JPH10247340A - Optical information recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to easily and visually check a recorded capacity and/or unrecorded residual capacity by constituting a protective layer of a material, which transmits visible light, and disposing a color-changing layer, which changes its color by the recording processing of information, between a reflection layer and this protective layer. SOLUTION: A recording layer 2 and the reflection layer 3 are successively formed on the front surface of a transparent substrate 1. Next, the front surface 4 of the reflection layer 3 is printed with graduations for indicating the recorded capacity by silk screen printing. A soln. prepd. diluting an irreversible temp.-indicating coating material which is discolored from colorless to gray color at 220 deg.C with alcohol is applied on the surface 4 printed with the graduations of the reflection layer 3 and is dried, to form the color-changing layer 5. The film thickness of the discoloration layer 5 is specified to the film thickness, at which the visual checking of the discoloration is possible. Finally, a UV curing resin is applied ton the surface of the color- changing layer 5 and is cured by irradiation with UV rays to form the protective layer. As a result, the graduations indicating the recorded capacity and the display of the recorded capacity indicated by these graduations are made visible from the rear surface through the protective layer and the discoloration layer 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical information recording medium on which information is recorded and reproduced using a light beam.

[0002]

2. Description of the Related Art In recent years, optical information recording media have rapidly spread. Normally, as shown in FIG. 7, the optical information recording medium has a recording layer made of an organic dye composition such as a cyanine dye on the surface of a transparent substrate 1 made of a resin (such as polycarbonate) on which guide grooves 9 are formed. 2, a reflective layer 3 made of a metal (such as gold), and a protective layer 6 made of a resin (such as an ultraviolet curable resin) are laminated in this order.

When information is recorded by changing the absorbance or reflectivity at the irradiation position by irradiating a light beam, the difference between the absorbance or reflectivity from the unrecorded area is usually determined by the transparent substrate 1 side. By visually observing from, the area where information is recorded can be recognized.

[0004]

However, it is difficult to accurately visually recognize subtle changes in reflectance and absorbance. In addition, since recording / reproducing of information is hindered, it is not possible to provide a scale on the recording layer or the transparent substrate surface on the light beam incident side for accurately grasping the capacity by visual observation. Therefore, in the identification based on the appearance of the recording layer, the recorded capacity (and the unrecorded remaining amount) can be grasped only vaguely.

Further, when the absorbance change of the recording layer 2 occurs in an invisible region or when information is recorded by a change in the magnetization direction as in a magneto-optical disk, it is not possible to visually grasp the capacity. .

Accordingly, an object of the present invention is to provide an optical information recording medium in which a recorded capacity and / or an unrecorded remaining capacity can be easily visually recognized.

[0007]

In order to achieve the above object, the present invention provides a transparent substrate, a recording layer, a reflective layer and a protective layer which are laminated in this order, wherein the protective layer is made of a material which transmits visible light. And a first optical information recording medium having a discoloration layer between the reflective layer and the protective layer, the discoloration layer being discolored by information recording processing. Note that the protective layer may be a discoloration layer that changes color due to information recording processing. In this case, the protective layer may not transmit visible light.

[0008] In this specification, "discoloration" includes all visible optical changes, including any visible change in chromaticity, lightness and / or saturation. Therefore, it includes not only a change in color in a colored state, but also a change between colored and colorless. In addition, of the front and back of the optical information recording medium, the surface on which the laser beam for recording information is incident is referred to as “front (front)”.
The opposite side is called the “back side”.

Further, the present invention has a transparent substrate, a recording layer, a reflective layer, and a protective layer which are laminated in this order, and a color-changing layer which changes color by the information recording process. A second optical information recording medium is provided which includes a plurality of discolored areas separated by concentric circles which are equal to the information recording medium, and which has a different color after recording processing for each of the discolored areas.
According to the second optical information recording medium, in the second optical information recording medium, the protective layer may be a discoloration layer,
Further, it may further have an independent color changing layer.

