JP2003242688A - Optical recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical recording medium in which the excessive rise of the failure rate of the medium or an error rate during recording signal regeneration is prevented in the optical recording medium on the surface of which an image is printed with an ink-jet printing system, and to prevent the peeling of each layer stack including an ink jet printing layer in the optical recording medium. <P>SOLUTION: The optical recording medium has at least a recording layer 3 on a discoid substrate, and has two or more layer stacks on a surface overcoat layer. One layer of the layer stacks exists at the uppermost layer as an ink jet printing layer on which the image is printed with the ink-jet printing system. The outermost circumference part of the ink jet printing layer 8 does not reach the outermost circumference part of a layer stack in contact with the undersurface of the ink jet printing layer. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention irradiates a laser beam to cause a change in a recording layer material to record / reproduce information.
The present invention relates to a rewritable optical recording medium, and more specifically to an optical recording medium capable of printing an image on the uppermost layer surface by an inkjet method.

[0002]

2. Description of the Related Art With the recent increase in the amount of information, a large amount of data can be recorded and reproduced at high density and at high speed.
The D-R / RW disc drive has been commercialized and is widely used. In recent years, in particular, CD-R / RW disk drives have become relatively inexpensive compared to when they were first commercialized, and have been widely used by individual users. Also, since the functionality of writing software for recording has been improved, an optical recording medium has come to be used easily as a recording medium for storing data by this disk drive. The optical recording medium is used for storing or editing data such as audio software, computer software, image data, documents, etc., backing up data in the computer, or a means for moving data, and is easily compatible with CD-ROM. As a recording medium, a CD-R that can be additionally written and has a dye recording layer, and a rewritable, phase-change type optical recording medium, CD-RW, have been developed and widely used.

When storing, organizing, or distributing an optical recording medium on which the above information is recorded, the optical recording medium is normally discriminated by displaying the recorded content with a writing instrument that does not damage the label surface. To be able to. A method is also used in which a label sticker on which characters and images are printed is attached so that the information content in the optical recording medium can be known. Recently, by using an inkjet printer, which is widely used by personal computer users, an image can be directly printed on the surface of an optical recording medium by an inkjet method to produce an original label surface for each user. The medium has been developed and put into practical use.

As the prior art of the present invention, various specifications have been disclosed for an optical recording medium capable of directly printing an image by an ink jet method, in order to exert an effect on the print quality such as the state of the printed image or bleeding. There is. For example, in JP-A-8-161769, a light absorbing layer, a light reflecting layer, a protective layer and / or a print receiving layer are sequentially laminated on a transparent substrate, and the outermost protective layer or print receiving layer is polyvinyl acetal. An optical recording medium containing a resin and a water-dispersible resin and / or a water-soluble resin is disclosed. According to this, since the outermost layer is not dissolved in the water-based or oil-based ink, the surface of the optical recording medium having good writability, printability, and peeling resistance can be obtained.

Further, for example, Japanese Patent Laid-Open No. 8-329530 discloses an optical recording medium which is an opaque layer laminated on a reflective layer and having a colored protective layer which is also the outermost layer.
In JP-A-188344, a transparent substrate is provided with at least a recording layer, a metal reflective layer, a white printed protective layer, and a hydrophilic surface layer containing a water-absorbing and / or oil-absorbing filler. An optical recording medium is disclosed in JP-A-11-1.
Japanese Patent No. 10824 discloses that a reflective layer, which serves as a base color on the surface of the protective layer, is composed of a white metal film composed of silver, aluminum, platinum or an alloy thereof, and is a printing layer film formed on the surface of the protective layer. An optical recording medium having a thickness of 10 to 30 μm is disclosed.

According to the technique disclosed in the above publication, the range of hues reproduced by an ink jet printed image is widened, so that an optical recording medium surface on which an image with good resolution and color can be printed can be obtained.

Further, for example, Japanese Patent Application Laid-Open No. 11-213445 discloses an optical recording medium in which the outermost layer of the protective layer is composed of a binder resin having a porous structure on the surface.
According to the technique disclosed in the publication, image reproducibility in printing by an inkjet method, image bleeding in which ink does not bleed even in a high-humidity atmosphere or when water drops adhere, and glossiness when full-color printing is achieved An excellent optical recording medium surface can be obtained.

