JPH02251495A - Optical card and preparation thereof - Google Patents

Abstract

PURPOSE:To obtain an optical card having high durability and excellent in mass productivity and having the good reproducibility of unevenness by forming the advance data region on a data recording surface as a recessed or protruding part and specifying the angle of inclination formed by the inclined surface constituting a V-shaped recessed or protruding part and the normal line of the data recording surface to specify the bending of the optical card. CONSTITUTION:Unevenness 5 is formed to the surface of an optical card 1 to record advance data. As the unevenness 5, recessed parts are formed or protruding parts are formed in a chevron-shape. Each of the chevron-shape protruding part 20 provided to the data region 9 present on the data recording surface 7 of the first base material 29 is provided so that the wall surface thereof is formed into an inclined surface 6 and the angle theta of inclination formed by the inclined surface 6 and the normal line A of the data recording surface 7 is formed so as to become 15-85 deg. over 50% or more of the total inclined surface. When the optical card 1 is placed on a support stand of a fulcrum-to-fulcrum distance of 20mm and load of about 15kg is applied to the optical card 1 at the almost central part between fulcrum points by a press wedge (prescribed in JIS K7203), the bending of the optical card 1 is 2mm or more. Therefore, the optical card having high durability and performing stable recording and reproduction even when accuracy forming the height or width of unevenness is slightly inferior is obtained.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an optical card that records or reproduces information using a light beam and a method for manufacturing the same, and is particularly suitable for use in a business card-sized optical card. be.

[Conventional technology]

In recent years, optical cards, which optically record and reproduce information, have been attracting attention as portable, large-capacity information recording media that are about the size of business cards. It is.

Such an optical card is, for example, Special Publication No. 58-500437.
As disclosed in the above publication, there is a recording surface on the surface, and a recording film for light reflection is provided on this surface. Then, predetermined information is recorded by forming irregularities such as pits on this recording film.

Recording films for optical cards include, for example, films in which silver particles are dispersed in a gelatin matrix, metal thin films such as tellurium and bismuth, organic thin films such as polystyrene and nitrocellulose, dye thin films such as cyanines and metal diorade complexes, Alternatively, a low tellurium oxide film using phase transition has been proposed. Then, predetermined information is recorded by irradiating the surface of this recording film with a light beam, for example, a laser beam, and carving minute pits on the order of several microns as the unevenness.

Optical cards are generally classified into write-once optical cards that can record additional data and read-only optical cards that can only be read, but in both cases, the recording film contains information such as address information and tracking control information. Some of them are pre-recorded. To reproduce this, a light beam is irradiated and the change in the amount of reflected light, that is, the contrast is read.

Optical discs have already been put into practical use as such optical information recording media. In many cases, at least a portion of information is pre-recorded on the information recording layer of an optical disc during its manufacture.

The pre-recorded information may be all the information, but it may also be information such as an address or part of the information ring for tracking control, for example, to control the operation of the optical head of the recording/reproducing device.

There is a method that utilizes unevenness with a rectangular cross section as minute pits with different reflectances on the recording surface based on the information recorded in advance.

There are the following methods for playing back optical discs. That is, predetermined information is recorded with the height of the unevenness provided on the recording film of the optical disk set to 1/4 or 1/8 of the wavelength of the laser beam, and during reproduction, the laser beam is irradiated onto the uneven portion of the recording film, and the height of the unevenness is set to 1/4 or 1/8 of the wavelength of the laser beam. There are two methods: one method reads the contrast caused by the interference effect due to the phase difference of the reflected light, and the other method irradiates the uneven portion of the recording film with a light beam and reads the contrast caused by the scattering effect of the reflected light due to the unevenness.

Therefore, the above-mentioned two methods can also be employed when reproducing an optical card.

To make such an optical disc, first, a stamper is made, such as a metal plate whose surface is patterned with irregularities based on the above information, and then this stamper is used to perform injection molding, 2P method, press A transparent copy board was created by transferring the above pattern using a method, etc., and the S! It is manufactured by applying a reflective film that also serves as a film, and applying a treatment to the other surface of the reflective film to protect the film.

An optical card in which all or part of information is recorded in advance by providing unevenness on the recording film surface has a structure very similar to the above-mentioned optical disk, and therefore can be manufactured using the above-described optical disk manufacturing method.

[Problem to be solved by the invention]

Unlike the optical disks mentioned above, optical cards are carried and used in the same way as conventional magnetic cards such as cash cards, and external mechanical forces such as bending and pressing are constantly applied to them. . For this reason, the shape of the unevenness provided on the recording film of the optical card may be permanently deformed, or
Furthermore, there is always a risk that the unevenness or the recording film itself may be damaged. Therefore, durability against external mechanical forces must be increased. Furthermore, since optical cards are exposed to environments such as high temperature and humidity, water, detergents, and alcohol, they are required to have characteristics that can withstand these conditions. In addition, in order to be used for general purposes, it must be possible to provide it at a low price. However, since conventional optical discs have a rectangular cross-section of the unevenness, there is a need to balance the width of the unevenness with the laser spot diameter of the optical head of the recording/reproducing device, and the deviation of the laser spot of the optical head of the recording/reproducing device from the track center. Depending on the amount, etc., the ratio of the amount of reflected light between areas with and without unevenness, that is, the contrast, is influenced. Therefore, the shape of the unevenness requires strict precision not only in height but also in width and length. In particular, the above-mentioned ratio of the laser spot diameter to the width of the unevenness has a narrow range that is preferable for recording and reproduction, and the contrast sharply decreases on either side of this narrow range. Therefore, the unevenness of such a shape must be made with very high precision. For this reason, if an optical card is made using conventional optical disk technology, the molding conditions must be made stricter in order to improve the reproducibility of the unevenness on which prior information is recorded, for example.