In the first and second optical information recording media, since the color-changing layer is discolored by the recording process, the recorded capacity and / or the unrecorded remaining capacity can be easily determined by visually observing the color of the color-changing layer from the back surface. Can be recognized. That is, when information is sequentially recorded along the radial direction, the stored capacity is determined by the position of the outer periphery of the discolored area of the discoloration layer, and the unstored capacity is determined by the position of the inner periphery of the undiscolored area. , Can be recognized respectively. In this case, the color changing layer may be provided on the entire surface of the optical information recording medium, or may be formed in a band shape in the radial direction. When information is stored at random, the stored capacity is determined by the ratio of the discolored area to the entire storable area, and the unstored capacity is determined by the ratio of the undiscolored area to the entire storable area. Can be recognized. In this case, the discoloration layer is desirably provided on the entire surface of the optical information recording medium, but may be formed in a band shape in the radial direction.

In the first and second optical information recording media, it is desirable that the color change layer contains a material having a thermochromic property. Such a material can be discolored by heat generated when information recording processing is performed by laser light irradiation, and thus is widely applied to an optical information recording medium for recording information by a generally used laser light. be able to. When the color change layer has a thermochromic property, heat generated by the laser light applied to the recording layer is transmitted to the color change layer via the reflection layer, and changes the color of the color change layer by a thermochromic reaction. For example, when the color change of the thermochromism reaction changes from dark and light to colorless, the recorded capacity or the remaining capacity is displayed as the recording proceeds, and when the color change is reversed, the display disappears as the recording progresses. Therefore, the recorded capacity or the remaining recording capacity of the optical information recording medium during the additional recording can be easily confirmed visually. When the color-changing layer is discolored using thermochromic properties, the color-changing layer should be formed so that heat is efficiently transmitted, and when the color-changing layer is formed on the back surface, it is in direct contact with the back surface of the reflective layer. Is desirable.

As the material having the thermochromic property, for example, for an optical information recording medium of a write-once optical information recording medium, a thermocolor which changes color irreversibly by heating at a certain temperature may be used.

Further, according to the present invention, there is provided an optical information recording medium for recording information with a laser beam, wherein the recorded recording capacity and the unrecorded volume are visible from the opposite side (ie, the back side) of the laser beam incidence surface. A third optical information recording medium having a scale for indicating at least one of a remaining recording capacity is provided. As the third optical information recording medium, for example,
One provided with a scale between the reflective layer and the protective layer or on the surface of the protective layer.

According to the third optical information recording medium, every time the information is updated, the recorded capacity is recorded on the back surface with a pigment or the like (that is, a mark is put on a scale, etc.). ), The recorded capacity and / or
Alternatively, the unrecorded remaining capacity can be easily recognized. This memo may be made manually or by an optical information recording device. Further, if the above-described color-change layer is provided, it is possible to accurately grasp the size of the color-changed (that is, recording-processed) area of the color-change layer without making such a memo. Therefore, it is preferable.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention is applied to an optical information recording medium for recording information by irradiating a laser beam. This optical information recording medium is usually laminated in this order, a transparent substrate,
It has a recording layer, a reflective layer, a color change layer and a protective layer.

As the transparent substrate, a transparent material which does not affect the laser beam is used. For example, a plastic material such as polycarbonate, PMMA (polymethyl methacrylate), polyolefin, epoxy resin, and a glass substrate can be used.

The recording layer is a recording material that is recorded by using thermal energy such as a semiconductor laser. For example, GeS
inorganic compound materials such as a phase change recording film using a chalcogenide compound represented by bTe and a magneto-optical recording film using a magnetic material represented by TbFeCo; and a cyanine dye;
Various commonly used recording layers such as an organic compound material of an organic dye recording film represented by a phthalocyanine dye are applicable to the present invention. When an inorganic material such as a chalcogenide compound or a magnetic material is used, a film is formed by a sputtering method or a vacuum evaporation method. In a vacuum chamber that has been subjected to sputtering or vacuum deposition, an inorganic dielectric protective layer is provided so as to sandwich the recording layer from both sides, and the recording layer is formed of two inorganic dielectric protective layers and an inorganic sandwiched therebetween. It is a laminated film with a recording material layer. When an organic dye compound is used as a recording material, a dye composition containing a dye and a solvent (if necessary, may further contain other components such as a quencher) is used, and a spin coating method, a coating method, or a film method is used. To form a film. For the reflective layer, for example, aluminum, gold, silver, copper, chromium and nickel, or an alloy thereof can be used. The reflection layer is formed by a sputtering method, a vacuum evaporation method, or the like.