[0008]

However, as described above, the effect of the technique relating to the optical recording medium capable of printing an image by the inkjet method disclosed in the publication is that the image quality after printing is general, that is, the inkjet method. It is only for the surface of the optical recording medium that can be printed with
The influence on each characteristic of the optical recording medium itself, such as storage reliability and scratch resistance, has not been discussed.

The ink-jet printed layer is usually laminated by coating by a screen printing method. The coating layer material used for the ink-jet printed layer has absorption and fixing properties of ink dots dropped during image printing, and Due to the requirement for quick drying, particles having a relatively large particle size are contained in the material. Therefore, the area where the inkjet print layer is directly laminated on the overcoat layer may be a recording layer or a reflection layer that is stacked below the overcoat layer depending on the material used for the inkjet print layer and the printing conditions at the time of screen printing. This will affect the layers and the like, and the defect rate of the relevant part of the optical recording medium will increase. In addition, at the same location, when the ink-jet printed layer has an extremely thin film thickness, the scratch resistance of the optical recording medium becomes insufficient.

Further, when the adhesion between the overcoat layer and the ink-jet printing layer is weak, the ink-jet printing layer peels off from the outer peripheral side due to rotation during high-speed recording and reproduction, making it impossible to directly print an image on the optical recording medium. , Not only the peeled inkjet-printed layer but also the intermediate layer, overcoat layer, reflection layer, and recording layer directly below the layer cannot be recorded / reproduced, which is the original purpose of the optical recording medium. .

In the present invention, when the optical recording medium is an optical recording medium on the surface of which an image can be printed by an ink jet system, the defect rate of the optical recording medium and the error rate at the time of recording signal reproduction are excessive. It is an object of the present invention to provide an optical recording medium capable of preventing rising. Another object of the present invention is to prevent film peeling of each laminated layer including the ink-jet printed layer in the optical recording medium.

[0012]

In order to solve the above-mentioned problems, the invention according to claim 1 is an optical recording medium having at least a recording layer on a disk-shaped substrate, wherein the surface is formed on an overcoat layer. In an optical recording medium having a laminate of two or more layers, one of which is the uppermost layer as an inkjet print layer capable of performing image printing by an inkjet method, the outermost peripheral portion of the inkjet print layer is an inkjet print layer. The most main feature is that it does not reach the outermost peripheral portion of the stack that contacts the lower surface of the print layer.

According to a second aspect of the present invention, in the optical recording medium according to the first aspect, the adhesive force between the uppermost ink-jet printed layer and the layer immediately thereunder is between the overcoat layer and the layer immediately above it. The main feature is that the adhesive strength is equal to or higher than that.

[0014]

FIG. 1 shows an example of the form of an optical recording medium according to the present invention. The basic configuration has a first protective layer 2, a phase change recording layer 3, a second protective layer 4, a reflection / heat dissipation layer 5, and an overcoat layer 6 on a substrate 1 having guide grooves. Further, the intermediate layer 7 and the inkjet print layer 8 are provided on the overcoat layer. Further, the lower surface of the substrate 1 has a hard coat layer 9.

As a material for the substrate 1, a polycarbonate resin, which is excellent in moldability, optical characteristics, and cost, is preferable. In addition, an optical recording medium (CD-
For application to RW), it is desirable that the width of the guide groove (groove) formed in the substrate to be used is 0.30 to 0.60 μm and the depth of the guide groove is 200 to 550Å. The thickness of the substrate is not particularly limited, but 1.2 mm is preferable. Depending on the shrinkage amount of the optical recording medium during the manufacturing process, such as when a film is formed by a sputtering method as described below or when the ultraviolet curable resin laminated on the overcoat layer is cured or contracted by ultraviolet irradiation, There are things that affect the characteristics. Therefore, the amount of warp of the substrate should be designed in consideration of the above effects.

