.

Then, in the hologram manufacturing method, in the display step, the hologram data generated in the hologram data generation step is displayed on the spatial light modulator. Further, in the hologram manufacturing method, in the recording step, a master hologram is manufactured by recording the interference fringes between the object light and the reference light on which the hologram data displayed in the display step is reflected on the first hologram recording medium.
As described above, in the hologram manufacturing method, the master hologram is recorded by separating the objects.

Further, in the hologram manufacturing method, in the arrangement step, the second hologram recording medium is arranged at a position at a distance on the front side of the master hologram. Then, in the hologram manufacturing method, in the duplication step, the duplication hologram is manufactured by recording the interference fringes of the master hologram on the second hologram recording medium arranged in the arrangement step.

In this way, in the hologram manufacturing method, the master hologram is duplicated by returning the master hologram by a distance when recording the master hologram. As a result, the fringes can be separated from the object when the hologram is reproduced, so that it is possible to prevent the fringes from being seen near the object.

The complex amplitude data is the light wave distribution data of the object. That is, since the complex amplitude data has amplitude and phase information, it can be processed into a desired light wave distribution.
The hologram data is data representing interference fringes between complex amplitude data and laser light incident on a spatial light modulator.

Further, in view of the above-mentioned problems, the hologram recording device according to the present invention reflects the light source for generating laser light, the hologram data generating device for generating hologram data, and the displayed hologram data on the laser light. A hologram recording device including a spatial light modulator that generates object light and recording interference fringes between the object light and reference light on a master hologram. The hologram data generation device includes a complex amplitude data generation means and a complex. The configuration includes an amplitude data correction means and a hologram data generation means.

According to this configuration, the hologram recording device uses the complex amplitude data generation means to generate complex amplitude data representing the light wave distribution when the object is placed at a preset initial position. Further, the hologram recording device corrects the complex amplitude data so that the object moves from the initial position to the position of the distance set in advance on the front side of the first hologram recording medium by the complex amplitude data correction means. Further, the hologram recording device generates hologram data from the complex amplitude data corrected by the complex amplitude data correction means by the hologram data generation means. Further, the hologram recording device displays the hologram data generated by the hologram data generating device by the spatial light modulator.

In this way, the hologram recording device records the master hologram by separating the object. Therefore, the master hologram may be duplicated by returning it by a distance when recording the master hologram. As a result, the fringes can be separated from the object when the hologram is reproduced, so that it is possible to prevent the fringes from being seen near the object.

According to the present invention, the following excellent effects are obtained.
According to the hologram manufacturing method and the hologram recording device according to the present invention, the fringes can be separated from the object during reproduction of the hologram, so that the fringes can be prevented from being seen near the object.
The quality of the hologram can be improved.

It is a block diagram which shows the structure of the hologram recording apparatus which concerns on embodiment of this invention. (A) to (d) are explanatory views for explaining the recording of the master hologram. It is a block diagram which shows the structure of the hologram duplication apparatus which concerns on embodiment of this invention. (A) to (c) are explanatory views for explaining the duplication of the master hologram. It is a flowchart which shows the hologram manufacturing method which concerns on embodiment of this invention. (A) is an explanatory diagram for explaining the recording of the master hologram, and (b) is an explanatory diagram for explaining the duplication of the master hologram. It is a block diagram which shows the structure of the hologram duplication apparatus in the modification of this invention. (A) to (e) are explanatory views of the prior art.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings as appropriate.
In the embodiment, the same means and the same member are designated by the same reference numerals, and the description thereof is omitted.

(Embodiment)
In the present embodiment, first, the hologram recording device 1 that records the _{master hologram 9 M will be described.} Next, the hologram duplication device 2 for duplicating the master hologram 9 _{M will be described.} After that, the procedure for duplicating the master hologram will be described.

[Configuration of hologram recording device]
The configuration of the hologram recording device 1 according to the embodiment of the present invention will be described with reference to FIG.
The hologram recording apparatus 1 is to record the interference fringes between the object beam and the reference beam to the master hologram 9 _M. That is, the hologram recording device 1 exposes the interference fringes between the object light and the reference light to the hologram recording medium (first hologram recording medium) 9 to obtain the master hologram 9 _M.

The hologram recording medium 9 is a medium for recording interference fringes between object light and reference light. For example, the hologram recording medium 9 includes a glass or plastic substrate on which a photopolymer and a photosensitive material are laminated.

