KR20000077362A - Optical recording medium and manufacturing method therefor - Google Patents

Abstract

The optical recording medium has a recording capacity similar to that of a two-layer DVD, is compatible with playback with a DVD player, and is equipped with a read-only area and a user recording area. The optical recording medium is formed on either of the optically transparent first substrates, and is equipped with a first information recording member having a first information recording section on which a read only area is mounted. And a second information recording member having a second information recording portion formed on one surface of the second substrate, and having a read only area and a recordable area, wherein the first information recording member and the second information recording member are optically By being coupled to each other through a transparent adhesive layer, the side surfaces on which the first information recording portion and the second information recording portion are formed face each other so that the information is optically recorded and reproduced when the laser beam is incident on the first substrate.

Description

Optical recording medium and manufacturing method therefor

The present invention relates to an optical recording apparatus manufactured by joining two information recording members to each other and a manufacturing method thereof.

In recent years, research and development have been actively carried out to increase the recording capacity of disk-type optical recording media (hereinafter referred to as "optical disks"). As a method for increasing the amount of information per unit area, a method in which a recording layer is formed in a multi-layered structure may be used. The amount of information per unit area of a type of read-only DVD (Digital Video Disc) having two recording layers is about twice the amount of information of a DVD having one recording layer.

The above-mentioned DVD is a read-only disk (DVD-ROM). In addition, research and development of information recording media that enable users to record and reproduce information has been actively carried out. A description of an optical recording medium on which a user can record information and which is somewhat compatible with a DVD-ROM, having previously described an optical recording medium having a recording layer incorporated with organic pigments (DVD-R). ) Has been developed. In addition, optical recording apparatuses (DVD-RAMs), which are incorporated with recording layers containing phase change materials and allow several times the information technology, have been developed. Each of the media described above has been standardized.

Since the DVD-R has playback compatibility with the DVD-ROM player, the recorded information can be played back by the DVD-ROM player. However, a DVD-R having only one recording layer has an insufficiently low recording capacity as compared to a DVD having two recording layers.

Types of DVD-RAMs with two recording layers have been reported (Applied Physics 59 lectures. Union, Fall, 1998, PP1008, Matushita). The reported recording medium is compatible with DVD-ROM in terms of recording capacity. The recording layer of the above-described medium using a phase change material has a low reflectance. Therefore, commercially available DVD-ROMs are not allowed for any compatibility. In other words, DVD-RAM requires a special playback device.

In addition, so-called hybrid discs of a structure in which one disc has a reproduction-only area in which information is recorded and then an area (user recordable area) where a user is allowed to record information have been developed. Hybrid discs have playback compatibility with CDs. Therefore, the hybrid disc can be played by the CD player.

Hybrid discs have the advantage that their ROM area can be used as the mass medium area. Thus, the user can use the user recording area to record the information required by the user. Another advantage is that illegal copying can be prevented when a personal identification number or the like is previously recorded in the user recording area.

Hybrid discs having a recording capacity similar to that of a CD are required to increase the recording capacity.

In view of the above, it is an object of the present invention to provide an optical recording medium having a recording capacity similar to that of a two-layer DVD and playback compatibility with a DVD player, and having a read only area and a user recording area mounted thereon and a method of manufacturing the same. To provide.

According to an aspect of the present invention, a first information recording member is formed on either side of an optically transparent first substrate and has a first information recording section on which a read only area is mounted, and is formed and reproduced on either side of the second substrate. And a second information recording member having a second information recording section on which a dedicated area and a recordable area are mounted, wherein the first information recording member and the second information recording member are provided. Are coupled to each other through an optically transparent adhesive layer, so that the sides on which the first information recording portion and the second information recording portion are formed face each other, and when the laser beam is incident on the first substrate, Optically recorded and reproduced.

As described above, the optical recording medium according to the present invention has a structure in which a first information recording member having a read only area and a second information recording member having a read only area and a recordable area are coupled to each other. Therefore, the user is allowed to record necessary information in addition to the recorded information. The above-described optical recording medium has a recording capacity similar to that of an optical recording medium having two recording layers.

