JPH09274738A - Optical disk - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make possible displaying a character or a pattern ranging a large area by providing a printed layer printing the character or the pattern between transparent substrates. SOLUTION: When an information surface 2 is reproduced, the transparent substrate 1 side is irradiated by reproducing laser light. The information is reproduced by a change of a return light quantity of the reflected laser light. Further, though the laser light transmitting through a translucent film 3 arrives at the printed layer 5 to be reflected and absorbed, since the printed layer 5 is formed on a position shifted from a focal position of an objective lens, its return light doesn't affect the quality of the reproduced signal. On the other hand, visible region white light incident from the transparent substrate 1 arrives at the printed layer 5 through the information surface 2, the translucent film 3 and a protection film 4, and the printed character or pattern is visible by reflection light from the printed 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 disc having a plurality of transparent substrates having one or a plurality of information surfaces.

[0002]

2. Description of the Related Art Microscopic depressions (pits) corresponding to recorded information are formed on one surface of a transparent substrate, and a laser beam is focused on the information recording surface having the pits through the transparent substrate. A compact disc (CD: Compact Disc) is used as an optical disc for irradiating and reproducing the information recorded on the information surface by the change of the reflected light amount of the laser light.
Is mentioned.

A CD has a diameter of 120 mm and a thickness of 1.2 mm.
The pit row having the shortest pit length of about 0.9 μm is formed on the transparent substrate with a track pitch of 1.6 μm. The linear velocity during reproduction is constant at about 1.3 m / s, about 650
It has a recording capacity of M bytes and stores digital data such as music. CD-ROM (Compact Disc-Read Only Memor) format is compatible with the CD standard.
y), Video-CD (Video-Compact Disc), and the like.

The CD has a single plate structure composed of one transparent substrate and has one information recording surface. Since laser irradiation is performed through the transparent substrate for reproduction, characters or a pattern representing the title of the disc or the like is printed on the surface of the transparent substrate opposite to the laser incident side.

On the other hand, in recent years, there is a DVD (Digital Video Disc) whose recording density is several times higher than that of a CD. This DVD has a structure in which two single-plate substrates on which one piece of information is recorded are bonded together, and a first information surface and a second information surface are formed in two layers on one substrate. There are some of the configurations. There are single-sided reproduction and double-sided reproduction as reproduction methods for reading information from these DVDs.

FIG. 6 is a schematic view showing a schematic cross section of a conventional optical disc. As shown in FIG. 6, the structure of the optical disk for double-sided reproduction is as follows: a first transparent substrate 1 having a diameter of 120 mm and a thickness of 0.6 mm, a first information surface 2 and a first reflective film 22.
Also has a diameter of 120 mm and a thickness of 0.6 m.
The second information surface 8 and the second reflective film 23 are formed on the second transparent substrate 7 of m, and the first transparent substrate 1 and the second transparent substrate 7 are adhesive layers such as an ultraviolet curable resin. It is the structure pasted together by 13. First reflective film 22 and second reflective film 2
3 is aluminum (A
l), metal such as gold (Au), the information recorded on the first information surface 2 is reproduced through the first transparent substrate 1 and the information recorded on the second information surface 7. Is reproduced through the second transparent substrate 7.

On the other hand, the structure of an optical disc for single-sided reproduction is as follows.
Instead of the metal reflection film only on the surface of the first information surface 1, a silicon nitride (S) that transmits a part of the laser beam and reflects the rest is used.
ixNy), aluminum nitride (AlxNy), or the like.
Also, the second information surface 7 is formed via the transparent adhesive layer 13 having a thickness of several tens of μm, and both are reproduced through the first transparent substrate 1.

[0008]

However, since the optical disk for double-sided reproduction reproduces the information through the light beam through both the first transparent substrate and the second transparent substrate, the characters or the information relating to the information recorded on the optical disk are reproduced. The picture cannot be displayed on the entire surface.

Therefore, in the case of printing a character such as a title or a pattern on an optical disk for double-sided reproduction, printing must be performed in an area where no information is recorded, that is, an area where the reproducing apparatus holds the optical disk. The characters or patterns may be damaged by holding the optical disk, or the characters or patterns may be difficult to read because the display range is narrow.

