JP2003233991A - Optical memory element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To increase the number of lamination layer, to improve recording capacity, and to improve yield, suppressing occurrence of warping as much as possible. <P>SOLUTION: An optical memory element comprises resin core layers and resin clad layers laminated on both surfaces of the resin core layers. The element is constituted by adhering two or more units holding lamination bodies in which light guide members of one or a plurality of layers having uneven surface part for information at one side of boundary of the resin core layers and the resin clad layers are laminated between base bodies. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical memory device constructed by using an optical waveguide device.

[0002]

2. Description of the Related Art In recent years, a technique has been proposed in which light is introduced into a plane type (card type) optical waveguide in which a pattern is engraved so as to generate predetermined scattered light, and an image is formed outside the optical waveguide surface. (IEEE Photon.Technol.Lett., Vol.9, p
p.958-960, JULY1997, etc.). That is, for example, as schematically shown in FIG. 15, a core (layer) 101 whose refractive index and film thickness are adjusted so as to function as an optical waveguide, and both sides (both sides) of the core layer 101 sandwiched therebetween. In the card type slab type optical waveguide device 100 including the (first and second) clads (layers) 102 provided in the above, fine irregularities are present at the interface between the core layer 101 and the clad layer 102. In this case, when the light (laser light) is introduced into the core layer (optical waveguide) 101 through the lens 103, a part of the introduced light is scattered at the uneven portions, and the scattered light goes out through the cladding layer 102. come.

Therefore, the scattering intensity and phase of light such that a specific image is formed at a predetermined distance from the optical waveguide surface (optical waveguide 101) are calculated, and a fine concavo-convex pattern corresponding to the calculation is calculated in advance in the core layer 101. By engraving it in, it is possible to form a desired image on the outside of the optical waveguide surface. That is, the core layer 101 functions as an information recording layer.

Then, for example, the CCD receiver 104 in which the scattered light coming out of the optical waveguide surface is installed at the above-mentioned predetermined distance
The light is received by the light source, and the formed image is converted into a two-dimensional digital pattern [for example, a binary pattern of light and dark, or a multi-valued pattern based on lightness (gray scale)] and converted into a digital signal. A processing device (not shown) can perform desired image processing on the formed image.

Further, as schematically shown in FIG. 16, when a plurality of optical waveguides (recording layers) 101 are laminated by repeatedly laminating the clad layer 102 and the core layer 101, a certain optical waveguide The light scattered by 101 will cross another optical waveguide 101, but normally, the core layer 101
Since the difference in refractive index between the clad layer 102 and the clad layer 102 is extremely small, the scattered light is hardly re-scattered by the unevenness formed in another optical waveguide 101, and the formed image is not disturbed.
Therefore, many images and patterns can be formed in proportion to the number of stacked layers.

That is, the optical waveguide device 100 can be used as an optical memory element (recording medium such as ROM) having a capacity proportional to the number of laminated layers. It is said that this optical memory device can theoretically have a capacity of about 1 gigabyte per layer, and can be stacked up to about 100 layers. It is considered promising to be used as a large-capacity ROM capable of sufficiently recording.

Further, by making the core layer and the clad layer made of resin, the above-mentioned concavo-convex pattern can be easily formed, and an optical memory element capable of holding a large amount of information in a limited volume can be easily and It has also been proposed to realize it at low cost (Japanese Patent Application No. 11-131512).
No. 11-131513). Here, when reproducing the information recorded in the optical memory element, the incident light (incident laser light) is introduced into the core layer as described above.
If the lateral width of the incident laser light (incident lateral width, lateral width of the reproduction light irradiation area) is too narrow, the incident laser light is introduced into only a part of the information area where the concavo-convex pattern is formed, and the other area The incident laser light is not introduced, and in the end,
Only part of the information recorded in the information area will be reproduced. Therefore, the lateral width of the incident laser light needs to be wider than the width of the information area.

On the other hand, if the incident laser light has a large vertical width (incident vertical width, vertical width of reproduction light irradiation region) (thickness in the vertical direction), the incident laser light is simultaneously applied between a plurality of adjacent core layers. Will be incident. Therefore, the vertical width of the incident laser light needs to be as narrow as possible so as not to reach the adjacent core layers. Therefore, in general, the spot shape of the incident laser light is a very long oblong shape with a narrow vertical width.

[0009]

By the way, in the above-mentioned optical memory device, it is desired to increase the number of stacked layers as much as possible in order to increase the recording capacity (information amount). However, as the number of stacked layers is increased, the warpage that occurs during the fabrication of the optical memory element is correspondingly increased. As described above, since the incident laser light is in the shape of an ellipse whose vertical width is as narrow as possible, when the warp becomes large, a region where the concave and convex portions of one core layer are formed in the incident end face of the optical memory element ( It becomes difficult to make incident light (reproducing light) incident on the entire information area and information recording area at the same time, and the information recorded in one core layer of the optical memory element cannot be reproduced at the same time.

Therefore, it is necessary to increase the number of layers while suppressing the occurrence of warpage as much as possible. In this case, in order to suppress the occurrence of warpage, it is conceivable to use a hard substrate or thicken the substrate when manufacturing the optical memory element, for example. For example, in the case of stacking 100 layers, if the thickness of the core layer is 1.8 μm and the thickness of the clad layer is 30 μm, the thickness of the resin forming the core layer and the clad layer alone is about 3.2 mm. in this case,
In order to suppress the occurrence of warpage, it is necessary to use a considerably thick substrate (for example, 5 mm or more) even if a glass substrate is used as the hard substrate.

Thus, in order to suppress the occurrence of warpage,
When a hard substrate is used or the thickness of the substrate is increased, not only the thickness of the substrate is increased but also the weight is increased. As a result, an optical memory device manufacturing apparatus for manufacturing an optical memory device ( This is not preferable because it increases the cost of the medium manufacturing device). Further, even if the number of laminated layers can be increased while suppressing the occurrence of warpage as much as possible, if the number of laminated layers is increased, the yield will be reduced accordingly. For example, if 100 layers are stacked in succession, the yield will be significantly reduced. If the number of stacked layers is further increased, the problem of reduced yield becomes more serious.

The present invention was devised in view of such problems, and when the number of layers is increased to increase the recording capacity,
To provide an optical memory device capable of suppressing the occurrence of warpage as much as possible so that recorded information can be reproduced accurately and surely and at the same time, the yield can be improved. With the goal.

[0013]

Therefore, in the optical memory device of the present invention, a resin core layer and a resin clad layer laminated on both sides of the resin core layer are provided. It is characterized in that two or more units are bonded to each other by sandwiching a laminated body formed by laminating one or a plurality of optical waveguide members each having an uneven portion for information on at least one of the interfaces with the clad layer and the base body. (Claim 1).

Particularly, it is preferable that the thickness of the laminated body sandwiched between the substrates is 2 mm or less (claim 2). Also,
The thickness of the substrate is preferably in the range of 10 μm to 500 μm (claim 3). Further, it is preferable that the difference in refractive index between the base and the resin clad layer and the difference in refractive index between the base and the resin core layer are both 0.2 or less (claim 4).

It is preferable that the resin core layer and the resin clad layer are made of a curable resin. Further, the curable resin is preferably an acrylic curable resin (claim 6). Further, it is preferable that an adhesive layer for adhering each unit is provided, and the adhesive layer is formed between each unit (claim 7).

Further, it is preferable that the adhesive layer is formed on the entire surface of the area corresponding to the information area where the information uneven portion is formed (claim 8). Further, it is preferable that the difference in refractive index between the adhesive layer and the resin clad layer and the difference in refractive index between the adhesive layer and the resin core layer are both 0.2 or less (claim 9). Further, it is preferable that the adhesive layer is formed in a region other than the region corresponding to the information region in which the information uneven portion is formed (claim 10).

Further, it is preferable that the information concavo-convex portion of the optical waveguide member is configured to be enlarged and reproduced, and the adhesive layer is formed in a region where the enlarged reproduction image from the information concavo-convex portion does not appear (claim 11). ). Furthermore, it is preferable to have an adhesive layer for adhering each unit, and the adhesive layer is formed so as to cover the end face of each unit (claim 12).

Further, it is preferable that the adhesive layer is formed on an end face other than the incident end face for making reproducing light enter the resin core layer of each unit (claim 13). Further, it is preferable that a connecting member for connecting each unit is provided, and the connecting member is provided so as to cover an end face of each unit (claim 14). Further, it is preferable that the number of units is 10 or less (claim 15).

Further, it is preferable that the positional deviation between the respective units in the reproduction light incident direction is within 200 μm (claim 16). Further, the inclination amount of the optical memory element with respect to the reference plane in the width of the information area where the information unevenness of the resin core layer on the reference plane of the unit is formed satisfies the condition represented by the following formula. Is preferred (claim 17).

| X | ≦ d-t x: amount of inclination of the information area width of the reference surface of the unit with respect to the reference surface d: vertical width of the reproduction light irradiation area t: thickness of the core layer in the information area The width of the information area is preferably 2 mm or more and 100 mm or less (claim 18).

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. An optical memory element (optical memory, multilayer optical memory) according to an embodiment of the present invention will be described with reference to FIGS. The optical memory device according to the present embodiment [laminated (planar) optical memory device; laminated waveguide hologram device, MWH device] basically includes a resin core layer 3 and a resin, as shown in FIG. The resin-made clad layer 2 laminated on both sides of the resin-made core layer 3, and the information unevenness portion including information for obtaining a reproduced image on at least one of the interfaces between the resin-made core layer 3 and the resin-made clad layer 2. 6 is a thin film substrate (substrate).
It has a sandwich structure sandwiched by 5, 5 '.

As described above, the thin film substrates 5, 5 are provided on both surfaces (upper and lower surfaces) of the laminated body (optical waveguide member 232) formed by laminating the resin core layer 3 and the resin clad layer 2 in the optical memory element 4.
A structure (sandwich structure) in which 5 ′ is provided and sandwiched between the thin film substrates 5 and 5 ′ is preferable because warpage and flexure (deflection amount) of the core layer 3 can be suppressed to a predetermined value or less.

The information concave / convex portion 6 is configured to include information regarding strength, phase, angle and the like. The information concavo-convex portion 6 may include intensity information and phase information, may include intensity information and angle information, or may include only intensity information. The reproduced image may be any image as long as it is a light and shade of light formed by the scattered light from the uneven portion 6 for information.

Here, it is preferable to use resin films as the thin film substrates 5 and 5 '. As the resin film, polycarbonate, amorphous polyolefin such as ARTON (manufactured by JSR), PET (polyethylene terephthalate), PEN (polyethylene naphthalate), etc. having excellent optical properties (PEN is also excellent in heat resistance) thermoplastic It is preferable to use the above resin film (particularly, the above-mentioned PET and PEN are both preferable because it is easy to obtain a film having a uniform thickness). As the thin film substrates 5 and 5 ', those transparent to the reproduction light wavelength are used.