As shown in FIG. 1, the hologram recording device 1 includes a laser (light source) 10, a polarizing plate 11, a 1/2 wave plate 12, lenses 13 and 14, a polarizing beam splitter 15, and a 1/2 wave plate. 16, a polarizing beam splitter 17, an SLM (spatial light modulator) 18, a lens 19, an HZP processing mask 20, lenses 21 to 23, mirrors 24 and 25, a spatial filter 26, and a stage 27. , The hologram data generation device 30 is provided.

The laser 10 is a laser light source that generates a laser beam. The wavelength of the laser light generated by the laser 10 is not particularly limited. In the present embodiment, the laser 10 is a monochromatic laser device that oscillates a green laser having a wavelength of 532 nm.

The polarizing plate 11 adjusts the polarization direction of the laser beam generated by the laser 10.
The 1/2 wave plate 12 changes the polarization direction of the laser light passing through the polarizing plate 11 in order to adjust the balance between the object light and the reference light branched by the polarization beam splitter 15 described later. The laser beam that has passed through the 1/2 wavelength plate 12 is emitted to the lens 13.

The lens 13 is a convex lens that expands the beam diameter of the laser light from the 1/2 wavelength plate 12. The lens 13 may be a single lens or a composite lens as long as it satisfies the function (the same applies to the lenses 14, 19, 21 to 23 described later).
The lens 14 is a convex lens that converts the laser light from the lens 13 into parallel light. The laser beam converted into parallel light by the lens 14 is emitted to the polarizing beam splitter 15.

The polarization beam splitter 15 splits the laser beam from the lens 14 into object light and reference light. That is, the polarization beam splitter 15 splits the laser beam from the lens 14 into P-polarized light and S-polarized light that are orthogonal to each other. In the present embodiment, the laser light transmitted through the polarizing beam splitter 15 is used as reference light, and the laser light reflected by the polarizing beam splitter 15 is used as object light.

In FIG. 1, the center of the optical axis of the laser beam is shown by a broken line, and both ends of the laser beam are shown by a solid line.
Further, in FIG. 1, the reference light is illustrated by the block arrow R, and the object light is illustrated by the block arrow O.

The 1/2 wave plate 16 rotates the polarization direction of the laser beam reflected by the polarization beam splitter 15 by π / 2.
The polarizing beam splitter 17 transmits the object light from the 1/2 wavelength plate 16 to the SLM 18 and reflects the object light from the SLM 18 toward the lens 19. That is, the polarization beam splitter 17 reflects the object light modulated by the SLM 18 toward the lens 19.

The SLM 18 reflects the hologram data generated by the hologram data generation device 30 described later on the laser light (object light) from the polarizing beam splitter 17. Specifically, the SLM 18 displays the hologram data generated by the hologram data generator 30, modulates the object light from the polarizing beam splitter 17 according to the hologram data, and transmits the object light reflecting the hologram data to the polarizing beam splitter 17. Reflects on.
The SLM18 is a general one, and examples of the modulation method thereof include an amplitude modulation type, a phase modulation type, and an amplitude / phase modulation type as the modulation method of the SLM18.

The lens 19 is a convex lens that focuses the object light reflected by the polarizing beam splitter 17 on the HZP processing mask 20. The light that has passed through the lens 19 is emitted to the HZP processing mask 20.
The HZP processing mask 20 is a mask that shields half of the object light from the lens 19 in order to perform the HZP processing for removing the disturbing light.

The lens 21 is a convex lens that converts object light that has passed through the HZP processing mask 20 into parallel light.
The lens 22 is a convex lens that collects the object light from the lens 21 onto the lens 23.
The lens 23 is a convex lens that emits the object light from the lens 22 to the hologram recording medium 9.

The mirror 24 reflects the reference light transmitted through the polarizing beam splitter 15 to the mirror 25.
The mirror 25 reflects the reference light from the mirror 24 to the spatial filter 26.
The spatial filter 26 is a filter that blocks the outer peripheral portion of the reference light that has passed through the polarizing beam splitter 15.

The stage 27 is equipped with a hologram recording medium 9 and is moved to an arbitrary position. For example, in the case of recording in element cell units, the stage 27 may move the mounted hologram recording medium 9 in the biaxial direction. At this time, the stage 27 may move the hologram recording medium 9 so that the element cells do not overlap each other (tiling). Further, the stage 27 may move the hologram recording medium 9 so that the element cells overlap each other (overlap).

