JP2001210089A - Hologram memory - Google Patents

Abstract

(57) [Problem] To provide a hologram memory having a recording capacity near the optical wavelength resolution limit. SOLUTION: In a hologram memory having a structure in which a number of slab type waveguides in which independent holograms are written are stacked, diffracted light reproduced from each of the slab type waveguide surfaces is placed on a plane outside the waveguide surface. The image is formed as a plurality of frame images composed of a minute spot array, and the magnification of the image on the hologram surface and the image formation surface is 1 or more, and at least each frame image on the image formation surface corresponds to the surface dimension shape of the surface type light receiving element In addition, a plurality of images corresponding to the surface dimensions and shape of the surface light receiving element are collectively reproduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hologram memory, and more particularly, to a laminated waveguide hologram memory with an increased memory capacity.

[0002]

2. Description of the Related Art A read-only laminated waveguide hologram memory has been proposed. (Japanese Patent Application No. 10-32578) This hologram memory is formed such that diffracted light from each waveguide forms a desired image on a two-dimensional detector such as a CCD arranged at a position several millimeters away. .

[0003]

Therefore, the resolution of image data during reproduction cannot exceed the resolution of a two-dimensional detector. For example, if the pixel period of the CCD is 5 μm, even if there is image data with higher definition than 5 μm, it cannot be reproduced while maintaining high definition, and the amount of information is lost.

On the other hand, the unevenness of the read-only laminated waveguide hologram memory can be formed with higher precision than the wavelength of visible light.
The information density per layer using visible light is determined by changing the wavelength of light to λ
Can have a high density of about 1 / λ ² . However, as described above, since the pixel size of the two-dimensional light receiving element is large, when the hologram size and the reproduced image size are one-to-one, the information amount is largely lost. For example,
The wavelength of the reproduction light is 680 nm, and the pixel period of the CCD is 5
Assuming μm, the information amount is 2.2 Mbit in optical resolution.
/ Mm ² , while having a recording density of 40 Kbit / mm ² due to the reading resolution of the CCD, the recording capacity is only 2%.

In order to couple light into each waveguide,
Although a 45-degree mirror is used as the light introducing portion, a width at least as large as the thickness of the recording medium is required to form the mirror portion, and information cannot be recorded in this portion. If the effective area of the recording medium is small, the portion of the recording medium where no information is written becomes large, which is a problem in increasing the recording capacity. Therefore, 4
It is important how to increase the area of the area where the hologram is written with respect to the area occupied by the mirror at 5 degrees. The present invention has been made in view of such circumstances, and has as its object to provide a hologram memory having a recording capacity near the optical wavelength resolution limit.

[0006]

Means for Solving the Problems To achieve the above object, an invention according to claim 1 is directed to a hologram memory having a structure in which a large number of slab type waveguides on which independent holograms are written are stacked. Diffracted light reproduced from each of the slab type waveguide surfaces is formed as an image having a minute spot array on a plane outside the waveguide surface, and the magnification of the image on the hologram surface and the image formation surface is 1 or more. There is a feature.

According to a second aspect of the present invention, there is provided a hologram memory having a structure in which a large number of slab-type waveguides on which independent holograms are written are stacked.
Diffracted light reproduced from each of the slab type waveguide surfaces is formed as an image having a minute spot array on a plane outside the waveguide surface, and the magnification of the image on the hologram surface and the image formation surface is 1 or more. The output area of the image on the imaging plane matches the size and shape of the light receiving surface of the light receiving element.

According to a third aspect of the present invention, there is provided a hologram memory having a structure in which a large number of slab type waveguides each having an independent hologram written therein are stacked, diffracted light reproduced from each of the slab type waveguide surfaces. Are formed on a plane outside the waveguide plane as images of a plurality of frames composed of minute spot arrays, and at least each frame image on the imaging plane corresponds to the surface size and shape of the surface-type light receiving element, and A plurality of images corresponding to the surface dimensions and shapes of the light receiving elements are collectively reproduced.

According to a fourth aspect of the present invention, there is provided a hologram memory having a structure in which a number of slab type waveguides each having an independent hologram written therein are stacked, diffracted light reproduced from each of the slab type waveguide surfaces. Are formed on a plane outside the waveguide plane as a plurality of frame images composed of a minute spot array, the magnification of the images on the hologram plane and the imaging plane is 1 or more, and at least each frame image on the imaging plane is A plurality of images corresponding to the surface dimensions of the surface light receiving element and corresponding to the surface dimensions of the surface light receiving element are collectively reproduced.