According to still another aspect of the present invention, a first information recording member is formed on either of an optically transparent first substrate and has a first information recording portion mounted thereon with a read only area and a recordable area, and any of the second substrates. An optical recording medium is provided which includes a second information recording member which is formed on the surface and has a second information recording section which is a reproduction-only area, wherein the first information recording member and the second information recording member are optically provided. Are bonded to each other through a transparent adhesive layer, so that the side surfaces on which the first information recording portion and the second information recording portion are formed face each other, and when the laser beam is incident on the first substrate, the information is optically recorded and reproduced. do.

An optical recording medium according to the present invention has a structure in which a first information recording member having a read only area and a recordable area and a second information recording member having a read only area are coupled to each other. Therefore, the user is allowed to record necessary information in addition to the recorded information. The above-described optical recording medium has a recording capacity similar to that of an optical recording medium having two recording layers.

According to another aspect of the invention, by forming an optically transparent first substrate and forming a pit corresponding to the information signals on both sides of the first substrate, the pit of the first substrate is formed to be completely formed with the first substrate. A process of manufacturing the first information recording member for forming the first information recording member by forming at least one light reflection layer on the side of the first substrate formed in the forming step and in the forming step of the first substrate on which the pits are formed; By forming the second substrate and forming grooves and pits corresponding to the information signals on both sides of the second substrate, forming the second substrate so that the grooves and pits are formed completely with the second substrate, A second information recording member is manufactured by sequentially laminating at least one light reflecting layer and a recording layer made of a light absorbing material on both sides of the second substrate formed in the forming step of the second substrate to be formed. And an optically transparent adhesive layer between the manufacturing step of the second information member and the first information recording member manufactured in the manufacturing step of the first information recording member and the second information recording member manufactured in the manufacturing step of the second information recording member. Provided is a method of manufacturing an optical record carrier, characterized in that it comprises a joining step for the side surfaces having grooves and pits formed by joining each other through each other.

A method of manufacturing an optical recording medium according to the present invention has a structure in which a first information recording member having a read only area and a second information recording member having a read only area and a recordable area are coupled to each other. Therefore, the user is allowed to record necessary information in addition to the recorded information. The above-described optical recording medium has a recording capacity similar to that of an optical recording medium having two recording layers.

According to another aspect of the present invention, a groove and a pit for forming an optically transparent first substrate and forming grooves and pits corresponding to the information signals on both sides of the first substrate are formed to be completely formed with the first substrate. By sequentially laminating at least one recording layer and a light reflection layer made of a material which absorbs light on both sides of the first substrate formed in the forming step of the first substrate and the forming first groove in which the grooves and pits are formed. 1 Manufacturing process of the first information recording member for forming the information recording member, and forming of the second substrate so that the pits are formed completely with the second substrate by forming the second substrate and forming the pits corresponding to the information signals. And a second tablet for manufacturing the second information recording member by forming at least one light reflection layer on the side of the second substrate formed in the step of forming the second substrate having the pits formed thereon. The manufacturing process of the recording member and the first information recording member manufactured in the manufacturing step of the first information recording member and the second information recording member manufactured in the manufacturing step of the second information recording member are coupled to each other through an optically transparent adhesive layer. There is provided a method of manufacturing an optical recording medium, characterized in that it comprises a joining step for the sides having grooves and pits formed to face each other.

A method for manufacturing an optical recording medium according to the present invention has a structure in which a first information recording member having a read only area and a recordable area and a second information recording member having a read only area are coupled to each other. Therefore, the user is allowed to record necessary information in addition to the recorded information. The above-described optical recording medium has a recording capacity similar to that of an optical recording medium having two recording layers.

Other objects, features and advantages of the present invention will become apparent from the preferred embodiments described below in detail with reference to the accompanying drawings.

1 is a cross-sectional view showing an example of an optical disk structure according to an embodiment of the present invention.

2 is a design diagram showing an arrangement of a reproduction-only area of the first information recording unit.

3 is a design diagram showing an example of the arrangement of the read only area and the recordable area of the second information recording unit.

4 is a design diagram showing an example of the arrangement of the read only area and the recordable area of the second information recording unit.

Fig. 5 is a design diagram showing an example of the arrangement of the read only area and the recordable area of the second information recording unit.

6 is a design diagram showing an example of the arrangement of the reproduction-only area and the recordable area of the second information recording unit.

Fig. 7 is a design diagram showing the arrangement of pits in the reproduction-only area of the second information recording section and grooves in the recordable section.

FIG. 8 is a cross-sectional view taken along the line A-A 'of FIG. 7.