Also in the optical disk for single-sided reproduction, characters or patterns are printed by being exposed on the surface of the transparent substrate on which the light beam does not enter, so that the characters or patterns may be damaged by external factors.

Therefore, an object of the present invention is to provide an optical disk capable of displaying a character or a pattern relating to information recorded on an optical disk having two transparent substrates over a large area.

[0012]

The present invention according to claim 1 is formed on at least one of a first transparent substrate, a second transparent substrate, and a first transparent substrate or a second transparent substrate. The optical disc having at least one information surface is characterized in that a print layer on which characters or patterns are printed is provided between the first transparent substrate and the second transparent substrate.

According to a second aspect of the present invention, a first transparent substrate having a first semitransparent film formed on one surface of a first transparent substrate and a second transparent substrate. A second substrate in which a second semitransparent film is formed on a second information surface formed on one surface of the substrate, and the first semitransparent film and the second semitransparent film are attached by an adhesive layer. The combined optical disc is characterized in that a printing layer having a character or a pattern printed thereon is formed on at least one of the first semitransparent film and the adhesive layer or the second semitransparent film and the adhesive layer.

According to a third aspect of the present invention, the first transparent substrate has a first information film formed on one surface of the first transparent substrate and a first reflective film formed on the first information surface, and a second transparent substrate. And a second substrate having a second reflective film formed on a second information surface formed on one surface of the optical disc, wherein the first reflective film and the second reflective film are bonded together by an adhesive layer. , The first reflective film and the second reflective film have a high reflectance with respect to the laser wavelength of the light beam with which the first information surface and the second information surface are irradiated and a high transmission with respect to other laser wavelengths. And a printing layer having a character or a pattern printed on at least one of the first reflective film and the adhesive layer or the second reflective film and the adhesive layer.

According to a fourth aspect of the present invention, a first transparent substrate, a second transparent substrate, a first transparent substrate or a second transparent substrate.
An optical disc having at least one information surface formed on at least one of the transparent substrates, the first substrate having a semitransparent film formed on at least one information surface formed on one surface of the first transparent substrate, A second transparent substrate having a printed layer on which characters or patterns are printed, and an adhesive layer for bonding the semitransparent film of the first substrate and the printed layer of the second substrate together. There is.

According to the present invention of claim 5, at least one information is formed on at least one of the first transparent substrate, the second transparent substrate, and the first transparent substrate or the second transparent substrate. In an optical disk having a surface, the optical disk having a high reflectance with respect to a laser wavelength of a light beam for irradiating at least one information surface formed on one surface of the first transparent substrate has a high transmittance with respect to another laser wavelength. A first substrate having a reflective film formed thereon, a second substrate having a second transparent substrate provided with a print layer having characters or patterns printed thereon, and a reflective film of the first substrate and the print layer of the second substrate bonded together It is characterized by including an adhesive layer.

The present invention according to claim 6 provides the invention according to claim 4.
And the optical disk according to claim 5, wherein the second substrate is
It is characterized by comprising a first print layer on which characters or patterns relating to the first information are printed and a second printing layer on which characters or patterns relating to second information different from the first information are printed.

In the optical disc of the present invention, since the printing layer on which characters or patterns are printed is formed between the first transparent substrate and the second transparent substrate, a large area can be obtained without deteriorating the recording / reproducing characteristics of information. Characters or patterns can be displayed over the entire length, and the characters or patterns can be visually recognized from the transparent substrate side of the optical disc.

Further, in an optical disc in which the first substrate and the second substrate are bonded together, a printing layer on which characters or patterns such as the title of the disc are printed is formed on the adhesive layer where the first substrate and the second substrate are bonded together. The first reflection film and the second
Since the reflective film of is a semi-transparent film, it is possible to display a character or a pattern over a large area without deteriorating the recording / reproducing characteristics of information, and the character or the pattern can be visually observed from the transparent substrate side of the optical disc. Can be recognized.

Further, in the optical disc of the present invention, since two printing layers can be formed over the entire surface of the optical disc, it is possible to display more characters or patterns than the conventional single-sided reproduction type optical disc. Each character or pattern can be visually recognized from both sides.