[0010] The invention described in claim 5 is the same as claim 3.
Or the hologram memory according to any one of 4, wherein an identification signal is reproduced at a boundary of each of a plurality of frames on the imaging plane.

[0011] The invention according to claim 6 is the first invention.
5. The hologram memory according to any one of claims 1 to 5,
It is characterized in that the mounted recording capacity is increased by multiplexing signals within a range not exceeding the recording capacity limit.

According to the first to sixth aspects of the present invention, enlarged reproduction is performed so that the reproduction image size is larger than the hologram size, and / or a plurality of (a plurality of frames) hologram images are collectively reproduced. Therefore, even when the size of one pixel of the surface-type light receiving element has a resolution of only a micron order, the hologram recording medium as the hologram memory must have a recording capacity near the resolution limit of the light wavelength. Can be.

[0013]

Embodiments of the present invention will be described below in detail with reference to the drawings. First, prior to the description of the embodiments of the present invention, the principle of the hologram memory according to the present invention will be described. The hologram memory according to the present invention is configured to perform enlarged reproduction so as to make the reproduced image size larger than the hologram size, and to reproduce a plurality of hologram images collectively.

First, a method of enlarging and reproducing a hologram will be described with reference to FIG. When an image of a hologram on the recording medium 1 is formed on a light receiving surface of a surface light receiver 2 such as a CCD, the hologram is formed by an image forming optical system (not shown) according to the size of the light receiving surface as shown in FIG. Can be enlarged from the plane. The recording area of the hologram is 48 mm × 79.
For a hologram memory in which 10 pages of slab-type waveguides are stacked with 5 mm, assuming the number of light receiving pixels of the surface light receiver 2 as 1024 × 1024, the recording capacity mounting limit and the theoretical capacity limit calculated in the arrangement shown in FIG. The magnification dependency is shown in FIG.

The square light receiving pixel 1 of the surface light receiver 2
The individual dimensions were used as parameters. That is, if the magnification is the same, the larger the size of the pixel, the larger the image forming area, so that the recording area is large. Then, when the theoretical limit of the recording capacity is calculated assuming that the entire hologram drawing area can be written with a refractive index of 1.5 at a resolution of 680 nm of light, the larger the pixel size is, as shown in FIG.
Since the recording area increases, the theoretical limit of the recording capacity increases.

In FIG. 3, reference numeral 3 denotes a hologram drawing area, and reference numeral 4 denotes a 45-degree mirror forming area. In the calculation, the width of the 45-degree mirror forming area and the separation area 5 between the 45-degree mirror forming area 4 and the hologram drawing area are set to 0.5.
mm. The dimensions of the hologram drawing area change depending on the magnification (magnification). As shown in FIG. 2, the capacity limit (the theoretical capacity of the storage capacity) increases as the pixel size increases, but decreases as the magnification increases because the effective recording area decreases. The recording capacity mounting limit ignoring readability is simply determined by the number of spots that become the size of a CCD pixel when enlarged on a recording medium, and therefore increases as the pixel size decreases, and increases as the magnification increases. Therefore, the smaller the pixel size, the sooner the limit (4.2 GB in the example of FIG. 2) is reached. In any case, it is possible to increase the recording capacity mounting limit within the range not exceeding the theoretical limit of the recording capacity by the enlarged reproduction method.

Next, a multi-frame enlargement reproduction method for collectively reproducing a plurality of hologram images will be described. FIG. 4 shows a schematic diagram of the four-frame enlargement reproduction method. In the figure, a hologram on a recording medium 6 is used to convert
Are formed on the light-receiving surface of the camera. The image for four frames is moved to the light receiving surface corresponding to each frame of the surface light receiver to read one frame at a time.
At this time, a method of embedding the identification signal of the boundary section shown in FIG. 5 in order to recognize the boundary of each frame may be considered.
FIG. 5A shows a 4-frame recording area of the recording medium 6, and reference numeral 6A shows a boundary portion between frames. FIG. 5B is a partially enlarged view of a boundary portion 6A between frames, and specifically shows an example in which an identification signal for identifying the boundary portion is embedded in the boundary portion between frames.

