JP2002260290A - Optical card and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a highly flexible and easy-to-carry optical card that can suppress variations in reproduced outputs between the cards and minimize warped cards when mass-produced. SOLUTION: This is a rectangular card that has at least a transparent base, a recording layer containing organic pigments, an adhesion layer, and a lining base formed in this order. The transparent base is made of an extruded film, and θ<=20 deg. at least within the recording region of the transparent base when the angle between the length side and the molecular orientation axis is θ(0<=θ<=90 deg.).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an optical card capable of optically writing and reading, and a method of manufacturing the optical card.

[0002]

2. Description of the Related Art Optical recording media have attracted attention as large-capacity recording media using laser light.

[0003] The optical recording medium has a cartridge type,
There are a disk type and a card type. Among them, the card type has advantages such as small size and can be stored in a wallet, and is excellent in portability. Optical cards are classified into read-only type, write-once type, and rewritable type. In the write-once type, a metal thin film or an organic dye film is used for the recording layer, and pits are formed in the recording layer by laser irradiation. Since the pit formation is irreversible and the recorded information cannot be rewritten, the write-once medium has the advantage of preventing data falsification.

A conventional write-once optical card has a basic structure in which a transparent substrate / recording layer / adhesive layer / backing substrate are laminated.
In the production, usually, a method is used in which a recording layer is provided on a transparent base material, an adhesive layer is provided on a backing base material, and the recording layer and the adhesive layer are superimposed so as to be in contact with each other and bonded by heat or the like. Can be Transparent substrates are generally made of polycarbonate (PC) or polymethyl methacrylate (PMM
The injection molded product of A) is used and is characterized by low birefringence. Such an optical card is described in, for example, JP-A-11-353717.

In the heat laminating step of bonding the transparent substrate side and the backing substrate side, the optical card is likely to be warped by heating. According to the card standard of ISO / IEC7810, 8
For a 5.6 mm × 53.98 mm card,
The curl amount is less than 5 mm. Generally, the resin used for the adhesive layer is tacky in the temperature range from room temperature to about 50 ° C to prevent the adhesive layer from sticking out to the cross section of the card, to prevent dust from adhering, and to prevent blocking due to storage of the card and the adhesive layer. Is required. Therefore, the adhesive layer is preferably made of a resin having a glass transition temperature of 50 ° C. or higher. In order for such a resin to obtain sufficient adhesion at the bonding portion, the heating temperature in the heat laminating step is preferably set to 80 ° C. or higher. Further, in consideration of the deterioration of the recording layer made of the organic dye due to heat, the occurrence of curling, the thermal deformation of the substrate, and the like, the heating temperature in the thermal laminating step is preferably about 130 ° C. or less.

[0006] In general, an optical card is manufactured under such laminating conditions and the warpage of the card is controlled by appropriately selecting a layer structure, a material and a manufacturing method.
-161770 and JP-A-2000-23346
No. 6 discloses this.

[0007]

As described above, a conventional optical card uses a transparent base material or a backing base material manufactured by an injection molding method. It is desirable that the transparent substrate in the optical card characterized by portability has chemical resistance, is thin and has flexibility. However, PC and P
MMA has low solvent resistance, and it is difficult to produce thin films by injection molding. Therefore, in the conventional optical card, the thickness of the transparent substrate is increased, resulting in low flexibility and insufficient portability.

[0008] The present invention has been made in view of the above problems. An object of the present invention is to provide an optical card having high flexibility and good portability. Also,
It is another object of the present invention to suppress variations in reproduction output between optical cards when such optical cards are mass-produced. Another object of the present invention is to reduce the twist of such an optical card.

[0009]

