JPH0659613A - Manufacture of hologram - Google Patents

Abstract

PURPOSE:To manufacture a hologram having a solid image whose individual picture element is uniform and steady in a very short time by only once exposure. CONSTITUTION:Master holograms 9 formed of plural elemental holograms which are arranged in a line in a space and project diffracted light to a mutually different specified range are piled up on the surface of photosensitive material, and space light modulating elements 2 having each cel corresponding to each element hologram are aranged on the master hologram 9, and the strength of transmitted light at the corresponding position is controlled by the element 2 according to parallax image data for a laser beam incident from the face of the element 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a stereoscopic image hologram for reproducing parallax images in a plurality of different directions, and particularly to a stable stereoscopic image in which individual pixels are uniform in a very short time. The present invention relates to a method for producing a hologram so that a hologram having a different image can be obtained.

[0002]

2. Description of the Related Art Conventionally, for example, there is a 3D printer as one of the techniques for producing a hologram of a three-dimensional image. This 3D printer automatically creates a hologram of a three-dimensional image using a computer.

That is, a computer calculates an original image pattern for exposing each point of a hologram from original three-dimensional data and displays it on a spatial modulation element (for example, a liquid crystal panel).

Further, the laser light is modulated by the original image pattern and focused on the surface of the photosensitive material placed on the XY stage to expose one element hologram. At this time, a dot composed of a desired diffraction grating is formed at that position.

Then, while the photosensitive material is sequentially moved by the XY stage in accordance with the image data, the photosensitive material is exposed so that the entire surface of the photosensitive material is filled, and dots are arranged according to the image data to produce a hologram for reproducing a parallax image. It is a thing.

By the way, in such a method for producing a stereoscopic hologram by a 3D printer, a hologram having parallax in the vertical and horizontal directions can be produced, but there are the following problems.

That is, it takes time to calculate the original image pattern, and it takes time to manufacture the hologram because each dot is exposed one by one.

Further, since the laser light is spread and used, it is not only difficult to manufacture a bright hologram, but also it is weak against vibration.

[0009]

As described above, in the conventional method for producing a hologram, there is a problem that not only it takes time to produce a hologram, but also a stable hologram cannot be produced.

The present invention has been made to solve the above problems, and an object thereof is to obtain a stable three-dimensional image in which an individual pixel is uniform in a very short time with only one exposure. An object of the present invention is to provide a highly reliable hologram production method capable of producing a hologram.

[0011]

In order to achieve the above object, in a method for producing a hologram of a three-dimensional image, first, in the invention described in claim 1, the photosensitive material surface is
A master hologram consisting of a plurality of element holograms that emit diffracted light in mutually different specific ranges is arranged side by side, and each cell corresponds to each element hologram on the master hologram. The spatial light modulation element is arranged, the intensity of the transmitted light at the corresponding position is controlled by the spatial light modulation element according to the parallax image data, and the laser light is incident from the surface of the spatial light modulation element.
A transmission type hologram is produced.

Further, in the invention described in claim 7, there is provided a master hologram in which a plurality of element holograms for emitting diffracted light in mutually different specific ranges are spatially arranged on the surface of the photosensitive material. Superimpose, on the surface of the photosensitive material opposite to the master hologram, place a spatial light modulation element in which each cell corresponds to each element hologram,
The spatial light modulator controls the intensity of the transmitted light at the corresponding position according to the parallax image data, and the laser light is incident from the surface of the spatial light modulator to produce a reflection hologram.

Here, particularly, as the laser beam, a laser beam expanded to a size that sufficiently covers the exposure area is used.

Further, as the laser light, a linearly expanded laser light is used, and scanning is performed in one direction to perform exposure.

Further, a laser beam is used as the laser beam, and scanning is performed in two directions to perform exposure.

As the master hologram,
Three sheets for R, G and B are used.

Further, as the master hologram, each element hologram for R, G, B which emits diffracted light in a first specific range and R, G which emits diffracted light in a second specific range. , And each element hologram for B as one set,
At least one set of these is used.

