JP2006031793A - Optical recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance design properties of an optical recording medium wherein print can be performed on a label surface side opposite to a light incident surface. <P>SOLUTION: The optical recording medium 10 is provided with a disk body 11 wherein a label surface 11b can be visually confirmed from the light incident surface 11a side, a print layer 12 provided on the label surface 11b of the disk body 11 and an ink reception layer 13 provided on the print layer 12. Thereby, print content of the print layer 12 can be visually confirmed from the light incident surface 11a side and a user can print a desired design on the ink reception layer 13. Not only design properties can be heightened but also possibility that a user mistakes handling of the optical recording medium is reduced and the optical recording mediums can be also visually discriminated for every manufacturer or brand. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an optical recording medium, and more particularly to an optical recording medium capable of printing on a label surface side opposite to a light incident surface.

  In recent years, optical recording media represented by CD (Compact Disc) and DVD (Digital Versatile Disc) have been widely used as recording media for recording large-capacity digital data. In particular, optical recording media of a type that can record data by users are rapidly spreading. If a recordable optical recording medium is used, digital data having a large file size, such as image data and music data, can be stored easily and inexpensively, so that it has been used by many users. As this type of optical recording medium becomes widespread, it is desired to produce an original optical recording medium by printing with a printer on the side opposite to the light incident surface (hereinafter referred to as “label surface”). There is a growing demand, and an optical recording medium capable of realizing this has been developed and sold.

In such an optical recording medium, an “ink receiving layer” for fixing ink is provided on the label surface side, and printing is performed on the label surface side by supplying ink to the ink receiving layer using an ink jet printer. It can be performed.
JP 2002-237103 A

  However, optical recording media capable of printing on the label surface side have a white ink-receiving layer on the majority of the label surface side, so there is room for some design on the label surface side in advance. rare. For this reason, the type of optical recording medium (whether it is write-once type or rewritable type), manufacturer name, brand name, etc. cannot be displayed prominently. As a result, the user can handle the optical recording medium. It was difficult to make a visual distinction between optical recording media by mistake or by manufacturer or brand.

  Accordingly, an object of the present invention is to improve the design of an optical recording medium capable of printing on the label surface side opposite to the light incident surface.

  An optical recording medium according to the present invention includes a disc main body with a label surface visible from the light incident surface side, a printing layer provided on the label surface of the disc main body, and an ink receiving layer provided on the printing layer. It is characterized by providing. As described above, the optical recording medium according to the present invention is provided with the printing layer and the ink receiving layer on the label surface side of the disc body from which the label surface can be viewed from the light incident surface side. In addition to being visible from the light incident surface side, the user can print a desired design on the ink receiving layer. This not only makes it possible to improve the design, but also greatly reduces the possibility that the user mishandles the optical recording medium, and further visually discriminates the optical recording medium by manufacturer or brand. It is also possible to make it.

  In the present invention, the average roughness (Ra) of the surface of the ink receiving layer is preferably 0.1 μm or less. According to this, the print quality when printing with an ink jet printer is improved, and it is possible to obtain color development and gloss, that is, so-called photographic image quality close to a silver salt photograph.

  In the present invention, the light receiving layer preferably has a lightness of 8 or more and a saturation of 4 or less. If the brightness of the ink receiving layer is 8 or more and the saturation is 4 or less, it becomes white or a light color close to this, so it is necessary to interpose a base layer such as white ink between the ink receiving layer and the disc body. The manufacturing process is simplified.

  The colors having lightness of 8 or more and saturation of 4 or less are white (hue: N, lightness: 9.5, saturation: 0 (expressed in the Munsell system, the same applies hereinafter)), snow white (hue: N, lightness). : 9.5, saturation: 0), baby pink (hue: 4R, lightness: 8.5, saturation: 4.0), shell pink (hue: 10R, lightness: 8.5, saturation: 3. 5), nail pink (hue: 10R, lightness: 8.0, saturation: 4.0), peach (hue: 3YR, lightness: 8.0, saturation: 3.5), ecru beige (hue: 7. 5YR, brightness: 8.5, saturation: 4.0), leg horn (hue: 2.5Y, brightness: 8.0, saturation: 4.0), cream yellow (hue: 5Y, brightness: 8.5) , Saturation: 3.5), ivory (hue: 2.5Y, lightness: 8.5, saturation: 1.5), cool white (hue: 10PB, Degrees: 9.5, chroma: 0.5), Cherry Blossom (hue: 10RP, lightness: 9.0, chroma: 2.5) and the like can be exemplified.