The recording layer 3 includes Ag, In, Sb, and T.
A material containing a quaternary phase-change recording material containing e as a main component is suitable because the recording (amorphization) sensitivity / speed, the erasing (crystallization) sensitivity / speed, and the erasing ratio are extremely good. ing. In order to satisfy the signal reproduction stability and the signal life as a whole, Ga, Zn,
Sn, Si, Pb, Co, Cr, Cu, Ge, Au, P
d, Pt, S, Se, Ta, Nb, V, Bi, Zr, T
It is effective to add at least one element selected from i, Al, Mn, Mo, Rh, C, N and O. This is because the crystallization of the amorphous mark can be suppressed by adding at least one kind of element selected from the above elements to the recording layer, and the reproduction stability of the signal and the life of the signal can be improved. Because you can. The mechanism is not clear, but these elements enter the spatial gaps of AgInSbTe or form chemical bonds,
It is believed that it forms a compound or alloy with gInSbTe and suppresses crystallization of amorphous marks. So C,
Elements such as N, O, Si, Sn, and Ge having a small atomic radius, a large chemical bonding force with AgInSbTe, and a large number of chemical bonds are effective. The thickness of the recording layer 3 is preferably 12 to 30 nm in consideration of initial characteristics such as jitter and mass production efficiency. It is preferable to form such a recording layer 3 by a sputtering method which is excellent in mass productivity and film quality.

As the recording layer material, a phase change type using an inorganic substance mainly composed of a metal is described, but the present invention mainly uses an organic substance composed of an organic dye.
It can also be applied to an optical recording medium using a write-once recording layer material.

Materials for the first protective layer 2 and the second protective layer 4 include SiO, SiO ₂ , ZnO, SnO ₂ , and Al.
Metal oxides such as ₂ O ₃ , TiO ₂ , In ₂ O ₃ , MgO and ZrO ₂ , nitrides such as Si ₃ N ₄ , AlN, TiN, BN and ZrN, ZnS, In ₂ S ₃ and TaS ₄ Sulfide,
Carbides such as SiC, TaC, B ₄ C, WC, TiC, and ZrC, diamond-like carbon, or a mixture thereof can be used. Like the recording layer 3, the sputtering method is excellent in mass productivity and film quality. It is preferable. First
Since the thickness of the protective layer 2 greatly affects the reflectance,
In order to satisfy the reflectance of 0.15 to 0.25 which is the standard of the CD-RW disc at the reproduction wavelengths of nm and 650 nm, it is preferable that the first protective layer 2 has a thickness of 65 to 130 nm. The thickness of the second protective layer 4 is preferably 20 to 40 nm from the viewpoint of heat resistance, sensitivity and repetitive recording performance.

As the reflection / heat dissipation layer 5, Al, Au, Ag,
A metal material such as Cu, Ta, Ti, or W, or an alloy thereof can be used, and C is added as its additive element.
r, Ti, Si, Cu, Ag, Pd, Ta or the like is used. Such a reflection / heat dissipation layer 5 can be formed by a sputtering method similarly to the recording layer 3 and the first and second protective layers 2 and 4, and the film thickness is preferably 100 to 160 nm.

It is desirable to have an overcoat layer 6 on the reflection / heat dissipation layer 5 as an antioxidant. As the overcoat layer 6, an ultraviolet curable resin produced by spin coating is generally used, and its thickness is preferably 3 to 15 μm from the viewpoint of preventing excessive errors and mechanical properties. Further, the hard coat layer 9 provided under the substrate 1
Similarly to the overcoat layer 6, an ultraviolet curable resin prepared by spin coating is generally used, and its thickness is preferably 2 to 6 μm from the viewpoint of scratch resistance and mechanical properties. It is also effective to mix an electrically conductive material as necessary to prevent static electricity and prevent dust and the like from adhering.

In the optical recording medium 0 having the above layer structure, a design label and a solid color layer are laminated on the overcoat layer 6. The scratch resistance of the optical recording medium can be improved by stacking this layer, which becomes the intermediate layer 7, before stacking the ink-jet printed layer 8.
The use of the colored layer is not a characteristic of the optical recording medium itself, but is effective in expanding the hue of the print image reproduced on the inkjet-printed layer 8 to be subsequently laminated on the uppermost layer. . For the lamination on the overcoat layer 6, a sputtering method, an ion plating method,
Lamination can be performed by a known method such as various vapor deposition methods such as plasma CVD method or various coating methods such as spin coating, spray coating, dip coating, etc., but a general method is coating by screen printing method. Therefore, it is preferable to use an ultraviolet curable resin for the laminated coating layer in view of the production efficiency of the process.