FIGS. 6 to 8 show a collective enlargement / reproduction method of 4, 9 and 16 frames, respectively. The relationship between the recording capacity of the hologram memory and the enlargement ratio by these collective enlargement / reproduction methods is calculated in the same manner as in FIG. The results obtained are shown in FIGS. 6 to 8, 10A, 10B, 10C
Is a recording medium. As can be seen from FIGS. 9 to 11,
Although the same tendency as that of the one-frame enlargement reproduction method is shown, the mounting limit value increases in accordance with the number of frames to 7.13, 9.25, and 10.57 GB. It is clear that the mounted recording capacity can be increased without exceeding the range.

Next, an embodiment of the present invention will be described. First, a comparative example as a comparative example of the embodiment of the present invention will be described. Comparative Example 1 In this comparative example, hologram data was recorded on the recording medium 20 in the form of a credit card shown in FIG. When a CCD having a pixel size of 6.7 μm × 6.7 μm square and 1024 × 1024 pixels is used as a light receiving element, the size of the light receiving surface is 6.7 μm × 1024 × 6.7 μm × 1024 square = 6.
860.8 × 6860.8 μm square.

FIG. 13 shows hologram drawing areas 22 and 4
5 degree mirror forming area 23 and 45 degree mirror forming area 23
FIG. 14 is a view showing the arrangement of a separation area 24 between the hologram drawing area 22 and the hologram drawing area 22. In the one-to-one imaging method, the distance between the 45 ° mirror and the hologram drawing nearest end is 2 mm as shown in FIG. The thickness of the card was 0.75 mm, and the holograms were arranged at 1 mm intervals from adjacent holograms. As shown in FIG. 14, one page of the recording medium 20 can accommodate 6 × 7 = 42 units of 8 mm × 11 mm, and the recording capacity of one unit is:
Pixel matching is performed, and 1024 × 1024 = 10
Since 48576 bits are about 1 Mbit, the capacity of one page is 42 × 1048576 bits = 44040192 bits, which is about 44 Mbit. With 10 pages, a recording capacity of about 440 Mbit was obtained.

The specifications of the recording medium as the hologram memory produced were as follows: core, cladding, and base film thicknesses were 1 μm, 20 μm, and 0.52 mm, respectively. Was used for the base film. The hologram was formed by electron beam lithography using an electron beam resist having a thickness of 0.1 μm. Then, the reproduction of the hologram was confirmed with light having a wavelength of 680 nm.

Next, a hologram memory according to the first embodiment of the present invention will be described. First Embodiment In the present embodiment, a recording medium used as a hologram memory that is reproduced by the unit arrangement shown in FIG. 30
Was prepared. At this time, the unit 31 of 2 mm × 5 mm is 24 × 16 = 384 as shown in FIG.
The capacity of one unit can be accommodated, and the capacity of one unit is about 1 Mbit at 1024 x 1024 = 1048576 bits by performing pixel matching, and the capacity of one page is 384 x 104
8576 bits = 402653184 bits and about 402 Mbit
Becomes On page 10, 4.0265 Gbit was obtained. According to the hologram memory according to the first embodiment of the present invention, the recording capacity is improved by one digit by the enlargement reproduction method as compared with Comparative Example 1.

Next, a hologram memory according to a second embodiment of the present invention will be described. Second Embodiment In the present embodiment, as shown in FIG. 17, the width of the mirror 41 and the mirror 41 and the hologram drawing area 40 in the recording medium used as the hologram memory according to the first embodiment Was changed from 1 mm to 0.5 mm to produce a recording medium used as a hologram memory.
At this time, 24 units of 2 mm x 3 mm are placed on one page.
× 26 = 624 can be accommodated, and the capacity of one unit is determined by performing pixel matching, and 1024 × 1024 = 1024
576 bits is about 1 Mbit, which is about 1 Mbit, and the capacity of one page is 624 × 1048576 bits = 65443114.
It is about 654 Mbit in 24 bits. On page 10, a recording capacity of about 6.54 Gbit was obtained.