Therefore, mass production has been difficult, and there has been a limit to cost reduction.

In view of the above-mentioned problems, the present invention provides a light beam that provides high durability, stable recording and reproducing performance, has a wide tolerance range for accuracy, is suitable for mass production, and has good reproducibility of unevenness. The purpose is to provide a card and its manufacturing method.

[Means to solve the problem]

In the optical card according to the present invention, the pre-information area on the information recording surface that is read by a light beam is formed as a concave portion or a convex portion. In order to protect the first base material on which the information recording surface is formed and the recording mark made of the metal thin film formed on the information recording surface,
a second base material provided on the base material, the recessed portion is formed in a V-shape, or the convex portion is formed in a mountain shape, and the V-shaped four parts or the mountain shape The angle of inclination between the inclined surface constituting the convex portion and the normal line of the information recording surface is 15° or more and 85° or less on 50% or more of the entire inclined surface, and the optical card is held at a distance between fulcrums of 20°.
Place it on a support stand (JIS K7203 standard) of mm and insert a pressure wedge (JIS K72
03 regulations), the deflection is 2 am or more when a load of approximately 15 kg is applied.

In addition, in the method of manufacturing an optical card, in which the pre-information area on the information recording surface to be read by a light beam is formed as a concave or convex portion, (a) coating a photosensitive resin on the substrate; (b) partially exposing the photosensitive resin layer in accordance with the prior information recorded in the prior information area; (c) partially exposing the above. Develop the photosensitive resin and perform post-processing as necessary to form a sloped surface on the photosensitive resin layer with an inclination angle of 15° or more and 85'' or less with respect to the normal line of the substrate at 50% or more of the total sloped surface. (d) manufacturing a stamper using the substrate with the unevenness formed on the photosensitive resin layer; and (e) manufacturing a replica of an optical card using the stamper. Equipped with

[Effect]

The recording film formed on the information recording surface on the first base material is protected by the second base material. In addition, the cross-sectional shape of the unevenness formed on the optical card for recording advance information is made into a V-shape or mountain-like shape with an inclination of 156 degrees or more and 85 degrees or less on 50% or more of the total slope. To widen the permissible range of precision for width and to prevent the contrast between a portion with unevenness and a portion without unevenness from changing much depending on the amount of deviation of a light beam spot from the track center during reproduction.

When the optical card in the above test has a deflection of 2 mm or more, the optical card follows the bending well, and the card itself has good durability against external mechanical forces. Since the optical card has sufficient flexibility and the cross-sectional shape of the unevenness is formed as described above, the unevenness does not easily become permanently deformed even if it is bent during carrying, for example. Good stability against external mechanical forces. In addition, since the unevenness having an inclined surface of 15° or more and 85° or less on 50% or more of all inclined surfaces has good reproducibility of shape, it is possible to loosen the conditions when manufacturing stampers and replicas. Mass production becomes possible.

〔Example〕

FIG. 1 is a plan view showing an embodiment of the optical card of the present invention, and FIG. 2 is an enlarged view of the portion indicated by the arrow ■ in FIG. As shown in FIGS. 1 and 2, the optical card 1 is about the size of a business card, that is, for example, 85 m5 wide and 54 square meters long. Further, the thickness may be approximately 0.1 to INIA, and in this embodiment, it is formed to be 0.8 mm. Then, irregularities 5 are formed on the surface to record prior information. That is, the second
As shown in the figure, a large number of tracking tracks 3 are provided linearly in the longitudinal direction of the optical card 1 at regular intervals. Clock tracks 8 are provided intermittently in the center longitudinal direction of the area between the tracking tracks 3, and recording areas 4 are provided between the clock tracks 8 and each of the tracking tracks 3, respectively. In the figure, the pre-recorded area is indicated by 4a, and the additionally recorded area is indicated by 4b. The pre-recorded information is, for example, address information.

Further, the additionally recorded area 4b is flat so that necessary information can be written therein, and in the future, information will be recorded by forming pits in this recording area 4b using, for example, a laser beam.

In this embodiment, as the unevenness 5, a concave portion is formed in a V shape, or a convex portion is formed in a mountain shape. To explain the case of a mountain-shaped convex part, as shown in the convex shape explanatory diagram in FIG. 20 has a wall surface formed into an inclined surface 6. The inclination angle θ between the inclined surface 6 and the normal line A of the information recording surface 7 is determined by assuming that the entire inclined surface 6 of the mountain-shaped convex portion 20 is a smooth curve, and by calculating any position on the curve. This is the angle formed by the normal A and a tangent that can be drawn as a point of contact. Therefore, the inclination angle θ in this example is
It changes at each position of the inclined surface 6. That is, for example, a point a (b
) is 15° (θ1), and as it approaches the top (as θ gradually increases, the point a near the top
In (b'), θ is 85° (θ2). The slope 6 having an inclination angle θ in the range of 15°<θ<B5° occupies 85% of all the slopes from the point a to the point constituting the mountain-shaped convex portion 20. be.

Note that a fully sloped surface is defined as the slope angle θ at the bottom of a convex or concave portion.
Starting point is the part where the angle is 87° or less, go beyond the top of the convex or concave part from the starting point, and do the same at 87° at the other hem.
The end point is the part that reaches this point.

The V-shaped recess or mountain-shaped protrusion in this embodiment may have various shapes as long as the above conditions are met. for example,
Although a modified example is shown in FIG. 4, a mountain-shaped convex portion 20 having a substantially constant inclination angle θ may be used. Further, although another modification is shown in FIG. 5, a mountain-shaped convex portion 20 having a constant inclination angle θ and a flat portion 20a at the top may be used. Furthermore, there may be two or more convex portions or concave portions as described above in one information area.