For the discoloration layer, for example, a thermochromic pigment, such as an ink, a paint, or a resin coloring material, which exhibits irreversible thermochromicity can be used. Examples of such irreversible thermochromic pigments include compounds such as cobalt, nickel, iron, copper, chromium, and manganese, whose composition contains an ammine or ammonium group, an amine, a carbonate group, an oxalic acid group, and water of crystallization. It is often used and its discoloration temperature ranges from a low temperature of 50 ° C to 5
It covers a wide range up to a high temperature of 00 ° C or higher. In the present invention, the discoloration temperature is preferably in the range of 100 to 300 ° C.
KPO ₄ .H ₂ O, NH ₄ VO ₃ , Cd (OH) ₂ , [Cu
(Pyr) ₂ ] (CNS) ₂ , [Cr (NH ₃ ) ₅ Cl] C
₂ O ₄ , 2PbCO ₃ .Pb (OH) ₂ , CdCO ₃ and the like. To these pigments, as a vehicle, a discoloration temperature of 200 ° C.
For the following, ethyl cellulose lacquer, 200 ° C
It is desirable to form a discoloration layer using a temperature-indicating paint to which a silicone varnish has been added for the above. The temperature indicating paint may be used after being diluted with a solvent such as alcohol or benzene. In addition, as a film formation method, a spin coating method, a spray method, or the like can be used.

When the thermochromic pigment is compatible with any resin such as the protective layer and the adhesive layer, the protective layer and the adhesive layer are formed using a mixture of the thermochromic pigment and the resin in advance. The layer may function as a discoloration layer.
In the case of using an irreversible thermochromic pigment that generates gas at the time of discoloration, it is desirable that the protective layer function as a discoloration layer because the discoloration becomes clear if the escape of the gas is not prevented.

Various resins can be used for the protective layer. When a thermosetting resin is used, the curing temperature is changed if the irreversible thermochromic material is used for the color changing layer. It is necessary that the temperature is not reached. Note that an ultraviolet curable resin is preferable because it is not necessary to perform a heat treatment at the time of curing. These resins are usually formed by a spin coating method, but other methods such as coating, dipping, and film sticking may be used. In addition, when a dummy substrate formed in a plate shape in advance is used as the protective layer, the dummy substrate may be attached via an adhesive layer.

The scale is formed by writing the surface of the reflective layer, the color change layer, the protective layer, and the like with a pigment, or making the surface of the protective layer and the like uneven. When a pigment is used, the scale can be easily provided by printing.
As a printing method, screen printing usually used for a CD (compact disk) or the like can be used.
The scale may indicate either the recorded capacity or the remaining recording capacity, or may indicate both. It is preferable that the position of the scale is determined in advance by checking the relationship between the recording capacity of each optical information recording medium and the diameter of the disk, and is suitable for each medium. In addition, it is desirable to attach a display of the stored capacity and / or the remaining recording capacity indicated by the scale near the scale.

It is desirable that the scale is formed on the back side of the reflection layer so as not to affect the laser beam for the recording process. And may be provided on the surface of any layer such as a protective layer, or may be provided inside the layer.

[0023]

【Example】

<Embodiment 1> In this embodiment, a CD-R (compact disk-recordable) 10 having a storage capacity of 650 Mbytes shown in FIG. 1 as an optical information recording medium was manufactured. This C
D-R10 has a recording layer 2 containing an organic dye compound, a reflective layer 3 made of gold, a color-changing layer 5 containing an irreversible thermochromic pigment, on a surface of a transparent substrate 1 made of a polycarbonate resin, and
A protective layer 6 made of an ultraviolet curable resin is laminated in this order, and a scale 22 is provided on the surface 4 a of the reflective layer 3 on the side of the color changing layer 5.
(Shown in FIG. 2) is printed. That is, in this embodiment, the back surface of the reflective layer 3 is the printing surface 4.

In this embodiment, first, a transparent substrate 1 having an injection-molded guide groove (groove) 2 (shown in FIG. 7) is formed.
An organic dye composition containing a cyanine dye or the like was formed into a film having a thickness of about 100 nm on the surface of
After that, the reflective layer 3 was sputtered to about 80
The film was formed to a thickness of nm. Next, a scale 22 for indicating the recorded capacity was printed on the surface 4 of the reflective layer 3 by silk screen printing. Then, an irreversible temperature-indicating paint that changes color from colorless to gray at a temperature of 220 ° C. (“F-220”, Japan Photographic Dye Laboratories Co., Ltd.) is applied to the surface 4 of the reflective layer 3 on which the scales 22 are printed. The solution diluted with alcohol was applied by spin coating and dried to form a discoloration layer 5. The thickness of the discoloring layer 5 may be any thickness as long as discoloration can be visually confirmed, and is preferably in a range of about 20 nm to 10 μm. Finally, a UV curable resin was applied to the surface of the discoloring layer 5 by a spin coating method, and cured by irradiating UV rays to form a protective layer 6.