Also, since the printed characters or patterns are not exposed to the outside of the optical disk,
Characters or pictures are not damaged by external factors.

[0022]

1 is a schematic diagram showing a schematic cross section of an embodiment of an optical disc of the present invention. In FIG. 1, the structure of the optical disc of the present invention comprises a first transparent substrate 1, a first information surface 2, a first semitransparent film 3, a first protective layer 4 and a first printing layer 5. A first substrate 6, a second transparent substrate 7, a second information surface 8, a second semi-transparent film 9, a second protective layer 10 and a second substrate 12 having a second printed layer 11; The first printed layer 5 of the substrate 6 and the second printed layer of the second substrate 12
The printed layers 11 of the above are opposed to each other, and are adhered by the adhesive layer 13.

The first substrate 6 has a first transparent substrate 1 and a first information surface 2 on which information is recorded with minute irregularities.
The first information surface 2 is covered with a first semitransparent film 3, and the first semitransparent film 3 is a semitransparent material that transmits a part of the laser beam at the time of reproduction and reflects the rest. . The material of the first translucent film 3 is specifically a dielectric material such as silicon nitride (SiXNY) or aluminum nitride (AlXNY), low lead oxide (Px).
An oxide such as bXOY) or a chalcogen-based material such as antimony sulfide (SbXSY) is used.

The first semitransparent film 3 is covered with a first protective layer 4 such as an ultraviolet curable resin, and a first printed layer 5 is formed on the first protective layer 4. Characters or patterns are printed on the first printing layer 5 by a silk screen printing method or the like. The ink used for printing is a mixture of an ultraviolet curable resin and a colored dye.

The second substrate 12 is formed in the same structure as the first substrate 6, and the first substrate 6 and the second substrate 12 are the first substrate 6 and the first substrate 6.
So that the printed layer 5 and the second printed layer 11 face each other, that is, the first transparent substrate 1 and the second transparent substrate 7 are on the outside, and the first printed layer 5 and the second printed layer 11 are on the inside. The first printed layer 5 and the second printed layer 11 are bonded to each other via the adhesive layer 12.

The reproduction of the optical disc having the above-mentioned structure will be described. For example, when reproducing the first information surface 2, a reproducing laser beam (not shown) is irradiated from the first transparent substrate 1 side. The laser light is converged on the first semitransparent film 3 by an objective lens (not shown), but the first semitransparent film 3 partially transmits and reflects the rest. Information is reproduced by a change in the amount of reflected light of the reflected laser light.

The laser light transmitted through the first semitransparent film 3 reaches the first printed layer 5 and is reflected and absorbed,
Since the first printed layer 5 is formed at a position deviated from the focal position of the objective lens, the returning light does not affect the quality of the reproduced signal.

On the other hand, the visible white light incident from the first transparent substrate 1 receives the first information surface 2, the first semitransparent film 3 and the first transparent film 3.
It reaches the first printed layer 5 through the protective film 4 and the reflected characters from the first printed layer 5 allow the printed characters or patterns to be visually observed.

Therefore, according to the bonded type optical disk of the present invention, the print layer on which the label of the optical disk is printed is formed inside the semitransparent film which transmits or reflects the laser beam when viewed from the transparent substrate, that is, Since it is formed at a position deviated from the focus position of the reproduction laser light, the laser light transmitted through the semitransparent film does not affect the quality of the reproduction signal. Further, the visible white light transmitted through the semitransparent film is reflected by the printing layer, so that the printed characters or patterns can be visually observed.

Next, a method of manufacturing the optical disc of the present invention will be described. FIG. 2 is a schematic view showing an embodiment of the manufacturing process of the optical disc of the present invention. (A) is an information surface forming step, (b) is a semitransparent film forming step,
(C) is a protective layer forming film, (d) is a printing layer forming process, (e) is a bonding process. FIG.
As shown in (a), by using the first stamper 14 or the second stamper 15 on which the signal to be recorded is formed, the first information surface is formed on the first transparent substrate 1 or the second transparent substrate 7. Two
Alternatively, the second information surface 8 is formed by injection molding. The first transparent substrate 1 or the second transparent substrate 7 has a diameter of 120 mm,
It has a thickness of 0.6 mm and a central hole diameter of 15 mm.
It is a transparent resin such as polycarbonate.