9 is a schematic diagram illustrating an example of an optical system that is information reproduced from a first disc.

10 is a schematic diagram showing an example of an optical system that is recording information of a second disc.

11 is a cross-sectional view showing an example of the optical disk structure according to the embodiment of the present invention.

12 is a design diagram showing an example of the arrangement of the reproduction-only area and the recordable area of the first information recording unit.

FIG. 13 is a design diagram showing an example of arrangement of the reproduction-only area and the recordable area of the first information recording unit. FIG.

Fig. 14 is a design diagram showing an example of arrangement of the reproduction-only area and the recordable area of the first information recording unit.

Fig. 15 is a design diagram showing an example of the arrangement of the read only area and the recordable area of the first information recording unit.

16 is a design diagram showing an arrangement of a reproduction-only area of the second information recording unit.

Fig. 17 is a design diagram showing the arrangement of pits in the reproduction-only area of the second information recording section and grooves in the recording permission section.

FIG. 18 is a cross-sectional view taken along the line A-A 'shown in FIG. 17.

19 is a schematic diagram showing an example of an optical system which is recording information of a first disc.

20 is a schematic diagram illustrating an example of an optical system that is information reproduced from a second disc.

First embodiment

The first embodiment of the present invention will now be described.

An example of the structure of the optical disc 1 according to this embodiment is shown in FIG. The optical disc 1 is mounted with a first disc 3 having a first information recording section 2 formed on either side thereof. In addition, the optical disc 1 has a second disc 5 having a second information recording section 4 formed on either side thereof. The first disk 3 and the second disk 5 can be coupled to each other through the adhesive layer 6 so that the first information recording section 2 and the second information recording section 4 face each other. At that time, the first disk 3 and the second disk 5 are joined to each other by the adhesive layer 6. As shown in Fig. 2, the first disk 3 is a ROM disk having a read-only area 20 provided as the first information recording section 2. As shown in Figs. As shown in Figs. 3 to 6, the second disk 5 is a so-called hybrid disk having a recordable area 22 and a read-only area 21 provided as the second information recording section 4. As shown in Figs. 2 to 6, the central pit 23 is actually formed in the center of the disk. Areas without data on the disc are indicated by diagonal lines.

The first disk 3 has a pit 8 corresponding to the information, and the pit 8 is formed on either side of the first substrate 7 which is a substrate through which light can pass. The light reflection layer 9 is formed on the side of the first substrate 7 on which the pits 8 are formed, thereby forming the first information recording section 2.

The first substrate 7 is made of an optically transparent resin. The first substrate 7 may be made of a known material which is usually used for constructing a substrate of the above-described type of optical recording medium. In particular, polycarbonate resins are preferably used because of the optical properties, low cost, and excellent moldability required as materials for producing DVDs. Polyolefin resin may be used. The refractive index of the first substrate 7 is approximately 1.55 ± 0.1.

Spiral pits 8 corresponding to the digital signals recorded on the first disc 3 are formed on either side of the first substrate 7. In this way, the first information recording section 2 is constructed. As described above, when the above-mentioned resin material is molded to manufacture the first substrate 7, pits 8 are completely formed in the first substrate 7 because information is transmitted from a stamper. . As shown in FIG. 2, the entire area of the first information recording unit 2 is the reproduction only area 20. As shown in FIG. The first information recording section 2 is an area in which information recording is not allowed after the first substrate 7 is molded.

The light reflection layer 9 may be composed of a thin metal film, an insulating multilayer film or an organic dye film. In particular, it is preferable to use an insulating multilayer film in view of the balance between light absorption and light reflectance. When a metal film is used, a multilayer structure such as an insulating multilayer film is not necessary. The light reflection layer 9 may consist of only one layer. Therefore, the cost can be reduced.

The second disc 5 is mounted with a second substrate 10 having either a pit 8 corresponding to the information and a groove 11 for a track. In addition, the light reflection layer 12, the recording layer 13, and the protective layer 14 are sequentially formed on one side of the second substrate 10 on which the pit 8 and the groove 11 are formed. In this way, the second information recording section 4 is formed.

The second substrate 10 may be made of a known material which is usually used for producing a substrate of the above-described type of optical record carrier. In particular, polycarbonate resins are preferably used because of the optical properties, low cost, and excellent moldability required as materials for producing DVDs. As an alternative to this, a polyolefin resin may be used.