  In the present invention, the light receiving layer preferably has a lightness of 9 or more and a saturation of 3 or less. If the brightness of the ink receiving layer is 9 or more and the saturation is 3 or less, higher print quality can be obtained. The colors having a lightness of 9 or more and a saturation of 3 or less are white (hue: N, lightness: 9.5, saturation: 0), snow white (hue: N, lightness: 9.5, saturation: 0). ), Cool white (hue: 10 PB, lightness: 9.5, saturation: 0.5), cherry blossom (hue: 10RP, lightness: 9.0, saturation: 2.5), and the like. .

  In the present invention, it is more preferable that the ink receiving layer has a lightness of 9.2 or more and a saturation of 0.5 or less. If the lightness of the ink receiving layer is 9.2 or more and the saturation is 0.5 or less, it is possible to obtain higher print quality. The colors having a lightness of 9.2 or more and a saturation of 0.5 or less are white (hue: N, lightness: 9.5, saturation: 0), snow white (hue: N, lightness: 9.5), Saturation: 0), cool white (hue: 10 PB, lightness: 9.5, saturation: 0.5), etc. can be exemplified.

  The optical recording medium according to the present invention may further include a base layer provided between the printing layer and the ink receiving layer. In this case, there is no problem that the print layer can be seen through from the ink receiving layer side, so that the thickness of the ink receiving layer can be set to a desired thickness.

  The disc body includes a light transmissive substrate, a support substrate, and a functional layer provided between the light transmissive substrate and the support substrate, and the thickness of the light transmissive substrate and the thickness of the support substrate are approximately equal. Preferably equal. The optical recording medium having such a structure is a so-called DVD type optical recording medium. The disc main body includes a light transmission layer, a support substrate, and a functional layer provided between the light transmission layer and the support substrate, and the thickness of the light transmission layer is thinner than the thickness of the support substrate. It is also preferable. The optical recording medium having such a structure is a next-generation optical recording medium in which a laser beam in a blue wavelength region is used.

  In this case, the functional layer preferably includes a recording layer capable of recording data. This is because such an optical recording medium is a write-once type optical recording medium or a rewritable type optical recording medium, and the user's desire to print on the label surface side is high.

  Thus, according to the present invention, not only can the design of the printable optical recording medium be improved, but also the possibility that the user mishandles the optical recording medium is greatly reduced. It is also possible to visually differentiate optical recording media for each manufacturer.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a cutaway perspective view schematically showing the appearance of an optical recording medium 10 according to a preferred embodiment of the present invention.

  The optical recording medium 10 according to the present embodiment is a disc-shaped optical recording medium having an outer diameter of about 120 mm and a thickness of about 1.2 mm. As shown in FIG. The printing layer 12 is provided on the surface 11 b and the ink receiving layer 13 is provided on the printing layer 12. A central hole 14 is provided at the center of the optical recording medium 10.

  The disc main body 11 has a light incident surface 11a to which a laser beam is irradiated during recording and / or reproduction and a label surface 11b which is the back surface thereof, and the label surface 11b can be visually recognized from the light incident surface 11a side. It has a degree of transparency. The type of the disk main body 11 is not particularly limited, and is a CD-type disk such as CD-ROM, CD-R, CD-RW, a DVD-type disk such as DVD-ROM, DVD-R, DVD-RW, or blue. It is possible to use a next-generation optical disc that uses a laser beam in the wavelength region. However, it is preferable to use a DVD-type disk or a next-generation type optical disk, and in particular, a next-generation type optical disk is used in order to give the label surface 11b transparency so that the label surface 11b can be viewed from the light incident surface 11a side. It is particularly preferred. This is because the required reflectance is relatively low for DVD-type discs and next-generation optical discs, particularly next-generation optical recording media.

