JP4173340B2 - Information recording medium manufacturing method and information recording medium manufacturing apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an information recording medium (hologram master) for reproducing a reproduction-only hologram card, and information for reproducing a reproduction-only hologram card suitable for use as a portable memory card such as a magnetic card or an IC card. The present invention relates to a recording medium manufacturing method and an information recording medium manufacturing apparatus.
[0002]
[Prior art]
Conventionally, as an information card that can be carried in a pocket, a magnetic card such as a telephone card is generally used. In recent years, IC cards have appeared and are considered to be applied to electronic commerce. Although magnetic cards are inexpensive, there is a risk of counterfeiting, and IC cards have drawbacks that the counter unit price is expensive although counterfeiting is difficult.
A reproduction-only hologram card has been devised to compensate for this drawback. Details are described in Patent Document 1, which will be briefly introduced here.
[0003]
FIG. 3 shows a conceptual diagram of a reproduction-only hologram card. A so-called slab optical waveguide with a structure consisting of a transparent plate-like medium such as quartz or plastic, with a lower refractive index medium, confines light near the core layer and propagates in the in-plane direction. It can be applied to optical communication parts. The reproduction-only hologram card is characterized in that the waveguides are stacked in layers, and each waveguide layer includes a hologram. FIG. 3 shows a cross-sectional view of the read-only hologram card, in which a state where the waveguiding layers are overlaid is depicted.
[0004]
As shown in the drawing, one end of the medium is cut by a surface inclined by 45 ° with respect to the card surface and polished to form a mirror, and the laser is narrowed down by the convex lens 2 from above. The light 1 is reflected by the 45 ° reflecting surface 3 and introduced into one of the waveguide layers composed of the core layer 8 and the cladding layer 9, and the guided light 4 propagates through the waveguide layer. In the waveguiding layer, a hologram 7 on which information has been placed in advance by a method such as modulating the refractive index is formed, and the light 5 diffracted thereby forms a hologram image 10. Information is read by capturing the hologram image 10 with a two-dimensional optical detector such as a CCD.
[0005]
Further, by moving the convex lens 2 in FIG. 3 in the optical axis direction, the waveguide layer for propagating light can be changed, and the information recorded in each layer can be read out separately.
Reproduction-only hologram cards are often produced using plastic (or resin) as the main material. This is because, like a typical information recording medium such as a CD or DVD, it can be mass-produced from a master by a stamping technique.
[0006]
FIG. 4 shows an example of application of the stamping technique to a reproduction-only hologram card manufacturing technique. Here, first, the core layer 8 is formed on the clad layer 9 (FIG. 4A). Next, the hologram master 11 having an uneven surface with a hologram shape is pressed against the core layer 8 to transfer the unevenness (FIG. 4B).
Furthermore, a clad layer 9 is coated thereon to form one waveguide (FIG. 4C), and a plurality of these are laminated to form a read-only hologram card as shown in FIG. 3 (FIG. 4D )).
[0007]
The conventional hologram master 11 is produced by drawing with an electron beam or a laser beam in accordance with a hologram pattern obtained by numerical calculation.
However, if an attempt is made to increase the area of the hologram in order to increase the information capacity of the medium, it takes time for both calculation and drawing. In order to shorten the production time of the hologram master, a master production method described in Patent Document 2 has been devised. This master production method is to produce a hologram using light interference as in the original holography technique. FIG. 5 shows this master production method.
[0008]
In FIG. 5, a glass plate 12 coated with a surface relief type hologram photosensitive resin on one side is prepared, and a first planar light wave 14 is applied to the spatial light modulator 15 from the photosensitive resin layer 13 side of the glass plate 12. The object light 16 generated in this way is irradiated. Here, the spatial light modulator is a device that spatially modulates the intensity and phase of light. A liquid crystal display element for a computer is an example of a spatial light modulator, and has a structure in which a large number of minute elements are arranged vertically and horizontally in a plane, using liquid crystal as a main material, and the light transmittance of individual pixels is increased. It can be controlled electrically. By using a computer or the like, information to be recorded can be placed on the spatial light modulator 15 and irradiated with light to superimpose information on the light.