The thin film substrates 5 and 5'are not limited to the resin film, but a laminated body (optical memory element 10).
As long as it is made of a material that can function as a substrate capable of suppressing the warp (flexure) (can hold bending), various materials such as glass and a dielectric can be used. However, when flexibility (flexibility) is required in the manufacturing process such as sticking (laminating), it is preferably made of resin. A resin thin film substrate may be prepared by applying various curable resins and then curing them, or by dissolving the resins in a solvent and applying and drying them.However, if a resin film is used, the sticking and peeling on the stamper can be repeated. It is easy and preferable in terms of productivity and workability.

By the way, the thin film substrates 5 and 5'as described above.
Sandwiched optical memory device 4
In order to fabricate the above, the resin-made clad layer 2 and the resin-made core layer 3 are laminated in this order on the first thin film substrate 5, and then the second thin film substrate 5 ′ is provided thereon. in this case,
Before the second thin film substrate 5'is provided, since the core layer 3 and the clad layer 2 made of a resin are laminated on the first thin film substrate 5, the structure is easily warped in one direction. There is. If the second thin film substrate 5 ′ is in a warped state before being provided and the second thin film substrate 5 ′ is provided in a warped state, the warped state is maintained,
Even if it has a sandwich structure, the optical memory element 4 is warped.

Therefore, it is preferable that the optical memory element manufacturing process for manufacturing the optical memory element 4 having the sandwich structure is, for example, an optical memory element manufacturing process using a light transmissive stamper. The optical memory device manufacturing process is not limited to this. Here, a structure and a manufacturing method of the light transmissive stamper will be described with reference to FIGS.

The light-transmitting stamper 13 is configured so as to be able to transmit light (for example, ultraviolet rays) applied to cure the core material or the clad material when manufacturing the optical memory element 4, as described later. For example, as shown in FIG. 3, the light transmissive stamper (optical memory element manufacturing stamper) 13 is engraved with a desired concavo-convex pattern (concavo-convex shape; pit) corresponding to an image (information) to be imaged on the surface. A clad layer 10 as a stamper layer having a stamper surface, a core layer 11 as an adhesive layer, and a base (base, base layer,
It has a three-layer structure including a resin film (resin film layer, resin base layer, base film layer) 12 as a base layer), and the resin film 12 is bonded to the clad layer 10 via the core layer 11. Composed.

As described above, in this embodiment, the light-transmitting stamper 13 is constituted by the clad layer 10, the core layer 11 and the resin film 12, and is formed as a flexible film stamper (film stamper). There is. Here, the clad layer 10, the core layer 11 and the resin film 1
All of 2 are transparent in the used light wavelength range [wavelength range of light (for example, ultraviolet rays) irradiated to cure the core material and the clad material when manufacturing the optical memory element] (that is, light can be transmitted). Stuff) is used. Therefore, the clad layer 10 is a light-transmissive clad layer (for example, a UV-transmissive clad layer), the core layer 11 is a light-transmissive core layer (for example, a UV transmissive core layer), and the resin film 12 is a light-transmissive resin film (for example, UV transparent resin film).

Of these, as the clad material for forming the clad layer 10, an ultraviolet curable resin material (UV resin material, photocurable resin material) which is cured by irradiation with ultraviolet rays (UV light) is used, and the surface thereof is used. A metal stamper (for example, a nickel stamper) having a desired uneven pattern (uneven shape; pit) according to an image (information) to be formed on
The ultraviolet-curable resin material is applied on the stamper surface (uneven pattern, uneven shape) and then irradiated with ultraviolet rays to be completely cured to form the resin clad layer 10.

Examples of the resin film (base film) 12 include amorphous polyolefins such as polycarbonate and ARTON (registered trademark of JSR Corporation),
Excellent optical properties such as PET (polyethylene terephthalate) and PEN (polyethylene naphthalate) (PEN
Is also excellent in heat resistance) Thermoplastic resin film 1
2 is preferable (in particular, PET and PEN are both preferable because it is easy to obtain a film having a uniform thickness). In particular, PET and polycarbonate, which are more rigid than Arton, are preferable.

Further, here, a single film is used as the resin film 12, but a continuous film may be used. In other words, by combining processes such as coating of clad material on the film, core material with a die coater, micro gravure, bar coater, etc., curing of the core material and clad material while the stamper is pressed, the resin film as the substrate is combined. The light transmissive stamper 13 may be manufactured by stacking a core layer and a clad layer on top.

The core layer 11 functions as an adhesive for adhering the clad layer 10 and the resin film 12, and is formed of a core material made of an ultraviolet curable resin material (photocurable resin material). This is because the core material 11 is used as a material for an optical memory element described later, so that the material can be shared and the core material 11 made of a photocurable resin or a thermosetting resin is Resin film 1
This is because it has excellent adhesiveness with 2 and is suitable.

Although the terms core layer (core material) 11 and clad layer (clad material) 10 are used herein, these are simply the core layer (core material) that constitutes an optical memory device, which will be described later. Since the same resin as the clad layer (clad material) is used and applied and cured in the same manner as in the case of manufacturing an optical memory element, the materials and manufacturing equipment are shared, These terms are only used, and core layers (core materials) and clad layers (clad materials) having a predetermined refractive index like optical memory devices are used.
Does not mean to use.

Although the concave-convex pattern of the metallic stamper 1 is transferred to the clad layer 10 and adhered to the resin film 12 via the core material 11 as an adhesive,
The present invention is not limited to this, and the concavo-convex pattern of the metallic stamper 1 may be transferred to the clad layer 10 and adhered to the resin film 12 via a clad material as an adhesive (in this case, the clad layer and the resin). It may be a two-layer structure with a film), or the uneven pattern of the metallic stamper 1 may be transferred to the core layer and bonded to the resin film via a clad material as an adhesive. The concavo-convex pattern of the metallic stamper 1 may be transferred and adhered to the resin film via a core material as an adhesive (in this case,
It has a two-layer structure of a core layer and a resin film).

Further, the core material 11 and the clad material 10 may be any resin that is liquid (having fluidity) at the time of application and can be cured thereafter, and may be any photocurable resin other than the above ultraviolet curable resin. A desired curable resin such as a resin or a thermosetting resin that cures when heat is applied may be applied. Alternatively, a heat-meltable resin may be used. In particular, the clad material (clad layer) 10 for transferring by the metal stamper 1 does not need to have a specific refractive index, and it is preferable to apply the above ultraviolet curable resin,
For example, acrylic resin, epoxy resin, thiol resin, and the like are preferable.

On the other hand, the core material (core layer) 11 as an adhesive (adhesive layer) does not need to have a specific refractive index, is transparent in the used light wavelength range, and is easily peeled off after bonding. Anything may be applied as long as it does not exist. For example, various types of adhesives such as a photo-curing type, a thermosetting type, a room temperature curing type, a hot melt type, and a two-liquid mixing type can be applied, and as a material, acrylic type, epoxy type, cyanoacrylate type, There are urethane type and olefin type. However, it is preferable to select a combination having a good adhesive compatibility in consideration of the materials of the resin film and the clad layer.

Further, it is preferable that the substrate holding the light-transmitting stamper 13 is made of the resin film 12 because it is easy to stick and peel on the metal stamper 1 and the productivity and workability are improved. However, it is not limited to the resin film 12, and for example, various curable resins are applied and then cured, or the resin is dissolved in a solvent and applied.
The resin base body may be formed by drying.

Further, here, the light-transmitting stamper 13 composed of the clad layer 10, the core layer 11 and the resin film 12 is formed as a film,
It does not necessarily have to be a film-shaped one, and may be a plate-shaped one (plate-shaped stamper, plate stamper) thicker than the film-shaped one, for example, and its thickness is not a problem.

As described above, the light transmissive stamper 13 can be made of any material or thickness as long as it can transmit the light (for example, ultraviolet rays) irradiated for curing the core material or the clad material when manufacturing the optical memory element. The above is not limited to the above. For example, ultraviolet rays (UV) irradiated to cure a core material or a clad material when manufacturing an optical memory device.
In addition to resin, glass and quartz can be used as materials that transmit light), and these materials can be used as the light-transmitting stamper 1.
3 may be configured. However, when the light transmissive stamper 13 is required to have flexibility, for example, it is necessary to attach (laminate) the light transmissive stamper 13 in the manufacturing process of the optical memory device, or the same process as the manufacturing process of the optical memory device. When the light transmissive stamper 13 is manufactured by the above method, the light transmissive stamper 13 is preferably made of resin.

In this embodiment, as will be described later,
Since an ultraviolet curable resin is used as the core material 11 and the clad material 10, the light transmissive stamper 13 may be an ultraviolet transmissive stamper that can transmit at least ultraviolet light. Further, in the present embodiment, the light-transmitting stamper (film stamper, plate stamper) 13 is used as a planar stamper, but the invention is not limited to this, and for example, a flexible film-shaped stamper is used. It may be used as a roll-shaped stamper (roll stamper) formed by rolling a light-transmitting stamper around a roll. By using the roll stamper in this way, the productivity of the transfer process from the stamper can be improved.

Next, a method of manufacturing the light transmissive stamper 13 having the above structure will be described. First, FIG.
As shown in (A), a metal stamper (for example, nickel) having a concave-convex pattern engraved on its surface so that a desired concave-convex pattern (concave-convex shape; pit) corresponding to an image (information) to be formed can be transferred. A clad material (liquid clad resin) 10 is applied to a stamper surface having a concavo-convex pattern of a stamper or the like (master, hard stamper) 1 so as to have a predetermined film thickness (for example, about 6 μm) and completely cured. . When the clad material 10 is completely cured in this way, the uneven pattern is transferred from the metal stamper 1 having the uneven pattern on the surface, and the resin clad layer (stamper layer) 10 having the uneven pattern is formed ( Transfer process).
A method in which a desired resin material functioning as the clad layer 10 is dissolved in a solvent and applied and dried may be used. In addition, this uneven pattern is actually a CD, for example.
Scattered on a flat surface like pits on a (compact disc).

After that, as shown in FIG. 4B, a predetermined film thickness (for example, about 1.8 μ when completely cured) is formed on the surface.
m), a core material (liquid core resin, liquid photocurable resin) 11 made of an ultraviolet curable resin material (photocurable resin material) that can function as an adhesive is applied. A method of applying and drying a desired resin material that functions as the core layer 11 dissolved in a solvent may be applied.

The coating method of the core material 11 and the clad material 10 includes, for example, a spin coating method, a blade coating method, a gravure coating method, a die coating method, and the like, as long as the coating film thickness and the uniformity are satisfied. Such a coating method may be used. Next, on the surface of the core layer 11, for example, as shown in FIG.
As shown in (B), a resin film (resin film member, base film) 12 as a base (base) is placed while being pressed by a roll or the like so that air bubbles do not enter.
That is, the resin film 12 is attached (laminated) to the clad material 10 via the core material 11.