The above object is achieved by the following (1).
This is achieved by the present invention according to (7). (1) A rectangular optical card having at least a transparent substrate, an organic dye-containing recording layer, an adhesive layer, and a backing substrate in this order, wherein the transparent substrate is composed of a stretch-formed film, In the optical card according to the above, when the angle between the long side and the molecular orientation axis is θ (0 ≦ θ ≦ 90 °), θ ≦ 20 ° at least in the recording target area of the transparent base material. (2) The backing substrate is composed of a stretch-formed film,
The optical card according to the above (1), wherein the angle between the average molecular orientation axis of the transparent substrate and the average molecular orientation axis of the backing substrate is 10 ° or less. (3) The backing substrate is composed of a stretch-formed film,
The optical card according to the above (1) or (2), wherein both the maximum thermal shrinkage of the transparent substrate and the maximum thermal shrinkage of the backing substrate are 0.5% or less. (4) A method for producing a rectangular optical card having at least a transparent substrate, a recording layer containing an organic dye, an adhesive layer, and a backing substrate in this order, wherein the transparent substrate is composed of a stretch-formed film. When punching a plurality of optical cards from a long web using a punching die in which a plurality of rectangular punching patterns corresponding to the shape of the optical card are arranged, the long side or short side of the punching pattern is radial. A method for manufacturing an optical card using the arranged punching die. (5) A method for producing a rectangular optical card having at least a transparent substrate, a recording layer containing an organic dye, an adhesive layer, and a backing substrate in this order, wherein the transparent substrate is composed of a stretch-formed film. When punching a plurality of optical cards from a long raw material using a punching die in which a plurality of rectangular punching patterns corresponding to the shape of the optical card are arranged, the raw material is cut with a cut surface parallel to the longitudinal direction. Two divided raw materials are obtained by dividing into two, and one of the divided raw materials is punched out by a punching die in which the long side or the short side of each punched pattern is parallel to each other. A method for manufacturing an optical card, wherein the optical card is punched out by the punching die in an upside down state. (6) When the angle between the long side and the molecular orientation axis in the transparent substrate is θ (0 ≦ θ ≦ 90 °), the raw material is punched out so that θ ≦ 20 ° in all optical cards. The method for manufacturing an optical card according to the above (4) or (5). (7) The optical card according to (1) above, wherein the optical card is manufactured.
(6) The method for manufacturing an optical card according to any of (6).

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The inventors of the present invention have selected a stretch-formed film as a film that is thin and has sufficient mechanical strength and can be used with a resin having good solvent resistance.
Using this as a transparent substrate, an optical card was produced. The stretch-formed film is a film in which a plastic film is stretched by a stretching method at a temperature equal to or higher than a secondary transition point and is molecularly oriented, and has a higher mechanical strength than an injection-molded film.
By using a stretch-formed film made of polyethylene terephthalate (PET), polyethylene naphthalate (PEN), or the like, chemical resistance and bending resistance are enhanced, which is effective for improving portability.

However, in the case of an optical card in which a transparent substrate is formed from a stretch-formed film, when mass-produced, the reproduction output among optical cards has a large variation. The reason is considered as follows.

First, the manufacturing process of the optical card will be described. As described above, the optical card has a basic structure in which a transparent base material / recording layer / adhesive layer / backing base material is laminated. However, the transparent base material and the backing base material are not punched in advance to have a card shape and card dimensions, but are usually punched into a card shape after being laminated to form a laminate. In the following description, the laminate before punching is referred to as a raw material. Usually, the raw material is used in a long shape.

In the case of a transparent substrate made of a stretch-formed film,
Since the base molecules are oriented substantially parallel to the stretching direction, birefringence depending on the molecular orientation occurs. In this specification, the direction of the molecular orientation is referred to as the direction of the molecular orientation axis. When linearly polarized reproduction light is incident on a transparent base material having a molecular orientation axis, a phase difference corresponding to the molecular orientation axis of the base material is generated on the plane of polarization of the light, so that return light becomes circularly polarized light. If the angle formed between the molecular orientation axis of the substrate and the plane of polarization of the light does not change in the reproduction light scanning region, the reproduction output is kept constant.

However, when examining the distribution of molecular orientation axes of a transparent substrate made of a biaxially stretched formed film produced by stretching in two orthogonal directions, as shown in FIG. The direction of the molecular orientation axis was varied. In the biaxially stretched film, the molecular orientation axes exist in two directions, but FIG. 2 shows only the molecular orientation axes extending in the longitudinal direction of the film. According to the study of the present inventors, the direction of the molecular orientation axis extending in the longitudinal direction in a biaxially stretched film almost coincides with the stretching direction near the center in the width direction of the film, but stretches toward the film end. It was found that the deviation from the direction became large. Also, in the biaxially stretched film, the direction of the molecular orientation axis extending in the width direction substantially coincides with the stretching direction near the center in the width direction of the film, but the deviation from the stretching direction becomes larger as approaching the film end. I understood.