Next, a hologram memory according to a third embodiment of the present invention will be described. Third Embodiment In this embodiment, as shown in FIG. 18, hologram drawing is performed based on a mirror width and a distance between a mirror and a hologram drawing area in a recording medium used as a hologram memory according to the second embodiment. A recording medium used as a hologram memory was manufactured so that the regions 50 were arranged in a staggered manner.
At this time, a unit of 2 mm x 4 mm is 24 x
20 = 480 can be accommodated, and the capacity of one unit is determined by performing pixel matching, and 1024 × 1024 × 2 = 20.
97152 bits, which is about 2.1 Mbit, and the capacity of one page is 480 x 2097152 bits = 100663296.
04 bits and about 1 Gbit. On page 10, about 10G
The recording capacity of bit was obtained.

Next, a hologram memory according to a fourth embodiment of the present invention will be described. Fourth Embodiment In the present embodiment, as shown in FIG. 19, the mirror width and the distance between the mirror and the drawing area of the hologram in the recording medium used as the hologram memory according to the second embodiment, The recording medium used as a hologram memory was prepared by arranging the hologram drawing areas 60 in a straight line. At this time, a unit of 3 mm x 1 mm is 16 x 7 per page.
9 = 1264 can be accommodated, and the capacity of one unit is determined by performing pixel matching, and 1024 × 1024 = 14855
It becomes 76 bits and about 1.05 Mbit, and the capacity of one page is
1264 × 1048576bit = 132560064b
It becomes about 1.3Gbit with it. At 10 pages, about 13Gb
The recording capacity of it was obtained.

Next, Comparative Example 2 which is compared with the embodiment of the present invention will be described. Comparative Example 2 With a pixel size of 3 μm × 3 μm square, 1024 × 1024
When using a pixel surface-type light receiving element, the size of the light receiving surface is 3μ.
m × 1024 × 3 μm × 1024 square = 3072 × 307
It is 2 μm square. A recording medium 70 as a hologram memory according to this comparative example is a one-to-one equal-magnification image forming method, and FIG.
As shown in (2), a 45-degree mirror was arranged only at the left end, at a distance of 2 mm from the nearest end of the hologram, and was arranged with no space between adjacent holograms. 3.072mm per page
15 × 25 = 375 units of × 3.072 mm can be accommodated, and the capacity of one unit is pixel-matched and 1024 × 1024 = 1048576 bits, which is about 1 Mb.
it, and the capacity of one page is 375 x 1048576
bit = 39326000 bits, which is about 393 Mbit.
On page 10, a recording capacity of about 3.93 Gbit was obtained.

Next, a hologram memory according to a fifth embodiment of the present invention will be described. Fifth Embodiment In this embodiment, as shown in FIG. 21, the pixel size is determined by the mirror width and the distance between the mirror and the hologram drawing area in the recording medium used as the hologram memory according to the second embodiment. 1024 × 10 in 3 μm × 3 μm square
A recording medium as a hologram memory was manufactured by arranging a hologram drawing area linearly by a 6-fold magnification reproduction method using a 24-pixel surface light receiving element. At this time, one page
19 × 159 = 302 for a unit of 5 mm × 0.5 mm
The capacity of one unit can be accommodated, and the capacity of one unit is about 1024 × 1024 = 1048576 bits and about 1.05 Mbit by performing pixel matching, and the capacity of one page is 3021 ×
1048576 bit = 3167748096 bit and about 3.
It becomes 17 Gbit. On page 10, a recording capacity of about 31.7 Gbit was obtained.

Next, Comparative Example 3 compared to the present embodiment
Will be described. Comparative Example 3 With a pixel size of 1.5 μm × 1.5 μm square, 1024 ×
When a 1024-pixel surface light receiving element is used, the size of the light receiving surface is 1.5 μm × 1024 × 1.5 μm × 1024 square =
The size is 1536 × 1536 μm square. A recording medium as a hologram memory according to this comparative example is arranged in a one-to-one equal-magnification image forming method with a 45-degree mirror width and a distance of 0.5 mm between a 45-degree mirror width and a hologram drawing end as shown in FIG. 1.53 per page with no space between adjacent holograms
31 × 22 = 68 for a unit of 6 mm × 1.536 mm
The capacity of one unit can be accommodated, and the capacity of one unit is about 1024 × 1024 = 1048576 bits and about 1 Mbit by performing pixel matching. The capacity of one page is 682 × 104
8576 bits = 71512882 bits and about 0.715 Gb
becomes it. On page 10, a recording capacity of about 7.15 Gbit was obtained.