[0018]

Therefore, in the hologram manufacturing method according to the first aspect of the present invention, a plurality of element holograms that emit diffracted light in different specific ranges are spatially arranged on the surface of the photosensitive material. Master holograms are superposed on each other, and a spatial light modulator for each cell corresponding to each element hologram is placed on top of the master hologram, and the spatial light modulator transmits the transmitted light at the corresponding position according to the parallax image data. By controlling the intensity of the light and making the laser light incident from the surface of the spatial light modulator, it is possible to manufacture a transmission hologram in which each parallax image can be observed only in a limited range. This makes it possible to produce a transmissive hologram capable of observing a stereoscopic image by binocular parallax with only one exposure.

Further, in the hologram manufacturing method of the invention described in claim 7, a plurality of element holograms that emit diffracted light in different specific ranges are spatially arranged on the surface of the photosensitive material. The master holograms that are made up of these are superposed, and on the surface of the photosensitive material opposite to the master hologram, a spatial light modulation element corresponding to each element hologram is arranged in each cell, and parallax image data is created by the spatial light modulation element. By controlling the intensity of the transmitted light at the corresponding position according to the above, and making the laser light incident from the surface of the spatial light modulator, each parallax image produces a reflection-type hologram that can be observed only from a limited range. be able to. As a result, it is possible to manufacture a reflection type hologram capable of observing a stereoscopic image by binocular parallax with only one exposure.

As described above, a transmission type or reflection type hologram having a stable three-dimensional image in which individual pixels are uniform can be produced in an extremely short time.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings. In addition, here, a case where a transmission type hologram is manufactured as a hologram will be described.

In this embodiment, a transmission type hologram is manufactured by the following steps.

First, as shown in FIGS. 1A and 1C, a spatial light modulator (a liquid crystal device, a film, etc.) as shown in FIG. ) Place 2.

Next, the spatial light modulator 2 selectively controls transmission / blocking of light so that a desired hologram is recorded only in a desired area (only the area for the left eye is transmitted), and the object light 3 and The first element divided into regions as shown in FIG. 3 so that the emission range of the diffracted light is limited to the first range (left direction in the drawing) by irradiating the reference light 4 from the illustrated direction, respectively. The hologram 5 is recorded on the dry plate 1.

Next, as shown in FIGS. 1B and 1C, the spatial light modulator 2 is arranged just before the dry plate 1 in the same manner as described above.

Next, the spatial light modulator 2 selectively controls transmission / blocking of light so that a desired hologram is recorded only in a desired area (only the area for the right eye is transmitted). The second element divided into regions as shown in FIG. 3 so that the emission range of the diffracted light is limited to the second range (right direction in the drawing) by irradiating the reference light 7 from the illustrated direction, respectively. The hologram 8 is recorded on the dry plate 1.

The above operation is repeated for one master hologram dry plate 1 for the number of types of element holograms (two types in this example). As a result, the transmission type master hologram as shown in FIG. 3 in which the first and second types of element holograms 5 and 8 are spatially arranged side by side
The hologram 9 is created.

In the above description, each cell of the spatial light modulator 2 (individual element for which transmission / blocking of light can be selected) corresponds to each element hologram 5, 8 of the master hologram 9,
The transmission / blocking of light to / from each of the element holograms 5 and 8 is controlled.

Next, as shown in FIG. 4, a dry plate 11 having a substrate coated with a photosensitive material is placed with the surface of the photosensitive material facing upward, and the master plate prepared above is placed on the surface of the photosensitive material of the dry plate 11. The hologram 9 is placed and overlapped, and the spatial light modulator 2 used above is arranged on the master hologram 9.

Next, parallax image data (two types in this example) is read by a computer (not shown), the spatial light modulator 2 controls the intensity of transmitted light at the corresponding position according to the parallax image data, and the laser light source 13 controls the intensity. The laser light 14 is reflected by the mirror 15 and is further expanded by the lens 16 to a size enough to cover the exposure area. The laser light is made incident from the surface of the spatial light modulator 12 and exposed. In this way
Recording of parallax images for the left eye and the right eye is completed in one time, and a transmission type stereoscopic image hologram (3D display) is manufactured.

FIG. 5 shows that the laser light 1 is applied to the spatial light modulator 2.
4 is an enlarged view showing a state when 4 is incident. FIG.