[0015] When a film having a molecular orientation axis that varies as described above is punched into a card shape and used as a transparent base material, when the optical head scans the recording area of the optical card, the birefringence axis at each position in the scanning direction. Because the direction of
The state of the circularly polarized light of the return light changes with scanning. When the polarization state of the return light changes, the beam splitter (B
Since the amount of light returning to the detector via S) fluctuates, the reproduction output fluctuates. However, since the card size is usually much smaller than the film width, the molecular orientation axis is almost constant in the card, and the reproduction fluctuation output does not substantially occur. However, in the blank 10 shown in FIG. 2, the optical card punched from the vicinity of the center of the blank 10 and the optical card punched from the end of the blank 10 have a direction of the molecular orientation axis of the transparent substrate with respect to the scanning direction of the reproduction light. In particular, if the width of the raw material is large, the direction of the molecular orientation axis is largely different, so that a plurality of optical cards having different punching positions have different reproduction outputs. Note that this output fluctuation is caused by a change in the polarization state when the reproduction light is reflected by the medium, and therefore occurs not only in the reproduction light of linear polarization but also in the reproduction light of circular polarization or elliptically polarization.

According to ISO / IEC11694-3, in an optical card,
It is stipulated that the variation in reflectance must be suppressed to 10% or less of the average reflectance. Therefore, it is sufficient that the fluctuation of the reproduction output is 10% or less of the average reproduction output.

According to the present invention, when a stretch-formed film, particularly a biaxially stretched film is used as a transparent substrate, a sufficiently large reproduction output and a fluctuation in the reproduction output are reduced by using a molecular orientation axis and a card. When the angle with the long side is represented by θ (0 ≦ θ ≦ 90 °), the transparent base material is punched from the stretch-formed film so that the angle θ is 20 ° or less in the recording area of the optical card. The reproduction output of the optical card of the present invention depends on the angle between the plane of polarization of the reproduction light (in the case of linearly polarized light; in the case of circularly polarized light, the plane of polarization of the linearly polarized light component) and the molecular orientation axis of the transparent substrate. for that reason,
In reproducing information from the optical card of the present invention, when the molecular orientation axis of the optical card is parallel to the long side of the optical card, that is, θ
When = 0 °, an optical head having a polarization system that can obtain the highest reproduction output is used. This makes it possible to suppress the reproduction output fluctuation due to birefringence to 10% or less of the average reproduction output within one card and between a plurality of cards, and to obtain a sufficiently high reproduction output.

Although the molecular orientation axis in the biaxially stretched formed film exists in two directions, in the present invention, it is sufficient that the angle θ is 20 ° or less in one of the molecular orientation axes.

The distribution of molecular orientation axes in the plane of the transparent substrate can be measured by an optical measurement method, for example, ellipsometry. Specifically, it can be measured by irradiating a linearly polarized laser beam to the transparent substrate and examining the polarization state of the reflected light or transmitted light. Strictly speaking, the direction of the molecular orientation axis determined by this measurement is an average value in the beam spot of the laser beam used for the measurement. In this specification, this is simply referred to as the direction of the molecular orientation axis. The beam spot diameter of the laser beam is preferably equal to the beam spot diameter of the laser beam used for reproducing the optical card.

In order to reduce the total thickness of the optical card and obtain sufficient flexibility, it is preferable that the backing substrate be formed of a stretched film in addition to the transparent substrate. However, it was found that when both substrates were composed of stretch-formed films, curling was likely to occur in the optical card. The stretched film has a distribution of the heat shrinkage in the in-plane direction depending on the molecular orientation axis. Therefore, when laminating a transparent substrate and a backing substrate, both made of stretch-formed films, if the direction of the molecular orientation axis is shifted between the two substrates, heat shrinkage occurs during cooling after lamination. A stress is generated due to the distribution of the ratio, and the stress causes a twist (twist) in the optical card, thereby curling the optical card. This curl increases as the heating temperature during thermal lamination increases. On the other hand, in the present invention, twisting of the card is prevented by laminating the transparent base material and the backing base material such that their average molecular orientation axes are substantially aligned. The maximum curl amount at the four corners of the optical card can be reduced to less than 1.5 mm by setting the deviation of the average molecular orientation axis of both substrates to 10 ° or less. In the biaxially stretched film, the average molecular orientation axis extends in two directions. Therefore, when using a biaxially stretched film, it is necessary to make the deviation between the transparent substrate and the backing substrate 10 ° or less for each of the two average molecular orientation axes.

In determining the deviation of the molecular orientation axis between the two substrates, the direction of the molecular orientation axis obtained by the above-described optical measurement is not used, but the direction of the molecular orientation axis obtained by the acoustic measurement is used. In the acoustic measurement, the direction of the molecular orientation axis is determined by measuring the distribution of the sound wave propagation velocity in the plane of the transparent substrate or the backing substrate in all directions. Thus, acoustic measurements can be performed even when the substrate is opaque. In the acoustic measurement, unlike the optical measurement, an average direction of the molecular orientation axis in the substrate surface is obtained instead of the distribution of the molecular orientation axis in each position in the substrate surface. In the present specification, the molecular orientation axis determined by acoustic measurement is referred to as an average molecular orientation axis. In addition, for the acoustic measurement, for example, a measuring device using an ultrasonic wave (for example, a supersonic tester manufactured by Nomura Corporation) can be used.