FIG. 2 shows a state of the thus obtained CD-R 10 viewed from the back side before recording information. The CD-R 10 of the present embodiment includes a scale 22 indicating the recorded capacity and a display 23 of the stored capacity indicated by the scale 22, and these are viewed from the back through the protective layer 6 and the color changing layer 5. The color change layer 5 remains colorless because the information recording process has not been performed yet. In this embodiment, the CD-
Except for the non-recordable area 20 of R10, the recordable area 21
Although the color changing layer 5 is formed only on the CD-R 10, the color changing layer 5 may be formed on the entire surface of the CD-R 10.

The CD-R 10 is irradiated with a laser beam, and has a recording linear velocity of 1.2 m / s and an EFM (Eight to Fourtee).
n Modulation) signal was recorded corresponding to 300 Mbytes. When the CD-R 10 after recording is viewed from the back surface, as shown in FIG.
The area 31 up to the scale 22 indicating M bytes has changed to gray, and it can be confirmed from the scale 22 that the recorded capacity is 300 Mbytes. In addition, the area from the scale 22 indicating the 300 MB to the outer edge does not change color, and the unrecorded area 2
Since it was left as 1, the total recording capacity of this CD-R was 650 Mbytes, so it was confirmed that the remaining recording capacity was 350 Mbytes. In FIG. 3, the discolored area 3
1 is illustrated by adding a dot pattern.

<Embodiment 2> In Embodiment 1, a CD having a single-plate structure is used.
In this embodiment, a DVD-R (digital video disc) having a laminated structure shown in FIG.
Recordable). In this example, a colored paint was used as the temperature indicating paint before heating.

First, as in the first embodiment, the transparent substrate 1
The recording layer 2 and the reflective layer 3 are formed on the surface of. Example 1
In the example, the scale 22 was printed on the surface of the reflective layer 3 before forming the color changing layer 5 because the color changing layer 5 was colorless before the recording process. However, in this embodiment, the color changing layer 5 is colored from the beginning. .
Therefore, in this embodiment, the color change layer 5 is formed first on the surface of the reflective layer 3, and the scale 22 is printed on the surface 4 b of the color change layer 5 in the same manner as in Example 1. That is, in this embodiment, the back surface 4 b of the color changing layer 5 is the printing surface 4. The discoloring layer 5 is formed by diluting an irreversible temperature-indicating paint (F-140, Japan Photographic Dye Laboratories Co., Ltd.) that changes color from rose to blue at a temperature of 140 ° C. on the surface of the reflective layer 3 with alcohol. The solution was applied by spin coating and dried. Next, a dummy substrate 8 was bonded to the printing surface 4 of the color changing layer 5 via an adhesive 7 made of an ultraviolet curable resin, thereby obtaining a one-sided dummy substrate bonded type DVD-R.

In this embodiment, the color-changing layer 5 is provided as an independent layer. However, by mixing a temperature indicating paint with the adhesive 7, the adhesive layer 7 can be provided without providing the independent color-changing layer 5.
May function as the color change layer 5. In this case, scale 2
2 is printed on one of the front and back surfaces of the dummy substrate 8.

When the obtained DVD-R was irradiated with a laser beam and the same recording experiment as in Example 1 was performed, the recorded area turned blue and the recorded capacity and the recorded capacity were changed as in Example 1. The remaining capacity could be easily visually recognized.

Example 3 In this example, a CD-R10 was formed in the same manner as in Example 1. However, in this embodiment, the printing step of the scale 22 is omitted, and the color-change layer 5 is composed of a plurality of color-change areas 51 to 54 as shown in FIG.
Was formed. The method for forming the color changing layer 5 will be described below.