[0009]
Simultaneously with the irradiation of the object light 16, the second planar light wave 17 is incident from the side surface of the glass plate 12 to illuminate the photosensitive resin layer 13 from below. Then, the two light waves interfere to form interference fringes, and the photosensitive resin layer 13 is exposed as it is to form irregularities. The unevenness is a hologram using the object light 16 and the second plane light wave 17 as reference light. The second planar light wave 17 is different from the guided light in the read-only hologram card, but the hologram shape equivalent to the case where the guided light is used as the reference light by appropriately adjusting the incident angle of the second planar light wave 17 And can be used as a master for producing a reproduction-only hologram card. When a hologram card is manufactured using this master disk, information previously displayed on the spatial light modulator 15 can be read by placing an image sensor instead of the position where the spatial light modulator 15 in FIG. 5 is placed. .
[0010]
[Patent Document 1]
JP 11-345419 (Japanese Patent Application No. 11-036540)
[Patent Document 2]
JP 2001-083865 (Japanese Patent Application No. 11-262588)
[0011]
[Problems to be solved by the invention]
The reproduction-only hologram card is based on the fact that each hologram of each layer generates one image, and a large medium capacity is obtained by increasing the number of layers to be stacked.
On the other hand, when a system called aperture multiplexing is used, a plurality of images can be recorded in a multiplexed manner from one hologram, and a further increase in the medium capacity can be expected. FIG. 6 is a diagram for explaining the aperture multiplexing method. This multiplexing method is characterized in that an optical mask 20 is inserted between the medium 18 and the image sensor 19 as shown in FIG. Here, the optical mask is obtained by patterning a portion through which light passes and a portion through which light does not pass in a plane.
[0012]
The optical mask is generally a chromium mask obtained by patterning a chromium thin film deposited on a glass substrate. However, since the optical mask is for two-dimensionally modulating the intensity of incident light, the spatial light modulator described above is used. It can be regarded as a kind. In FIG. 6A, several openings 21 are vacant in the optical mask 20, and only a part of the diffracted light 5 is transmitted. The hologram 7 is designed so that one image is connected on the image pickup device 19 with light of only a part of the components.
[0013]
On the other hand, in FIG. 6B, the diffracted light component transmitted in FIG. 6A is blocked by the optical mask 20, and the image observed by the image sensor 19 in the state shown in FIG. 6A is not observed. . Instead, another light component is transmitted through the optical mask 20, whereby an image different from that in FIG. 6A is observed on the image sensor 19.
From this, it can be seen that a plurality of images can be independently reproduced from one hologram by the aperture mask. In this figure, the structure is such that only two images are multiplexed, but the degree of multiplexing can be further increased by the arrangement of the aperture pattern on the optical mask or the spatial light modulator.
[0014]
For a reproduction-only hologram card, this aperture multiplexing system is a very important technique for dramatically increasing the capacity. However, in the conventional hologram master (information recording medium) manufacturing method (see Patent Document 2), the aperture multiplexing method is not considered, and the master disk manufacturing method for manufacturing a corresponding hologram has not been studied. .
Moreover, the hologram reproduced | regenerated by the aperture multiplexing system shown in FIG. 6 was produced with the CG hologram at present, and there existed a problem that a long time was required for hologram production.
The present invention has been made in view of such circumstances, and an object of the present invention is to provide an information recording medium manufacturing method and an information recording medium manufacturing apparatus capable of manufacturing a hologram master (information recording medium) simply and at high speed. And
[0015]
[Means for Solving the Problems]
In order to achieve the above object, the invention according to claim 1 is an information recording medium manufacturing method for manufacturing an information recording medium by using hologram interference recording by multiplexing a plurality of images using interference between two lights. The information recording medium has a photosensitive resin layer on which a hologram is recorded, and transmits information to be recorded by transmitting one of the two lights through the first spatial light modulator. The light is superimposed on the one light and then transmitted through the aperture pattern generated by the second spatial light modulator to be spatially modulated, and the photosensitive light simultaneously with the other of the two lights. When hologram recording is performed by irradiating the resin layer, multiple recording is performed by changing the opening pattern for each image to be recorded .
[0017]
The invention according to claim 2, in the information recording medium manufacturing method according to claim 1, wherein the second spatial light modulator is characterized in that an optical mask.