In order to reduce the curl of the optical card when both substrates are formed from stretch-formed films, it is preferable to reduce the heat shrinkage of both the transparent substrate and the backing substrate. If both the transparent base material and the backing base material have a maximum thermal shrinkage of 0.5% or less, the maximum curl amount at the four corners of the optical card can be less than 1.5 mm. In order to reduce the heat shrinkage of the stretched film to 0.5% or less,
The films may be annealed in advance and bonded. The heat shrinkage rate limited in the present invention is JIS C231
This is the heat shrinkage specified in 8-72. In addition, the heat shrinkage of the substrate made of the biaxially stretched molded film differs between the width direction and the longitudinal direction in the state of the long film before the substrate is punched into a card shape. Therefore, in the present invention, the heat shrinkage in both directions is set to 0.5% or less, that is, the maximum heat shrinkage is set to 0.5% or less.

If the control of the deviation of the average molecular orientation axis in both substrates and the control of the heat shrinkage in both substrates are performed together, the curl of the optical card can be further reduced.

Hereinafter, the specific structure of the optical card of the present invention will be described with reference to the drawings.

FIG. 1 shows a configuration example of the optical card of the present invention. This optical card has a transparent substrate 1, a recording layer 2 containing an organic dye, an adhesive layer 3, and a backing substrate 4 in this order. This optical card first has a recording layer 2 on a transparent substrate 1.
Is formed, and then an adhesive layer 3 is provided between the recording layer 2 and the backing substrate 4 and bonded to each other.

A stretch-formed film is used for the transparent substrate 1. The transparent base material is preferably a material having high transparency to a laser beam for recording and reproduction, and from the viewpoint of portability and the like, a material having high solvent resistance, high tensile strength and high impact strength is preferable. . Specifically, for example, polypropylene, polyvinyl chloride, polyethylene, polystyrene,
PET, PEN, PC and the like are preferred. The stretching method may be any of uniaxial stretching and biaxial stretching. However, from the viewpoint of high mechanical strength, relatively low cost, excellent solvent resistance, etc., PE
A biaxially stretched T or PEN film is preferred.

The transparent substrate may contain an antistatic agent, a UV absorber and the like. Also, a multilayer structure in which a primer layer or the like for adhering the adjacent layers is laminated may be used. The thickness of the transparent substrate may be appropriately determined in consideration of the refractive index of the transparent substrate and the spot diameter of the recording / reproducing laser beam. However, in order to obtain sufficient flexibility, the thickness is preferably set to 500 μm or less, while, in order to obtain sufficient mechanical strength, the thickness is set to 50 μm.
It is preferably at least μm.

The organic dye contained in the recording layer 2 is a material that forms pits by photothermal conversion by irradiation with a laser beam. The organic dye used is not particularly limited, and may be, for example, any of triphenylmethane, polymethine, porphine, indanthrene, quinone, and dithiol. A quencher or the like may be added to the recording layer to improve light resistance. The thickness of the recording layer is
What is necessary is just to determine suitably according to the optical characteristic of the organic dye used so that high S / N may be obtained. However, since the optical card of the present invention has flexibility, the thickness of the recording layer is desirably 100 nm or less in order to suppress cohesion and destruction of the organic dye. The method for forming the recording layer is not particularly limited. For example, an organic dye is dissolved in various solvents such as aqueous, alcohol, ketone, amine, ester, ether, and hydrocarbon solvents, and roll coating, spin coating, A method of applying by a spray coat or the like can be used, and a vacuum evaporation method can also be used.

The adhesive layer 3 is provided for bringing the recording layer 2 and the backing substrate 4 into close contact with each other. It is desirable that the constituent material of the adhesive layer has no problem with light resistance and heat resistance and does not lower the recording / reproducing characteristics of the recording layer. For example, various thermoplastic resins such as acrylic, polyurethane, polyester, and epoxy are used. it can. The resin used for the adhesive layer desirably does not have tackiness in the range of room temperature to about 50 ° C. in order to avoid troubles in the adhesive layer forming step, the card productizing step, and the card storing step. Also, 80 to 13
It is desirable that a material having sufficient adhesion to the adherend surface be obtained by heating at about 0 ° C. Various additives such as a pigment may be mixed in the adhesive layer. The thickness of the adhesive layer may be appropriately determined so as to obtain sufficient adhesion, but is preferably 1 to 20 μm, more preferably 3 to 20 μm. If the adhesive layer is too thin, sufficient adhesion strength cannot be obtained. On the other hand, if the adhesive layer is too thick, the flexibility of the adhesive layer is so low that it cannot follow the optical card when it is bent, and as a result cracks tend to occur in the layer. The adhesive layer may be in the form of a sheet in advance, or may be coated on at least one of the adhered surfaces. As a coating method,
For example, roll coating, spin coating, curtain flow coating, spray coating and the like can be used. The resin used for the coating method may be any of a solution type, an emulsion type, a hot melt type and the like.