By the way, the cross-sectional shape of the unevenness is made into a rectangular shape, and the height of these depressions or protrusions is set to 174 or 1/8 of the wavelength of the laser beam of the optical head of the recording/reproducing device. In the case of a method of reading information using the interference effect due to a phase difference, as described above, the shape of the unevenness requires strict precision not only in height but also in width and length. In particular, the ratio of the laser beam spot diameter to the width of the unevenness has a narrow range that is preferable for recording and reproduction, and around this narrow range, the contrast sharply decreases as the ratio increases or decreases.

However, in the case of the uneven shape of the present invention, the above-mentioned contrast does not change much, and therefore, the height and width of the above-mentioned unevenness do not require strict accuracy, so that efficient reproduction production is possible.

Furthermore, since high dimensional accuracy as mentioned above is not required, the optical card of the present invention is effective against bending, temperature and humidity changes, temporary deformation caused by chemicals, etc. when the optical card is used in a portable manner. .

On the other hand, when information is read mainly by utilizing the scattering effect on the recording surface of the light irradiated by the light beam of the optical head of the recording/reproducing device, the inclination angle θ of the wall portion of the uneven portion can be set to an arbitrary value. However, as a result of various experiments and studies conducted by the present inventors, the contrast is very good when the inclination angle θ is 25° or more and 75° or less;
It has become clear that if the angle exceeds 5°, the above-mentioned contrast that is practically sufficient cannot be obtained. - h inclination angle θ is 1
If the angle is less than 5°, the surfaces other than the wall portion and the information area 9 where the unevenness is formed are required to be extremely smooth, and the contrast is reduced due to slight deformation due to external force applied when carrying the device.

Further, the same applies when the above-mentioned inclination angle θ exceeds 85°.

Also, when reading information with a light beam, the information 'lfVtw
Although it is preferable that the amount of reflected light in the I region 9 be O, in reality it does not need to be O, and the contrast may be large enough to be readable by a recording/reproducing device. Rather, from the viewpoint of stability during portability and productivity, it is desirable that the top and bottom portions of the uneven portion 5 be somewhat gentle. As a result of various experiments, the shape of the uneven portion 5 has an inclination angle θ of 15° or more 85
It is not necessary for the walls below ° to cover the entire slope, but it is preferable that the wall covers 50% or more of the total slope, and 70% of the total slope.
It is particularly preferable if it is above.

FIG. 6 is a sectional view of the optical card 1 of FIG. 1 in which V-shaped recesses 19 are formed in the information area 9 as the unevenness 5, and the first base material 29, the recording film 31 made of a metal thin film, and Second
The base materials 32 are laminated in the above order. A V-shaped recess 19 that serves as a recess for the light beam L used for recording and reproduction is provided in the information area 9 on the first base material 29.

The recording film 31 preferably has high recording sensitivity (and high reflectance).As a result of various experiments, tellurium-selenium alloy, tellurium-selenium-lead alloy, tellurium-selenium-gold alloy, tellurium-selenium Alloys containing tellurium-selenium, such as selenium-platinum alloys, are preferred.

Tellurium-selenium-platinum alloy is particularly preferred because it has high durability against external mechanical forces and high temperature and high humidity. The thin film of the tellurium-selenium alloy described above is fragile, but in the case of this example, it can withstand bending that occurs when the optical card is used as a portable device, temporary deformation caused by changes in temperature and humidity, chemicals, etc. The film is less likely to be destroyed, and an optical card with good recording and reproducing performance can be obtained.

Note that the reflective film of an optical card in which all of the information is recorded in advance on the recording film surface is preferably made of a material that provides high reflectance, such as a metal thin film such as gold, silver, or aluminum. Among them, aluminum is particularly preferred because of its low cost.

The thickness of the recording film 31 is 100λ to 1500, and may be appropriately set so as to obtain an appropriate reflectance.

In the optical card 1 of this embodiment, one side of the recording film 31 is protected by the second base material 32, but in order to stably hold the optical card against various external forces received when carrying the optical card, , the first base material 29 needs to be a resin with good shape stability. The resin is preferably a polymer compound having a glass transition temperature of 60°C or higher, preferably 75°C or higher. As the polymer compound, polymethyl methacrylate, polyamide, acrylic acid/methacrylic acid copolymer, polycarbonate, polyester, polyolefin, polystyrene, etc. are used.

Furthermore, unless the second base material 32 is also selected appropriately, it will be difficult to obtain a good optical card even if the shape of the information area 9 and the recording film 31 are combined. As a result of experiments and studies on various materials, we found that using a softer material provides stable recording and reproducing characteristics against various external forces that are applied when carrying an optical card, and has good recording sensitivity. The shear modulus is 1. OX I O" dyn/am
``It has become clear that the following materials are preferable.Among the materials having the above dynamic shear modulus, urethane-based adhesives are particularly preferable, and silicone-based and acrylic-based adhesives are also preferable. The term "adhesive" refers to adhesives in a broad sense, including so-called adhesives.

As the substrate 33 applied to the recording film 31 via an adhesive, the above-mentioned polymer compounds can be used alone, or two or more types can be used in a stacked manner. If it is not on the light beam irradiation side of the head, a metal plate or the like can also be used.

Note that the surface of the optical card according to the present invention, that is, the first base material 2
Surface hardening N30 may be formed on each surface of the substrate 9 and the substrate 33 by a surface treatment that is normally performed on the surface of a resin or the like.

In particular, when applied to the surface of the first base material 29 on the side that is irradiated with the light beam of the optical head of the recording/reproducing device, effects such as improved wear resistance and prevention of UV transmission can be obtained. Furthermore, a metal plate or the like can be applied directly or via an adhesive to the surface that is not on the side irradiated with the light beam.