First, 100M from the inside of the surface of the reflective layer 3
The temperature indicating paint used in Example 2 was applied to the byte area by screen printing (or tampon printing or the like) and dried to form a first discolored area 51. In the area of 200 Mbytes adjacent to the outer periphery of the first discolored area, the first embodiment
The temperature indicating paint used in the above was applied and dried to form a second discolored area 52. Next, the temperature indicating paint used in Example 2 was applied to an area of 200 Mbytes adjacent to the outer periphery of the second discolored area 52 and dried to form a third discolored area 53. Finally, 20 adjacent to the outer periphery of the third color changing area 53
The temperature indicating paint used in Example 1 was applied to an area of 0 MB and dried to form a fourth discolored area 54.

The CD-R10 obtained in this example is
Areas 51 and 53 that are rose before recording and blue after recording.
Storage area 5 that is colorless before recording and gray after recording
2, 54 are alternately arranged.

When the obtained CD-R 10 was observed from the back side before recording, as shown in FIG. 5, from the inner side, rose-colored areas 51a and 53a and colorless (ie, the reflection layer 3 can be seen as it is) area 52a were shown. , 54a were alternately observed. When a recording experiment was performed on this CD-R10 in the same manner as in Example 1, the blue region 51b was sequentially printed from the inside.
And a gray area 52b, a rose area 53b, and a colorless area 54b were observed. In FIGS. 5 and 6, the colored area is illustrated by adding a dot pattern.

From this visual result, the first discolored area 51
(For 100 Mbytes) and the second discolored area 52 (200 Mbytes).
(For bytes), the recording process was performed, but the third and fourth
It can be seen that no recording processing has been performed on the discolored areas 53 and 54 of FIG. Therefore, it was easily recognized that the recorded capacity was 300 Mbytes and the remaining recording capacity was 350 Mbytes. As described above, according to the present embodiment, the recorded capacity and the remaining recording capacity could be easily visually recognized by the difference in color without any particular scale. Although the graduations 22 are not provided in the present embodiment, the graduations 22 may be provided on either the front or back of the protective layer 6. In this manner, by using the color difference and the scale 22 together, it becomes easier to visually recognize the correct recording capacity.

[0036]

As described above, according to the optical information recording medium of the present invention, the recorded capacity and / or the unrecorded remaining capacity and the used / unused can be easily visually recognized.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view of an optical information recording medium according to a first embodiment.

FIG. 2 is a plan view of the optical information medium of Example 1 as viewed from the back surface before recording.

FIG. 3 is a plan view of the optical information medium of Example 1 as viewed from the back after recording.

FIG. 4 is a partial cross-sectional view of an optical information recording medium according to a second embodiment.

FIG. 5 is a plan view of the optical information medium of Example 3 viewed from the back surface before recording.

FIG. 6 is a plan view of the optical information medium of Example 3 viewed from the back after recording.

FIG. 7 is a partial sectional view of a conventional optical information recording medium.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Transparent substrate, 2 ... Recording layer, 3 ... Reflection layer, 4 ... Printing layer,
5: discoloration layer, 6: protective layer, 7: adhesive layer, 8: dummy substrate, 9: guide groove, 10: compact disk, 20: non-recordable area, 21: recordable area, 22: scale, 23 ...
Capacity display, 31: discolored area.

Claims (6)

[Claims] 1. An optical information recording medium comprising a transparent substrate, a recording layer, a reflective layer and a protective layer laminated in this order, wherein the protective layer is made of a material that transmits visible light, and the reflective layer and the protective layer are An optical information recording medium, characterized by having a discoloration layer that changes color by recording information. 2. An optical information recording medium comprising a transparent substrate, a recording layer, a reflective layer and a protective layer laminated in this order, wherein the protective layer is a color-changing layer that changes color by recording information. Optical information recording medium. 3. An optical information recording medium comprising a transparent substrate, a recording layer, a reflective layer and a protective layer laminated in this order, comprising: a color-changing layer which changes color by an information recording process; An optical information recording medium, comprising: a plurality of discolored areas separated by concentric circles which are equal to an optical information recording medium, wherein the color after the recording process is different for each of the discolored areas. 4. The optical information recording medium according to claim 3, wherein said color changing layer is said protective layer. 5. The optical information recording medium according to claim 1, wherein the color-change layer contains a material having a thermochromic property. . 6. An optical information recording medium for recording information by laser light, wherein at least one of a recorded recording capacity and an unrecorded remaining capacity, which is visible from a surface opposite to the laser light incident surface, is shown. Information recording medium having a scale for reading.