The constituent material of the backing substrate 4 is not particularly limited. However, in order to obtain sufficient flexibility by reducing the total thickness of the optical card, it is preferable to use a stretch-formed film for the backing substrate as well as the transparent substrate. Further, in order to reduce the curl of the card, it is preferable that the backing substrate and the transparent substrate are made of the same kind of resin. Various additives such as an antistatic agent may be contained in the backing substrate. Also, a multilayer structure in which a primer layer or the like for adhering the adjacent layers is laminated may be used. Like the transparent substrate, the thickness of the backing substrate is preferably 50 to 500 μm in order to secure sufficient flexibility and sufficient mechanical strength. If the transparent base material and the backing base material have the same thickness, the warpage of the card can be reduced. Also, in this case, the recording layer is located at the center in the thickness direction of the card, so that the bending of the recording layer when the card is bent is compared to the case where the position of the recording layer is biased to one side in the thickness direction. Is reduced, and as a result, recording layer destruction due to card bending can be suppressed.

In order to improve the scratch resistance of the light incident surface of the card and to improve the shock resistance and chemical resistance of the card, as shown in FIG. It is preferable to provide the coat layer 5. The hard coat layer may be made of, for example, various resins such as silicone, acrylic, and fluorine. The hard coat layer is
It may be formed by various coating methods such as roll coating, spin coating, spray coating, etc., or a vacuum evaporation method.

When writing the index or content of the information recorded on the optical card as characters or images, it is preferable to provide an image forming layer 6 on the surface of the backing substrate as required, as shown in the figure. The image forming method can be selected without particular limitation as long as it does not affect the recording layer.For example, any one of thermal transfer recording, sublimation transfer recording, ink jet recording, electrophotographic recording, coloring type thermal recording, reversible thermal recording, etc. There may be. The constituent material of the image forming layer may be appropriately determined according to the image forming method to be used. For example, when a color material receiving type system such as thermal transfer recording, sublimation transfer recording, ink jet recording, and electrophotographic recording is used, a resin or filler whose acceptability and absorptivity are adjusted according to the color material characteristics may be selected. I just need. In the case of using a self-coloring system such as a coloring type thermosensitive recording and a reversible thermosensitive recording, a constituent material may be selected according to a coloring function, and a multilayer structure may be used if necessary. The thickness of the image forming layer is usually 0.1 to 2
Preferably, the thickness is about 0 μm.

Next, a method for manufacturing the optical card of the present invention will be described. The optical card is manufactured by laminating a transparent substrate 1 provided with a recording layer 2 and a backing substrate 3. However, the transparent base material 1 and the backing base material 3 are not punched in advance to have a card shape and card dimensions, but are usually punched into a card shape after bonding. In the following description, the transparent base material and the backing base material before bonding are referred to as a raw material.

It is preferable that the raw material of the transparent base material and the raw material of the backing base material are annealed before the bonding step. This annealing is a heat treatment for reducing the thermal shrinkage of both substrates as described above. The annealing temperature is
It is desirable that the temperature be equal to or higher than the heating temperature during lamination. Annealing may be performed before or after the formation of the recording layer or the like. The thermal contraction rate of the raw material before annealing is 2
In the case of axially stretched PET stock, 0.2 to 0.3 in the width direction
%, About 3% in the longitudinal direction, and after heat treatment, hardly changes in the width direction, and decreases to about 0.2% in the longitudinal direction.

At the time of lamination, the two raw materials are overlapped so that the angle between the average molecular orientation axis of the raw material of the transparent substrate and the average molecular orientation axis of the raw material of the backing substrate is 10 ° or less. Is preferred. The reason is as described above. The bonding means desirably applies heat and pressure simultaneously in order to obtain a sufficient adhesive force. For example, a press or a roll press while heating can be used. The laminating temperature is preferably set to be about 80 to 130 ° C.