As described above, the core layer (resin layer) 11
When laminating the resin film (film-like member) 12 thereon, the resin film 12 is pressed against the core layer 11 by a roll (laminating roll) and placed under pressure (while applying a pressing force). However, in order to prevent the thickness of the core layer 11 from changing at this time, the surface on which the core layer (resin layer) 11 is coated (the upper surface of the clad layer 11) and the roll are It is preferable to adhere the resin film (film member) 12 while keeping the distance between them constant. The details will be described later.

Next, as shown in FIG. 4B, with the resin film 12 adhered as described above, ultraviolet rays are irradiated from the resin film 12 side (the side opposite to the metal stamper 1) to expose the core material. When the resin layer 11 is completely cured, the resin core layer 11 is formed, and the resin film 12 and the clad layer 10 are bonded together via the core layer 11. The step of adhering the resin film 12 to the clad layer 10 to which the concavo-convex pattern has been transferred in this way is called an adhering step.

Then, as shown in FIG. 4C, the core layer 11, the cladding layer 10 and the resin film 12 are integrally separated (separated) from the metal stamper 1 (separation step),
As shown in FIG. 4D, a resin film 12 is used as a resin base layer, a resin core layer 11 is formed on the resin film 12, and an uneven pattern of the metal stamper 1 is formed on the resin core layer 11 (hereinafter also simply referred to as “unevenness”). (3) is transferred (formed) to form a resin-made clad layer 10 to produce a light-transmitting stamper (here, a film stamper) 13 for manufacturing an optical memory element.

In the present embodiment, further, as shown in FIG. 4D, ultraviolet rays are radiated to the surface of the resin clad layer 10 having the concavo-convex pattern transferred from the concavo-convex pattern of the metal stamper 1. Then, by further curing, the adhesiveness of the concave / convex pattern (concave / convex shape; pit) formed in the cladding layer 2 is further lowered (this is called overcure treatment). Preferably, for example, about 12
A high temperature treatment of about 0 ° C. is performed. This high temperature treatment time is preferably about 1 hour. This can further reduce the adhesiveness (also referred to as overcure treatment). By performing such an overcure treatment, the releasability of the light transmissive stamper 13 from the core material or the clad material forming the optical memory element is improved.

Next, a description will be given of an optical memory element manufacturing process (a method for manufacturing an optical memory element) in the case where the resin films 5 and 5'are used as the thin film substrate using the light transmissive stamper 13 thus manufactured. To do. In the present process, the thin film substrate 5 is first provided on a substrate such as glass (≠ substrate), and the resin core layer 3 and the resin clad layer 2 are laminated on the thin film substrate 5. Go. Finally, a thin film substrate 5'is provided thereon, and in a state where the sandwich structure is completed, the optical memory element 4 having the structure sandwiched by the thin film substrates 5 and 5'is peeled from the substrate.

The optical memory device manufacturing process will be described in more detail below with reference to FIGS. First, as shown in FIG. 5A, a clad material (liquid clad resin) 2X is applied onto a base substrate 21 for optical memory device production so as to have a predetermined film thickness (for example, about 5 μm when completely cured). .

In this embodiment, the clad material 2X is made of an ultraviolet curable resin material (UV resin material, photocurable resin material) which is cured by irradiation with ultraviolet rays (UV light). After being coated on the surface of the optical memory element manufacturing base substrate 21 in this manner, the resin clad layer 2X is formed by irradiating ultraviolet rays to completely cure the resin. A method in which a desired resin material functioning as the cladding layer 2X is dissolved in a solvent and applied and dried may be used.

Here, as the optical memory element manufacturing base substrate 21, for example, a hard substrate such as a glass substrate having a thickness of several mm, a substrate made of polycarbonate, or a substrate made of amorphous polyolefin such as Arton (manufactured by JSR Corporation) (for example, The thickness is about 0.1 mm to about 3 mm, preferably about 1 mm). The reason why such a hard substrate is used is as follows.

That is, as described later, since the sandwich structure is not formed while the resin core layer 3 and the resin clad layer 2 are laminated on the substrate 21, the core layer 3 and the clad layer 2 are formed. Internal stress in the resin acts in such a direction as to warp the substrate in one direction. In this case, the substrate 2
If the strength of No. 1 is not sufficient, the substrate 21 is warped, and if the warping is large, processes such as resin application and resin film attachment cannot be performed.

Further, when the thin film substrate 5 is provided with the substrate 21 warped to complete the sandwich structure and the sandwich structure is peeled from the substrate 21, the optical memory device 4 having the sandwich structure can be manufactured, but the warp is maintained. It will be left as it is. Therefore, a hard substrate is used as the substrate 21 in order to suppress the warp of the substrate 21 while the resin core layer 3 and the resin clad layer 2 are being laminated.

Thus, due to the strength of the hard substrate 21, the ultraviolet curable resin material as the clad material or the core material shrinks during curing even while the resin core layer 3 and the resin clad layer 2 are being laminated. It is possible to prevent the substrate 21 from being warped (curved or curled). On the other hand, the hard substrate 21 can be used as described above for the following reason.

That is, since the substrate is finally removed from the optical memory element 4, the thickness and weight of the substrate do not affect the thickness and weight of the optical memory element 4. Therefore, even if the thick and heavy substrate 21 is used, the practicality of the optical memory element 4 is not lost.
It is possible to use a substrate having sufficient strength so that warpage does not occur.

In the case of using a metal stamper, if the base substrate is a hard substrate, it is difficult to bend (bend) the metal stamper. Therefore, the laminate consisting of the clad layer and the core layer is peeled from the metal stamper. Difficult to (separate). For this reason, a hard substrate could not be used as the base substrate, but in the present embodiment, since a light-transmitting resin stamper (film stamper) 13 having flexibility is used, it is possible to use Stamper 1
Since the peeling (separation) of 3 was easy, it became possible to use a hard substrate as the base substrate.

The base substrate 21 for manufacturing the optical memory device
Is a material that withstands the contraction of the ultraviolet curable resin when the ultraviolet curable resin material used as the clad material 2 or the core material 3 is irradiated with ultraviolet rays and has a strength that does not warp the clad layer 2 or the core layer 3. If it is good. Next, after the clad material 2X is completely cured in this way, as shown in FIG. 5A, a core material (liquid core) made of an ultraviolet curable resin material (photocurable resin material) is formed on the surface thereof. Resin) 3Xa is applied so as to have a predetermined film thickness (about 1.8 μm when completely cured). A method in which a desired resin material functioning as the core layer 3Xa is dissolved in a solvent and applied and dried may be used.

Next, after applying the core material 3Xa in this way, as shown in FIG. 5A, a resin film (resin film member, resin film member) to be a thin film substrate (base) is formed on the surface of the core material 3Xa. The base film) 5 is placed under pressure using, for example, a roll so that air bubbles do not enter. That is, the resin film 5 is attached (laminated) to the clad layer 2X via the core material 3Xa.

As described above, the core material (resin material) 3X
When laminating the resin film (film member) 5 on a, the resin film 5 is pressed against the core material 3Xa by a roll (laminating roll) and pressed (while pressing force is applied). However, in order to prevent the thickness of the core material 3Xa from changing at this time, the surface coated with the core material (resin material) 3Xa (the upper surface of the clad material 2X) and the roll are It is preferable to stick the resin film (film-like member) 5 while keeping the distance between them constant. The details will be described later.

In this state, the core material 3 is irradiated with ultraviolet rays.
When Xa is completely cured, the resin core layer 3Xa is formed and the resin film 5 and the core layer 3Xa are bonded together. Here, the resin film 5 is transparent (capable of transmitting scattered light) in the used light wavelength range (wavelength range of laser light guided in the core layer 3), and has optical characteristics and film thickness uniformity,
As far as mechanical strength allows, it is better to be as thin as possible. This is to allow the scattered light scattered by the unevenness to be finally emitted to the outside and to reduce the thickness of the finally manufactured optical memory element 4 ', but in the present embodiment, Not only that, but also for making it difficult for bubbles to enter into the core material 3Xa between the resin film 5 and the cladding layer 2X.

That is, in the step of sticking the resin film 5 on the clad layer 2X coated with the core material 3Xa, if the resin film 5 is thin, the flexibility (flexibility) is excellent.
By gradually contacting the resin film 5 while bending it, the mounting area can be slowly increased, and bubbles are mixed in the clad material 2X to change the refractive index and the film thickness of that portion. It is possible to suppress the effects such as being lost.

For this reason, the resin film 5 has, for example,
Amorphous polyolefin films such as polycarbonate and ARTON (made by JSR Corporation), and thermoplastic resin films such as PET (polyethylene terephthalate) and PEN (polyethylene naphthalate) that have excellent optical properties (PEN is also excellent in heat resistance) 5 is preferable (especially, the above P
ET and PEN are both suitable because it is easy to obtain a film having a uniform thickness), and it is preferable that one of these is made to have a thickness of 100 μm or less by a method such as hot stretching or solvent casting.

If the thickness is larger than this, the flexibility of the resin film 5 becomes poor, and bubbles tend to be mixed when the resin film 5 is placed on the core material 3Xa. On the contrary, when the resin film 5 is extremely thin, for example, thinner than 1 μm, when peeling (separating) the laminated body including the clad layer 2 and the core layer 3 from the optical memory element manufacturing base substrate 21. In addition, the resin film 5 may not be able to fulfill the function of holding the laminate, which is not preferable.

In the above steps, the clad layer 2X is formed on the optical memory device manufacturing base substrate 21, and the resin film 5 is attached to the clad layer 2X via the core material 3Xa, but the present invention is not limited to this. Alternatively, the clad layer 2X may be formed on the base substrate 21 for manufacturing an optical memory element, and the resin film 5 may be attached to the clad layer 2X via a clad material that functions as an adhesive. In this case, the resin film 5 is formed on the optical memory element manufacturing base substrate 21 with the clad layer interposed therebetween.
Will be stacked.

The base substrate 21 for manufacturing the optical memory device
A core layer may be formed on top of which a resin film 5 may be attached via a clad material that functions as an adhesive. In this case, the resin film 5 is laminated on the optical memory element manufacturing base substrate 21 via the core layer and the clad layer. Further, the base substrate 21 for manufacturing the optical memory element
You may form a core layer on it and stick the resin film 5 to this via the core material which functions as an adhesive agent. In this case, the resin film 5 is laminated on the base substrate for producing the optical memory element with the core layer interposed therebetween.

Since these are all for adhering the resin film 5 as a base on the base substrate for optical memory element production, these are referred to as a base adhering step.
Here, as the core material (core layer) or the clad material (clad layer) as the adhesive (adhesive layer), it is not necessary to use a material having a specific refractive index, and the resin film 5 or the optical memory element manufacturing base substrate 21 is used. It is only necessary to select a combination having a good adhesive compatibility in consideration of the material of. Therefore, for example, various types of adhesives such as photo-curing type, heat-curing type, room-temperature curing type, hot-melt type, and two-liquid mixing type can be applied, and the material can be acrylic type, epoxy type, cyano type, or the like. Acrylate-based,
Urethane type, olefin type, etc. can be used.