Next, a hologram memory according to a sixth embodiment of the present invention will be described. Sixth Embodiment In the present embodiment, as shown in FIG. 23, only the arrangement of the 4-frame reproduction system is different from that of Comparative Example 3. 3.072mm x 5.072m per page with 1x angle imaging
15 × 15 = 225 m units can be arranged, and the capacity of one unit is 1024 ×
1024 × 4 = 4,194,304 bits. Approximately 4.19 Mbit, and the capacity of one page is 225 x 4194304 bits
= 943718400 bits, which is about 0.944 Gbit.
On page 10, a recording capacity of about 9.44 Gbit was obtained.

Next, a hologram memory according to a seventh embodiment of the present invention will be described. Seventh Embodiment In the present embodiment, as shown in FIG. 24, a 3 × 3 μm square pixel is used in a 6.2 × magnification imaging method, and is used for a hologram memory corresponding to a 4-frame batch reproduction method. A recording medium was manufactured. 16 × 79.5 = 1272 units of 3 mm × 1 mm can be accommodated in one page, and the capacity of one unit is 1024 by performing pixel matching.
× 1024 × 4 = 4,194,304 bits, which is about 4.2 Mbit, and the capacity of one page is 1,272 × 4,194,304 bits
= 5335154688 bits and about 5.34 Gbits.
In 10 pages, a recording capacity of 53.4 Gbit was obtained.

Next, a hologram memory according to an eighth embodiment of the present invention will be described. Eighth Embodiment In this embodiment, as shown in FIG. 25, a recording medium used as a hologram memory compatible with a pixel size of 3 μm × 3 μm square and a 9-frame batch reproduction 6.2 × magnification imaging method was manufactured. 32 × 22 = 704 units of 1.5 mm × 3.5 mm can be accommodated in one page, and the capacity of one unit is 1024 × 102
4 × 9 = 94337154 bits and about 9.4 Mbits,
The capacity of the page is 704 × 94337154 bits = 664
3777536 bits and about 6.64 Gbits. On page 10, 66.4 Gbit was obtained.

Next, a hologram memory according to a ninth embodiment of the present invention will be described. Ninth Embodiment In the ninth embodiment, as shown in FIG. 26, a recording medium used in a hologram memory compatible with a 6.2-times magnification imaging method for 16 frames collective reproduction with a pixel size of 3 μm × 3 μm square is used. Produced. One page can accommodate 12 × 39 = 468 units of 4 mm × 2 mm, and the capacity of one unit is 1024 × 1024 ×
16 = 16777216 bits, which is about 16.8 Mbit,
The capacity of one page is 468 x 16777216 bits = 78
51737088 bits and about 7.85 Gbit. On page 10, a recording capacity of 78.5 Gbit was obtained.

Next, a hologram memory according to a tenth embodiment of the present invention will be described. Tenth Embodiment In the present embodiment, a recording medium used as a hologram memory corresponding to a 4.5 × 10 × 4 reproduction of 4 × 1050 × 4 × 3 × 50 μm pixels shown in FIG. It was manufactured as shown in FIG. 14 x 56 = 7 units of 3.4 mm x 1.4 mm per page
The capacity of 84 units can be accommodated, and the capacity of one unit is determined by pixel matching, and 1024 × 1024 × 4 = 4194304
bit and about 4.2Mbit, the capacity of one page is 280
× 4,194,304 bits = 3,288,334 bits, which is approximately 3.29 Gbits. 10 pages, 2 multiplexes, about 6
A recording capacity of 5.8 Gbit, about 8.22 GB was obtained.
As a method of duplexing, a method of distinguishing the light intensity of each point on the image forming plane into four steps and a method of setting two image forming positions and distinguishing the light intensity at each position into two steps were used. .

[0034]

As described above, according to the present invention, enlarged reproduction is performed so as to make the reproduction image size larger than the hologram size, and / or a plurality of (multiple frames) hologram images are collectively obtained. Since it was made to play,
Even when the size of one pixel of the surface type light receiving element has only a resolution on the order of microns, a hologram recording medium as a hologram memory can realize a recording capacity near the resolution limit of the light wavelength. Therefore, even a large-capacity recording medium can be made thinner, smaller, and lighter, and has a great effect in terms of portability and space saving.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing the principle of an enlarged reproduction method applied to a hologram memory according to the present invention.