In FIG. 5, the light (0th-order diffracted light) 17 transmitted through the light transmitting portion of the spatial light modulator 2 and the master hologram 9 is a reference light to the photosensitive material 11A (11B is a substrate) of the dry plate 11. Then, the first-order diffracted light 18 of the master hologram 9 becomes object light and interferes, and the interference fringes are recorded on the photosensitive material 11A of the dry plate 11.

At this time, if the distance between the master hologram 9 and the photosensitive material 11A of the dry plate 11 is small, the exposed portion becomes a dot having the shape of the light transmitting portion of the spatial light modulator 2 as it is. By expressing a parallax image using these dots as pixels, the direction (left eye direction or right eye direction) for reproducing this image is determined by the element hologram corresponding to this dot.

Therefore, when observing the transmissive hologram produced as described above, as shown in FIG. 6, the diffracted light from the dots produced using the first element hologram 5 of the master hologram 9 is obtained. 5A enters the left eye of the observer 19 and also diffracts light 8A from a dot created using the second element hologram 8 of the master hologram 9.
However, by entering the right eye of the observer 19, it is possible to observe different images from different directions, and it is possible to recognize a stereoscopic image.

As described above, in the present embodiment, when a transmission type three-dimensional image hologram is produced, first, on the surface of the photosensitive material of the dry plate 11 in which the photosensitive material 11A is applied to the substrate 11B, different specific images are provided. Of the first and second kinds of element holograms 5 and 8 which emit diffracted light in the range (left direction, right direction) are superposed on each other, and a master hologram 9 is superposed on the master hologram 9. The spatial light modulator 2 is arranged on the hologram 9, the spatial light modulator 2 controls the intensity of the transmitted light at the corresponding position according to the parallax image data, and the laser light 14 is reflected by the mirror 15 by the mirror 15. A laser beam expanded to a size that sufficiently covers the exposure area by the lens 16 is made incident from the surface of the spatial light modulation element 2 to produce a transmission hologram. Than it is.

Therefore, the following various effects can be obtained.

(A) Since the copy method is used, it is resistant to vibration and the light is effectively used, so that the exposure time is short, and as a result, a bright and stable hologram can be produced in an extremely short time. Is possible.

(B) Further, as the master hologram 9, two kinds of element holograms 5 and 8 of the first and second types, which emit diffracted light in specific ranges (left direction and right direction) different from each other, are provided. Since the holograms spatially arranged side by side are used, it is possible to produce the desired hologram in a shorter time and at a lower cost with only one exposure.

(C) Since different images can be recorded in the left and right directions, it is possible to manufacture a hologram that allows stereoscopic viewing.

(D) For the above reasons, it is possible to automate the production of holograms.

(E) Since the image can be directly output, an intermediate work such as outputting to a film as in the conventional case is unnecessary.

(F) Since the hologram can be produced using only the laser light source 13, the mirror 15, the lens 16, the master hologram 9 and the dry plate 11, the device structure can be simplified.

(G) Since the laser beam 14 is made incident on the master hologram 9 through the spatial light modulation element (liquid crystal element, film, etc.) 2, the shape of the dot is not limited and is suitable for individual images. It is possible to make a different shape.

(H) As the laser light 14 is a laser light that is spread to a size that sufficiently covers the exposure area, exposure with an intensity distribution (usually a Gaussian distribution) in a plane perpendicular to the optical axis of the laser beam is used. It is possible to eliminate the unevenness and make the brightness uniform within the dots.

(I) As for the hologram pixel, that is, the resolution is about 80 μm when the laser beam is used, but when the spatial light modulator 2 is, for example, a liquid crystal element, the diameter is about 30 μm. It is possible to achieve high resolution.

(J) When gradation is expressed using a laser beam, the exposure time is changed to change the size and brightness of the exposed dot, but the dot size is not constant. Although the image is hard to see, as in the present embodiment, for example, by using a liquid crystal element, by providing gradation in each cell of the liquid crystal element, it is possible to easily create dots of uniform brightness and different brightness. It becomes possible.

Next, another embodiment of the present invention will be described. In addition, here, a case where a reflection type hologram is manufactured as a hologram will be described.

In this embodiment, a reflection type hologram is manufactured by the following steps.