Next, as shown in FIG. 2B, the first semitransparent film 3 or the first semitransparent film 3 is formed on the first information surface 2 or the second information surface 8 formed by injection molding by a sputtering method or the like. The second semi-transparent film 9 is formed. First translucent film 3 or second
The semi-transparent film 9 has a reflectance of about 25 to 40% with respect to a laser wavelength of 635 nm to 650 nm and transmits the rest.

Next, as shown in FIG. 2C, the first protective layer 4 or the second protective layer 4 is formed on the first semitransparent film 3 or the second semitransparent film 9 by spin coating or the like. The protective layer 10 is formed. The first protective layer 4 or the second protective layer 10 is an ultraviolet curable resin or the like. The ultraviolet curable resin is a resin which is applied to an optical disk by a spin coating method and then cured by being irradiated with ultraviolet rays.

Next, as shown in FIG. 2 (d), the first printing layer 5 or the second printing layer is formed on the first protection layer 4 or the second protection layer 10 by the silk screen printing method or the like. 11 is formed. As a result, the first substrate 6 and the second substrate 12 are manufactured. The first printing layer 5 or the second printing layer 11 is formed by applying inks of a single color in an overlapping manner to form characters or patterns, and irradiating ultraviolet rays to cure the inks for printing.

Then, as shown in FIG. 2E, an adhesive layer 13 is formed on the first printed layer 5 or the second printed layer 11 of the first substrate 6 or the second substrate 12 by spin coating or the like. By coating and bonding the first substrate 6 and the second substrate 12 together, a bonded optical disk can be manufactured.

Although the bonded type optical disk of the present invention can be manufactured by the above-mentioned steps, it is not limited to the structure or manufacturing method of the optical disk. That is, in the process described above, the first semi-transparent film 3 or the second semi-transparent film 3
The first print layer 5 or the second print layer 11 on the semi-transparent film 9 of
To directly form the first printed layer 5 or the second printed layer 11
May be bonded with the adhesive layer 13 that also serves as the first protective layer 4 or the second protective layer 10. With such a configuration, the number of manufacturing steps can be reduced.

FIG. 3 is a schematic diagram showing a schematic cross section in the case where the information surface of the optical disc of the present invention is one layer. In FIG. 3, the first substrate 6 has an information surface 17 formed on the first transparent substrate 16 by injection molding using a stamper (not shown). A reflective film 18 of Al or the like is formed on the information surface 17 by a sputtering method or the like, and an adhesive layer 13 is formed on the reflective film 18 by a spin coat method or the like. The second substrate 12 has a printing layer 20 formed on one side of a transparent smooth substrate 19 by a silk printing method or the like. Then, by bonding the adhesive layer 13 of the first substrate 6 and the printed layer 20 of the smooth substrate 19 to each other, a bonded optical disk can be manufactured.

In the above-mentioned bonded optical disk, a protective layer is formed on the reflective film 18, and the print layer 2 is formed on the protective layer.
It may be configured to form 0. Alternatively, the print layer 20 may be directly formed on the reflective film 18. further,
A semitransparent film may be used instead of the reflective film 18. In this case, the character or the pattern can be recognized from both sides of the optical disc.

FIG. 4 is a schematic diagram showing a schematic cross section in the case where the optical disc of the present invention has two printing layers. In FIG. 4, the first substrate 6 has an information surface 17 formed on the transparent substrate 16 by injection molding using a stamper (not shown). The semitransparent film 21 is formed on the information surface 17 by a sputtering method or the like, and the adhesive layer 13 is formed on the semitransparent film 21 by a spin coating method or the like. The second substrate 12 has the first printed layer 5 formed on one surface of the smooth substrate 19 by a silk printing method or the like, and the second printed layer 11 is formed on the first printed layer 5. Then, by bonding the adhesive layer 13 of the first substrate 6 and the second printed layer 11 of the second substrate 12 to each other, a bonded optical disk can be manufactured.