Any number of layers may be laminated on the overcoat layer 6, and colorless and transparent layers may be used other than the uppermost layer of the layers formed at this time. The film thickness of the intermediate layer 7 is not particularly limited, but it is more preferably an intermediate layer having only one layer or an intermediate layer composed of a plurality of layers described above, and in any case, 5 to
It is 30 μm.

Finally, the ink jet layer 8 which is the uppermost layer
Are stacked. Similar to the intermediate layer 7, a screen printing method is suitable for stacking the ink-jet printed layer 8, and an ultraviolet curable resin is used as a material for the coating layer to be stacked due to the production efficiency of the process. Is preferred. In addition, it is desirable that the material of the coating layer used in the ink-jet printed layer has a quick-drying property that can well absorb and fix the ink dots that are dropped during image printing and can suppress bleeding. In particular, most inks used in inkjet printers are anions, so organic fillers and inorganic fillers containing cations are suitable.

In the optical recording medium capable of image printing by the ink jet system of the present invention, the outermost peripheral portion of the ink jet printed layer 8 does not reach the outermost peripheral portion of the laminated layer which is in contact with the lower surface of the ink jet printed layer. It is valid. The coating layer material used for the ink-jet printing layer is required to absorb and fix ink dots that are dropped during image printing and to have fast drying properties. Therefore, it is suitable that the material contains particles having a relatively large particle size such that the surface of the optical recording medium after being coated with the material is rough to the touch, that is, about 10 μm. When the ink-jet printed layer 8 made of such a material is laminated by the screen printing method, the portion directly laminated on the overcoat layer 6 may be different depending on the material and the printing conditions at the time of the screen printing, such as squeegee hardness and pressure. The pressure from the particles in the coating material affects the recording layer 3 and the reflection / heat dissipation layer 5 laminated under the overcoat layer 6, and the defect rate of the relevant part of the optical recording medium increases. In addition, at the same location, the inkjet print layer 8
When the film thickness is extremely thin, the scratch resistance of the optical recording medium becomes insufficient, and the reproduction error rate of the recording signal at the portion corresponding to the scratched portion on the surface of the optical recording medium increases. Therefore, when the ink-jet printed layer 8 is laminated, the ink-jet printed layer 8 is laminated so as not to protrude from the laminated portion of the one or more intermediate layers 7 existing on the overcoat layer 6, that is, the uppermost ink-jet layer 8 It is effective that the outermost peripheral portion of the layer does not reach the outermost peripheral portion of the layer in contact with the lower surface of the inkjet print layer.

The outermost peripheral portion of the ink-jet printed layer 8 is
0.1 to 0.1% more than the outermost periphery of the laminate that contacts the bottom surface
It is preferable to set the inside by a diameter of 3.0 mm. More preferably, when the layers are radially laminated by 0.5 to 2.0 mm inward, it is not directly related to the characteristics of the optical recording medium itself, but the ink ejected in the inkjet image printing is inkjet-printed. When the ink is absorbed in the layer and diffused in the layer, the ink does not overflow to the clamp area or the edge portion of the optical recording medium, and the range of the printed image can be widened.