The pit 8 and the groove 11 corresponding to the digital information recorded on the second disk 5 are formed spirally on either side of the second substrate 10. In this way, the second information recording section 4 is constructed. The pit 8 and the groove 11 are transferred from the stamper to form completely with the second substrate 10 when the above-mentioned resin material is molded to manufacture the second substrate 10.

The area of the second information recording section 4, in which the pit 8 is formed, is a reproduction-only area 21. The above-described area is an area in which information is not allowed to be recorded after the second substrate 10 is molded. The portion of the second information recording section 4 in which the groove 11 is formed is the recordable area 22. When the second substrate 10 is molded, no information is input in the above-mentioned area. After the second substrate 10 is molded, information can be recorded in the above-described area. The groove 11 is used to track the laser beam when information is recorded. The recordable area 22 is a write once area.

As shown in Figs. 3 to 6, the arrangement of the read only area 21 and the recordable area 22 of the second information recording section 4 is not limited. The arrangement may be arbitrarily determined in order to suit the purpose of use of the optical disc 1.

For example, as shown in Fig. 3, the recordable area 22 and the read-only area 21 may be formed sequentially from the inside thereof. As shown in Fig. 4, an arrangement in which the read only area 21 and the recordable area 22 are sequentially formed from the inside of the disc may be used. As shown in Fig. 5, the read only area 21, the recordable area 22, and the read only area 21 may be formed sequentially from the inside of the disc. As shown in Fig. 6, the recordable area 22, the read only area 21, and the recordable area 22 may be formed sequentially from the inside of the disc.

As described above, the positions of the read only area 21 and the recordable area 22 may be arbitrarily determined. As shown in Figs. 7 and 8, notice that the read only area 21 and the recordable area 22 are formed sequentially. The pit 8 of the read only area 21 and the groove 11 of the recordable area 22 are formed in one spiral. Since the pit 8 of the read only area 21 and the groove 11 of the recordable area 22 are formed in one spiral, the movement from the read only area 21 to the recordable area 22 is performed or When the movement is performed from the recordable area 22 to the read-only area 21, deviation of tracking can be prevented. In this way, information can be recorded and reproduced sequentially.

The light reflection layer 12 may be composed of, for example, a thin metal film, an insulating multilayer film, or an organic dye film.

The recording layer 13 is made of a light absorbing material such as, for example, an organic dye or an inorganic compound.

The protective layer 14 protects the recording layer 13. The protective layer 14 may be composed of an inorganic film or a polymer film.

In the optical disc 1 according to the present embodiment, the first disc 3 and the second disc 5 are coupled through the adhesive layer 6 so that the side surfaces having the first or second information recording portions 4 face each other. It is composed. The position of the first information recording section 2 and the position of the second information recording section 4 preferably coincide with each other when the first disk 3 and the second disk 5 are coupled to each other. Note that it does not always have to match.

The adhesive layer 6 may be made of an optically transparent adhesive sheet, a photocurable resin, or a thermosetting resin.

The thickness of the adhesive layer 6 is adjusted in such a way that the first disc 3 and the second disc 5 satisfy the DVD standard. For example, the predetermined interval is about 55 ± 15 μm. The refractive index of the adhesive layer 6 is approximately (the refractive index of the first substrate 7 ± 0.1).

As shown in Figs. 9 and 10, the optical disc 1 has the above-described structure so that information is recorded and reproduced about the application of the laser beam to the substrate surface of the first disc 3. The optical system 30 for recording and reproducing information about the optical disc 1 comprises a laser beam generating means 31, a half mirror 32, an objective lens 33 and a returned-light. The detection means 34 is mounted. The laser beam emitted from the laser beam generating means 31 passes through the half mirror 32 to be incident on the objective lens 33. The laser beam incident on the objective lens 33 is collected at one point by the objective lens 33 to focus on the optical disc 1.

As shown in Fig. 9, when the information is reproduced from the first disc 3, the laser beam is focused on the light reflection layer 9 of the first disc 3. When information is reproduced from the second disc 5, the laser beam is focused on the recording layer 13 of the second disc 5.

The light returned from the optical disc 1 passes through the objective lens 33 to be incident on the half mirror 32. The laser beam incident on the half mirror 32 is reflected by the half mirror 32 to be incident on the gray detecting means 34. In this way, an information signal is detected.