After the bonding, the original optical card is punched into a card shape by using a punching die having a plurality of punching patterns corresponding to the card shape (rectangle) to obtain a plurality of optical cards. At this time, punching is performed so that the angle θ between the long side and the molecular orientation axis is 20 ° or less in each optical card.
If the angle between the molecular orientation axis and the length direction of the raw material is within 20 ° in the entire width direction of the raw material, the long side of each punched pattern is parallel to the length direction of the raw material. May be punched. In the biaxially stretched film,
If the angle between the molecular orientation axis generated by stretching in the width direction of the raw material and the width direction of the raw material is within 20 °, the long side of each punched pattern is parallel to the width direction of the raw material. You may punch out so that it becomes.

However, when a relatively wide raw material is used, the angle between the length direction of the raw material or the width direction of the raw material and the molecular orientation axis may exceed 20 °. In that case,
Punching is preferably performed using the method described below.

As shown in FIG. 2, in the optical card raw material 10 in which the transparent base material is a stretch-formed film, particularly a biaxially stretch-formed film, the optical card is produced by stretching in the longitudinal direction (vertical direction in the figure) of the raw material. The molecular orientation axis extends radially around the longitudinal direction of the raw material. Therefore, as shown in FIG. 2, if a punching die in which the long sides of the punching pattern are arranged radially is used, the angle θ between the direction of the molecular orientation axis at the punching position and the long side of each punching pattern 20 is punched out. In addition, it is possible to fit within 20 ° in all the optical cards, and it is also possible to make θ of each optical card substantially equal. Therefore, if such a punching die is used, even if a wide web is punched at once, it is possible to suppress variations in reproduction output among all punched optical cards.

Although not shown, when the raw material is a biaxially stretched film, the molecular orientation axis generated by stretching the raw material in the width direction is radially centered on the raw material in the width direction. Extending. Therefore, when applying the present invention paying attention to the molecular orientation axis in this direction, the punching pattern shown in FIG.

In addition to the method shown in FIG. 2, the method shown in FIG. 3 can also be used. In this method, the raw material is divided into two by a cutting plane parallel to the longitudinal direction to obtain two divided raw materials 11 and 12, and a punching die in which the long sides of each punching pattern 20 are parallel to each other is used. The split raw material 11 is punched out while the other split raw material 12 is turned upside down. If the divided raw material 12 is turned over, the molecular orientation axis distributions of the two divided raw materials 11 and 12 are substantially the same. Therefore, as in the case of punching a relatively narrow raw material, it is easy to set θ in each optical card to within 20 °.

As described above, the present invention has been described with reference to the typical example. However, a configuration in which a metal reflective layer is provided between the recording layer and the adhesive layer may be adopted. Further, a diffusion preventing layer may be provided between the recording layer and the adhesive layer in order to prevent the recording layer constituent material from diffusing into the adhesive layer and prevent the recording layer from deteriorating. The diffusion preventing layer is formed by directly applying a resin or a solution thereof on the recording layer. Therefore, it is preferable not to use a solvent for dissolving the organic dye contained in the recording layer as a paint for forming the diffusion prevention layer, and specifically, it is preferable to use an aqueous paint containing an aqueous resin. The aqueous resin is not particularly limited as long as water can be used as a solvent, and may be a water-soluble resin or an emulsion resin. As the resin type, for example, acrylic, polyurethane,
Any of epoxy type, polyester type and the like may be used. Further, a configuration may be adopted in which a buffer layer for improving recording sensitivity is provided.

[0042]

Next, an embodiment of the present invention will be described.

Example 1 Optical card No. 101 An optical card having the structure shown in FIG. 1 was manufactured by the following procedure. However, the image forming layer 6 was not provided. In the transparent substrate 1,
Biaxially stretched molded film provided with a hard coat layer 5 (transparent PET having a thickness of 100 μm: tough top manufactured by Toray Industries, Inc.)
It was used. Next, on the surface of the transparent substrate 1 opposite to the surface on which the hard coat layer 5 is formed, a cyanine dye (manufactured by Hayashibara Biochemical Laboratory Co., Ltd .: NK1414) is applied by spin coating, and a recording layer having a thickness of 0.1 μm is formed. 2 was formed. As the backing substrate 4, a biaxially stretched formed film (white PET having a thickness of 100 μm: E20 manufactured by Toray Industries, Inc.) was used. Vinyl acetate modified resin (Nippon Synthetic Chemical Co., Ltd.)
(Corponyl 102X) was applied to form an adhesive layer 3 having a thickness of 5 μm. Next, the recording layer 2 and the adhesive layer 3 were bonded so as to face each other. At the time of bonding, heating was performed so that the temperature of the adhesive layer became 100 ° C. Finally, an optical card having a total thickness of 208 μm was obtained by punching out a card so that the angle θ formed between one of the two molecular orientation axes of the transparent substrate 1 and the long side of the card was 5 °. In addition, the direction of the molecular orientation axis was measured by ellipsometry. No distribution of molecular orientation axes was observed in the card, and θ was 5 ° over the entire area of the card.