The optical card 1 configured as described above is placed on a support stand (JIS K7203 standard) with a distance between fulcrums of 20 m, and a pressure wedge (JIS K7203) is placed in the center between these fulcrums.
When a load of approximately 15 kg was applied (according to the regulations), the deflection was 5×1 or more, and returned to its original state when the load was removed, confirming T11 that the optical card had sufficient flexibility.

Next, information is written into the recording area 4b of this optical card l using a laser beam with a wavelength of 8300 m and a beam diameter of 4.5 μm at half width of the light intensity, and information including pre-recorded information is written on the optical card l. A reading test was conducted. In this case, pits were formed with a write power of 10 mW and a write time of 20 μs, and information was read with a read power of Q and 4 mW.

As a result, when reading information including pre-recording after additional recording has been written, reflected light is scattered in the V-shaped recess 19 for pre-recording, and the reflected light is scattered in the above-mentioned pits for additional recording. The reflective film disappeared and a sufficient contrast of reflected light was obtained in both cases, and the results were successful. There were also no problems with tracking.

Further, the optical card 1 was subjected to a bending test and a high temperature test. That is, a bending fatigue test was performed in which the optical card 1 was bent 20 meters in the long side direction and 10 m5 in the short side direction at a repetition rate of 30 times/minute, and the optical card 1 was bent 250 times each in the front direction and the back direction, for a total of 1000 times. was subjected to repeated bending deformation. In addition, an accelerated deterioration test was conducted in which the optical cart was held for 100 hours at a high temperature and humidity of 75° C. and 85% RH to examine the durability of the optical cart I.

As a result, when the external appearance of the optical card 1 was visually observed after the above two tests, it was found that each of the above-mentioned structural members (for example, recording) I! No cracks were observed in 31), and no changes in appearance were observed. Also, no change was observed in the writing and reading characteristics.

In addition, in order to compare with this example, the structure is similar to that of Example 1 described above, and the dynamic shear modulus of the material constituting the second base material 32 is 1 x to" dyn at 25°C.
The case of 7 cm" or more will be explained.

That is, three types of recordable optical cards 1 having second base materials 32 each made of three types of adhesives as shown in the table below are obtained. When writing was performed on the additional recording area 4b of the optical card 1 under the same conditions as in Example 1, the writing and recording was defective as shown in the table below.

Note that the dynamic shear modulus in the table below was determined under the same conditions as in Example 1.

As described above, the second base material 32 has a dynamic shear modulus of 25°C.
It can be seen that if the material is made of a material having a value of 1×10” dyn/− or more, the recording sensitivity decreases and additional recording cannot be written satisfactorily.

In order to manufacture an optical card with such a configuration, the present invention includes (a) a step of applying a photosensitive resin to a substrate, and (b) a step of prerecording information on the optical card with the photosensitive resin applied to the substrate. (c) The partially exposed photosensitive resin coated on the substrate is developed,
Alternatively, a step of performing development and post-processing to make the photosensitive resin develop unevenness having an inclined surface of 15e' or more and 85'' or less on 50% or more of the total inclined surface. (d) The above (a) to ( A step of manufacturing a stamper using the substrate obtained in step (c), and (e) a step of performing duplication processing using the stamper obtained in step (d) above. .

For the step (d) above, various conventional methods can be applied. For example, the developed substrate may be used as it is, or a thin film of metal or the like is formed on the photosensitive resin and then the resin stamper is used. Alternatively, a metal stamper can be manufactured by electroforming after forming a metal thin film on the photosensitive resin of the substrate after development, or if a metal is used as the substrate, a metal stamper can be manufactured by an etching method after development. Various methods can be applied, such as manufacturing. However, because the stamper completed in this process has already gone through the processes (a), (b), and (c), which will be described later, it has a pattern on its surface consisting of many fine irregularities. ing.

Various conventional methods can also be applied to the step (e) above. For example, using the stamper described above, a copy plate is created by transferring the above pattern by an injection molding method, a 2P method, a press method, etc., a reflective film that also serves as a recording film is applied to this, and other layers of this reflective film are added. A method is applied that consists of a series of steps in which the surface is treated to protect the film. Therefore, the characteristics of the manufacturing method of the present invention can be broadly classified as follows:
■Substrate coated with photosensitive resin in step (a) (
(hereinafter abbreviated as RM), the photosensitive characteristics (sensitivity) and/or development characteristics (sensitivity) of the photosensitive resin are adjusted, and mainly due to this, in the step (c). A method for producing fine irregularities with desired sloped surfaces.

■When partially exposing the RM photosensitive resin in the step (B), the light source is adjusted to increase or decrease the exposure energy, and mainly due to this, the desired slope is created in the step (C). A method for producing fine irregularities.

(2) A method in which the developing conditions are adjusted in the step (c) and, mainly due to this, fine irregularities having a desired slope are developed in the step (c).

■Processing after development, mainly due to this (c)
A method of developing fine irregularities with desired sloped surfaces in the process.

ΦThere is a method of using the above methods ■ to ■ in combination.

As method (2), for example, a photosensitive resin composition with high absorbance is used to create an RM consisting of a coating film thereof, and then the photosensitive resin layer of the RM is formed by the development treatment in the step (c) above. 15° or more and 85° on 50% or more of all slopes
It is possible to develop unevenness having the following inclined surfaces.

In addition, the RM is created using a photosensitive resin with low photosensitivity (sensitivity) and/or development characteristics (sensitivity), exposed for a long time, and the development process in step (c) above increases the photosensitivity of the RM. The resin layer has an angle of 15° or more on 50% of the total slope 8
It is possible to develop unevenness having an inclined surface of 5° or less.