  2A and 2B are diagrams showing some examples of the disk main body 11 to which the present invention can be applied. FIG. 2A shows a next-generation type disk, and FIG. 2B shows a cross section of a DVD type disk.

  As shown in FIG. 2A, the next-generation disc has a support substrate 21 having a thickness of about 1.1 mm, one side of which becomes a label surface 11b, and a functional layer provided on the other side of the support substrate 21. 22 and a light transmission layer 23 having a thickness of about 0.1 mm that covers the functional layer 22, and the surface of the light transmission layer 23 serves as the light incident surface 11 a. Therefore, when the next-generation type disk shown in FIG. 2A is used as the disk body 11, the printing layer 12 and the ink receiving layer 13 are provided on the surface (label surface 11b) of the support substrate 21.

  As a material for the support substrate 21, it is necessary to use a transparent material in the visible light region. As a transparent material in the visible light region, a resin such as a polycarbonate resin, a polyolefin resin, an acrylic resin, an epoxy resin, a polystyrene resin, a polyethylene resin, a polypropylene resin, a silicone resin, a fluorine-based resin, an ABS resin, or a urethane resin is preferably cited. Can do. Among these, it is particularly preferable to use a polycarbonate resin or a polyolefin resin for reasons such as excellent workability.

  On the other hand, the material of the light transmission layer 23 is transparent in the visible light region and transparent in the wavelength region of the laser beam (for example, about 405 nm) because it is an optical path of the laser beam irradiated during recording and / or reproduction. It is necessary to use materials. Preferred examples of such a material include acrylic or epoxy ultraviolet curable resins. Moreover, you may form the light transmissive layer 23 using the light transmissive sheet | seat which consists of light transmissive resin, various adhesive agents, or an adhesive instead of the film | membrane which hardens ultraviolet curable resin.

  The structure and material of the functional layer 22 vary depending on the type of disk. That is, in the case of a ROM type disc, the functional layer 22 can be constituted by the reflective layer 22a as shown in FIG. 3, and in the case of a write-once disc, the functional layer 22 is composed of the reflective layer 22a and the reflective layer 22a as shown in FIG. In the case of a rewritable disc, the functional layer 22 includes a recording layer 22b and a plurality of dielectric layers sandwiching the recording layer 22b as shown in FIG. 22c and the reflective layer 22a. However, since the optical recording medium targeted by the present invention is an optical recording medium capable of printing on the label surface side, it is intended for a write-once disc (FIG. 4) and a rewritable disc (FIG. 5). It is preferable to do.

In the present invention, since it is necessary to be able to visually recognize the label surface 11b from the light incident surface 11a side, it is necessary to select a material with high transparency for each layer. Therefore, the material of the reflective layer 22a is not a metal material with high reflectivity such as an alloy mainly composed of aluminum (Al) or silver (Ag), but a predetermined material such as silicon (Si) or titanium oxide (TiO ₂ ). It is preferable to select or omit a material having the above reflectivity and high transmittance. For recording layer 22b is oxygen if the write-once disc, the dielectric base material and materials magnesium (ZnS and SiO such as ₂ mixture) (Mg) and / or aluminum (Al) is added, and bismuth (Bi) It is preferable to use a material mainly composed of (O), and in the case of a rewritable disc, it is preferable to use a phase change material. The dielectric layer 22c, it is preferable to use a mixture including a transparent dielectric material of ZnS and SiO _2. If such a material is selected, the disc main body 11 becomes almost transparent, and the label surface 11b can be viewed from the light incident surface 11a side. The recording layer containing bismuth (Bi) and oxygen (O) as main components becomes transparent when the oxygen ratio is 63 atomic% or more.

  On the other hand, as shown in FIG. 2B, the DVD-type disc has a light-transmitting substrate 31 having a thickness of about 0.6 mm with one surface serving as a light incident surface 11a and one surface serving as a label surface 11b. A dummy substrate (support substrate) 32 having a thickness of about 0.6 mm, a functional layer 33 provided on the other surface of the light transmissive substrate 31, a protective layer 34 covering the functional layer 33, a light transmissive substrate 31, An adhesive layer 35 for adhering the laminate including the functional layer 33 and the protective layer 34 and the dummy substrate 32 is provided. Therefore, when the DVD-type disk shown in FIG. 2B is used as the disk body 11, the printing layer 12 and the ink receiving layer 13 are provided on the surface (label surface 11b) of the dummy substrate 32.