Further, it is preferable that the adhesion between the uppermost ink-jet printed layer 8 and the layer immediately below it is equal to or more than the adhesion between the overcoat layer 6 and the layer immediately above it. When the adhesion between the ink-jet printed layer 8 and the layer immediately below is weak, the ink-jet printed layer 8 peels from the outermost peripheral side due to rotation of the optical recording medium during high-speed recording and reproduction, and an image is directly formed on the optical recording medium. Printing becomes impossible, or the printed image does not remain on the optical recording medium. This phenomenon is likely to occur especially in a hot and humid environment. In some cases, not only the ink-jet printable layer 8 but also the intermediate layer 7, the overcoat layer 6, the reflection / heat dissipation layer 5, and the recording layer 3 immediately below should also be peeled off in a form sticking to the ink-jet printable layer 8. This makes it impossible to record / reproduce information, which is the original purpose of the optical recording medium. Therefore, the adhesive force between the inkjet print layer 8 and the layer immediately below the inkjet print layer 8 must be such that film peeling does not occur due to rotation of the optical recording medium during high-speed recording and reproduction, and the adhesive force is the inkjet print. The stacking range is wider than that of the layer 8, and the intermediate layer 7 existing on the overcoat layer 6 has the same strength as the intermediate layer 7 that can withstand high-speed recording / reproduction, that is, the adhesive force between the overcoat layer 6 and the layer immediately above it. Alternatively, it may be set higher.

[0027]

EXAMPLES The present invention will be described below with reference to examples.
However, the following examples do not limit the present invention in any way. The phase change type optical recording medium used for the optical disk capable of printing the image on the surface by the ink jet method has a guide groove with a width of 0.5 μm and a depth of 35 nm of 1.2 mm
A thick polycarbonate substrate 1 was molded, and a first protective layer 2, a recording layer 3, a second protective layer 4 and a reflection / heat dissipation layer 5 were sequentially laminated on this substrate by a sputtering method. ZnSSiO ₂ is used for the first protective layer 2 and the second protective layer 4,
The film thicknesses are 90 nm and 30 nm, respectively, and the composition of the recording layer 3 is Ag _4.0 In _6.0 Sb _61.0 Te _29.0 and the film thickness is 18 n.
m. An aluminum alloy is used for the reflection / heat dissipation layer 5, and the substrate / ZnSSiO ₂ (90 nm) / AgInSb is used.
Te (18 nm) / ZnSSiO ₂ (30 nm) / Al
A layer structure of alloy (140 nm) was formed. further,
An overcoat 6 and a hard coat 9 were formed by spin coating an ultraviolet curable resin. This phase change type optical recording medium was subjected to a crystallization treatment on the entire surface of the recording layer of the optical recording medium by an initialization device having a large diameter LD.

After leaving the completed phase change optical recording medium for 24 hours or more in an environment of temperature 25 ° C./humidity of 50%, it becomes a base of the ink jet print layer 8 on the formed overcoat layer 6. The intermediate layer 7 and the inkjet print layer 8 were sequentially laminated. That is, the number of the inkjet print layer 8 and the intermediate layer 7 of the overcoat layer 6 was set to one. These two layers were laminated by applying a solid UV-curable resin as a layer material by a screen printing method and irradiating with ultraviolet rays. By using a white UV curable resin on the overcoat layer 6, that is, as the intermediate layer 7 which is a base of the ink-jet printing layer, it is possible to reproduce the hue of the ink-jet printed image in a wide area, and the film thickness thereof. Is 10 μm in order to obtain sufficient scratch resistance. The adhesive strength of the intermediate layer 7 to the overcoat layer 6 was such that the adhesive layer could not be peeled off even after 30 times of sticking / peeling of Cellotape (registered trademark) on the surface of the intermediate layer. As for the uppermost inkjet-printed layer 8, the rubber hardness of the squeegee used was 80 ° and the pressure was 0.6 MPa as conditions for screen printing. As the coating material, milky white A to E types of UV curable resin are used,
The film thickness was 15 μm. The layered regions of the intermediate layer 7 and the ink-jet printed layer 8 to be solidly coated are set to have radial positions of 19 to 59 mm and 21 to 57 mm, respectively.
Only in Comparative Examples 1 and 2, the laminated area was reversed from that of the example.

The outer peripheral portion (ATIP Time 71:00 to 74: 0) of the optical recording medium shown in Examples and Comparative Examples.
The defect rate of 0) was measured by a defect inspection machine before and after the lamination of the intermediate layer 7 and the ink-jet printed layer 8 and the results are shown in Table 1.
Comparative Example 1 (Coating Material A) and Comparative Example 2 as shown in FIG.
In (Coating material D), the defect rate after lamination was remarkably increased. Among them, in Comparative Example 1, when the laminated regions of the intermediate layer 7 and the inkjet print layer 8 were reversed from Example 1,
This resulted in a large increase in the defect rate in the portion where the inkjet print layer 8 was directly laminated on the overcoat layer 6.