As for method (2), for example, when performing so-called mask exposure, in which a mask is patterned with areas to be exposed and areas not to be exposed in accordance with the information recorded in advance on the optical card, the mask is tightly attached to the RM. Either the RM and the light source are placed at a certain distance apart from each other, or a light scattering plate is placed between the RM and the light source for exposure, and the development process in step (c) above completely coats the photosensitive resin layer of the RM. On 50% or more of the sloped surface, it is possible to develop unevenness having a slope of 156 or more and 85@ or less. In addition, when exposing the exposed portion of the RM using a laser cutting device in accordance with the information recorded in advance on the optical card, the exposure is performed while changing the laser power in the direction perpendicular to the optical vinyl scanning direction of the recording/reproducing optical head. By performing the development treatment in step (c) above, it is possible to cause the photosensitive resin layer of the RM to develop irregularities having an inclined surface of 15 @ or more and 85 @ or less on 50% or more of the total inclined surface.

As for the method (2), -i-wise, partially exposed RM
When developing, as the development progresses, the portion of the photosensitive resin that is removed progresses with a gradient in the thickness direction of the photosensitive resin coating, and the gradient becomes larger over time. Therefore, it is only necessary to track the progress of development and stop development when the slope reaches a suitable level. However, in general, the slope changes rapidly within a very short time after the start of development, so it is recommended to It is extremely difficult to stop development when mountain-shaped unevenness, in which the slopes of 85" or less account for 50% or more of the total slopes, appears over the entire surface of the RM. However, it is extremely difficult to stop the development when the above method By combining the measures taken in step (b), it becomes possible to control the slope, and the mountain-shaped unevenness, in which 50% or more of the total slope is sloped at 15° or more and 85° or less, extends over the entire surface of the RM. Development can be stopped at the point where it appears.

As mentioned above, no matter which method (1) to (2) is used, the resin layer of RM has a slope of 15° or more and 85° or more on 50% or more of the total slope.
It is possible to develop irregularities with slopes of less than 100°C. However, with general photoresists, if development is stopped at a halfway point in the residual film rate, the residual film rate tends to change due to fluctuations in the exposure amount, and reproducibility is difficult. In other words, photoresist is convenient for producing a rectangular cross-section with a slope close to a right angle with good reproducibility, but it is difficult to control the slope of the wall surface to be gentle and create a chevron-shaped bit. .

Therefore, the reproducibility is poor when desired unevenness is developed using methods ① to ②.

Moreover, when methods (1) and (2) are used, the developed pattern may have a trapezoidal cross section. If the cross section is trapezoidal, the conditions for molding into resin etc. will be stricter than when the cross section is arcuate. Figure 7 shows the glass transition temperature of 145 under the same conditions.
The cross-sectional shape when molded into a polycarbonate sheet at ℃ is shown.

In this case, molding was performed at a temperature of 140° C., a pressure of 100 kg/d, and a time of 1 minute. As is clear from FIGS. 7A and 7B, the plastic sheet 11 molded with the mold 10 having the convex portion 10a having an arcuate cross section is better than the plastic sheet 11 molded with the mold 12 having the convex portion 12a having a trapezoidal cross section. The molded plastic sheet 13 is better molded than the plastic sheet 13. In this case, the mold is only male, and the thickness of the plastic sheets 11 and 13 is the same as that of the mold 1.
This is much larger than the height of the arcuate or trapezoidal convex portions 10a and 12a of 0.12.

Note that when molding a plastic sheet, if the molding temperature is set above the glass transition point, the moldability will be good, but the sheet will tend to warp or warp. However, such problems can be avoided if molding is performed at a temperature slightly lower than the glass transition point. Therefore, as mentioned above, when the molding temperature is slightly lower than the glass transition temperature, a convex arcuate cross section is more advantageous than a trapezoidal cross section. Convex portions 10a and 1 having respective cross-sectional shapes shown in FIG. 7 above.
FIG. 8 shows a graph plotting the molding groove depth dl against the molding temperature when molding was performed using a mold 10.12 having a mold size 2a.

As is clear from FIG. 8, it is better to use the mold lO having the convex part 10a with an arcuate cross section, since the convex part 12 with a trapezoidal cross section is
It was possible to obtain results with a wider moldable temperature range and better reproducibility than when using the mold 12 having a.

Particularly, when a fine pattern must be formed on a thin plastic substrate of 0.7 mm or less, such as an optical card, injection molding is not easy, so it is preferable to press the pattern onto a plastic sheet. In this case, it is very effective for mass production that there is little change in performance due to variations in molding conditions. In this respect, an arcuate cross-sectional shape is advantageous.

It has been found that heat treatment after pattern formation is effective in obtaining the above-mentioned arcuate cross-sectional shape with good reproducibility. In other words, photoresists are generally heat-treated (bost-baked) at an appropriate temperature after development to remove residual solvent, but if this temperature is raised further, the corners are rounded and trapezoidal cross sections are formed. The temperature range in which the cross section becomes arcuate is near the softening point of the photosensitive resin. Commercially available positive resists were used in Figures 9 to 12 at 140°C, 135°C, and 130°C.
The results of shape measurement when heat treated at temperatures of 120°C and 120°C are shown.

As is clear from each figure, an arcuate cross-sectional shape could be easily obtained by heating to 140°C. Furthermore, since it is sufficient to develop a pattern having a trapezoidal cross-sectional shape at the development stage, reproducibility is good. therefore,
This property makes it possible to form a pattern with an arcuate cross-sectional shape with good reproducibility. Therefore, using the mold obtained from this, it has become easy to create a replica for an optical card.

Hereinafter, specific examples of the method for manufacturing an optical card to which the present invention is applied will be described for Examples 1 to 3 with reference to the drawings.

1j0- Figures 13A to 131 show the manufacturing process A-1 of Example 1, and the manufacturing process will be explained in this order. In addition, process A-I
Each symbol corresponds to each alphabet of the drawing number.