  As a material for the light transmissive substrate 31, it is necessary to use a material that is transparent in the visible light region and transparent in the wavelength region of the laser beam (for example, about 650 nm). Must be transparent. As such a material, a material exemplified as a preferable material of the support substrate 21 such as a polycarbonate resin or a polyolefin resin may be selected. In addition, as a material for the protective layer 34 and the adhesive layer 35, it is necessary to select a material that is transparent in the visible light region, such as an ultraviolet curable resin. The structure and material of the functional layer 33 differ depending on the type of disc as in the next-generation type optical recording medium, but in a write-once DVD type disc such as a DVD-R, an organic dye is generally used as a material for the recording layer. Therefore, it is considered difficult to apply the present invention to a write-once DVD type disc.

  Although not particularly limited, in the present invention, it is most preferable to select a next-generation disk as the disk body 11. This is because the next generation type optical recording medium having a high recording density has a low required reflectance and a high transparency is easily obtained.

  Next, the printing layer 12 and the ink receiving layer 13 provided on the label surface 11b side of the disc body 11 will be described.

  The print layer 12 is a layer composed of ink or the like, and is provided to give a desired design to the light incident surface 11 a side through the disc body 11. However, since the printing layer 12 is covered with the ink receiving layer 13, the design cannot be viewed from the side opposite to the light incident surface 11a. The printing content of the printing layer 12 is not particularly limited, but the type, manufacturer name, brand name, and the like of the optical recording medium can be displayed. Since the printed content of the printing layer 12 is visible from almost the entire surface of the light incident surface 11a, not only can the design of the optical recording medium be greatly improved, but also the type, manufacturer name, brand name, etc. of the optical recording medium. It can be displayed prominently. As a result, the possibility that the user will mishandle the optical recording medium is greatly reduced, and the optical recording medium can be visually differentiated by manufacturer or brand.

  The ink receiving layer 13 is a layer constituting one outermost layer of the optical recording medium 10 and plays a role of receiving and fixing ink supplied from an ink jet printer. In this embodiment, the ink receiving layer 13 is colored white (hue: N, lightness: 9.5, saturation: 0) by the addition of a white pigment. As a material for the ink receiving layer 13, it is preferable to use a material in which a hydrophilic resin such as polyvinyl alcohol or polyvinyl acetal is a main component and a cationic polymer or the like as an ink fixing agent is mixed. Examples of white pigments to be added include titanium oxide, zinc oxide, aluminum oxide, aluminum hydroxide, lead white (basic lead carbonate), strontium titanate, calcium carbonate, mica, barium sulfate, silica, talc, carion clay, Preferred examples include rholite clay and zeolite. Among them, it is most preferable to select titanium oxide having a high refractive index and capable of developing color with a small amount.

  The particle size of the white pigment is preferably fine for the purpose of reducing the surface roughness. Specifically, the thickness is preferably 0.1 to 1.0 μm. When titanium oxide is used as the white pigment, the particle size is particularly preferably 0.1 to 0.3 μm. The addition amount of the white pigment is preferably about 2 to 20 wt% with respect to the resin. This is because if it is less than 2 wt%, the effect of whitening cannot be sufficiently obtained, and if it exceeds 20 wt%, the smoothness is lowered and curing by ultraviolet rays is hindered. In order to adjust the white hue, other coloring pigments, organic pigments, and dyes may be used in combination.

  The smaller the average roughness (Ra) of the surface of the ink receiving layer 13, the better the print quality when printing with a printer, in particular the color development and gloss. In order to obtain color development and luster close to a silver salt photograph, so-called photographic image quality, it is preferable that the average roughness (Ra) of the surface of the ink receiving layer 13 is 0.1 μm or less. The thickness of the ink receiving layer 13 is not particularly limited, but is preferably set to 10 μm or more and 30 μm or less.