[0018]
The invention according to claim 3 is an information recording medium manufacturing apparatus for manufacturing an information recording medium by using hologram interference recording by multiplexing a plurality of images on a photosensitive resin layer using interference between two lights. The apparatus includes a first light source that generates a first plane light wave, a first spatial light modulator that superimposes information of an image to be recorded on the first plane light wave emitted from the first light source, and The object light having an opening pattern is modulated by partially transmitting the object light transmitted through the first spatial light modulator by the opening pattern, and the object light is irradiated onto the photosensitive resin layer of the information recording medium. and second spatial light modulators, and a second light source for generating a second planar lightwave irradiating simultaneously as the reference light and the object light to the photosensitive resin layer of the information recording medium possess, the reference and the object beam Simultaneously illuminate the photosensitive resin layer with light When hologram recording than that, characterized by multiple recording by changing the opening pattern for each image to be the recording.
[0019]
According to a fourth aspect of the present invention, in the information recording medium manufacturing apparatus according to the third aspect , the opening pattern of the second spatial light modulator is fixedly formed, and the second The spatial light modulator is characterized in that the second spatial light modulator is moved or replaced so as to change the opening pattern every time hologram recording is performed on the photosensitive resin layer of the information recording medium.
[0020]
The invention according to claim 5 is the information recording medium manufacturing apparatus according to claim 3 , wherein the second spatial light modulator is configured such that the opening pattern can be changed every time hologram recording is performed. It is characterized by.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
In the embodiment of the present invention, like a normal hologram, an interference fringe between an object light carrying information and another light is generated in a photosensitive resin, and an uneven pattern is generated by the photosensitive action of this resin. Then, this is used as a hologram master. At this time, object light is generated using at least two or more spatial light modulators, thereby producing a hologram master (information recording medium) of a reproduction-only hologram card corresponding to the aperture multiplexing system. . This will be specifically described below.
[0022]
FIG. 1 shows a configuration of an information recording medium manufacturing apparatus according to an embodiment of the present invention. The information recording medium creating apparatus according to the embodiment of the present invention is based on the premise that multiple images are separated and reproduced by the system shown in FIG. The second spatial light modulator 23 is used in addition to the first spatial light modulator 22, and is configured to be placed at a position where the optical mask 20 is placed in the system shown in FIG. Yes.
[0023]
That is, the information recording medium manufacturing apparatus according to the present embodiment has a function of manufacturing an information recording medium that is holographically recorded on the photosensitive resin layer 13 by using interference between two lights. A first light source 100 that generates the planar light wave 14, a first spatial light modulator 22 that superimposes information to be recorded on the first planar light wave 14 emitted from the first light source 100, and an aperture pattern A second spatial light modulation which modulates the object light transmitted through the first spatial light modulator 22 by partially transmitting the light through the opening pattern and irradiates the photosensitive resin layer 113 with the object light 16 And a second light source 200 that generates a second planar light wave 17 that irradiates the photosensitive resin layer 13 simultaneously with the object light.
[0024]
The recording operation of the information recording medium manufacturing apparatus according to the embodiment of the present invention having the above configuration will be described below.
A first planar light wave 14 is generated by the first light source 100 and emitted toward the first spatial light modulator 22. The spatial light modulator 22 first superimposes the first image information to be recorded on the first planar light wave 14 to generate object light. At this time, the opening is patterned by the second spatial light modulator 23 so as to have the same shape as the optical mask 20 in the system shown in FIG. As a result, as shown in FIG. 1A, the object light is partially transmitted and modulated, and this object light 16 is irradiated onto the photosensitive resin layer 13 formed on the glass substrate 12, and at the same time, the reference light. The second planar light wave 17 corresponding to is irradiated from the side of the glass plate 12 toward the lower surface of the photosensitive resin layer 13 from the second light source 200.
[0025]
Subsequently, the second spatial light modulator 22 superimposes the second image information on the first planar light wave 14 to generate object light. At this time, the second spatial light modulator 23 is also used. Thus, the object light transmitted through the first spatial light modulator 22 is modulated with the same opening pattern as in FIG. At the same time as the modulated object light is irradiated onto the photosensitive resin layer 13, the second planar light wave 17 is irradiated onto the photosensitive resin layer 13 from the second light source in the same manner as described above, and the second image information is recorded.