With the above configuration, the polarization direction of the laser beam emitted by the laser 10 is adjusted by the 1/2 wavelength plate 12. Then, the laser beam is split into object light and reference light by the polarizing beam splitter 15.

The object light passes through the 1/2 wave plate 16 and enters the SLM 18. Then, the object light incident on the SLM 18 reflects the hologram data displayed on the SLM 18 and is incident on the HZP processing mask 20. Further, the object light incident on the HZP processing mask 20 is removed from the disturbing light and emitted to the hologram recording medium 9.

Further, the reference light is reflected by the mirrors 24 and 25, and is narrowed down to the same beam diameter as the object light by the spatial filter 26. Then, the reference light is emitted to the hologram recording medium 9. In this way, both the object light and the reference light are applied to the hologram recording medium 9, and the interference fringes of the object light and the reference light are recorded. In this way, the hologram recording device 1 can record the _{master hologram 9 M.}

[Configuration of hologram data generator]
Next, the configuration of the hologram data generation device 30 will be described.
The hologram data generation device 30 generates hologram data so that the object T is located on the front side of the hologram recording medium 9, and includes the complex amplitude data generation means 31, the complex amplitude data correction means 33, and the hologram data generation. The means 35 is provided.

The complex amplitude data generation means 31 generates complex amplitude data representing a light wave distribution when an object is placed at a preset initial position.
The complex amplitude data correction means 33 corrects the complex amplitude data generated by the complex amplitude data generation means 31 so that the object moves from the initial position to the position of the preset separation distance. That is, the corrected complex amplitude data represents the light wave distribution when the object is separated from the hologram recording medium 9 by the distance.
The details of the complex amplitude data generation means 31 and the complex amplitude data correction means 33 will be described later.

The hologram data generation means 35 generates hologram data from the complex amplitude data corrected by the complex amplitude data correction means 33. That is, the hologram data generation means 35 converts the complex amplitude data that the SLM 18 cannot display into the interference fringe data that the SLM 18 can display. After that, the hologram data generation means 35 outputs the hologram data to the SLM 18.

For example, hologram data can be obtained by a general computer-generated hologram (CGH) such as a calculation from a point light source or a calculation from an integral stereoscopic image (element image group). When calculating from a point light source, the object is treated as a set of point light sources, the light generated by each point light source propagates, the light wave distribution on the hologram surface is individually obtained, and all the obtained light wave distributions are added. , Generate complex amplitude data. Then, in the computer composite hologram, the result (interference fringe) of calculating the interference phenomenon with the complex amplitude data and the reference light data is generated as hologram data.

<Generation of hologram data: First example>
With reference to FIG. 2, the methods of the first example and the second example will be described in order for the generation of hologram data (see FIG. 1 as appropriate).

In the method of the first example, as shown in FIG. 2A, after generating complex amplitude data in which the object T is arranged at the initial position D1, the object T moves from the initial position D1 to the position of the separation distance D2. The complex amplitude data is corrected as described above.
Here, "movement" means changing the distance in the depth direction (Z-axis direction) perpendicular to the recording surface (XY plane) of the hologram recording medium 9. The right side of the drawing is the back side in the depth direction, and the left side of the drawing is the front side in the depth direction.

First, the complex amplitude data generation means 31 generates complex amplitude data when the object T is arranged at the initial position D1.
This initial position D1 is preset in the vicinity of the hologram recording medium 9 as in the prior art. For example, the initial position D1 is a position 5 cm on the front side of the hologram recording medium 9.

As described above, since the complex amplitude data has amplitude and phase information, it can be processed into a desired light wave distribution. Therefore, the complex amplitude data correction means 33 corrects the complex amplitude data generated by the complex amplitude data generation means 31 so that the object T moves from the initial position D1 to the position of the separation distance D2.
The separation distance D2 is preset so as to be on the front side of the hologram recording medium 9 and farther than the initial position D1. For example, the separation distance D2 is 50 cm on the front side of the hologram recording medium 9.

Subsequently, as shown in FIG. 2B, the hologram data generation means 35 generates hologram data from complex amplitude data in a state where the object T is at the position of the separation distance D2. After that, the hologram recording device 1 displays the hologram data on the SLM 18, and records the interference fringes between the object light and the reference light on which the hologram data is reflected on the master hologram 9 _M. At this time, the master hologram 9 _M records the interference fringes of the object T as well as the grid-like fringes.