A. After Freon cleaning and drying a glass substrate 21 with a diameter of 127n+ and a thickness of 1.4 fins, a photoresist was applied using a spin code method to a dry thickness of 0.9 μm, and then a convection film was applied. A photoresist layer 22 was formed by baking in an oven at 110° C. for 30 minutes.

B. In order to form the tracking track 3 shown in FIG. 2, the line pattern light shielding part 24 has a light shielding part width 24a=3.
A photomask 23 is provided with a light shielding portion 24 having a width 24a of 3 μm and an arbitrary length for forming advance information recording 4a such as an address and unevenness 5 such as a clock track 8. is placed on the surface of the photoresist layer 22 and exposed. The exposure conditions in this case were as follows.

Exposure energy: 30 mJ/ad Print gap dos 10 μm At this time, when exposing with the print gap d0 as described above, the light intensity distribution will be as shown in FIG. 14 due to diffraction at the edge of the light shielding part 24 of the photomask. become.

C3 The exposed glass substrate 21 was immersed in a developer to dissolve and remove the exposed photoresist, thereby forming convex portions 15 corresponding to the pattern on the photoresist N22.

The pattern formed after development, that is, the convex portion 15 is the 13th C.
As shown in the figure, a flat portion 15a remained at the top and had a trapezoidal shape.

D. After the above development, the glass substrate 21 was heat-treated at 140° C. for 60 minutes in a convection oven. After the treatment, the flat portion 15a of the convex portion 15 disappeared and the shape became a mountain shape with a smooth sloped surface 15b.

This convex portion 15 is shown in an enlarged scale in FIG.
According to the shape measurement results, the inclination angle θ'' between the normal B of the surface of the substrate 21 and the tangent drawn to an arbitrary point on the inclined surface 15b of the convex portion 15 is in the range of 15° or more and 85° or less. The slopes accounted for 85% of the total slopes.

E. A nickel film 25 with a thickness of 750 mm is formed by sputtering on the surface on which the convex portion 15 is formed to form a conductive film for electroforming, and then a nickel layer is formed on this surface by electrodeposition to form this. A stamper mother 27 having a thickness of 0.6+n was obtained by performing peeling electroforming.

F. This stamper mother 27 was again subjected to nickel electroforming to obtain a molding stamper 28 having a thickness of 0.3 mm and having a convex portion 17 corresponding to the convex portion 15 described above. The height h of this convex portion 17
was 0.80 μm.

G. Using the molding stamper 28 described above, a replica 29 was prepared by hot press molding a 0.4 mm thick polycarbonate sheet having a glass transition temperature of 145° C. as a base material for the replica 29. A surface hardening layer 30 is formed on the opposite surface of the polycarbonate sheet from the hot press molding surface using a silicone surface hardening agent. The press molding conditions were as follows.

Molding temperature: 140°C Molding pressure: 100 kg/cj Molding time: 60 seconds on molding time When the recess 5a formed on the surface of Rika 29 was inspected using a stylus type surface inspection machine, the depth d was 0° and the width was 75 μm. The pit had a mountain-shaped cross section with W of 4.0 μm.

The sloped surfaces of the pits having the above-mentioned slope angle θ in the range from 15'' to 85'' accounted for 85% of all sloped surfaces. Further, the overall warpage of the replica 29 was about 3 mm at most in the longitudinal direction, and no damage was observed in the surface hardened layer 30.

H1 Recording made of an alloy of platinum, tellurium, and selenium in an atomic ratio of 5:15:20 on the pattern transfer surface on which the recessed portion 5a of the replica 29 is formed) l! i! 31
was formed to a thickness of 360 mm by sputtering.

(2) 2 on the surface of the recording film 31 formed on the replica 29;
An adhesive layer 32 was formed using a liquid polyurethane adhesive, and a substrate 33 of a white polycarbonate sheet containing Ti0z and having a thickness of 0.3 mm was adhered to the backing through the adhesive layer 32. The dynamic shear modulus of the above adhesive after curing is 5X10'dyn/- at 25°C and an angular frequency of 1 rad/sec.
Met. Thereafter, the optical card 1 as shown in FIG. 1 was obtained by punching into a size of 54 mm x 85.5 mm. The thickness of the optical card 1 was approximately 0.8 mm.

Note that in the drawing shown in FIG. 131, the optical card 1 is used so that light enters from above.

Therefore, in this case, the concave portion 5a becomes convex with respect to the light, and corresponds to the mountain-shaped convex portion 20 shown in FIG.

Regarding the optical card 1 thus formed, write-once recording and reading tests were conducted under the same conditions as described above.

As a result, good contrast was obtained from the prerecorded portion, and recording reading and tracking were performed without any problems. Therefore, it was confirmed that the unevenness having an inclined surface as described above can be used as an unevenness for recording prior information.

It should be noted that good contrast was obtained even from the written portion of the additional recording, and reading was sufficiently possible.

Further, the above-mentioned bending test and high temperature test were similarly conducted on the optical card 1. When the appearance of the optical card 1 was visually inspected after these two tests, no cranks or the like were observed in each of the aforementioned constituent members (for example, the recording film 31).
No change in appearance was observed. Further, no changes were observed in the writing and reading characteristics.

The deflection of the optical card 1 was also measured by the method described above and was 5 dragons or more.

As described above, in this example, smooth convex portions 15 can be formed on the photoresist layer 22, and by using the molding stamper 28 obtained from this, mountain-shaped pits that are almost the same as the convex portions 15 are formed. It was possible to form the recess 5a on the replica 29. In addition, the recess 5a of the replica 29
The depth d was almost the same as the height h of the protrusion 17 of the molding stamper 28. Therefore, according to the method described above, a replica of an optical card can be processed with high reproducibility.