An optical card was manufactured in the same manner as in the optical card No. 101, except that the optical card No. 102 to No. 105 were punched out so that θ became the value shown in Table 1.

Evaluation The reproduction output of each of the above optical cards was measured. Table 1 shows the results. The playback output shown in Table 1 is based on the optical card N
This is a relative value when the reproduction output of o.101 is 1.

FIG. 4 shows an optical system used in the present embodiment as an example of the reproducing apparatus for evaluation. The polarizing beam splitter (PBS) used in this optical system is a special one called SBS, which transmits 75% of the P component, reflects 25%, and reflects 100% of the S component and does not transmit. This P
The incident light is incident on the card as linearly polarized light of the P component by the BS. The return light polarized by the card has its S component returned to the detector at 100% and its P component returns to the detector at 25%. Therefore, the S component of the return light is dominant in the reproduction output. In this reproducing apparatus, by adjusting the relationship between the direction of the plane of polarization of the linearly polarized light of the reproducing light and the scanning direction of the incident light, the reproducing is performed when the angle θ between the long side of the card and the molecular orientation axis is 0 °. The output is set to be the highest.

[0047]

[Table 1]

As shown in Table 1, by setting θ to 20 ° or less in each card, a sufficiently high reproduction output can be obtained in each card, and the reproduction output fluctuation between the cards can be reduced by the average reproduction output (0.91 in Table 1). ) Can be suppressed to 10% or less.

In each of the above optical cards, the maximum thermal shrinkage of the transparent substrate was 0.5%, and the maximum thermal shrinkage of the backing substrate was 0.2%. In each optical card, the angle between the direction of the average molecular orientation axis of the transparent substrate and the direction of the average molecular orientation axis of the backing substrate is 10 ° or less in any of the two average molecular orientation axes. Was. The average molecular orientation axis was measured by a supersonic tester of Nomura Corporation.

Example 2 The temperature of the adhesive layer was set to 100 ° C. during lamination of optical cards No. 201 to No. 206, and the average molecular orientation axis of the transparent substrate and the average molecular orientation axis of the backing substrate were adjusted . Optical card No. 101 of Example 1 was used except that both substrates were bonded so that the displacement became the value shown in Table 2.
In the same manner as in the above, an optical card was produced. In each optical card, the average molecular orientation axis exists in two directions substantially orthogonal to each other, but the deviation of the average molecular orientation axis in these two directions was almost the same.

Evaluation The curl amounts at the four corners of each of the above optical cards were measured.
Table 2 shows the results.

[0052]

[Table 2]

From Table 2, it can be seen that curling of the card can be reduced by setting the difference between the average molecular orientation axis of the transparent substrate and the average molecular orientation axis of the backing substrate to 10 ° or less.

Example 3 Optical card No. 301 except that a diffusion preventing layer was provided between the recording layer and the adhesive layer.
An optical card having the same structure as that of was manufactured by the following procedure. As the transparent substrate 1, a biaxially stretched film provided with an easy-adhesion layer (transparent PET having a thickness of 100 μm: tough top manufactured by Toray Industries, Inc.) was used. The backing substrate 4 has a 2
Axial stretched white PET film (E08J manufactured by Toray Industries, Inc.,
(Thickness: 100 μm) was used. The transparent substrate 1 is at 100 ° C.
0.5% by heat annealing for 30 minutes
And The backing substrate was annealed at 150 ° C. for 30 minutes to have a heat shrinkage of 0.2%. The recording layer 2 was formed in the same manner as in Example 1. The diffusion preventing layer was formed by spin-coating the surface of the recording layer 2 with a thickness of 1 μm of Joncryl J63 manufactured by Johnson Polymer Co., Ltd. The adhesive layer 3 was formed in the same manner as in Example 1. At the time of bonding, the adhesive layer 3 was heated to a temperature shown in Table 3 to obtain five types of cards having different bonding temperatures. Further, upon bonding, the deviation between the average molecular orientation axis of the transparent base material and the average molecular orientation axis of the backing base material was set to 10 ° or less.

Optical card No. 301 except that the maximum thermal shrinkage of the backing substrate was changed to the value shown in Table 3 by changing the annealing conditions of optical cards No. 302 to No. 303.
In the same manner as in the above, an optical card was produced.