  The ink receiving layer 13 is preferably formed by spin coating or slit coating. As is well known, the spin coating method applies a coating liquid (a liquid obtained by diluting the material of the ink receiving layer 13 dissolved in a solvent with water or another solvent) to the surface of the object to be processed (disk main body 11). 11b) is a method of dripping at or near the center, rotating the object to be treated, and spreading the coating liquid in the outer peripheral direction by centrifugal force. On the other hand, the slit coating method is a method in which the coating liquid is supplied from the slit provided in the head and the coating liquid is spread on the surface of the processing object by moving the relative position between the head and the processing object. is there.

  The reason why the spin coating method or the slit coating method is preferably used in forming the ink receiving layer 13 is that the average roughness (Ra) of the surface can be reduced by using these coating methods.

  As a coating solution used for spin coating or slit coating, water is preferably used as a solvent in addition to the above-described hydrophilic resin and white pigment, but for adjusting the solubility of the resin and the drying property of the coating film, alcohols and the like are used. A hydrophilic organic solvent may be mixed with the solvent. When mixing a hydrophilic organic solvent with a solvent, it is preferable to set the density | concentration to 20-100 weight part with respect to 720 weight part of water.

  The concentration of the hydrophilic resin is preferably set to 80 to 90 parts by weight with respect to 720 parts by weight of water as a solvent. The concentration of the white pigment is preferably set to 5 to 15 parts by weight with respect to 720 parts by weight of water as a solvent. If the concentration of the hydrophilic resin and the white pigment is set within this range, it is possible to form a coating film having a uniform film thickness and high smoothness during spin coating or slit coating.

  Further, it is preferable to add a surfactant to the coating solution. The type of surfactant may be appropriately selected according to the type of white pigment or hydrophilic resin. The concentration of the surfactant is preferably set to 0.1 to 0.5 parts by weight with respect to 720 parts by weight of water as a solvent.

  Further, it is more preferable to add colloidal silica to the coating solution. If colloidal silica is added, glossiness can be added to the surface of the ink receiving layer 13. In this case, for the stability of the coating material, silica having a cationic surface treatment is preferable. The concentration of colloidal silica is preferably set to 20 to 30 parts by weight with respect to 720 parts by weight of water as a solvent.

  When the spin coating method or the slit coating method is used, the film thickness distribution of the ink receiving layer 13 tends to be larger than when the screen printing method is used. Since it is formed, the film thickness distribution hardly affects the print quality.

  When the ink receiving layer 13 is formed by the spin coating method or the slit coating method, the surface property of the base is greatly reflected, unlike the case of using the screen printing method. That is, the average roughness (Ra) of the underlayer appears as it is as the average roughness (Ra) of the surface of the ink receiving layer 13. Therefore, if the average roughness (Ra) of the printing layer 12 is 0.1 μm or less, the average roughness (Ra) of the surface of the ink receiving layer 13 can also be 0.1 μm or less.

  As described above, the optical recording medium 10 according to the present embodiment is provided with the printing layer 12 and the ink receiving layer 13 on the label surface 11b side of the transparent disc body 11, so that the printing contents of the printing layer 12 are displayed. While being visible from the light incident surface 11 a side, the user can print a desired design on the ink receiving layer 13. This not only makes it possible to improve the design, but also greatly reduces the possibility that the user mishandles the optical recording medium, and further visually discriminates the optical recording medium by manufacturer or brand. Can be realized.

  Moreover, in the optical recording medium 10 according to the present embodiment, since the ink receiving layer 13 itself is colored white, it is necessary to interpose a base layer such as white ink between the ink receiving layer 13 and the printing layer 12. In addition, the manufacturing process can be simplified.

  FIG. 6 is a cutaway perspective view schematically showing the appearance of an optical recording medium 40 according to another preferred embodiment of the present invention.

  The optical recording medium 40 according to the present embodiment is different from the optical recording medium 10 according to the above-described embodiment in that a base layer 41 is provided between the printing layer 12 and the ink receiving layer 13. Since the other points are the same as those of the optical recording medium 10, the same elements are denoted by the same reference numerals, and redundant description is omitted.

  The base layer 41 is provided as a base of the ink receiving layer 13 for the purpose of improving the printing quality mainly by improving the color development. Therefore, in the optical recording medium 40 according to the present embodiment, the ink receiving layer 13 does not need to be colored white and may be transparent.