In Example 2, steps B, H, and (2) of Example 1 described above are partially different from each other as follows.

That is, the photomask 23 used in step B is one for a read-only optical card in which openings in a pattern for pre-recording are formed over the entire surface.

In addition, in step H, 70% aluminum was used as the recording film 31.
Vacuum deposited to a thickness of 0.

Next, in step I, 0.3
A white polycarbonate sheet containing IIn+[Sano TiO□ is adhered to the backing. The dynamic shear modulus of the above adhesive was determined under the same conditions as in Example 1.
It was 1. Then, the same punching process as in Example 1 is performed to obtain a read-only optical card. The optical card thus obtained was subjected to the same test as in Example 1, and it was confirmed that there was no problem in seeding.

[3 Figures 15A to 15G show manufacturing steps A' to G of Example 3.
', and the manufacturing process will be explained below in this order.

A': A photoresist 35 is applied to one surface of the glass substrate 21 described above, and after drying, nickel is electroformed to a thickness of 0.3 mm on this surface by sputtering. As a result, a nickel substrate 28 for a molded stamper with a smooth surface was obtained, which was processed into a size of 105 mm x 95 mm.

B': After Freon cleaning and drying the nickel substrate 28, a photoresist (same as in Example 1) was applied using a spin code method so that the dry thickness was 1.9 μm. A photoresist layer 22 was formed by performing the same baking process as in Example 1.

C', exposure was carried out using the same photomask 23 as in Example 1 under the following conditions.

Exposure energy: 18 mJ/cd Print gap: None (hard contact exposure) D': The exposed nickel substrate 28 was immersed in a developer, and the photoresist layer 22 in the exposed area was dissolved and removed in the same manner as in Example 1. In this case, the convex portions 15 obtained after development were trapezoidal.

B': After development, heat treatment was performed at 140° C. for 60 minutes in a convection open environment, and the flat portion 15a disappeared and a convex portion 15 having a smooth sloped surface 15b was obtained.

F': Regarding the nickel substrate 28, argon plasma etching was performed on the surface on which the developed photoresist N22 was formed, thereby etching the photoresist and nickel at the same time.

Argon gas pressure: 5 x 10-'' Torr Applied voltage: 150 W Etching time: 4 hours and 45 minutes Most of the photoresist layer 22 is removed by the above etching, and at the same time the photoresist layer 22 is removed. A protrusion 1 is formed on the nickel substrate 28 corresponding to the protrusion 15 formed thereon.
7 was formed. In this way, a molding stamper 28 having a convex portion 17 corresponding to the convex portion 15 could be obtained directly from the nickel substrate.

G': A replica 29 was obtained using the molding stamper 28 in the same manner as in Example 1.

When the recess 5a formed on the surface of the replica 29 was inspected using the same method as in Example 1, it was found that the recess 5a had a substantially ■-shaped shape with a depth d of 0.7 μm and a width W of 4.0 μm. , that is, pits with a chevron-shaped cross section, and the sloped surfaces of the bit with the above-mentioned slope angle θ in the range of 15° to 85'' accounted for 75% of the total sloped surfaces. The condition of the hardened surface layer 30 was also the same as in Example 1.

Using the replica 29, an optical card 1 was obtained through a process similar to process HX I in Example 1 described above. The optical card thus obtained was subjected to the same tests as in Example 1, and it was confirmed that there were no problems in various respects.

Next, FIG. 16 shows a modification of the exposure method in step B of Example 1. That is, the above-mentioned photomask 23 is placed on the photoresist layer 22, and the exposure light source 5 above it is placed.
A light scattering plate 43 is disposed between the photomask 23 and the photomask 23, and exposure is performed. The light is scattered by this scattering plate 43, resulting in the light intensity distribution shown in FIG. 14, which is the same as in the first embodiment.

The above-described exposure can also be performed using a laser cutting device. In other words, the exposure intensity is changed from weak to strong and weak in the direction perpendicular to the scanning direction of the recording and reproducing light beam for each exposed part that is partially exposed in accordance with the information recorded on the optical card in advance. In this method, exposure is performed so that the cross-sectional shape of the exposed portion becomes arcuate.

In Example 4, the steps in Example 1 described above are not provided, and Step B
Parts of and H are different as follows.

That is, in step B, exposure was performed while changing the laser power of the laser cutting device in the direction perpendicular to the track.

In step H, an alloy film containing tellurium and selenium in an atomic ratio of 80:20 was vacuum deposited as the recording film 31 to a thickness of 400 mm.

In the thus obtained optical card 1, the unevenness was formed in a chevron-shaped convex portion 20 having a V-shaped cross section in the direction perpendicular to the track, as shown in FIG. This mountain-shaped convex portion 20 had a shape in which the inclined surface 6 was inclined straight, and the distance between axa' (b and b'') of the U-shaped cross section shown in FIG. 3 was almost a straight line. Therefore, the inclination angle θ formed by the above-mentioned inclined surface 6 and the normal line A of the above-mentioned information recording surface 7 is uniquely determined and was approximately 70 @ in this example. The slope 6 is 10 in this example.
It becomes 0%. Further, the width W of the cross-sectional shape of the mountain-shaped convex portion 20 in the direction perpendicular to the track is 4.0 μm, and the depth d is 0.7 μm.
It was m. This optical card 1 was subjected to the same tests as in Example 1, and it was confirmed that there were no problems in various respects.

Although the tellurium-selenium alloy film used for the recording film 31 in this example is brittle, it was found to exhibit sufficient durability when applied to the present invention.

Note that as the photosensitive resin, negative or positive photoresists can be used;
A photogenic polymeric material comprising a polymeric compound having an unsaturated bond and a dopant having a carbonyl group, as disclosed in JP-A-95525 and JP-A-62-95526, can be used.