[0026]
In FIG. 6, a reproduction method when two pieces of image information are recorded in a multiplexed manner is introduced. As described above, the multiplicity can be further increased by appropriately selecting an aperture pattern. In that case, the above-described recording operation is repeated for the number of images, and the images are recorded on the same photosensitive resin layer. After all the images have been recorded, an appropriate development process according to the characteristics of the photosensitive resin is performed to generate a relief-type hologram pattern. Subsequently, the hologram master is produced by a method such as copying to a mold in the same manner as in the prior art.
[0027]
Various types can be used for the second spatial light modulator 23, which is an essential part of the present invention. For example, a chrome mask generally used as a light mask is excellent in light shielding characteristics, and therefore has a feature that crosstalk between images to be multiplexed is small. Further, a liquid crystal element may be used. A liquid crystal device can be handled in the same manner as a chrome mask because it can transmit and block light with individual elements arranged in a matrix. Although the extinction ratio does not reach that of the chrome mask, the pattern can be changed by an electric signal. Therefore, it is not necessary to change or move each image when hologram recording is performed unlike the chrome mask.
[0028]
In addition to liquid crystal devices that change the light transmittance of individual elements, there are types of liquid crystal devices that change the optical phase or change the polarization state. Multiple recording is possible even using such a device. However, in that case, it is necessary to use the same device as the optical mask 20 of the system shown in FIG. In FIG. 1, the modulated object light is incident on the glass plate 12 from the photosensitive resin layer 13 side, but the present invention is not particularly limited in the light propagation direction including this. Conversely, object light may be incident on the glass plate 12 from the surface on which the photosensitive resin layer 13 is not formed, and the opposite side of the photosensitive resin layer 13 may be irradiated.
[0029]
<Example>
First, a photoresist-based surface relief type hologram material resin was applied on a mirror-polished glass and dried. This glass plate was exposed to interference fringes with the optical system shown in FIG. A semiconductor laser with a wavelength of 650 nm was used as the light source. A chromium mask as shown in FIG. 2 was used as the second spatial light modulator 23. In FIG. 2, only the white squares are openings that transmit light without the chromium film. One side of the square was 0.5 mm. The chrome mask was placed about 3 mm away from the glass plate coated with the resin.
[0030]
Also, as the first spatial light modulator 22, four glass plates on which a picture is drawn with a chromium film are prepared and placed one by one from the chrome mask as the second spatial light modulator 23 by 2 mm apart. It was.
At the beginning of the recording operation, the first glass plate on which the picture was drawn was placed at a predetermined position. Further, the second spatial light modulator 23 was placed so that the opening came to the position (1) in FIG. 2, and light irradiation was performed in this state. The first image recording was completed as described above, and when the second image was next, the chrome mask was moved in parallel so that the opening was located at the position (2), and the same recording operation was performed.
[0031]
Thereafter, recording was performed in the same manner with an opening placed at the position of (3) for the third sheet and at the position of (4) for the fourth sheet. Subsequent development processing was followed by observation of the surface of the resin with a scanning electron microscope. As a result, stripe-like irregularities with an interval of about 450 nm were confirmed, which were similar to the hologram pattern obtained by numerical calculation.
The obtained concavo-convex mold was transferred to a metal mold, and a read-only hologram card was produced by the method of FIG. 4 using this metal mold. Resin having a refractive index of 1.484 was used for the cladding layer and a refractive index of 1.492 was used for the core layer. The lower clad layer prepared first in FIG. 4 had a thickness of 0.5 mm, the core layer had a thickness of 1.7 μm, and the thickness of the clad layer coated on the upper portion after hologram transfer was 20 μm. Only one core layer was used.
[0032]
When the semiconductor laser light having a wavelength of 650 nm was introduced into the waveguide of the completed read-only hologram card by the method shown in FIG. 5, a hologram image was observed in a plane about 5 mm away from the core layer, but recorded. All four images were superimposed.
However, when the optical system shown in FIG. 6 is used to observe an image using the chromium mask shown in FIG. 2 as the optical mask 20, the image drawn by the above-described chromium film is individually observed in the image sensor 19. I was able to.