As shown in FIG. 10, when information is recorded on the second disk 5, the laser beam is focused on the recording layer 13 of the second disk 5. As shown in FIG. A part of the recording layer 13 composed of light absorbing organic pigments is heated to deform. Reflectance difference occurs. In this way, the pit 8 is formed.

According to this embodiment, the optical disk 1 having the above-described structure is characterized in that the first disk 3 having the first information recording section 2 and the second disk 5 having the second information recording section 4 are mutually different. It is prepared by combining with. Therefore, a large capacity can be obtained when compared with an optical record medium composed of only one disc. Since the optical disc 1 is incorporated with the read only areas 20 and 21 and the recordable area 22, the required disc can be configured to meet the needs.

The optical disc 1 according to the present embodiment is a medium in which a computer program having a large capacity can be recorded by a user. Therefore, it is possible to prevent the program from being deleted undesirably.

The optical disc 1 according to the present embodiment has a large capacity and allows information of pre-recorded sounds, images or properties, and information recorded by a user to be stored in one medium.

The optical disc 1 according to the present embodiment is a medium for storing entertainment lists such as music or games, a medium for storing a document formatted for use in an office, a medium for storing a program such as a weed processor, and the like. Alternatively, it may be used as a medium for storing educational materials or as a medium for electronic publishing. In the case described above, the comparison (simultaneous reproduction) between the user information and the distributed information, and the change or recording of the information distributed by the user (to suit personal preferences, addition of information by the user and recording of the reproduction frequency, etc.) Is allowed.

When the person distributing a large amount of information uses the recordable area 22, the serial number and password of the disc can be recorded personally. Therefore, illegal copying or illegal use of information can be prevented. In addition, the number of readings of information may be limited.

When the recording operation is performed by the user, necessary information, for example, the optimum value of the recording laser power, the adjustment of the pulse length of the laser beam to be applied, and the like are recorded in advance in the reproduction-only areas 20 and 21. In this way, the user can record information under optimal conditions.

The manufacturing process of the optical disc 1 will now be described. Note that the present invention is not limited to the specific values of the film thickness and the conditions for forming the film described below by way of example. The value may be arbitrarily changed within the scope of the present invention.

First, the first disc 3 is manufactured as follows.

First, the polycarbonate resin is injection molded by using a stamper to manufacture the first substrate 7. When the first substrate is formed, a pit 8 is formed at a portion to be provided as the first information recording portion 2, and the pit 8 is formed completely with the first substrate 7. At this time, the pitch of the track is 0.74 占 퐉, the ratio of the width of each pit to the land is 0.10 ± 0.01, and the depth of each pit is 125 nm.

The DVD coat 2000 (manufactured by Shibaura) is operated to perform sputtering gold on the surface of the first substrate 7 on which the pit 8 is formed at a power of 1.5 mW per second. In this way, the light reflection layer 9 is formed by depositing the gold thin film. The thickness of the gold thin film is approximately 15 nm.

As described above, the first disc 3 having the first information recording section 2 constituted by the read only area 20 is manufactured.

The second disk 5 is manufactured as follows.

First, the polycarbonate resin is injection molded by using a stamper to manufacture the second substrate 10. When the second substrate 10 is formed, the pit 8 corresponding to the information is formed at the portion to be formed as the reproduction-only area 21 of the second information recording section 4, and the pit 8 is the second. It is formed completely with the substrate 10. The pitch of the track is 0.74 mu m, the ratio of the width of each pit to the land is 0.12 ± 0.01, and the depth of each pit is 125 nm.

When the second substrate 10 is formed, the groove 11 for tracking the laser beam is formed in the portion of the second information recording portion 4 to be formed as the recordable area 22. The pitch of the track is 0.74 占 퐉, the ratio of the width of each pit to the land is 0.54, and the depth of each pit is 150 nm.

The DVD coat 2000 is operated to perform sputtering of the surface of the second substrate 10 on which the pits 8 and the grooves 11 are formed at a power of 1.5 mW per 9.0 seconds. In this way, the gold thin film is deposited to form the light reflection layer 12 having a thickness of approximately 200 nm.