As described above, in the method of the first example, since the initial position D1 of the object T is close to the hologram recording medium 9, the complex amplitude data can be generated with a small amount of calculation. Then, since the parallel movement from the initial position D1 to the position of the separation distance D2 can be performed by the Fourier transform, the complex amplitude data can be corrected with a small amount of calculation.

As shown in FIG. 2C, the method of the first example can also be applied when the initial position D1 is on the inner side of the hologram recording medium 9. In this case, the complex amplitude data correction means 33 may correct the complex amplitude data so that the object T moves from the back side to the front side of the hologram recording medium 9. Here, in FIG. 2C, a minus sign is added to indicate that the initial position D1 is on the back side of the hologram recording medium 9.
Further, in the method of the first example, when the initial position D1 is both the labor side and the back side of the hologram recording medium 9 (for example, when the object T is located on the front side and the back side of the hologram recording medium 9, respectively). Can also be applied to.

<Generation of hologram data: 2nd example>
As shown in FIG. 2D, the method of the second example directly generates complex amplitude data in which the object T is arranged at the distance D2 without arranging the object T at the initial position D1. Is.

Specifically, the complex amplitude data generation means 31 generates complex amplitude data when the object T is arranged at the position of the separation distance D2. Then, the hologram data generation means 35 generates hologram data as in the first example.

In the method of the second example, since the separation position D2 of the object T is far from the hologram recording medium 9, the calculation process for generating the complex amplitude data becomes complicated and the amount of calculation increases.
It should be noted that which method of the first example or the second example is used is set in advance. Further, when the method of the second example is used, the complex amplitude data correction means 33 may not be provided.

[Configuration of hologram duplication device]
The configuration of the hologram duplication device 2 will be described with reference to FIG.
Hologram duplicating apparatus 2 is intended to replicate the master hologram 9 _M of the hologram recording apparatus 1 has been recorded. As shown in FIG. 3, the hologram duplicating device 2 includes a laser (second light source) 100, a half mirror (optical branching means) 110, a reference light irradiating means 120, an illuminating light irradiating means 130, and a holding means 140. And.
In FIG. 3, both ends of the laser beam are shown by solid lines.

The laser 100 is a laser light source that generates laser light. The laser 100 is the same as the laser 10 (FIG. 1) of the hologram recording device 1.
The half mirror 110 branches the laser beam generated by the laser 10 toward the master hologram 9 _M and the hologram recording medium 9.

Here, the laser beam branched to the side of the master hologram 9 _{M becomes the illumination light. Further, since the master hologram 9 M} is a reflection type due to the structure of the hologram recording device 1, this illumination light is used as parallel light.
Further, the laser light branched to the side of the hologram recording medium (second hologram recording medium) 9 serves as the reference light. Since this reference light can be arbitrarily set, the direction of the reference light can be freely set by using the light from a point light source.

The reference light irradiating means 120 emits the light branched by the half mirror 110 to the hologram recording medium 9, and includes a mirror 121 and a lens 123.
The mirror 121 reflects the laser beam from the half mirror 110 onto the lens 123.
The lens 123 is a convex lens that expands the beam diameter of the laser beam from the mirror 121. The lens 123 may be a single lens or a composite lens as long as it satisfies the function (the same applies to the lenses 131 and 105 described later).
In this way, the laser light reflected by the half mirror 110 is emitted to the hologram recording medium 9 as reference light.

The illumination light irradiating means 130 emits the light branched by the half mirror 110 to the master hologram 9 _M , and includes lenses 131 and 133, a mirror 135, and a half mirror 137.
The lens 131 is a convex lens that enlarges the beam diameter of the laser light that has passed through the half mirror 110. The laser beam magnified by the lens 131 is emitted to the lens 133.
The lens 133 is a convex lens that converts the laser light from the lens 131 into parallel light. The laser beam converted into parallel light by the lens 133 is emitted to the mirror 135.

The mirror 135 reflects the laser beam from the lens 133 to the half mirror 137.
Half mirror 137 is for reflecting the laser light from the mirror 135 to the master hologram _{9 M.} The laser light reflected by the half mirror 137 is emitted to the _{master hologram 9 M as illumination light.}

In this way, the hologram duplication device 2 records the interference fringes of the _{master hologram 9 M on the hologram recording medium 9 via the half mirror 110.} That is, in the hologram duplicating device 2, the master hologram 9 _M reflects the laser light, and the reflected light passes through the half mirror 110 and reaches the hologram recording medium 9, so that _{the interference fringes of the master hologram 9 M} are recorded on the hologram recording medium. Can be recorded at 9.