First, as shown in FIGS. 7A and 7C, the spatial light modulator 2 similar to the above is arranged immediately before the dry plate 21 in which the substrate is coated with the photosensitive material.

Next, the spatial light modulator 2 selectively controls transmission / blocking of light (transmission of only the region for the left eye) so that the desired hologram is recorded only in the desired region. By irradiating each of the reference lights 23 from the illustrated direction, the emission range of the diffracted light is limited to the first range (left direction in the drawing), and the first element is divided into regions as shown in FIG. The hologram 25 is recorded on the dry plate 21.

Next, as shown in FIGS. 7B and 7C, the spatial light modulator 2 is arranged just before the dry plate 21 in the same manner as above.

Next, the spatial light modulator 2 selectively controls transmission / blocking of light (transmission of only the right eye region) so that the desired hologram is recorded only in the desired region, and the object light 26 and The area-divided second element as shown in FIG. 8 is arranged so that the emission range of the diffracted light is limited to the second range (right direction in the drawing) by irradiating the reference light 27 from the illustrated direction, respectively. The hologram 28 is recorded on the dry plate 21.

The above operation is repeated on the single master hologram dry plate 21 for the number of types of element holograms (two types in this example). This allows
A reflection type master hologram 29 as shown in FIG. 8 in which the first and second element holograms 25 and 28 of two kinds are spatially arranged side by side is created.

In the above, each cell of the spatial light modulator 2 (individual element for which transmission / blocking of light can be selected) corresponds to each element hologram 25, 28 of the master hologram 29. Transmission of light to 25/28 /
Control the interruption.

Next, as shown in FIG. 9, a dry plate 31 having a substrate coated with a photosensitive material is placed on the master hologram 29 prepared above with the surface of the photosensitive material facing downward, and is superposed. The spatial light modulator 2 used above is arranged on the surface of the material opposite to the master hologram 29.

Next, the parallax image data is read by a computer (not shown), the spatial light modulation element 2 controls the intensity of the transmitted light at the corresponding position according to the parallax image data, and the laser light 34 from the laser light source 33 is mirrored by the mirror 35. The laser light is reflected and further expanded by the lens 36 to a size that sufficiently covers the exposure area, and the laser light is made incident on the surface of the spatial light modulation element 2 for exposure. In this way, recording of the left-eye and right-eye parallax images is completed at once, thereby producing a reflection type stereoscopic image hologram (3D display).

FIG. 10 is an enlarged view showing a state in which the laser light 34 is incident on the spatial light modulator 2.

In FIG. 10, the light 37 transmitted through the light transmitting portion of the spatial light modulator 2 and the dry plate 31 serves as reference light for the photosensitive material 31A (31B is a substrate) of the dry plate 31, and the master hologram 29 is used. The reflected first-order diffracted light 38 is
It becomes object light and interferes, and the interference fringes are recorded on the photosensitive material 31A of the dry plate 31.

At this time, if the distance between the master hologram 29 and the photosensitive material 31A of the dry plate 31 is small, the exposed portion becomes a dot having the shape of the light transmitting portion of the spatial light modulator 2 as it is. By expressing a parallax image using these dots as pixels, the direction (left eye direction or right eye direction) for reproducing this image is determined by the element hologram corresponding to this dot.

Therefore, when observing the reflection hologram produced as described above, the master hologram 2
The diffracted light from the dot created using the first element hologram 25 of No. 9 enters the observer's left eye, and the diffracted light from the dot created using the second element hologram 28 appears to the observer. By entering the right eye, it becomes possible to observe different images from different directions, and it is possible to obtain a hologram of a reflective stereoscopic image.

Also in the method of manufacturing the reflection type image hologram of the present embodiment, the same effect as in the above embodiment can be obtained.

The present invention is not limited to the above embodiments, but can be implemented in the same manner as described below.

(A) In each of the above-described embodiments, the case where the laser light from the laser light source 14 which is spread to a size that sufficiently covers the exposure area is used as the laser light, but the present invention is not limited to this. 11, the dry plate 11 is placed on the XY stage 41, the transmittance of the corresponding position of the spatial light modulator 2 is controlled according to the parallax image data, and the XY stage 41 is moved. Alternatively, even if the laser beam 42 from the laser light source 13 is incident through the mirror 43 while scanning the laser beam 42 in two directions, the entire area having parallax image data is exposed. The same effect as is obtained. The same applies to the case of a reflection hologram.