[0030]

[Table 1]

FIG. 2 shows a general optical recording / reproducing apparatus using the optical recording medium according to the present invention. Reference numeral 0 is the above-mentioned optical recording medium. Reference numeral 11 is a drive unit composed of a spindle motor for rotationally driving the optical recording medium 0 , and 12 is a wavelength 780n for recording / reproducing information on / from the optical recording medium.
m is a pickup with NA 0.5, 13 is a drive circuit for driving a laser diode or the like used in the pickup, and 14 is a setting circuit for setting the laser power for recording and reproduction. Using such an optical recording / reproducing apparatus, full-face recording (linear velocity 4.8 m / s) and reproduction (linear velocity 24 m / s) were performed. The phase-change type optical recording medium used for the above defect rate measurement is repeated under a high temperature and high humidity environment of temperature 35 ° C./humidity 85% before sticking / peeling of cellophane tape on the inkjet print layer before recording / reproducing, The same optical recording media as Comparative Example 2 and Comparative Example 3 (Coating Material E) in which the inkjet print layer was peeled off at the 22nd time and the 13th time, respectively, not only in the inkjet print layer at the time of reproduction after recording but also immediately below Film peeling of the intermediate layer, the reflective layer, and the recording layer also occurred. That is, when the adhesive force between the inkjet print layer and the intermediate layer was equal to the adhesive force between the overcoat layer and the intermediate layer (Examples 1 to 3 and Comparative Example 1), no film peeling occurred.

[0032]

As described above, according to the first aspect of the present invention, there is provided an optical recording medium having at least a recording layer on a disk-shaped substrate, wherein an overcoat layer on the surface has a laminate of two or more layers. In an optical recording medium whose layer is the uppermost layer as an inkjet printable layer capable of performing image printing by an inkjet method, the outermost peripheral part of the inkjet printable layer is in contact with the lower surface of the inkjet printable layer. By the optical recording medium, which is characterized in that it does not reach up to the inkjet recording layer, if the ink-jet printing layer overflows the lower layer, the adverse effect on the recording layer due to the pressure of the particles contained in the inkjet-printing layer at the protruding portion is prevented, It is also possible to prevent the adverse effects of the ejected ink jet, and the defect rate of the optical recording medium and the error rate at the time of reproducing the recording signal become excessive. To be able to prevent.

According to a second aspect of the present invention, in the optical recording medium according to the first aspect, the adhesive force between the uppermost ink-jet printed layer and the layer immediately thereunder is such that the adhesive force between the overcoat layer and the layer immediately above it. With an optical recording medium having a strength equal to or higher than the force, it is possible to provide an optical recording medium capable of preventing film peeling of each laminated layer including the inkjet print layer.

[Brief description of drawings]

FIG. 1 is a cross-sectional view schematically showing a configuration example of an optical recording medium according to the present invention.

FIG. 2 is a diagram showing a recording / reproducing apparatus using the optical recording medium according to the present invention.

[Explanation of symbols]

1 substrate 2 First protective layer 3 recording layers 4 Second protective layer 5 Reflective heat dissipation layer 6 Overcoat layer 7 Middle class 8 Inkjet print layer 9 Hard coat layer

Claims (2)

[Claims] 1. An optical recording medium having at least a recording layer on a disk-shaped substrate, wherein two or more layers are laminated on an overcoat layer on the surface, one layer of which is image-printed by an inkjet method. In the optical recording medium existing in the uppermost layer as the ink-jet printed layer that can be, the outermost peripheral portion of the ink-jet printed layer does not reach the outermost peripheral portion of the laminate in contact with the lower surface of the ink-jet printed layer. recoding media. 2. The optical recording medium according to claim 1,
An optical recording medium, wherein the adhesion between the uppermost ink-jet printed layer and the layer immediately below it is equal to or greater than the adhesion between the overcoat layer and the layer immediately above it.