On the second substrate 12, the first printed layer 5
For example, a character or a pattern relating to the title or artist of the optical disk is printed. Further, on the second print layer 11, the recorded tracks and track order of the optical disc are printed. In this way, by printing a lot of information such as titles or songs on the first print layer 5 and the second print layer 11, more characters or patterns relating to the information recorded on the optical disc can be displayed. You can Moreover, since it is not necessary to form the protective layer, the number of manufacturing steps can be reduced.

On the second substrate, the first printed layer 5
The adhesive layer 13 may be formed between the second printed layer 11 and the second printed layer 11, and the second substrate 12 and the first substrate 6 may be bonded together by the adhesive layer 13. The adhesive layer 13 formed between the first printed layer 5 and the second printed layer 11 may be a colored adhesive layer 13 such as black or blue instead of a semitransparent or transparent substrate.

Since the adhesive layer 13 is colored,
Since it is not necessary to print the background color when printing characters or patterns, the printing process is reduced. Further, when reading the characters or the pattern on the first printing layer 5, the characters or the pattern on the second printing layer 11 can be seen through, and the characters or the pattern on the first printing layer 5 are not difficult to read.

The optical disk of the present invention is not limited to the bonded optical disk having the adhesive layer as described above. In other words, the effect of the present invention can be obtained with an optical disc that has a first transparent substrate and a second transparent substrate and forms a print layer between the first transparent substrate and the second transparent substrate. It is a thing.

The optical disk of the present invention is not limited to the above-mentioned semitransparent film. FIG. 5 is a schematic diagram showing the reflectance characteristic of the reflective film in the optical disc of the present invention. As another embodiment, as shown in FIG. 5, it has a high reflectance with respect to the laser wavelength of the light beam for reproducing the information surface, and with respect to other laser wavelengths or laser wavelengths longer than the laser wavelength. A reflective film having high transmittance (low reflectance) may be formed. That is, in the configuration of FIG. 1, the reflective film is formed instead of the first translucent film 3 and the second translucent film 9 and in the configuration of FIG. 4 instead of the translucent film 21. You may.

Specifically, the material of the reflective film is, for example, S
bXSY, NaXAlFY and the like. These materials are shown in FIG.
As shown in, a high reflectance can be obtained in a narrow wavelength range of several 100 nm. These materials are coated on the information surface of the optical disk described above by a method such as vapor deposition.

For example, when a material of SbXSY is used for the reflection film, the reflection film has a thickness of about 350 nm to 5 nm as shown in FIG.
It has a high reflectance at 80 nm. Laser wavelength 530
When a light beam of nm is used, the reflection film has a laser wavelength of 5
A light beam of 30 nm is reflected with a high reflectance and a wavelength of 580
Visible light with a wavelength longer than nm is transmitted.

With this material, the wavelength range having a high reflectance or the width of the wavelength range can be set depending on the composition or film thickness of the material. Therefore, the laser wavelength longer than the above-mentioned laser wavelength of 530 nm, For example, when a light beam with a laser wavelength of 650 nm is used for reproduction, the wavelength range having high reflectance can be set to a range including the laser wavelength of 650 nm by changing the composition or film thickness of the material. Further, by changing the composition or film thickness of the material, the width of the wavelength range having a high reflectance can be adjusted so that the light beam used for reproduction, for example, the laser wavelength 530n.
It can be set within a range of ± several tens nm centering on m.

As described above, since the reflective film having a high reflectance in the narrow wavelength range is formed on the information surface, it is possible to obtain a larger amount of reflected light than in the case where the semitransparent film is formed on the information surface, and the reproduction is performed. Visible light is transmitted in a wavelength range longer or shorter than the laser wavelength of the light beam used for, so that the visibility of characters or patterns is better than when a semitransparent film is formed on the information surface.

[0048]

According to the present invention, in an optical disc,
It is possible to display the characters or patterns recorded on the optical disc over a large area without disturbing the reproduction characteristics of information. Further, since the print layer is formed inside the optical disc, it is possible to protect characters or patterns.

[Brief description of drawings]

FIG. 1 is a schematic view showing a schematic cross section of an embodiment of an optical disc of the present invention.