〔Effect of the invention〕

As mentioned above, in zero sailing, an information recording surface is formed on a first base material, and this information recording surface is protected by a second base material to form a highly flexible optical card body. The shape of the concave or convex portions formed in advance on the information recording surface of the optical card for recording information shall be in the shape of a 7-shape or a mountain with an inclined surface, and the inclination angle of 50% or more of the total inclined surface shall be adjusted. Since the angle is 15" or more and 85 degrees or less, it has extremely high durability against mechanical external forces and environments such as high temperature and humidity, and can withstand portable use, as well as accuracy in forming the height and width of the unevenness. An optical card that can perform stable recording and reproduction even if the performance is somewhat poor can be obtained.

Therefore, it is possible to relax the molding conditions when manufacturing optical cards and to manufacture them in large quantities and at low cost. In addition, the contrast between areas with and without unevenness does not change much depending on the amount of deviation of the reproduction beam spot from the track center, and various non-coherent light beams can be used as the reproduction light beam. Therefore, the range of conditions when designing and manufacturing a recording/reproducing device can be widened.

In addition, on the substrate for making a stamper, a recess (
Since the stamper and replica are created based on this substrate, it is easy to create an optical card that can obtain good reproducibility even if the conditions for creating the stamper and replica are significantly relaxed. can be manufactured.

[Brief explanation of drawings]

FIG. 1 is a plan view of an optical card manufactured according to an embodiment of the present invention, FIG. 2 is an enlarged view of the arrow ■ in FIG. A cross-sectional view for
FIG. 4 is a cross-sectional view showing a modification of the mountain-shaped convex portion, FIG. 5 is a cross-sectional view showing another modification of the mountain-shaped convex portion, and FIG. 6 is a cross-sectional view in the Ml-V1 direction of FIG. Figure 7 is a diagram showing an example of the shape of the mold and the shape of the molded product, Figure 8 is a graph showing the relationship between the shape of the mold and molding temperature, and Figures 9 to 12 are heat treatment temperatures and recessed parts. FIG. 13 is a schematic cross-sectional view for explaining the manufacturing method of Example 1, and FIG.
Figure 4 is a diagram showing the relationship between the exposure state and the exposure intensity distribution in the depth direction of the photoresist layer, Figure 15 is a schematic cross-sectional view for explaining the manufacturing method of Example 3, and Figure 16 is FIG. 17 is a schematic cross-sectional view showing a modification of the exposure method, and is a cross-sectional view for explaining the inclination angle of the convex portion formed on the photoresist layer. In addition, in the symbols used in the drawings, 1-...----...-- Optical card 5--...----...----... Unevenness 6...-
...--m-slanted surface 7 ・-1-----...--
Information recording surface 9--・------1---Information area 15
・−・・−・・−・・−・Convex portion 19 of photoresist layer
···········································V-shaped recess 20····················································································································································. ...Photomask 24--Light blocking portion 28--Molding stamper 29--First base material (replica) 31--
--- Recording film 32 --- Second base material (adhesive layer) 43
.--Scattering plate 50--111--Exposure light sources A, B--Normal line.

Claims (1)

[Scope of Claims] 1. An optical card in which a pre-information area on an information recording surface read by a light beam is formed as a concave or convex portion, a first base material on which the information recording surface is formed; and a second base material provided on the first base material to protect a recording film made of a metal thin film formed on the information recording surface, and the recessed part is formed in a V-shape. or the convex portion is formed in a mountain shape, and the inclination angle between the slope forming the V-shaped recess or the mountain-shaped convex portion and the normal line of the information recording surface is 50% of the total slope. 15° or more and 85° or more
The optical card is mounted on a support stand (JISK) with a distance between fulcrums of 20 mm.
7203) and having a deflection of 2 mm or more when a load of approximately 15 kg is applied to the approximate center between the supporting points using a pressure wedge (JISK 7203 regulations). 2. The first base material is a polymer compound having a glass transition temperature of 60°C or higher, and the second base material is a 25%
The optical card according to claim 1, having a dynamic shear modulus of 1 x 10^5 dyn/cm^2 or less at °C. 3. In the method of manufacturing an optical card in which the pre-information area on the information recording surface to be read by a light beam is formed as a concave or convex portion, (a) a photosensitive resin layer is formed by applying a photosensitive resin on the substrate. (b) partially exposing the photosensitive resin layer in accordance with the prior information recorded in the prior information area; (c) developing the partially exposed photosensitive resin; performing post-processing as necessary to form unevenness on the photosensitive resin layer having an inclined surface having an inclination angle of 15° or more and 85° or less with respect to the normal line of the substrate on 50% or more of the total inclined surface; (d) manufacturing a stamper using the substrate having irregularities formed on the photosensitive resin layer; and (e) manufacturing a replica of an optical card using the stamper. Method of manufacturing optical cards. 4. The exposure in the above step (b) is characterized by being a mask exposure performed by arranging a mask in which openings or light-shielding portions with a pattern corresponding to the prior information are formed without being in close contact with the photosensitive resin. 4. The method for manufacturing an optical card according to claim 3. 5. The exposure in step (b) above is mask exposure performed by placing a light scattering plate between the exposure light source and a mask in which a pattern of openings or light shielding parts corresponding to the prior information is formed. The method for manufacturing an optical card according to claim 3, characterized in that: 6. The optical card according to claim 3, wherein the exposure in the step (b) is laser cutting in which exposure is performed while changing the exposure intensity in a direction perpendicular to the scanning direction of the recording/reproducing light beam. Production method. 7. The optical card according to any one of claims 3 to 6, wherein the post-processing in the step (c) is a heat treatment of the photosensitive resin after development at a temperature near its softening point. manufacturing method.