Evaluation The curl amounts at the four corners of each of the above optical cards were measured.
Table 3 shows the maximum curl amount of each card.

[0057]

[Table 3]

From Table 3, it can be seen that the maximum thermal shrinkage of both the transparent substrate and the backing substrate is 0.5% or less, and
It can be seen that curling when laminated in a temperature range of 130 ° C. can be reduced.

[0059]

According to the present invention, the stretch-formed film is used as a transparent substrate of an optical card or a backing substrate thereof. Since the stretch-formed film has high mechanical strength, the optical card can be made thin. Therefore, according to the present invention, an optical card having flexibility and excellent portability can be provided.
Further, unlike injection molding, in stretch molding, PET having good solvent resistance can be used, so that when a recording layer containing an organic dye is formed by a coating method, the selection range of the solvent is widened.
Further, the stretch-formed film can be used in the form of a roll, and therefore, the recording layer, the adhesive layer and the like can be roll-coated. The roll coating is superior in mass productivity as compared with a conventionally used single-wafer spin coating, so that a low-cost optical card can be provided.

Further, in the present invention, problems when the transparent base material or the backing base material and the backing base material are formed from a stretch-formed film, that is, variation in reproduction output between a plurality of cards and twisting of the cards can be reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a configuration example of an optical card of the present invention.

FIG. 2 is a plan view showing a raw material of an optical card using a transparent substrate made of a biaxially stretch-formed film and a card punching die.

FIG. 3 is a plan view showing a raw material of an optical card using a transparent substrate made of a biaxially stretched molded film and a card punching die.

FIG. 4 is a schematic diagram showing an optical system of an optical card evaluation reproducing apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Transparent base material 2 Optical recording layer 3 Adhesive layer 4 Backing base material 5 Hard coat layer 6 Image forming layer 10 Raw optical card 11, 21 Split raw material 20 Punched pattern

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Rei Takeuchi 1-5-1, Taito, Taito-ku, Tokyo Tokyo Magnetic Printing Co., Ltd. F-term (reference) 2H111 EA14 FA01 FA15 FA35 FA39 FA45 FB42 5B035 AA07 AA08 BA05 BB04 BC00 5D029 JA04 KC14 TA08 TA10 5D121 AA02 DD13 DD17 GG24

Claims (7)

[Claims] 1. A rectangular optical card having at least a transparent base material, a recording layer containing an organic dye, an adhesive layer, and a backing base material in this order, wherein the transparent base material is composed of a stretch-formed film, In the base material, the angle between the long side and the molecular orientation axis is θ (0 ≦ θ ≦
90 °), the optical card satisfies θ ≦ 20 ° at least in the recording target area of the transparent substrate. 2. The optical card according to claim 1, wherein the backing substrate is composed of a stretch-formed film, and the angle between the average molecular orientation axis of the transparent substrate and the average molecular orientation axis of the backing substrate is 10 ° or less. 3. The light according to claim 1, wherein the backing substrate is composed of a stretch-formed film, and both the maximum thermal shrinkage of the transparent substrate and the maximum thermal shrinkage of the backing substrate are 0.5% or less. card. 4. A method for producing a rectangular optical card having at least a transparent substrate, a recording layer containing an organic dye, an adhesive layer, and a backing substrate in this order, wherein the transparent substrate is formed from a stretch-formed film. When punching a plurality of optical cards from a long raw material using a punching die in which a plurality of rectangular punching patterns corresponding to the shape of the optical card are arranged, the long side or the short side of the punching pattern is A method for manufacturing an optical card using radially arranged punching dies. 5. A method for producing a rectangular optical card having at least a transparent substrate, a recording layer containing an organic dye, an adhesive layer, and a backing substrate in this order, wherein the transparent substrate is formed from a stretch-formed film. When punching a plurality of optical cards from a long raw material using a punching die having a plurality of rectangular punching patterns corresponding to the shape of the optical card, the raw material is cut parallel to the longitudinal direction. The raw material is divided into two by the surface, and two raw materials are obtained. One raw material is punched out by a punching die in which the long side or the short side of each punched pattern is parallel to each other, and the other raw material is made with the longitudinal direction as an axis. A method for producing an optical card, wherein the optical card is punched out by the punching die in a state where the sheet is turned upside down. 6. In a transparent base material, when an angle between a long side and a molecular orientation axis is θ (0 ≦ θ ≦ 90 °), an original film is formed so that θ ≦ 20 ° in all optical cards. 6. The method for manufacturing an optical card according to claim 4, wherein the optical card is punched. 7. The method for manufacturing an optical card according to claim 4, wherein the optical card according to claim 1 is manufactured.