(B) In each of the above embodiments, the case where the laser light from the laser light source expanded to a size that sufficiently covers the exposure area is used as the laser light has been described. As shown in, the dry plate 11
Is placed on the X stage 44, and a laser beam 45 from the laser light source 13 is linearly spread and made incident through a mirror 46 and a cylindrical lens 47 so that scanning is performed in one direction to perform exposure. However, the same effect as described above can be obtained. The same applies to the case of a reflection hologram.

(C) In each of the above-described embodiments, the case of all two left and right parallax images has been described, but the number of parallax images is not limited to this, and the corresponding master
By preparing element holograms for holograms,
A hologram of a three-dimensional stereoscopic image that is easier to see can be obtained by the same manufacturing process as described above.

(D) In each of the above embodiments, the master
It is also possible to realize colorization by using three R, G and B holograms (per one emission range) as holograms.

That is, in this case, R of each emission range,
By arranging the master holograms of G and B as element holograms on one master hologram, a color hologram can be obtained by only one exposure.

However, in the case of producing a reflection type hologram, exposure is performed three times in the R direction, G direction and B direction for each emission range, or a frequency filter (color filter or the like is provided immediately before the spatial light modulator. ) Is placed, R, G,
The exposure may be performed once with laser light of B3 colors (three).

FIG. 13 is thus prepared,
It is a figure which shows the structural example at the time of forming three types of element holograms for R, G, and B on one master hologram.
In FIG. 13, 51R, 51G and 51B are element holograms for R, G and B in the first emission range, and 52R and 52.
G and 52B respectively represent element holograms for R, G, and B in the second emission range, and are arranged as shown.

(E) In each of the above embodiments, the case where the spatial light modulator selects transmission / blocking of light at the corresponding position according to the parallax image data has been described. The intensity of transmitted light at the corresponding position may be controlled according to the data.

(F) In each of the above embodiments, the master
The method for creating the hologram is not limited to the above-mentioned method, and the master hologram may be any method as long as the emitting direction of the diffracted light is limited.

[0072]

As described above, according to the present invention, a plurality of element holograms that emit diffracted light in different specific ranges are spatially arranged side by side on the surface of the photosensitive material. The holograms are overlapped, and each cell has a spatial light modulator corresponding to each element hologram on the master hologram, and the spatial light modulator controls the intensity of the transmitted light at the corresponding position according to the parallax image data. , A master hologram in which a plurality of element holograms are arranged spatially side by side so that laser light is incident from the surface of the spatial light modulation element or that diffracted light is emitted to a specific range different from each other on the surface of the photosensitive material. Superimpose holograms, and place a spatial light modulation element where each cell corresponds to each element hologram on the surface of the photosensitive material opposite to the master hologram Te, and controls the intensity of the transmitted light of the corresponding positions in accordance with the parallax image data by the spatial light modulator,
Since the laser light is made to enter from the surface of the spatial light modulator, it is possible to create a stable multi-gradation stereoscopic image hologram in which each pixel is uniform and in a very short time with just one exposure. It is possible to provide a highly reliable method for producing a hologram.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an example of a case where a transmission type master hologram according to the present invention is created.

FIG. 2 is a schematic diagram showing an example of a spatial light modulator in the same Example.

FIG. 3 is a schematic diagram showing an example of a transmission type master hologram in the embodiment.

FIG. 4 is a schematic configuration diagram showing an embodiment in the case of manufacturing a transmission hologram according to the present invention.

FIG. 5 is an enlarged view showing a state when laser light is incident on the spatial light modulator according to the embodiment.

FIG. 6 is a schematic diagram for explaining a method of observing a hologram produced by the method of the example.

FIG. 7 is a schematic diagram showing an example of a case where a reflective master hologram according to the present invention is created.

FIG. 8 is a schematic diagram showing an example of a reflection type master hologram in the embodiment.

FIG. 9 is a schematic configuration diagram showing an embodiment in the case of manufacturing a reflection hologram according to the present invention.

FIG. 10 is an enlarged view showing a state when laser light is incident on the spatial light modulator according to the embodiment.