Next, as shown in FIG. 5B, an ultraviolet curable resin material is formed on the resin film 5 so as to have a predetermined film thickness (for example, about 1.8 μm when completely cured). After applying the core material (liquid core resin) 3Xb, the resin core layer 3X is obtained by irradiating ultraviolet rays to completely cure the resin.
b is formed. The above-mentioned two core layers 3Xa and 3X
Unlike the core layer 3 which will be described later, the pattern b is not provided with a concavo-convex pattern, is used exclusively for bonding between the clad layer 2X and the resin film 5, and does not function as an information reproducing layer. Also, the above-mentioned clad layer 2X does not constitute an optical waveguide device unlike the clad layer 2 described later, and is used exclusively for bonding the glass substrate 21 or the like as the base substrate for optical memory device fabrication and the core layer 3Xa. Has been.

Then, as shown in FIG. 5C, a clad material (liquid clad resin) is formed on the surface of the core layer 3Xb so as to have a predetermined film thickness (for example, about 15 to about 20 μm when completely cured). ) Apply 2. In the present embodiment, as the clad material 2, a material made of an ultraviolet curable resin material (UV resin material) which is cured by irradiation with ultraviolet rays (UV light) is used, and is applied on the surface of the core layer 3Xb. Then, the resin clad layer 2 is formed by irradiating ultraviolet rays to completely cure the resin. A method in which a desired resin material functioning as the clad layer 2 is dissolved in a solvent and applied and dried may be used.

After the clad material 2 is completely cured in this manner, as shown in FIG. 5C, a core material (made of an ultraviolet curable resin material having a refractive index larger than that of the clad layer 2 is formed on the surface thereof ( Liquid core resin 3 is applied so as to have a predetermined film thickness (about 1.8 μm when completely cured). A method of applying and drying a desired resin material that functions as the core layer 3 dissolved in a solvent may be applied.

Then, after applying the core material 3 in this manner, as shown in FIG. 5C, a desired concavo-convex pattern (convex shape) corresponding to an image (information) to be formed is formed on the surface thereof. A light-transmitting stamper (film stamper, resin stamper) 13 having pits carved on the surface is laminated (attached). In addition, when laminating the light-transmitting stamper (film member) 13 on the core material (resin material) 3 as described above, the light-transmitting stamper 13 is attached to the core material 3 by, for example, a roll (bonding roll). The core material (resin material) 3 is placed against the core material 3 while pressing and pressing it (while applying a pressing force), in order to prevent the thickness of the core material 3 from changing. It is preferable to attach the light transmissive stamper (film member) 13 while keeping the distance between the coated surface (upper surface of the clad material 2) and the roll constant. The details will be described later.

In this state, as shown in FIG.
Ultraviolet rays are radiated from the back surface side (the resin film 12 side, the side opposite to the surface having the concavo-convex pattern) of the laminated light-transmitting resin stamper 13 to obtain the light-transmitting stamper 1.
Part of the core material 3 is incompletely cured by the ultraviolet rays that have passed through the core material 3. Here, the partial incomplete curing means that only a part of the core material is not completely cured but is incompletely cured,
For example, it means a state in which only the edge portion of the core layer, which is slow to cure due to exposure to air, is not completely cured but is incompletely cured.

As described above, the reason why the core layer 3 is partially cured instead of completely cured is that the light-transmitting stamper 13 is used.
This is because if the core layer 3 is completely cured in the laminated state, the light-transmitting stamper 13 cannot be separated from the core layer 3. Next, as shown in FIG. 5E, a core layer 3 of a laminated body in which a light-transmissive resin stamper 13 is laminated on a base substrate 21 for an optical memory medium.
After being peeled (separated) from the stamper, a light-transmitting resin stamper 1
The resin-made core layer 3 to which the uneven pattern 3 (hereinafter, also simply referred to as “unevenness”) is transferred (formed) is irradiated with ultraviolet rays to completely cure the core layer 3. As a result, the resin-made clad layer 2 is formed on the optical memory medium base substrate 21,
Further, a resin core layer (recording layer, optical waveguide) 3 to which the concavo-convex pattern of the light-transmitting resin stamper 13 is transferred is laminated thereon. It should be noted that the uneven pattern is actually scattered on a plane like pits on a CD (compact disc).

Next, an ultraviolet curable resin material having a smaller refractive index than the core layer 3 is formed on the surface of the core layer 3 so that a predetermined film thickness (for example, about 15 to about 20 μm when completely cured) is obtained. After coating the clad material (liquid clad resin) 2 made of the above, the resin clad layer 2 is formed by irradiating ultraviolet rays to completely cure the clad layer 2. After that, by repeating the same processing (processing shown in FIGS. 5C to 5E) as described above,
The core layer 3 is formed on the optical memory element manufacturing base substrate 21 without interposing a resin film or the like as a base body, for example.
And the clad layer 2 in succession with a desired number of layers (for example, 10
Laminate until it reaches 0 layer).

As described above, the step of sequentially laminating the clad layer 2 and the core layer 3 on the resin film 5 as the base to form a laminated body having a desired number of laminated layers is called a laminated body forming step. By the way, in this embodiment, as shown in FIG.
As shown in (A), after laminating a desired number of layers as described above, a predetermined film thickness (for example, complete layer) is formed on the surface of the clad layer 2 (the uppermost clad layer 2d) finally laminated. A core material (liquid core resin) 3Xc made of an ultraviolet curable resin material is applied so as to have a thickness of about 1.8 μm when cured.

Next, after applying the core material 3Xc in this way, as shown in FIG. 6A, a resin film (resin film member, base) serving as a base (base) is formed on the surface of the core material 3Xc. The film 5'is attached (laminated) while being pressed using, for example, a roll so that air bubbles do not enter. In addition, as described above, the core material (resin material) 3
When laminating the resin film (film-like member) 5'on Xc, for example, the resin film 5'is pressed against the core material 3Xc by a roll (laminating roll) while being pressed (while applying a pressing force. ) In order to prevent the film thickness of the core material 3Xc from varying at this time, the surface coated with the core material (resin material) 3Xc (the upper surface of the clad material 2) and the roll are placed. Resin film (film member) 5'while keeping the distance between
Is preferably attached. The details will be described later.

In this state, if the core material 3Xc is further cured by further irradiating with ultraviolet rays, the resin core layer 3Xc
And the resin film 5'and the core layer 3X are formed.
c and are bonded. After that, the optical memory device manufactured in this way (that is, the structure in which the laminated body in which the clad layer 2 and the core layer 3 as the ultraviolet curable resin layer are laminated is sandwiched between the resin films 5 and 5 ′) is shown in FIG. As shown in (B), the laminated body and the resin films 5, 5'are integrally peeled (separated) from the optical memory element manufacturing base substrate 21 while being supported by these resin films 5, 5 '. The process of separating the resin films 5 and 5 ′ as the base and the laminated body from the optical memory element manufacturing base substrate 21 as a unit is called a laminated body separating step.

Then, the incident end face is formed on the optical memory element 4 peeled from the optical memory element manufacturing base substrate 21 in this manner, and a protective film is attached, a resin coating is applied, and the like, for example, an optical memory card. Etc. optical memory medium is manufactured. In the above description, any resin may be applied to the core material 3 as long as it is a liquid at the time of application and can be subsequently cured, but a suitable substance is, for example, an ultraviolet curable resin. Examples thereof include photo-curable resins such as and curable resins such as thermosetting resins. However, when the transfer is performed by the stamper as described above, it is preferable to apply the photocurable resin,
For example, acrylic photocurable resin (acrylic curable resin), epoxy photocurable resin (epoxy curable resin), thiol photocurable resin (thiol curable resin) and the like are preferable.

The clad material 2 may be any material (resin) which is transparent and has a refractive index slightly smaller than that of the core material 3, but it is easy to apply the clad material 2 made of various resins. For example, a clad material 2 made of a curable resin such as a photocurable resin such as an ultraviolet curable resin or a thermosetting resin.
Is excellent in adhesiveness with the resin film 5, and is preferable. In particular, it is preferable to use a photo-curable resin, for example, an acrylic photo-curable resin (acrylic curable resin), an epoxy photo-curable resin (epoxy curable resin), a thiol-based photo curable resin ( Thiol-based curable resin) and the like are preferable.

Further, the coating method of the core material 3 and the clad material 2 includes, for example, a spin coating method, a blade coating method, a gravure coating method, a die coating method, and the like, as long as the coating film thickness and the uniformity are satisfied. Such a coating method may be used. The clad layer 2 may be formed as one layer as described above, but may be formed in two layers in order to stabilize the film thickness.

As described above, in the present embodiment, both the laminated core layer 3 and clad layer 2 are made of resin, and the core layer (core material) 3 on which irregularities are formed is exposed to light or heat. Since a curable resin that can be cured is used, it is possible to easily obtain a desired pattern at the interface between the core layer 3 and the clad layer 2 by transfer from the stamper without using the exposure and development processing of the photoresist as in the conventional case. It becomes possible to form the uneven portion 6 having a shape.

Here, in the optical memory element 4 thus manufactured, the information recording area (that is, the information uneven portion 6 provided at the interface between both layers of the resin core layer 3 and the resin clad layer 2). An incident end face (incident light introduction end face) for guiding the incident light (reproduction light) for reading the information recorded in the area (where the light is formed) to the resin core layer 3 is formed.

Here, each optical memory element 4 cut out to a desired size from the optical memory element 4 manufactured by using the circular stamper is 90 degrees (optical waveguide member 323).
The end face that forms an angle of 90 degrees with the surface of the
Degree incident end face). The incident end face for guiding the incident light to the resin core layer 3 is not limited to this, and various types can be considered. For example, the optical memory device 4
One of the end faces is cut at 45 degrees (the angle with the surface of the optical waveguide member is 45 degrees), and if necessary, a reflection film is formed to form a mirror end surface (tilted end surface, micromirror). The incident end face (45 ° incident end face) may be used. In this case, light is made incident on the 45-degree incident end face from a direction perpendicular to the surface of the optical memory element 4,
The incident light is reflected by the incident end face to guide the incident light to the resin core layer 3.

Optical memory device 4 manufactured in this way
Then, for example, when light is introduced into the core layer 3 as an optical waveguide through the incident end face, the introduced light propagates while being scattered by the uneven portion of the interface. The scattered light at this time propagates (transmits) in each of the up and down directions (directions intersecting) with the introduced light, and finally is emitted from both sides of the optical memory element to the outside, and an image corresponding to the uneven pattern is formed. It will form an image.

Further, in the above description, the method using the sheet-shaped film as the resin film 5 as the thin film substrate has been described, but it is also possible to use a continuous film. By combining processes such as core coating on film, die coater of micro clad material, micro gravure, bar coater, etc., core curing under pressure of stamper, hardening of clad material, etc., clad / core member is formed on the support. Laminated structures can be made. Further, it is possible to improve the productivity of the transfer process from the stamper by using a roll stamper processed into a shape that can be wound into a roll as the stamper.