The holding means 140 holds the master hologram 9 _M and the hologram recording medium 9 apart by a distance D2. The holding means 140 includes a stage 141 _{M on which the master hologram 9 M is mounted and a stage 141 C on} which the hologram recording medium 9 is mounted.

Here, in the hologram duplicating device 2, _{either the hologram recording medium 9 or the master hologram 9 M} may be moved. For example, the stage 141 _C may be driven in the depth direction according to the separation distance D2 input from the hologram recording device 1 to move the hologram recording medium 9.
The stage 141 _M may be driven in the depth direction to move the _{master hologram 9 M.}

<Duplicate master hologram>
Referring to FIG. 4, it will be described the replication of the master hologram 9 _M (appropriately with reference Figure 3).
In the present embodiment, when the master hologram 9 _M is manufactured, the object T is moved to the front side to obtain hologram data. Therefore, when duplicating the master hologram 9 _M , it is necessary to return the position of the object T to the back side by that distance.

Specifically, in the hologram duplicating device 2, as shown in FIG. 4A, the hologram recording medium 9 is arranged at a position of a separation distance D2 on the front side of the _{master hologram 9 M.} As a result, the position of the object T is returned to the back side when viewed from the hologram recording medium 9.

Then, as shown in FIG. 4B, the hologram duplication device 2 manufactures the _{duplicate hologram 9 C by recording the interference fringes of the master hologram 9 M on} the hologram recording medium 9. Accordingly, as shown in FIG. 4 (c), when playing a copy hologram 9 _C, since fringes α is away from the object T, the observer 90, fringe α becomes less visible. That is, when the eyes of the observer 90 focus on the object T in order to see the object T, the fringes α away from the object T are out of focus, and the fringes α become inconspicuous.
In FIG. 4, illustrating the fringe α formed by duplicate hologram 9 _C by dashed lines.

[Hologram manufacturing procedure]
The hologram manufacturing procedure will be described with reference to FIG. 5 (see FIGS. 1 and 3 as appropriate).
As shown in FIG. 5, this hologram manufacturing procedure includes _{a hologram recording step S1 in which the hologram recording device 1 records the master hologram 9 M} , and a hologram duplication step S2 in which the hologram duplicating device 2 replicates the master hologram 9 _M. Has been done.

The hologram recording step S1 is composed of the processes of steps S10 to S14, and will be described in detail. In this hologram recording step S1, hologram data is generated by the method of the first example described above.

The complex amplitude data generation means 31 generates complex amplitude data representing the light wave distribution when the object is placed at the initial position (step S10: initial position complex amplitude data generation step).
The complex amplitude data correction means 33 corrects the complex amplitude data generated in step S10 so that the object moves from the initial position to the position of the separation distance (step S11: complex amplitude data correction step).
The processing of steps S10 and S11 constitutes the complex amplitude data generation step S3.

The hologram data generation means 35 generates hologram data from the complex amplitude data corrected in step S11 (step S12: hologram data generation step).
The hologram data generation device 30 displays the hologram data generated in step S12 on the SLM 18 (step S13: display step).
_{The hologram recording device 1 manufactures the master hologram 9 M} by recording the interference fringes between the object light and the reference light on which the hologram data displayed in step S13 is reflected on the hologram recording medium 9 (step S14: recording step). ).

The hologram duplication step S2 is composed of the processes of steps S20 and S21, and will be described in detail.
The hologram duplication device 2 arranges the hologram recording medium 9 at a _{distance on the front side of the master hologram 9 M} (step S20: arrangement step).
In the hologram duplicating apparatus 2, by recording the interference fringes of the master hologram 9 _M on the hologram recording medium 9 arranged in step S20, to replicate the master hologram 9 _M (Step S21: duplication step).

In the above hologram manufacturing procedure, the method of the first example is used, but the method of the second example may be used. In this case, the complex amplitude data generation means 31 generates complex amplitude data when the object T is arranged at the position of the separation distance D2 (step S10A). Then, the hologram duplicating device 2 may perform the processes after step S12 without performing step S11.