As described above, the information recording medium manufacturing apparatus according to the present embodiment employs a method of directly manufacturing a hologram to be reproduced by the aperture multiplex method by the interference of two lights. It becomes possible to directly produce a hologram to be reproduced by a multiplexing method in a short time.
[0033]
【The invention's effect】
As described above, according to the present invention, when producing an information recording medium on which hologram recording is performed by using interference between two lights, one of the two lights is used as a first space. By passing through the light modulator, the information to be recorded is superimposed on the one light, and then, after passing through the second spatial light modulator and spatially modulated, the information recording medium is exposed to light. Since hologram recording is performed by irradiating the resin layer, it is possible to directly and easily produce a hologram master of a reproduction-only hologram card compatible with the aperture multiplexing system.
As a result, the manufacturing cost of the hologram master (information recording medium) can be reduced, and a reproduction-only hologram card can be produced at a low cost.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of an information recording medium manufacturing apparatus according to an embodiment of the present invention.
FIG. 2 is an explanatory diagram showing a configuration of a chrome mask used as a second spatial light modulator in the information recording medium manufacturing apparatus shown in FIG.
FIG. 3 is an explanatory diagram showing a structure of a reproduction-only multiplex hologram card and a state during hologram reproduction.
FIG. 4 is an explanatory diagram showing an application example of a stamping technique to a reproduction-only hologram card manufacturing technique.
FIG. 5 is an explanatory diagram showing a configuration example of a conventional hologram master production optical system.
FIG. 6 is an explanatory diagram showing an aperture multiplexing system.
[Explanation of symbols]
1: laser beam, 2: convex lens, 3: 45 ° reflection surface, 4: guided light, 5: diffracted light, 6: coupling point, 7: scattering factor (hologram), 8: core layer, 9: cladding layer, 10 : Hologenram image, 11: Hologram master, 12: Glass plate, 13: Photosensitive resin layer, 14: First plane light wave, 15: Spatial light modulator, 16: Object light, 17: Second plane light wave, 18: Medium: 19: Image sensor, 20: Optical mask (spatial light modulator), 21: Aperture, 22: First spatial light modulator, 23: Second spatial light modulator, 100: First light source, 200 : Second light source

Claims (5)

In an information recording medium manufacturing method for manufacturing an information recording medium by using hologram interference recording by multiplexing a plurality of images using interference between two lights,
The information recording medium has a photosensitive resin layer on which a hologram is recorded,
By transmitting one of the two lights through the first spatial light modulator, the information to be recorded is superimposed on the one light, and then the second spatial light modulator When the hologram recording is performed by irradiating the photosensitive resin layer simultaneously with the other of the two lights after passing through the generated opening pattern and spatially modulating, for each image to be recorded A method for producing an information recording medium, wherein multiple recording is performed by changing the opening pattern.   The information recording medium manufacturing method according to claim 1, wherein the second spatial light modulator is an optical mask. In an information recording medium manufacturing apparatus for manufacturing an information recording medium by using hologram interference recording by multiplexing a plurality of images on a photosensitive resin layer using interference between two lights,
The device
A first light source for generating a first planar light wave;
A first spatial light modulator for superimposing information of an image to be recorded on a first planar light wave emitted from a first light source;
A second object that has an opening pattern, modulates the object light transmitted through the first spatial light modulator by partially transmitting the light through the opening pattern, and irradiates the photosensitive resin layer of the information recording medium with the object light. A spatial light modulator of
A second light source that generates a second plane light wave that irradiates the photosensitive resin layer of the information recording medium as reference light simultaneously with the object light;
Have
The information recording medium is manufactured by multiplex recording by changing the opening pattern for each image to be recorded when holographic recording is performed by simultaneously irradiating the photosensitive resin layer with the object light and the reference light. apparatus. The aperture pattern of the second spatial light modulator is fixedly formed,
The second spatial light modulator moves or replaces the second spatial light modulator so as to change the opening pattern each time hologram recording is performed on the photosensitive resin layer of the information recording medium. 4. The information recording medium manufacturing apparatus according to claim 3, wherein   The information recording medium manufacturing apparatus according to claim 3, wherein the second spatial light modulator is configured to be able to change an opening pattern each time hologram recording is performed.

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