In the above embodiment, the light-transmitting stamper 13 is laminated on the core layer 3 to transfer the concavo-convex pattern (this is referred to as core transfer or core layer transfer method), but the present invention is not limited to this. Instead, a light-transmitting stamper (resin stamper, film stamper) may be laminated on the clad layer 2 to transfer the concavo-convex pattern (this is called a clad transfer or a clad layer transfer method).

Comparing the image output by the optical memory element manufactured by the clad transfer with the image output by the optical memory element manufactured by the core transfer, the output image of the optical memory element manufactured by the clad transfer shows a hologram. No virtual image is observed (for example, the image is 2
There is no phenomenon that the image looks double), and the image quality becomes excellent.

Here, since the core layer is thinner than the clad layer, the film thickness is less likely to change during lamination, and the laminating conditions can be widely selected, so that the core transfer in the above-described embodiment is preferable. However, if the laminating conditions are optimized, the clad layer transfer method
Good transfer can be achieved.

Therefore, if the laminating conditions are set in this way, good transfer can be performed regardless of whether the thickness of the cladding layer is thick or thin (regardless of the thickness), so that the cladding layer remains thick. It is also possible to transfer it, or it is possible to first cure a clad layer having a predetermined thickness, then apply a thin clad material for transfer, and transfer to this thinly applied clad material.

The method of manufacturing the optical memory device is not limited to that of the above embodiment. That is, in the method of manufacturing the optical memory device according to the above-described embodiment, after the base (resin film) is bonded onto the substrate, the clad layer and the core layer are sequentially stacked on the base (resin film) to obtain a desired number of stacked layers. However, the present invention is not limited to this, and for example, by directly laminating the clad layer and the core layer directly on the substrate without adhering the base (resin film) on the substrate. You may form the laminated body which has a desired laminated number.

By the way, without complicating the structure of the reading device, the recorded information can be reproduced accurately and surely by performing a simple control at the time of reading, and the reading can be automated. It is also desired to make it suitable for the purpose. That is, in order to reproduce the information recorded in the optical memory device 4 having the above-mentioned multilayer structure, the optical memory device 4 is driven (optical memory device recording / reproducing apparatus).
Mounted on the optical memory device 4, and the plane-shaped incident light (reproducing light; for example, laser light) is made incident from the incident end face of the optical memory element 4, but the irradiation state of the incident light (for example, irradiation position, irradiation angle,
When the focal length, the inclination of the reproduction light, etc.) are not good, only a part of the incident light is incident on the core layer 3 of the optical memory element 4,
The reproduced image becomes dark (low brightness), or only part of it is reproduced.

Therefore, it is very important to improve the accuracy of alignment of the incident light with respect to the incident end face of the optical memory element 4. That is, in order to reproduce the information recorded in the optical memory device 4 having a multi-layer structure, the optical memory device 4 mounted at a predetermined position in the drive is irradiated with the incident light (for example, the focal length, the irradiation position, the irradiation position). It is very important to adjust the position, angle, inclination, etc. of the incident light output part (for example, laser light head) of the drive so that the angle, the inclination of the reproduction light, etc. are optimized.

Generally, in order to adjust the irradiation state (for example, focal length, irradiation position, irradiation angle, inclination of incident light, etc.) of the incident light (reproducing light) on the optical memory element 4, the incident light (laser) on the optical memory element 4 (laser) is adjusted. For controlling the position, angle, and inclination of the light source and the lens system), as shown in FIG. 7, for example, vertical position control (Z direction position control), separation direction position control (Y direction position control; optical memory element 4 and light source). Distance control, position control in the direction along the incident light incident direction, horizontal position control (X direction position control; position control in a direction orthogonal to the incident light incident direction), elevation angle control (angle control) , Rotational position control), vertical tilt control, horizontal tilt control, and the like.
In order to control the position, angle, and inclination of the incident light, the laser light source and the lens system must be moved as a set, but only the lens 23 is shown in FIG. 7 for the sake of clarity. There is. In FIG. 7, reference numeral 24 is a CCD image receiver.

However, if the vertical inclination θ of the incident light is adjusted for each core layer 3 at the time of reading, the control becomes complicated and it is difficult to automate the reading. For example, the incident light is moved in the vertical direction (Z direction) so that a part of the incident light is incident on the core layer 3, and then the incident light is rotated to adjust the inclination θ in the vertical direction. When the entire incident light is incident on the core layer 3 to be reproduced, the center of rotation when rotating the incident light is the center of the core layer 3 to be reproduced (the center in the thickness direction and the width direction). If it is not located in the center), when the incident light is rotated, the irradiation region of the incident light will deviate from the core layer 3.

In this case, the incident light is again moved in the vertical direction to control the position in the vertical direction, and then the incident light is rotated to adjust the inclination θ in the vertical direction. That is, if the vertical inclination θ of the incident light is to be adjusted, the vertical position of the incident light is adjusted by repeatedly adjusting the vertical position of the incident light and the vertical inclination θ of the incident light. It is necessary to adjust the inclination θ of the incident light in the vertical direction while adjusting the position so that the incident light does not deviate from the core layer.

Here, in order to read the inclination θ of the incident light in the vertical direction without adjusting each layer, it is necessary that the variation of the inclination of each core layer 3 be within a certain range. is there. For this purpose, the “inclination amount” of each core layer 3 (particularly the information area of each core layer 3) at the incident end face 7 of the optical memory element 4 with respect to the reference plane may satisfy a predetermined condition.

Specifically, the amount of inclination of the information area of the incident end surface 7 where the information concave-convex portion 6 of each core layer 3 is formed with respect to the reference plane satisfies the condition represented by the following equation (1). It may be used (see FIG. 8). This means that it is sufficient that the entire information area of the incident end face 7 where the information concave-convex portion 6 of the core layer 3 is formed falls within the reproduction light irradiation area.

| A | ≦ d−t (1) a: amount of inclination of the information region of the core layer 3 with respect to the reference plane at the incident end face d: vertical width t of reproduced light t: core layer 3 Thickness in Information Area Here, the “inclination amount” means the information area (data recording area,
This is an amount indicating how much the core layer 3 deviates from the reference plane in the width of the information recording area and the drawing area).

Specifically, as shown in FIG. 8, the inclination angle of the core layer 3 with respect to the reference plane (or a plane parallel to the reference plane; here, a horizontal plane) is α, and the width of the information area is w. Then, the inclination amount a is calculated by the following equation. a = w × tan α Here, when the core layer is rotating clockwise with respect to the reference plane (or a plane parallel to the reference plane; here, a horizontal plane) (in FIG. 8, the core layer 3 on the upper side is When the left end is inclined so that the left end is higher than the right end), the amount of inclination is positive and the reference plane (or a plane parallel to the reference plane; here, a horizontal plane) Inclination when the core layer is rotated counterclockwise (in FIG. 8, when the left side end is lower than the right side end like the lower core layer 3 in FIG. 8) Negative amount.

It is to be noted that the fact that the inclination amounts of all the core layers 3 satisfy the condition represented by the above equation (1) means that the inclination amounts of all the core layers 3 satisfy the above equation (1). It means that there is a reference plane. However, the core layer 3
Any reference plane may be used for measuring the inclination amount of the. That is, any surface can be defined as long as it can be defined in the three-dimensional coordinate system, and does not have to be a surface that the optical memory device 4 has (specifically, a virtual surface). However, the reference plane that defines the inclination amount of the core layer 3 may be the plane of the optical memory element 4, for example, the upper side or the lower side of any one of the core layers 3. It may be the outer surface of the optical memory element 4 or the surface perpendicular to the side surface of the optical memory element 4.

Particularly, in the optical memory device 4 having a plurality of core layers 3, the upper surface (upper surface) or the lower surface (lower surface) of the outermost core layer 3 (outermost core layer), or The uppermost surface or the lowermost surface of the optical memory element 4 is preferably used as the reference surface. As a result, reading can be performed by a reading device (drive) having a simple configuration (mechanism).

For example, when the surface outside the element is used as the reference surface, the uppermost surface of the optical memory element 4 or
The bottom surface may be the reference surface. Thus, if the reference surface is the uppermost surface or the lowermost surface of the optical memory element 4, the drive (reading device) is, for example, the lowermost surface (stage surface) or the uppermost surface (stage) of the optical memory element 4 mounted on the stage. Since it suffices if the reference surface is a surface distant from the surface by a predetermined distance), it is not necessary to adjust the vertical inclination θ of the reproduction light for each optical memory element 4 at the time of reproduction to find the reference surface. A reading device (drive) having a simpler configuration (mechanism) can be realized. In this case, the reading device can perform the reading operation based on the reference surface outside the element without adjusting the inclination θ of the reproduction light in the vertical direction.

Here, the inclination amount | a | is set so as to satisfy the condition represented by the above equation (1). However, when the predetermined surface is used as the reference surface, Within the width, the condition that the amount of inclination of the upper (or lower) boundary surface of the core layer 3 in the direction perpendicular to the reference plane is equal to or smaller than the width d of the reproduction light in the vertical direction (vertical direction) Means to meet. The reproduction light is assumed to be incident in parallel with the reference plane.

In this case, since the reproduction light has a thickness in the direction perpendicular to the reference plane, the thickness of the reproduction light in the vertical direction is defined as the vertical width of the reproduction light. As the vertical width d of the reproduction light, for example, the half value width of the reproduction light intensity distribution may be used. By the way, in the present embodiment, since the optical memory element 4 manufactured (manufactured) as described above is manufactured using the circular stamper, the manufactured optical memory element 4 is cut out to have a desired size. .

Here, the optical memory device 4 manufactured (produced) as described above includes one or a plurality of optical waveguide members 2.
The laminate having 32 is the resin film 5 serving as a substrate.
As a result of being sandwiched by 5 ′, it goes without saying that the cut-out individual optical memory elements 4 also have resin on both sides (upper surface and lower surface) of the laminated body having one or a plurality of optical waveguide members 232. It has a structure sandwiched between films 5 and 5 '.

In the present embodiment, each of the individual optical memory elements 4 thus cut out constitutes one unit (one block), and as shown in FIG. 1, the optical memory elements as these units (blocks). Two or more (plural) 4 are stacked (laminated) to form an optical memory element 4'used as a medium (optical memory) such as an optical memory card.

Incidentally, FIG. 1 shows an optical memory element 4'in which three units (optical memory elements 4) are stacked. Further, in FIG. 1, each optical memory element 4 is shown as including only one optical waveguide member 232, but this is for the sake of clarity of explanation, and in reality, each unit (optical memory element 4) is shown. Is provided with a laminated body in which one or a plurality of optical waveguide members 232 are laminated.

For example, 25 (25 layers) optical waveguide members 2
Producing an optical memory device 4 comprising a stack having 32,
It is cut into a desired size to form a unit (25-layer laminated unit). And stack 4 units,
An optical memory device 4 '(100-layer medium) as a medium having 00 (100-layer) optical waveguide members 232 is manufactured.