  As the material of the underlayer 41, it is preferable to use an ultraviolet curable resin, in particular, an ultraviolet curable acrylic resin having a low shrinkage rate. In this embodiment, white (hue: N, brightness: 9. 5 and saturation: 0). Examples of the white pigment to be added include materials preferable as the white pigment to be added to the ink receiving layer 13 of the optical recording medium 10 according to the above embodiment. The same applies to the particle size and addition amount of the white pigment.

  The average roughness (Ra) of the surface of the underlayer 41 is preferably 0.1 μm or less. This is because the average roughness (Ra) of the ink receiving layer 13 provided on the surface can be easily set to 0.1 μm or less.

  As described above, the optical recording medium 40 according to the present embodiment is provided with the base layer 41 between the printing layer 12 and the ink receiving layer 13, so that the printing layer 12 can be seen through from the ink receiving layer 13 side. Such a problem can be surely prevented. Thereby, the thickness of the ink receiving layer 13 can be set to a desired thickness.

  The present invention is not limited to the embodiments described above, and various modifications are possible within the scope of the invention described in the claims, and these are also included in the scope of the present invention. Needless to say.

  For example, in each of the above embodiments, the print layer 12 is directly formed on the label surface 11b of the disc body 11, but the label surface 11b of the disc body 11 is not affected as long as the visibility from the light incident surface 11a side is not impaired. Other layers may be interposed between the printing layer 12 and the printing layer 12.

  Further, in each of the above embodiments, the ink receiving layer 13 and the base layer 41 are colored white by the addition of the white pigment, but the white color is not added to the ink receiving layer 13 or the base layer 41 itself. By using a material or the like, the brightness may be 8 or more and the saturation may be 4 or less.

  Further, each of the optical recording media 10 and 40 according to each of the above embodiments has a disk shape with a thickness of about 1.2 mm and a diameter of about 120 mm, but the disk to which the present invention can be applied is limited to this. It is not something. Moreover, it is not essential that the outer shape is a disk shape, and the light incident surface 11a and the label surface 11b may be rectangular.

  Hereinafter, although the Example of this invention is described, this invention is not limited to this Example at all.

  [Example 1]

  An optical recording medium having the same structure as the optical recording medium shown in FIG. 1 was produced by the following method. The disc body has a structure shown in FIG.

  First, a disk-shaped support substrate made of polycarbonate having a thickness of about 1.1 mm and a diameter of about 120 mm and having a land and a groove formed on the surface was produced by an injection molding method. The groove depth was set to about 21 nm, and the groove width was set to about 169 nm. The track pitch was set to about 320 nm.

Next, the support substrate is set in a sputtering apparatus, and a land and a groove are formed using both a mixed target mainly composed of ZnS and SiO ₂ and a target mainly composed of magnesium (Mg). A recording layer having a thickness of 32 nm was formed on the surface of the film by sputtering. The compositions of Zn, Si, Mg, O, and S contained in the recording layer were 21.5, 10.1, 20.8, 20.1, and 27.5 atomic%, respectively. The analysis of the composition was performed using a fluorescent X-ray analyzer ZSX100e manufactured by Rigaku Corporation.

  Next, an acrylic ultraviolet curable resin was coated on the recording layer by a spin coating method, and this was irradiated with ultraviolet rays to form a light transmission layer having a thickness of about 100 μm. The disc body thus produced was almost transparent.

  Then, a printing layer was formed on the label surface of the disc body by screen printing, and an ink receiving layer was formed on the surface by slit coating. The printed content of the printed layer was clearly visible from the light incident surface side, but the ink receiving layer was opaque and the printed content of the printed layer could not be visually recognized through this. The conditions for forming the ink receiving layer are as follows.

  First, 10 parts by weight of titanium oxide A-190 made by Sakai Chemical as a white pigment, 85 parts by weight of polyvinyl alcohol as hydrophilic resin, 25 parts by weight of SNOWTEX AK made by Nissan Chemical as colloidal silica, and made by Nippon Oil and Fats as a surfactant 0.2 parts by weight of a surfactant and 720 parts by weight and 40 parts by weight of water and isopropyl alcohol as solvents were mixed to prepare a coating solution. In preparing the coating solution, first, a hydrophilic resin (polyvinyl alcohol) was dissolved in water, and then the remaining materials were added and mixed with stirring.