[Action / Effect]
As described above, when the hologram recording device 1 _{manufactures the master hologram 9 M} , the object T is moved to the front side to obtain hologram data. _{Then, when duplicating the master hologram 9 M} , the hologram duplication device 2 arranges the hologram recording medium 9 on _{the front side of the master hologram 9 M by} the distance, so that the position of the object T is returned to the back side. .. As a result, the fringes can be separated from the object T during reproduction of the hologram, so that it is possible to suppress the appearance of the fringes near the object T and improve the quality of the hologram.
Further, when the method of the first example is applied to the hologram recording device 1, the complex amplitude data can be obtained with a small amount of calculation, so that the speed can be increased.

For example, consider the case where the face of a person is the object T. In this case, hologram data for displaying a face is generated 50 cm in front of the hologram recording medium 9, and the master hologram 9 _M is recorded. Then, the hologram recording medium 9 is arranged so that the face returns 50 cm to the back side, and the master hologram 9 _M is duplicated.

Further, for example, consider the case where a plurality of objects T are arranged in a wide depth range. In this case, hologram data for displaying the object T is generated 50 cm in front of the hologram recording medium 9, and the master hologram 9 _M is recorded. Then, the hologram recording medium 9 is arranged so that the object T returns 50 cm to the back side, and the master hologram 9 _M is duplicated.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and includes design changes and the like within a range that does not deviate from the gist of the present invention.

(Modification example: Use of virtual lens)
The hologram recording device 1B and the hologram duplication device 2B according to the modified example of the present invention will be described with reference to FIG. 6 in different points from the embodiments (see FIGS. 1 and 7 as appropriate).

The hologram recording device 1 is different from the embodiment in that it obtains complex amplitude data as a Fourier transform hologram using a virtual lens 37. Further, the hologram duplicating device 2B is different from the embodiment in that the lens 150 is provided between _{the master hologram 9 M and the hologram recording medium 9.}

[Configuration of hologram recording device]
The configuration of the hologram recording device 1B will be described with reference to FIG.
As shown in FIG. 1, the hologram recording device 1B includes a laser 10, a polarizing plate 11, a 1/2 wave plate 12, lenses 13 and 14, a polarizing beam splitter 15, a 1/2 wave plate 16, and the like. It includes a polarizing beam splitter 17, an SLM 18, a lens 19, an HZP processing mask 20, lenses 21 to 23, mirrors 24 and 25, a spatial filter 26, a stage 27, and a hologram data generator 30B.

The hologram data generation device 30B generates hologram data, and includes a complex amplitude data generation means 31B, a complex amplitude data correction means 33, and a hologram data generation means 35.
Since each means other than the complex amplitude data generation means 31B is the same as that of the first embodiment, the description thereof will be omitted.

As shown in FIG. 6A, the complex amplitude data generation means 31B generates complex amplitude data as a Fourier transform hologram in which a virtual lens 37 is arranged between the object T and the hologram recording medium 9. That is, the complex amplitude data generation means 31B obtains the light wave distribution from the object T by the Fourier transform in the virtual lens 37. Here, the parameters (for example, diameter, focal length) of the virtual lens 37 are set in advance.

[Configuration of hologram duplication device]
The configuration of the hologram duplication device 2B will be described with reference to FIG. 7.
As shown in FIG. 7, the hologram duplicating device 2B includes a laser (second light source) 100, a half mirror (optical branching means) 110, a reference light irradiating means 120, an illuminating light irradiating means 130, and a holding means 140. And a lens 150.

As shown in FIG. 6B, the lens 150 is a lens corresponding to the virtual lens 37. For example, the lens 150 is a lens having the same parameters as the virtual lens 37.
Since each means other than the lens 150 is the same as the embodiment including the point that the hologram recording medium 9 and the master hologram 9 _M are separated by the separation distance D2, the description thereof will be omitted.
Further, since the hologram manufacturing procedure is the same as that of the embodiment, the description thereof will be omitted.

As described above, in the hologram duplication device 2B, since the _{lens 150 is arranged between the master hologram 9 M} and the hologram recording medium 9, the frame is formed at infinity as shown in FIG. 6 (b). Thus, when playing a copy hologram 9 _C, hardly visible streaks on the viewer 90, it is possible to increase the quality of the hologram.