FIG. 2 is a schematic view showing an example of a manufacturing process of an optical disc of the present invention. (A) is an information surface forming step,
(B) is a semi-transparent film forming step, (c) is a protective layer forming film, (d) is a printing layer forming step,
(E) is a bonding process.

FIG. 3 is a schematic view showing a schematic cross section in the case where the information surface of the optical disc of the present invention is a single layer.

FIG. 4 is a schematic view showing a schematic cross section in a case where the optical disc of the present invention has two printing layers.

FIG. 5 is a schematic diagram showing reflectance characteristics of a reflective film in the optical disc of the present invention.

FIG. 6 is a schematic view showing a schematic cross section of a conventional optical disc.

[Explanation of symbols]

 1 ... 1st transparent substrate 2 ... 1st information surface 3 ... 1st semi-transparent film 4 ... 1st protective layer 5 ... 1st printing layer 6 ... 1st substrate 7 ... 2nd transparent substrate 8 ... 2nd information surface 9 ... 2nd semi-transparent film 10 ... 2nd protective layer 11 ... 2nd printing layer 12・ ・ ・ Second substrate 13 ・ ・ ・ Adhesive layer 14 ・ ・ ・ First stamper 15 ・ ・ ・ Second stamper 16 ・ ・ ・ Transparent substrate 17 ・ ・ ・ Information surface 18 ・ ・ ・ Reflecting surface 19 ・ ・ ・Smooth substrate 20 ・ ・ ・ Printing layer 21 ・ ・ ・ Semi-transparent film 22 ・ ・ ・ First reflective layer 23 ・ ・ ・ Second reflective layer

Claims (6)

[Claims] 1. An optical disc having a first transparent substrate, a second transparent substrate, and at least one information surface formed on at least one of the first transparent substrate and the second transparent substrate, wherein: An optical disk comprising a print layer on which characters or patterns are printed between a first transparent substrate and the second transparent substrate. 2. A first transparent substrate formed on one surface of a first transparent substrate.
A first substrate having a first semi-transparent film formed on its information surface, and a second substrate
And a second substrate having a second semitransparent film formed on a second information surface formed on one surface of the transparent substrate, the first semitransparent film and the second semitransparent film being In an optical disc laminated with an adhesive layer, a printing layer having characters or a pattern printed on at least one of the first semitransparent film and the adhesive layer or the second semitransparent film and the adhesive layer is formed. An optical disc characterized by. 3. A first transparent substrate formed on one surface of a first transparent substrate.
A first substrate having a first reflective film formed on its information surface, and a second substrate having a second reflective film formed on a second information surface formed on one surface of a second transparent substrate. In an optical disc in which the first reflective film and the second reflective film are bonded together with an adhesive layer, the first reflective film and the second reflective film are:
The first information film and the second information surface have a high reflectance with respect to the laser wavelength of the light beam and a high transmittance with respect to other laser wavelengths; An optical disc, wherein a printing layer having a character or a pattern printed thereon is formed on at least one of the adhesive layer or the second reflective film and the adhesive layer. 4. An optical disc having a first transparent substrate, a second transparent substrate, and at least one information surface formed on at least one of the first transparent substrate and the second transparent substrate, A first substrate having a semi-transparent film formed on at least one information surface formed on one surface of a first transparent substrate, and a second substrate having a printing layer on which characters or patterns are printed on the second transparent substrate. And an adhesive layer for bonding the semi-transparent film of the first substrate and the printed layer of the second substrate to each other. 5. An optical disc having a first transparent substrate, a second transparent substrate, and at least one information surface formed on at least one of the first transparent substrate and the second transparent substrate, At least one information surface formed on one surface of the first transparent substrate is provided with a reflection film having a high reflectance for the laser wavelength of the light beam and a high transmittance for the other laser wavelength. A first substrate,
The second transparent substrate includes a second substrate having a printed layer on which characters or patterns are printed, and an adhesive layer for bonding the reflective film of the first substrate and the printed layer of the second substrate. An optical disc characterized in that. 6. The optical disc according to claim 4 or 5, wherein the second substrate has a first printed layer on which characters or patterns relating to the first information are printed, and a second printed layer different from the first information. And a second print layer on which a character or a pattern relating to the information is printed.