FIG. 2 is a characteristic diagram showing an enlargement ratio dependency of a recording capacity limit determined by a recording capacity mounting limit and an optical wavelength resolution.

FIG. 3 is an explanatory diagram showing a hologram arrangement on a hologram recording medium.

FIG. 4 is an explanatory diagram showing a multi-frame reproduction method applied to the hologram memory according to the present invention.

FIG. 5 is an explanatory diagram showing an example of an identification signal between frames in a 4-frame hologram image reproduction area in the hologram memory according to the present invention.

FIG. 6 is an explanatory diagram showing an arrangement of a hologram drawing area and a 45-degree mirror formation area and a separation area between the 45-degree mirror formation area and the hologram drawing area in the four-frame magnification reproduction method.

FIG. 7 is an explanatory diagram showing an arrangement of a hologram drawing area and a 45-degree mirror formation area and a separation area between the 45-degree mirror formation area and the hologram drawing area in a 9-frame enlargement / reproduction method.

FIG. 8 is a diagram showing an arrangement of a hologram drawing area and a 45-degree mirror formation area and a separation area between the 45-degree mirror formation area and the hologram drawing area in a 16-frame enlargement / reproduction method.

FIG. 9 is a characteristic diagram showing the enlargement rate dependency of the mounting recording capacity of the hologram memory and the limit of the recording capacity in the four-frame enlargement / reproduction method.

FIG. 10 is a characteristic diagram showing the enlargement ratio dependency of the mounting recording capacity of the hologram memory and the recording capacity limit in the 9-frame enlargement / reproduction method.

FIG. 11 is a characteristic diagram showing a mounting recording capacity of a hologram memory and an enlargement ratio dependency of a recording capacity limit in a 16-frame enlargement / reproduction method.

FIG. 12 is an explanatory diagram showing external dimensions of a hologram recording medium.

FIG. 13 shows a hologram drawing area, 4 in Comparative Example 1.
FIG. 4 is an explanatory diagram showing the arrangement of separation regions between a 5-degree mirror formation region and a 45-degree mirror formation region and a hologram drawing region.

FIG. 14 is an explanatory diagram showing an overview of a recording medium in Comparative Example 1.

FIG. 15 shows the arrangement of a hologram drawing area, a 45 ° mirror formation area, and a separation area between the 45 ° mirror formation area and the hologram drawing area in the recording medium used as the hologram memory according to the first embodiment of the present invention. FIG.

FIG. 16 is an explanatory diagram showing an overview of a recording medium used as a hologram memory according to the first embodiment of the present invention.

FIG. 17 is a diagram illustrating an arrangement of a hologram drawing area, a 45-degree mirror formation area, and a separation area between the mirror formation area and the hologram drawing area in a recording medium used as a hologram memory according to the second embodiment of the present invention. FIG.

FIG. 18 shows the arrangement of a hologram drawing area, a 45-degree mirror formation area, and a separation area between the 45-degree mirror formation area and the hologram drawing area in a recording medium used as a hologram memory according to the third embodiment of the present invention. FIG.

FIG. 19 illustrates the arrangement of a hologram drawing area, a 45 ° mirror formation area, and a separation area between the 45 ° mirror formation area and the hologram drawing area in a recording medium used as a hologram memory according to the fourth embodiment of the present invention. FIG.

FIG. 20 is an explanatory diagram showing an overview of a recording medium in Comparative Example 2.

FIG. 21 shows an arrangement of a hologram drawing area, a 45-degree mirror formation area, and a separation area between the 45-degree mirror formation area and the hologram drawing area in the recording medium used as the hologram memory according to the fifth embodiment of the present invention. FIG.

FIG. 22 shows a hologram drawing area, 4 in Comparative Example 3.
FIG. 4 is an explanatory diagram showing the arrangement of separation regions between a 5-degree mirror formation region and a 45-degree mirror formation region and a hologram drawing region.

FIG. 23 illustrates the arrangement of a hologram drawing area, a 45-degree mirror formation area, and a separation area between the 45-degree mirror formation area and the hologram drawing area in a recording medium used in the hologram memory according to the sixth embodiment of the present invention. FIG.