In this case, up to 25 layers may be laminated on the substrate, and the warpage that occurs during fabrication may be small.
There is an advantage that a thin substrate (for example, a glass substrate) having a thickness of about 1 to 2 mm can be used as a substrate for manufacturing.
Further, four units (optical memory elements 4) each including a laminated body in which 25 optical waveguide members 232 are laminated are prepared, and these units are stacked to form a medium (optical memory element) having 100 optical waveguide members 232. If 4 ') is manufactured, there is also an advantage that a reduction in yield can be suppressed as compared with the case where 100 layers of optical waveguide members 232 are laminated to manufacture a medium (optical memory element 4').

Here, in each unit 4, the thickness of the laminated body formed by laminating the optical waveguide members 232 (that is, the thickness of the laminated body sandwiched between the resin films 5 and 5'as the base body) is 2 mm or less (more preferably 1.5 mm or less)
Is preferred. This is a problem in the manufacturing process. That is, as the number of stacked layers increases, the warp gradually increases, but if the thickness of the stacked body is 2 mm or less (more preferably 1.5 mm or less), the magnitude of warpage that occurs during manufacturing This is because the value can be suppressed within the allowable range. In this way, by suppressing the magnitude of the warp within the allowable range, when the optical memory element 4'is mounted on the drive and information is reproduced, the information recorded in each unit 4 can be accurately and surely recorded. You will be able to read it.

On the other hand, when two or more units 4 are stacked to manufacture the optical memory element 4 ', if the number of stacked units is large, each unit 4 contains the resin films 5 and 5'as the base. The thickness of the entire optical memory element 4'thus increases accordingly. In this case, if the laminated body included in each unit 4 is too thin (that is, the number of the optical waveguide members 232 included in the laminated body is small), the recording capacity of each unit 4 is small (and thus each unit is small). Although the total recording capacity of the optical memory element 4'made by stacking 4 is small), the thickness of the optical memory element 4'will be unnecessarily increased.

Therefore, in each unit 4, the thickness of the laminated body formed by laminating the optical waveguide members 232 (that is, the thickness of the laminated body sandwiched between the resin films 5 and 5'as the base body) is It is preferably at least 0.1 mm or more. Regarding the thickness of the core layer 3 and the clad layer 2,
It suffices that the core layer 3 and the clad layer 2 have a film thickness that functions as an optical waveguide.
It is considered to be about m. In this case, the film thickness of the cladding layer 2 is not particularly limited, but it is preferably 100 μm or less in consideration of reducing the total thickness. If the lower limit is specified, it will be 0.1 μm or more.

By the way, it is preferable that the substrate has a small thickness. Specifically, the thickness (film thickness) of the substrate is 5
The thickness is preferably 00 μm or less (preferably 250 μm or less, more preferably 100 μm or less). Note that a thin base body is also referred to as a thin film base body because it has a thin film shape.
The reason why the thickness of the substrate is reduced is as follows.

When the signal (information) recorded in the optical memory element 4 is read out, it is desirable to place a detector such as a CCD as close as possible to the core layer 3 to be read out. Specifically, it needs to be within 5 mm, for example. If this distance is long, the signal becomes weak and the S / N ratio becomes small. In the present embodiment, since the substrate is located above and below each unit (optical memory element 4), when the recording information (signal) is read from the upper side of the optical memory element 4 ', the lowest unit of the optical memory element 4' ( Even if only the thickness of the substrate is taken into consideration, the signal from the bottom unit) will be separated from the detector such as CCD if the thickness or more (distance or more) obtained by the following equation is satisfied.

(Number of units-1) × base thickness × 2 + base thickness For example, when the base has a thickness of 1 mm, when 6 units are laminated, the core layer to be read from the lowest unit to the CCD, etc. The detector will be separated by at least 1 cm or more, which makes it impossible to obtain a practical S / N ratio. Therefore, as described above, the thickness (film thickness) of the substrate is 500 μm or less (preferably 250 μm or less) in order to obtain a practical S / N ratio without reducing the S / N ratio. , And more preferably 100 μm or less).

On the other hand, the substrate preferably has a thickness of 10 μm or more. In short, the thickness of the substrate is 10 μm-5
00 μm (10 μm to 250 μm, 10 μm to 100 μm
It is preferably within the range of m). In particular, when the substrate is the resin film 5, 5 ', the resin film such as the polycarbonate as described above is formed by a method such as heat stretching or solvent casting, and has a thickness of, for example, 10 μm or more and 500 μm or less (preferably 100 μm or less). You can do it.

The strength (bending strength) in the bending direction of the substrate is not particularly important, but the strength (tensile strength, compressive strength) in the compression / tension direction is important. Therefore, the substrate has an elastic modulus (Young's modulus) of 9.8 × 1.
It is desirable to use a material of 0 ⁷ Pa or higher (preferably 4.9 × 10 ⁸ Pa or higher). Specific examples of the material include a polycarbonate film and an Arton film.

Further, it is desirable that the refractive index of the substrate is as close as possible to the refractive index of the core or the clad. This is because if there is a large difference between the refractive index of the substrate and the refractive index of the core 3 or the clad 2 that constitutes the laminated body, the output light (signal light) will be reflected at the interface between the substrate and the laminated body. Then, the amount of signal light (output light) is reduced, and the S / N is also reduced.

Therefore, it is desirable that the difference between the refractive index of the core or clad constituting the laminated body and the refractive index of the material constituting the substrate is 0.2 or less. That is, it is preferable that the difference in refractive index between the core and the substrate is 0.2 or less, and the difference in refractive index between the clad and the substrate is 0.2 or less. By the way, in the present embodiment, in order to fabricate a medium (optical memory element 4 ′) by laminating two or more units 4, an adhesive is uniformly applied to the entire surface of one unit 4 and another unit is formed on top of it. The units 4 are stacked and adhered to each other to stack two or more units 4 to produce a medium.

In this case, as shown in FIG. 1, the adhesive layer 20 is formed between the units 4. That is, each unit 4 is adhered via the adhesive layer 20. In this case, the refractive index of the adhesive layer 20 formed between the units 4, that is, the refractive index of the adhesive applied to the units 4 (refractive index after curing) and the refractive index of the core or the clad are If the difference is large, the signal light (output light, emitted light) is reflected at the interface between the adhesive layer 20 and the core layer 3 or the cladding layer 2, and the light amount of the signal light (output light) decreases. As a result, the S / N will also decrease.

Therefore, the difference between the refractive index of the adhesive applied to bond the units 4 (refractive index after curing) and the refractive index of the core and the clad is 0.2 or less. Preferably. Preferably, the ultraviolet curable resin (UV resin) used for the core material and the clad material is used as it is as an adhesive. In this case, the refractive index of the adhesive is very close to (or equal to) the refractive index of the core or the clad, and the signal light is prevented from being reflected at the interface between the adhesive layer 20 and the core layer 3 or the clad layer 2. Therefore, the light amount of the signal light is hardly reduced.

In particular, the adhesive layer 20 formed between the units 4 is formed so that the thickness (film thickness) thereof is substantially uniform (particularly, the optical waveguide member 232 constituting each unit 4 is formed). As will be described later, the information area (information recording area) is formed by forming an adhesive layer on the entire surface corresponding to the information area in which the information uneven portion 6 is formed so that the thickness of the area is substantially uniform. , A high quality optical memory device 4'is obtained as compared with the case where the adhesive layer is formed only in the regions (non-information recording region, non-information region) other than the regions corresponding to the data region and the hologram region.

By the way, as described above, one unit 4
In many cases, it is practically difficult to apply the adhesive evenly on the surface of and to laminate the other unit 4 thereon so that air bubbles do not enter. This is because each unit 4 has a certain thickness and often loses the flexibility required for lamination. Therefore, when the units 4 are bonded, bubbles are likely to be mixed between the units 4, and the mixed bubbles become a scattering factor, and the adhesive layer 20
Stray light due to the noise may become noise in the reproduced image and affect the reading of data (reproduction of the reproduced image).

Considering this point, as shown in FIG.
It is preferable that each unit 4 is adhered by applying an adhesive to a region (location) other than the region corresponding to the information region of the optical waveguide member 232 constituting each unit 4. That is, it is preferable that the adhesive layer 20 is formed in a region other than the region corresponding to the information region between the units 4. here,
As the formation location of the adhesive layer 20 (adhesive application location),
Various patterns are possible.

For example, as shown in FIG. 10, in the area around the area corresponding to the information area of the optical waveguide member 232 forming each unit 4, the adhesive layer 2 is formed over the entire area.
0 may be formed, or, as shown in FIG. 11, in regions around the regions corresponding to the information regions of the optical waveguide member 232 forming each unit 4, at four corners of the surface of each unit 4, The adhesive layer 20 may be formed by applying an adhesive in spots. The place where the adhesive layer 20 is formed is not limited to these patterns.

In this case, since the signal light (reading light) does not pass through the adhesive layer 20 formed between the units 4, the adhesive is not required to have the above optical characteristics. In particular, the refractive index of the adhesive does not have to be selected, and there is no problem even if a scatterer is mixed in the adhesive. Therefore, for example, an epoxy adhesive or the like can be used. Further, as described above, when the adhesive layer 20 is formed only in the area other than the area corresponding to the information area of the optical waveguide member 232 forming each unit 4, the adhesive having a uniform thickness is adhered to the information area. Layer 20
Is simpler than the formation of the optical memory device 4'and the optical memory device 4'is easily manufactured.

In this case, since no adhesive is applied to the area corresponding to the information area of the optical waveguide member 232 constituting each unit 4 and the adhesive layer 20 is not formed,
There will be air in this part. Therefore, the amount of signal light (readout light) from each unit 4 may be reduced due to reflection or the like by the air layer existing between the units 4. This is not a problem when the number of units to be laminated is small, but it becomes a problem because the influence becomes large when the number of units to be laminated is large.

For example, when the refractive indices of the core, the clad, and the base are all 1.52, the output of the signal light is 0.957 times due to the reflection by one air layer. If 11 units 4 are stacked, the signal light output from the lowermost unit (lowermost unit) 4 is about 0.64 times the signal light output from the uppermost unit (uppermost unit) 4. Become. Thus, if an air layer exists between the units 4, a difference in the output of the signal light will occur between the stacked units 4, and it is not preferable that such an output difference occurs.

Therefore, the number of units to be stacked is 1
It is practical that the upper limit is about 0. That is, the number of units to be stacked is preferably 10 or less. The information uneven portion 6 of the optical memory element 4 (optical waveguide member 232).
However, when it is formed so as to form an image at a predetermined magnification (for magnifying and reproducing) (when the optical memory element 4 is a magnifying and reproducing element), the adhesive layer 20 forms the optical memory element 4 (optical waveguide member 232). It is preferable to form it in a region (for example, a peripheral region of the enlarged information reproducing region) in which the enlarged reproduced image from the information concave-convex portion 6 does not appear.