  Next, the said coating liquid was apply | coated to the surface of the printing layer using the slit coat apparatus. The slit width of the slit coater is 0.08 mm at the innermost circumference and 0.12 mm at the outermost circumference, and the disk body is rotated at 14 rpm, so that the slit coat is within a radius of 20 mm to 58 mm from the center of the disk body. did. The coating was leveled by rotating the disk body at 100 rpm for 15 seconds, and then the coating was dried at 80 ° C. for 5 minutes. As a result, an ink receiving layer having a thickness of 20 μm was formed.

  When the hue, lightness, and saturation of the ink receiving layer thus formed were measured, the hue was N, the lightness was 9.5, and the saturation was 0. Moreover, when the surface roughness (Ra) was measured, it was about 0.05 μm.

  In addition, when printing was performed on the ink receiving layer using an ink jet printer, color development and gloss similar to a silver salt photograph were obtained.

  [Example 2]

In forming the recording layer, sputtering is performed using both a mixed target mainly composed of LaSiON (a mixture of La ₂ O ₃ , SiO ₂ and Si ₃ N ₄ ) and a target mainly composed of magnesium (Mg). Otherwise, an optical recording medium of Example 2 was produced in the same manner as Example 1. The thickness of the recording layer is about 32 nm, and the composition of La, Si, Mg, O, and N contained in the recording layer is 6.2, 24.1, 23.1, 24.6, 22.0, respectively. Atomic%. The disc main body was almost transparent like the disc main body constituting the optical recording medium of Example 1.

  Also in the optical recording medium of Example 2, the print content of the print layer was clearly visible from the light incident surface side, but the ink receiving layer was opaque, and the print content of the print layer was changed through this. It was not possible to see.

  [Example 3]

  An optical recording medium of Example 3 was produced in the same manner as in Example 1 except that in the formation of the recording layer, sputtering was performed in a argon and oxygen atmosphere using a target containing bismuth (Bi) as a main component. The thickness of the recording layer was about 45 nm, and the compositions of Bi and O contained in the recording layer were 27 atomic% and 73 atomic%, respectively. The disc main body was almost transparent like the disc main body constituting the optical recording medium of Example 1.

  Also in the optical recording medium of Example 3, the printed content of the printed layer was clearly visible from the light incident surface side, but the ink receiving layer was opaque, and the printed content of the printed layer was changed through this. It was not possible to see.

1 is a cutaway perspective view schematically showing the appearance of an optical recording medium 10 according to a preferred embodiment of the present invention. It is a figure which shows some examples of the structure of the disc main body 11, (a) is a next generation type disc, (b) has shown the cross section of the DVD type disc, respectively. It is a schematic sectional drawing which shows the structure of the functional layer 22 in a ROM type disc. It is a schematic sectional drawing which shows the structure of the functional layer 22 in a write-once disc. It is a schematic sectional drawing which shows the structure of the functional layer 22 in a rewritable disc. It is a notch perspective view which shows typically the external appearance of the optical recording medium 40 by other preferable embodiment of this invention.

Explanation of symbols

10, 40 Optical recording medium 11 Disc body 11a Light incident surface 11b Label surface 12 Print layer 13 Ink receiving layer 14 Center hole 21 Support substrate 22, 33 Functional layer 22a Reflective layer 22b Recording layer 22c Dielectric layer 23 Light transmission layer 31 Light Transparent substrate 32 Dummy substrate 34 Protective layer 35 Adhesive layer 41 Underlayer

Claims (4)

  A light comprising: a disc main body with a label surface visible from a light incident surface side; a printing layer provided on the label surface of the disc main body; and an ink receiving layer provided on the printing layer. recoding media.   The optical recording medium according to claim 1, wherein an average roughness (Ra) of the surface of the ink receiving layer is 0.1 μm or less.   The optical recording medium according to claim 1, wherein the ink receiving layer has a lightness of 8 or more and a saturation of 4 or less. The optical recording medium according to claim 1, further comprising a base layer provided between the printing layer and the ink receiving layer.

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