FIG. 24 shows the arrangement of a hologram drawing area, a 45-degree mirror formation area, and a separation area between the 45-degree mirror formation area and the hologram drawing area in the recording medium used in the hologram memory according to the seventh embodiment of the present invention. FIG.

FIG. 25 shows the arrangement of a hologram drawing area, a 45-degree mirror formation area, and a separation area between the 45-degree mirror formation area and the hologram drawing area in the recording medium used in the hologram memory according to the eighth embodiment of the present invention. FIG.

FIG. 26 shows the arrangement of a hologram drawing area, a 45 ° mirror formation area, and a separation area between a 45 ° mirror formation area and a hologram drawing area in a recording medium used in a hologram memory according to a ninth embodiment of the present invention. FIG.

FIG. 27 shows the arrangement of a hologram drawing area, a 45-degree mirror formation area, and a separation area between the 45-degree mirror formation area and the hologram drawing area in the recording medium used in the hologram memory according to the tenth embodiment of the present invention. FIG.

FIG. 28 is a diagram showing an overview of a recording medium used in a hologram memory according to a tenth embodiment of the present invention.

[Explanation of symbols]

 1, 6, 10A to 10C, 20 Recording medium 2 plane type photodetector 3 Hologram drawing area 4 Mirror formation area 5 Separation area

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Kinyuki Imai Inventor 2-3-1 Otemachi, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Corporation (72) Inventor Manabu Yamamoto 2-3-3, Otemachi, Chiyoda-ku, Tokyo No. 1 Inside Nippon Telegraph and Telephone Corporation (72) Takaya Tanabe, Inventor 2-3-1 Otemachi, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Corporation (72) Yoshiaki Kurokawa, Otemachi 2 Chiyoda-ku, Tokyo F-term (reference) 3-1, Nippon Telegraph and Telephone Corporation 2K008 AA04 CC00 EE07 5B003 AA09 AB00 AC02 AD04 5B072 CC35 DD01 LL19 5D090 AA03 BB02 BB12 CC04 CC14 DD03 EE18 FF11 FF41 LL05

Claims (6)

[Claims] 1. A hologram memory having a structure in which a large number of slab-type waveguides on which independent holograms are written are stacked, wherein diffracted light reproduced from each of the slab-type waveguide surfaces is converted into a plane outside the waveguide surface. A hologram memory formed as an image having a fine spot array thereon, wherein the hologram surface has an image magnification of 1 or more on the imaging surface. 2. A hologram memory having a structure in which a large number of slab-type waveguides on which independent holograms are written are stacked, wherein diffracted light reproduced from each of the slab-type waveguide surfaces is converted into a plane outside the waveguide surface. The image is formed as an image having a minute spot array on the hologram surface, the magnification of the image on the hologram surface is 1 or more, and the output area of the image on the hologram surface is the size and shape of the light receiving surface of the light receiving element. A hologram memory characterized by matching. 3. A hologram memory having a structure in which a number of slab-type waveguides on which independent holograms are written are stacked, wherein diffracted light reproduced from each of the slab-type waveguide surfaces is formed on a plane outside the waveguide surface. The image is formed as an image of a plurality of frames composed of a minute spot array, and at least each frame image on the image forming surface corresponds to the surface dimension shape of the surface type light receiving element, and corresponds to the surface dimension shape of the surface type light receiving element. A laminated waveguide hologram memory, wherein a plurality of images are reproduced collectively. 4. A hologram memory having a structure in which a number of slab-type waveguides on which independent holograms are written are stacked, wherein diffracted light reproduced from each of the slab-type waveguide surfaces is formed on a plane outside the waveguide surface. The image is formed as a plurality of frame images composed of a minute spot array, and the magnification of the images on the hologram surface and the imaging surface is 1 or more, and at least each frame image on the imaging surface conforms to the surface dimension shape of the surface light receiving element. A hologram memory, wherein a plurality of images corresponding to the surface dimensions and shapes of the surface light receiving elements are collectively reproduced. 5. The hologram memory according to claim 3, wherein an identification signal is reproduced at a boundary of each of a plurality of frames on the image plane. 6. The hologram memory according to claim 1, wherein the mounted recording capacity is increased by multiplexing signals within a range not exceeding a recording capacity limit.