In the case of an enlargement reproducing element, this is
Since the reproduced image formed by the original scattered light from the information concave-convex portion 6 is wide, a stray light due to the adhesive layer 20 is enlarged by applying an adhesive to the area where this enlarged reproduced image does not appear. This is to prevent the reproduced image from becoming a noise and affecting the reproduced image. In addition, the uneven portion 6 for information
The size of the reproduced image for reproducing the information is determined by conditions such as the shape of the information uneven portion 6 regardless of the device.

For example, when the information concavo-convex portion 6 is a 4 × reproducing element formed so as to form an image with a size of 4 times, the area of the region where the information concavo-convex portion 6 is provided is Since the quadrupled area is the area where the enlarged reproduced image appears, an adhesive is applied to the peripheral portion of this area to form the adhesive layer 20.
By the way, the surface of the unit 4 (top or bottom)
If the layers are laminated so that the surfaces of the other units 4 facing each other (the lowermost surface or the uppermost surface) are parallel to each other, the core layer 3 forming the unit 4 does not tilt, but as described above, When the adhesive layer 20 is formed between the units 4 and the units 4 are adhered to each other, if the adhesive layer 20 has unevenness in film thickness, the units 4 are stacked in an inclined state, and as a result, In addition, the optical waveguide member 23 constituting each unit 4
An inclination will occur between the two core layers 3.

If the core layers 3 are tilted in this manner, the reproduction light cannot be made incident on the entire information area of the core layer 3 at the same time, and only a part of the recorded information can be reproduced. It will be. In this case, in order to perform reading without adjusting the inclination θ of the incident light in the vertical direction for each unit 4, the inclination of each unit 4 falls within a predetermined range (within an allowable range) where the inclination varies. Need to be.

Specifically, with respect to the reference surface of the optical memory element 4'with respect to the width of the information area in which the information uneven portion 6 of the resin core layer 3 (optical waveguide member 232) of the reference surface of each unit 4 is formed. It is sufficient that the amount of tilt satisfies the condition represented by the following formula (see FIG. 12). | X | ≦ d−t x: amount of inclination of the information area width of the reference surface of the unit 4 with respect to the reference surface of the optical memory element 4 ′: vertical width of reproduction light t: thickness of the core layer 3 in the information area The reference surface of the optical memory element 4'is a surface that defines the amount of inclination of the reference surface of each unit 4 that constitutes the optical memory element 4 '. The reference plane of each unit 4 is
In the description of the above formula (1) (see FIG. 8), it is the reference plane used to define the tilt amount of the core layer 3.

The “inclination amount” of the reference plane of the unit means that when each unit 4 is inclined, the reference plane has a width of the information area (data recording area, information recording area, drawing area). Is a quantity that indicates how much it deviates from the reference plane of the optical memory element 4'by tilting. The reference surface of the optical memory element 4'may be any surface that can be defined in the three-dimensional coordinate system, and does not have to be the surface of the optical memory element 4'specifically. However, it may be the surface of the optical memory element 4 ', or the uppermost surface (front surface) or the lowermost surface (front surface) of the optical memory element 4'may be the reference surface.

Specifically, as shown in FIG. 12, when the inclination angle of the unit 4 with respect to the reference plane (or a plane parallel to the reference plane; here, a horizontal plane) is β, and the width of the information area is w. , The inclination amount x is calculated by the following equation. x = w × tan β Here, when the upper unit 4 is rotating clockwise with respect to the plane parallel to the surface (uppermost surface) of the lower unit 4 as the reference plane (that is, from the right end portion). Also, if the left end is tilted so that it is on the upper side, the amount of tilt is positive.

Since the reproduction light has a thickness in the direction perpendicular to the reference plane, the thickness of the reproduction light in the vertical direction is defined as the vertical width of the reproduction light. As the vertical width d of the reproduction light, for example, the half value width of the reproduction light intensity distribution may be used. Further, in order to prevent unevenness in the thickness of the adhesive layer 20 and to satisfy the condition represented by the above formula, when laminating (bonding) each unit 4, a bonding roll (laminate) is used. While keeping the distance between the roll) and the surface on which the adhesive layer is formed constant (constant value), one unit 4
Should be attached (laminated).

Various methods are conceivable in order to keep the distance between the laminating roll and the adhesive layer constant. For example, a sticking device (an optical memory device manufacturing device) for sticking (laminating) one unit 4 onto the surface of another unit 4 via an adhesive layer is used. Is provided with a position adjusting mechanism that adjusts the height position of the bonding roll so that the height does not fall below a predetermined distance.

Here, the position adjusting mechanism may be constituted by (1) a mechanism which is provided in a supporting portion for supporting the bonding roll and moves in the height direction of the bonding roll (roll height direction moving mechanism). Good, (2) The bonding roll is supported on the stage so that the distance between the stage and the bonding roll does not become a predetermined distance or less (that is, the bonding roll does not go below a certain height). Regulate the movement of the laminating roll)
A spacer (spacer component) may be provided, and the height position of the bonding roll may be adjusted by this spacer.

In order to realize a more practical optical memory device 4 ', it is preferable that the width of the information area is wide so that the amount of data that can be read at one time is large. However, if the width of the information area is wide, The amount of inclination between the units 4 tends to increase. Therefore, when the width of the information area is 2 mm or more and 100 mm or less on the incident end surface of the resin core layer 3, it is preferable to satisfy the condition represented by the above formula.

If the condition represented by the above equation is satisfied, the inclination generated in each unit 4 is within the allowable range, and therefore, when reproducing the information recorded in each unit 4, it is incident on each unit 4. Since it is not necessary to adjust the inclination of light, information can be read by a simple operation in a short time, and the configuration of the reading device (drive) can be simplified.

In the above description, the adhesive layer 20 is formed between the units 4 and the units 4 are adhered and laminated, but the present invention is not limited to this.
For example, as shown in FIG. 13, each unit 4 is simply stacked (stacked) without applying an adhesive between the units 4, and the end faces (side surfaces) of the stacked (stacked) units 4 are stacked. For example, apply an adhesive such as curable resin,
By covering the end surface of each unit 4 with an adhesive (adhesive layer),
It is also possible to adhere each unit 4 via the adhesive layer 20. In particular, it is preferable that the adhesive layer 20 is formed on an end surface other than the incident end surface of each unit 4. As a result, when reproducing the information recorded in the optical memory element 4, it is possible to prevent the amount of the reproducing light (incident light) incident on the optical memory device 4 from decreasing and the coupling efficiency from decreasing.

According to this, since no adhesive is applied between the units 4 and the adhesive layer 20 is not formed, there is an advantage that the scattering of the signal light and the decrease in the light amount of the signal light do not occur. In addition, since each unit 4 is simply piled up and the adhesive layer 20 is not formed between the units 4, there is no inclination of each unit 4 due to the uneven thickness of the adhesive layer 20. When reproducing the recorded information, it is not necessary to adjust the inclination of the incident light for each unit 4, the information can be read by a simple operation in a short time, and the structure of the reading device (drive) is simplified. There is also an advantage that it can be realized.

Also, as shown in FIG. 14, for example, without applying an adhesive between the units 4, the units 4 are simply stacked (laminated), and the end faces of the stacked units 4 are stacked. An adhesive such as a curable resin is applied to the (side surface) so as to cover the end face (which forms an adhesive layer), and a planar member (film-shaped member, plate-shaped member, It is also possible to adhere (connect) each unit 4 by attaching the connecting member) 22 via the planar member 22. In this case, the planar member 22 is adhered to the end surface of each unit 4 via the adhesive layer 20, whereby the units 4 are connected.

In particular, it is preferable that the planar member 22 is formed on an end surface other than the incident end surface of each unit 4. As a result, when reproducing the information recorded in the optical memory element 4, it is possible to prevent the amount of the reproducing light (incident light) incident on the optical memory device 4 from decreasing and the coupling efficiency from decreasing. Now, as described above, in order to increase the recording density, the individual optical memory elements 4 cut into a desired size.
When the (units) are stacked and adhered to each other to form one optical memory element 4 '(medium) (each optical memory element 4 has 9
In the case of having a 0-degree incident end face), it is preferable to stack the units 4 so that the positional deviation amount (alignment error of each unit 4) of each unit 4 in the reproduction light incident direction falls within a predetermined positional deviation amount range. .

For example, it is preferable that one unit 4 serving as a reference is laminated so that the positional deviation amount of the other unit 4 is within a range of ± 100 μm. That is, it is preferable to stack the units 4 so that the positional shift amount between the units 4 that are most shifted from each other is 200 μm or less. The predetermined range is such that the position adjustment (alignment;
Even if the depth of focus is not adjusted), it is set as a positional deviation amount capable of introducing an amount of incident light necessary for reproducing information into each core layer 3 of the optical waveguide member 232 constituting each unit 4. It

As a result, it is not necessary to adjust the position of the incident light (reproducing light) in the reproducing light incident direction for each unit 4, and as a result, the information recorded in each unit 4 can be recorded in a short time. It becomes possible to read. in this way,
To reproduce the information recorded in the optical memory device 4,
Since it is not necessary to adjust the position of each unit 4 in the reproduction light incident direction, the configuration of the reading device (drive) can be simplified.

Therefore, according to the optical memory element of the present embodiment, it becomes possible to manufacture a practical optical memory element 4 having a multilayer structure. That is, according to the present optical memory element, when increasing the number of stacked layers to increase the recording capacity, it is possible to suppress the occurrence of warpage as much as possible, it is possible to accurately and surely reproduce the recorded information, and to improve the yield. There is an advantage that it can be improved.

Further, since it is not necessary to increase the thickness of the substrate in order to suppress warpage as much as possible in order to increase the number of stacked layers, an optical memory element manufacturing apparatus (medium manufacturing apparatus) for manufacturing the optical memory element 4 is formed. There is also an advantage that the cost can be kept low.

[0149]

[Embodiment] The surface has an uneven shape according to image information,
An acrylic UV-curable resin (refractive index n = 1.49), which is a clad material, is applied on a stamper made of metallic nickel, and then irradiated with 800 mJ / cm ^{2 of} ultraviolet rays to be cured to form a clad layer having a thickness of 5 μm. did. After coating a core material (refractive index n = 1.49) made of acrylic UV curable resin on this clad layer, an Arton film member having a thickness of 100 μm (made by JSR, refractive index n = 1.51)
Was slowly attached while being pressure-bonded with a rubber roller.
Ultraviolet rays of 800 mJ / cm ^{2 were} radiated from above to cure to form a core layer having a thickness of 1.8 μm, and the film member was bonded to the core / clad layer. Then, the clad layer, the core layer and the Arton film are separated from the stamper,
A light transmissive stamper was produced.

Next, an acrylic ultraviolet curing resin (refractive index n =
1.49) and then 800mJ / cm ^{2 of} ultraviolet rays
It was irradiated and cured to form a 5 μm clad layer. A core material (refractive index n = 1.49) made of an acrylic ultraviolet curable resin was applied on the clad layer, and then a thickness of 10
A 0 μm Arton film member (manufactured by JSR Co.) was slowly attached while being pressed by a rubber roller. The film member was bonded to the core / clad layer by irradiating ultraviolet rays at 800 mJ / cm ² from above.