(Other variants)
In the above-described embodiment, the monochromatic laser has been described, but in the present invention, red, green, and blue color lasers can also be used.
In the above-described embodiment, the configuration example of the optical system in the hologram recording device and the hologram duplication device has been described, but the present invention is not limited to the configuration example.
In the above-described embodiment, the hologram recording device and the hologram duplicating device have been described as independent devices, but in the present invention, the hologram duplicating device may be incorporated into the hologram recording device to be integrated.

1,1B hologram recording device 10 Laser (light source)
18 SLM (Spatial Light Modulator)
30,30B Hologram data generation device 31,31B Complex amplitude data generation means 33 Complex amplitude data correction means 35 Hologram data generation means 2,2B Hologram duplication device 100 Laser (second light source)
110 Half mirror (optical branching means)
120 Reference light irradiation means 130 Illumination light irradiation means 140 Holding means 150 Lens

Claims (4)

This is a hologram manufacturing method in which interference fringes between object light and reference light reflecting hologram data are recorded on a master hologram and the master hologram is duplicated.
A complex amplitude data generation step of generating complex amplitude data which is a light wave distribution when an object is placed at a position of a preset separation distance on the front side of the first hologram recording medium, and a complex amplitude data generation step.
A hologram data generation step for generating the hologram data from the complex amplitude data generated in the complex amplitude data generation step, and a hologram data generation step.
A display step of displaying the hologram data generated in the hologram data generation step on the spatial light modulator, and
A recording step of manufacturing the master hologram by recording the interference fringes between the object light reflecting the hologram data displayed in the display step and the reference light on the first hologram recording medium.
An arrangement step of arranging the second hologram recording medium at a position of the separation distance on the front side of the master hologram, and
A duplication step of duplicating the master hologram by recording the interference fringes of the master hologram on the second hologram recording medium arranged in the arrangement step is provided .
The complex amplitude data generation step
An initial position complex amplitude data generation step for generating complex amplitude data representing a light wave distribution when the object is placed at a preset initial position, and
A hologram manufacturing method comprising: a complex amplitude data correction step of correcting the complex amplitude data so that the object moves from the initial position to the position of the separation distance. This is a hologram manufacturing method in which interference fringes between object light and reference light reflecting hologram data are recorded on a master hologram and the master hologram is duplicated.
A complex amplitude data generation step of generating complex amplitude data which is a light wave distribution when an object is placed at a position of a preset separation distance on the front side of the first hologram recording medium, and a complex amplitude data generation step.
A hologram data generation step for generating the hologram data from the complex amplitude data generated in the complex amplitude data generation step, and a hologram data generation step.
A display step of displaying the hologram data generated in the hologram data generation step on the spatial light modulator, and
A recording step of manufacturing the master hologram by recording the interference fringes between the object light reflecting the hologram data displayed in the display step and the reference light on the first hologram recording medium.
An arrangement step of arranging the second hologram recording medium at a position of the separation distance on the front side of the master hologram, and
A duplication step of duplicating the master hologram by recording the interference fringes of the master hologram on the second hologram recording medium arranged in the arrangement step is provided.
In the complex amplitude data generation step, the complex amplitude data is generated as a Fourier transform hologram in which a virtual lens is arranged between the object and the first hologram recording medium.
Wherein in the arrangement step, between the master hologram and the second hologram recording medium, wherein the sulfo program producing method placing a lens corresponding to the virtual lens. It includes a light source that generates laser light, a hologram data generator that generates hologram data, and a spatial light modulator that reflects the displayed hologram data on the laser light to generate object light, which is referred to as the object light. A hologram recording device that records interference fringes with light on a master hologram.
The hologram data generator is
A complex amplitude data generation means for generating complex amplitude data representing a light wave distribution when an object is placed at a preset initial position, and
A complex amplitude data correction means for correcting the complex amplitude data so that the object moves from the initial position to a position of a preset separation distance on the front side of the first hologram recording medium.
A hologram data generating means for generating the hologram data from the complex amplitude data corrected by the complex amplitude data correcting means is provided.
The spatial light modulator is a hologram recording device that displays hologram data generated by the hologram data generation device. To duplicate the master hologram
The second light source and
An optical branching means for branching the light from the second light source into the master hologram and the second hologram recording medium.
Illumination light irradiation means that emits light branched by the light branching means to the master hologram, and
A reference light irradiating means that emits the light branched by the optical branching means to the second hologram recording medium, and
A holding means for holding the master hologram and the second hologram recording medium at a distance of the distance, and
The hologram recording apparatus according to claim 3, further comprising.

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