FIG. 11 is a schematic view showing another example of the case of producing a transmission type master hologram according to the present invention.

FIG. 12 is a schematic view showing another example of a case where a transmission type master hologram according to the present invention is created.

FIG. 13 is a schematic diagram showing another example of a master hologram according to the present invention.

[Description of Codes] 1 ... Dry plate, 2 ... Spatial light modulator, 3 ... Object light, 4 ... Reference light, 5 ... First element hologram, 6 ... Object light, 7 ... Reference light, 8 ... Second element Hologram, 9 ... Master hologram, 11 ... Dry plate, 13 ... Laser light source, 14 ... Laser light, 15 ... Mirror, 16 ... Lens, 17 ... 0th-order diffracted light, 18 ... First-order diffracted light, 19 ... Observer, 21 ... Dry plate Two
2 ... Object light, 23 ... Reference light, 25 ... First element hologram, 26 ... Object light, 27 ... Reference light, 28 ... Second element hologram, 31 ... Dry plate, 33 ... Laser light source, 34 ... Laser light, 35 ... Mirror, 36 ... Lens, 37 ... Transmitted light, 38 ... First-order diffracted light, 41 ... XY stage, 42 ...
Laser beam, 43 ... Mirror, 44 ... X stage,
45 ... Laser beam, 46 ... Mirror, 47 ... Cylindrical lens, 51R, 51G, 51B ... Element holograms for R, G, B in the first emission range, 52R, 52
G, 52B ... Element holograms for R, G, B in the second emission range.

Claims (12)

[Claims] 1. A method for producing a hologram for displaying a three-dimensional image, wherein a plurality of element holograms for emitting diffracted light in mutually different specific ranges are spatially arranged on a surface of a photosensitive material. The master hologram is superposed, and the spatial light modulation element in which each cell corresponds to each element hologram is arranged on the master hologram, and the spatial light modulation element transmits the corresponding position according to the parallax image data. A method for producing a hologram, wherein the intensity of light is controlled and laser light is made incident from the surface of the spatial light modulator to produce a transmissive hologram. 2. The method for producing a hologram according to claim 1, wherein the laser light is a laser light expanded to a size that sufficiently covers an exposed area. 3. The method for producing a hologram according to claim 1, wherein a linearly expanded laser beam is used as the laser beam, and scanning is performed in one direction to perform exposure. 4. The method for producing a hologram according to claim 1, wherein a laser beam is used as the laser light, and scanning is performed in two directions to perform exposure. 5. As the master hologram, R,
3. The method for producing a hologram according to claim 1, wherein three sheets for G and B are used. 6. A first hologram as the master hologram
R, G, and B element holograms that emit diffracted light in a specific range and R, G, and B element holograms that emit diffracted light in a second specific range are set as one set, The method for producing a hologram according to claim 1, characterized in that at least one set of these is used. 7. A method of producing a hologram for displaying a three-dimensional image, wherein a plurality of element holograms for emitting diffracted light in mutually different specific ranges are spatially arranged on a surface of a photosensitive material. And superimposing a master hologram on the surface of the photosensitive material opposite to the master hologram, each cell has a spatial light modulation element corresponding to each element hologram, and the spatial light modulation element causes parallax. A method for producing a hologram, characterized in that the intensity of transmitted light at a corresponding position is controlled according to image data and a laser beam is made incident from the surface of the spatial light modulation element to produce a reflection type hologram. 8. The method for producing a hologram according to claim 7, wherein the laser light is a laser light expanded to a size that sufficiently covers an exposed region. 9. The method for producing a hologram according to claim 7, wherein a linearly expanded laser beam is used as the laser beam, and scanning is performed in one direction to perform exposure. 10. The method for producing a hologram according to claim 7, wherein a laser beam is used as the laser beam, and scanning is performed in two directions to perform exposure. 11. The method of producing a hologram according to claim 7, wherein three R, G, and B sheets are used as the first and second master holograms, respectively. 12. The element holograms for R, G and B that emit diffracted light in a first specific range and R and G that emit diffracted light in a second specific range as the master hologram. 8. The method for producing a hologram according to claim 7, wherein each element hologram for B, B is set as one set, and at least one set is arranged.