A core material (refractive index n = 1.49) made of an acrylic ultraviolet curable resin was applied to this film member, and then irradiated with ultraviolet rays at 2400 mJ / cm ² to cure the core material, and a core having a thickness of 1.8 μm was applied. Layers were formed. On top of that, a clad material made of acrylic UV curable resin (layer folding ratio n =
After applying 1.49), a light transmissive stamper was slowly attached in such a direction that the transfer surface was in contact with the clad material while being pressed by a rubber roller. At this time, the distance between the roller and the glass substrate was controlled to be constant, and the clad thickness was adjusted to be uniform. From above, ultraviolet rays of 10 mJ
/ Cm ² irradiation to partially incompletely cure the cladding layer (partially incompletely cured), and then only the light transmissive stamper was peeled off. After that, further ultraviolet rays of 800 mJ / cm ²
Irradiation was performed to completely cure the clad layer. As a result,
A 15 μm thick clad layer was formed. After coating a core material (refractive index n = 1.49) made of an acrylic ultraviolet curing resin on this clad layer, ultraviolet rays of 2400 mJ are applied.
/ Cm ^{2 It was} irradiated and cured to form a core layer having a thickness of 1.8 μm. The refractive indexes of the formed core layer and cladding layer were 1.52 and 1.51, respectively. 25 this step
By repeating this, a laminated body having a multilayer structure of 25 layers was obtained.

Next, an acrylic ultraviolet curing resin (refractive index n = 1.49), which is a clad material, was applied and then irradiated with ultraviolet rays at 800 mJ / cm ² to be cured to form a 15 μm thick clad layer. On this clad layer, a core material made of an acrylic UV curable resin (layer folding ratio n = 1.4
After applying 9), an Arton film member (manufactured by JSR) having a thickness of 100 μm was slowly attached while being pressure-bonded with a rubber roller. 800 mJ / c ultraviolet light from above
The film member was bonded to the core / clad layer by irradiation with m ² .

Finally, the 25 pieces sandwiched between Arton films
The layered laminate was peeled from the glass substrate. In this way, an optical memory device was produced by sandwiching the 25-layer structure laminate with an Arton film. Then, the optical memory device thus manufactured was cut into a size of about 1.5 cm in length and about 2.5 cm in width using a dicing saw, and four pieces were prepared. An equal amount of epoxy adhesive was dispensed at the four corners so as not to cover the information recording area, and then four samples (units) were laminated and adhered while evenly applying pressure from above to fabricate a 100-layer optical memory device. did.

Evaluation was performed by introducing laser light from a predetermined direction of this sample. At this time, the measurement was performed without preparing a clamp mechanism or the like for flattening the sample.
The laser light was a semiconductor laser having a wavelength of 680 nm and an intensity of about 5 mW. The light flux was adjusted to 4 μm in length and about 1 cm by combining a lens so that the light flux enters the core layer. The width of the area (information area) in which data was recorded in each layer was 6.5 mm.

As a result, the laser light propagates in the core layer,
The light slightly scattered by the unevenness was transmitted in the direction perpendicular to the core layer and imaged. This image was projected directly onto the CCD and observed, and it was confirmed that the image was a desired image (test pattern). It was also confirmed that by changing the core layer into which laser light is introduced, these images recorded in 100 core layers can be read independently without affecting each other.

Next, the inclination of the reference plane of each block was measured. The bottom core layer surface of each block was used as the reference surface of the block. The tilt amount was measured using the reference plane of the bottom block as a reference for the inter-block tilt amount. As a result, in order from the bottom block, 0 μm, 0 μm, +0.9 μm, +0.9
The amount of inclination was μm. Since the incident laser width (vertical width of the reproduction light irradiation area) is 4 μm and the core thickness is 1.8 μm, the expression x ≦ d−t (x: tilt amount of information area, d: vertical direction of reproduction light irradiation area). Direction width, t: thickness of the resin core layer)
The tilt amount allowed by is 2.2 μm, but it can be seen that the tilt amount of each unit is within the allowable range.

[0157]

As described above in detail, according to the optical memory device of the present invention, when the number of stacked layers is increased to increase the recording capacity, the occurrence of warpage can be suppressed as much as possible, and the recorded information can be recorded. There is an advantage that the reproduction can be performed accurately and surely and the yield can be improved.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an overall configuration of an optical memory element according to an embodiment of the present invention.

FIG. 2 is a schematic diagram for explaining an overall configuration of an optical memory device according to an embodiment of the present invention.

FIG. 3 is a schematic cross-sectional view showing the overall configuration of a light transmissive stamper according to an embodiment of the present invention.

FIG. 4 is a schematic cross-sectional view showing a method for manufacturing a light-transmitting stamper according to an embodiment of the present invention, in which (A) is a step of forming a clad layer and a core layer, and (B) is a resin film. The step of adhering, (C) shows the step of peeling (separating) the light transmissive stamper, and (D) shows the step of performing overcure treatment.

5A and 5B are schematic cross-sectional views showing a method for manufacturing an optical memory device according to an embodiment of the present invention, in which FIG. 5A is a step of adhering a resin film on a base substrate for manufacturing an optical memory device, and FIG. A step of forming a core layer on the resin film,
(C) is a step of forming a clad layer and a core layer on the core layer, (D) is a step of transferring an uneven pattern from the light-transmitting stamper, and (E) is a step of peeling (separating) the light-transmitting stamper. Shown respectively.

FIG. 6 is a schematic cross-sectional view showing the overall configuration of an optical memory element manufactured by the method for manufacturing an optical memory element according to the embodiment of the present invention, in which (A) is formed on a base substrate for manufacturing an optical memory element. The state (B) shows the state of being peeled (separated) from the optical memory element manufacturing base substrate.

FIG. 7 is a schematic diagram for explaining control of incident light during reproduction of the optical memory element according to the embodiment of the present invention.

FIG. 8 is a schematic diagram for explaining the amount of inclination of the core layer of the optical memory element according to the embodiment of the present invention.

FIG. 9 is a schematic diagram for explaining a bonding method of each unit that constitutes the optical memory element according to the embodiment of the present invention.

FIG. 10 is a schematic diagram for explaining an example of a formation position of an adhesive layer when bonding each unit constituting the optical memory element according to the embodiment of the present invention.

FIG. 11 is a schematic diagram for explaining another example of the formation position of the adhesive layer when bonding the respective units constituting the optical memory element according to the embodiment of the present invention.

FIG. 12 is a schematic diagram for explaining an allowable range of the tilt amount of each unit that constitutes the optical memory element according to the embodiment of the present invention.

FIG. 13 is a schematic diagram for explaining a modified example of the bonding method of each unit that constitutes the optical memory element according to the embodiment of the present invention.

FIG. 14 is a schematic diagram for explaining another modified example of the bonding method (coupling method) of each unit constituting the optical memory element according to the embodiment of the present invention.

FIG. 15 is a schematic perspective view for explaining the operation principle of a conventional optical memory device.

FIG. 16 is a schematic perspective view for explaining the operation principle of a conventional optical memory device.

[Explanation of symbols]

1 Metal Stamper (Hard Stamper) 2 Clad Layer (Clad Material) 2X Clad Layer (Adhesive Layer) 3 Core Layer (Core Material, Recording Layer, Optical Waveguide) 3Xa, 3Xb, 3Xc Core Layer (Adhesive Layer) 232 Optical Waveguide Member (Optical memory device for one layer, laminated body) 4 Optical memory device (unit, block) 4'Optical memory device (medium) 5, 5 'Resin film (base, thin film base) 6 Concavo-convex portion for information (concavo-convex portion) 10 Cladding layer (Clad material, stamper layer) 11 Core layer (core material, adhesive layer, adhesive) 12 Resin film (base material, base material layer) 13 Light-transmitting stamper (stamper for manufacturing optical memory element) 20 Adhesive layer 21 Base for manufacturing optical memory element Substrate (base material) 22 Planar member (film member, plate member, connecting member)

Claims (18)

[Claims] 1. A resin core layer and a resin clad layer laminated on both sides of the resin core layer, wherein at least one of the interfaces between the resin core layer and the resin clad layer is for information. A unit formed by sandwiching a laminated body formed by laminating one or a plurality of optical waveguide members each having a concave-convex portion by a base, and being configured by bonding two or more units together,
Optical memory device. 2. The thickness of the laminate sandwiched between the bases is 2 mm or less.
The optical memory device described. 3. The optical memory device according to claim 1, wherein the substrate has a thickness of 10 μm to 500 μm. 4. The refractive index difference between the base and the resin clad layer and the refractive index difference between the base and the resin core layer are both 0.2 or less. The optical memory device according to claim 1. 5. The optical memory element according to claim 1, wherein the resin core layer and the resin clad layer are made of a curable resin. 6. The optical memory element according to claim 5, wherein the curable resin is an acrylic curable resin. 7. The adhesive layer according to claim 1, further comprising an adhesive layer for adhering the units, wherein the adhesive layer is formed between the units. Optical memory device. 8. The optical memory element according to claim 7, wherein the adhesive layer is formed on the entire surface of the area corresponding to the information area where the information concave-convex portion is formed. 9. The refractive index difference between the adhesive layer and the resin clad layer and the refractive index difference between the adhesive layer and the resin core layer are both 0.2 or less. 9. The optical memory device according to claim 7 or 8. 10. The optical memory element according to claim 7, wherein the adhesive layer is formed in a region other than a region corresponding to the information region in which the information uneven portion is formed. 11. An information concavo-convex portion of the optical waveguide member is configured to be enlarged and reproduced, and the adhesive layer is formed in a region where an enlarged reproduction image from the information concavo-convex portion does not appear. The optical memory device according to claim 7, which comprises: 12. An adhesive layer for adhering each unit, wherein the adhesive layer is formed so as to cover an end face of each unit. An optical memory device according to item. 13. The optical memory device according to claim 12, wherein the adhesive layer is formed on an end face other than an incident end face for making reproducing light enter the resin core layer of each unit. 14. A connecting member for connecting each unit, wherein the connecting member is provided so as to cover an end face of each unit. An optical memory device according to item. 15. The optical memory device according to claim 1, wherein the number of units is 10 or less. 16. The optical memory device according to claim 1, wherein a positional deviation between the respective units in a reproduction light incident direction is within 200 μm. 17. The amount of inclination of the optical memory element with respect to the reference plane in the width of the information area of the resin core layer of the reference plane of the unit, in which the information uneven portion is formed,
The optical memory device according to claim 1, wherein a condition represented by the following formula is satisfied. | X | ≦ d−t x: amount of inclination of the information area width of the reference surface of the unit with respect to the reference surface d: vertical width of the reproduction light irradiation area t: thickness of the core layer in the information area 18. The information area has a width of 2 mm or more and 10 or more.
18. The optical memory device according to claim 17, wherein the optical memory device has a length of 0 mm or less.