At that time, a recording layer 13 made of an organic dye film is formed in the light reflection layer 12. The organic pigment is NK-4288 (manufactured by Nihon Photosensitive Color Matter) having a structure represented by the formula (1). While the second substrate 10 on which the light reflection layer 12 is formed is rotated at 2000 rpm, the tetrafluoropropanol solution (0.4 wt%) of NK-4288 is spin-coated to form an organic dye film. The organic dye film is formed on the entire surface of the second substrate 10 irrespective of the read only area 21 and the recordable area 22. The organic dye film is formed in the recordable area 22 provided as the recording layer 13.

At that time, while the second substrate 10 on which the recording layer 13 is formed is being recorded at 2000 rpm, the polyvinyl alcohol solution (1.0 wt%) is spin coated. In this way, a protective layer 14 composed of polyvinyl alcohol is formed.

Thus, the second disk 5 having the second information recording section 4 composed of the read only area 21 and the recordable area 22 is manufactured.

By combining the first disk 3 and the second disk 5 manufactured in this manner with each other, side surfaces having the first information recording section 2 or the second information recording section 4 are formed to face each other. The bonding process is usually an optically transparent UV curing resin. In this way, the optical disc 1 is manufactured.

Although the first substrate 7 and the second substrate 10 are manufactured by injection molding as described above, the present invention is not limited to the above-described method. As an alternative to this, a photopolymer method in which an ultraviolet curable resin is deposited on a surface of a glass plate or the like may be used to irradiate ultraviolet rays to cure the ultraviolet curable resin while the stamper is pressed against the ultraviolet curable resin.

The first disk 3 may have a protective layer 14 for protecting the light reflection layer 9 on the light reflection layer 9. The protective layer 14 may be composed of an inorganic film or a polymer film. An interference layer or the like may be formed between the light reflection layer 9 and the protective layer 14.

In the above-described embodiment, the first disk 3 and the second disk 5 are coupled to each other. An ultraviolet curable resin is used to join the first disk 3 and the second disk 5 to each other. The present invention is not limited to the method described above. An optically transparent double-sided adhesive film (for example, having a thickness of 50 µm) may be used to bond the first disk 3 and the second disk 5 to each other.

The characteristics of the optical disc 1 having the structure described above were examined. The result is as follows.

Optical properties

The optical characteristics of the irradiated first disc 3 and the second disc 5 are light transmittance and reflectance. Transmittance and reflectance were measured using spectrometer U-3210 (manufactured by Hitachi) to which a 5 degree specular reflectance unit was added. The test sample was manufactured in the same manner as mentioned above except for the structure in which the grooves 11 and the pit 8 were omitted.

In order to evaluate the light transmittance of the light reflection layer 9 of the first disk 3, gold is deposited on a substrate made of the same material as the first substrate 7 and having the same thickness and flat surface, whereby the light reflection layer ( 9) is formed. At that time, a test sample is manufactured by laminating the adhesive layer 6 on the light reflection layer 9. The test sample has 66% transmittance and 26% reflectance for light with a wavelength of 650 nm.

In order to evaluate the light transmittance of the light reflection layer 12 of the second disk 5, the light reflection layer 12 and the recording layer are made of the same material as the first substrate 7 and have the same thickness and the flat surface. (13) And the protective layer 14 is laminated sequentially. In addition, a test sample is produced by laminating the adhesive layer 6 on the protective layer 14. For light with a wavelength of 650 nm, the reflectance of the test sample is 64%. The light transmittance of the light reflection layer 12 is 0%, and the light reflectance is 92%.

The test sample of the first disk 3 and the test sample of the second disk 5 are usually coupled to each other by using optically transparent ultraviolet curable resins. For light having a wavelength of 650 nm, the reflectance is as follows: The reflectance from the first substrate 7 and the reflectance from the second substrate 10 is 26%.

Record / Playback Characteristics

The recording / reproducing characteristics of the double-layer optical disc 1 produced by combining the first disc 3 and the second disc 5 with each other were evaluated by the following recording / reproducing conditions.

Recording condition (second disc 5)

Objective lens 33NA: 0.70

Laser diode:

Wavelength: 640.9 nm

Brightness: Rad: 0.31

Tan: 0.52

Polarization state: circularly polarized light

Speed: 3.49 m / s

Record signal: EFM +

Recording method: set randomly

Control system: focus, tracking, spindle, slide

System clock: 26.16 MHz

Playback conditions (first disc 3 and second disc 5)

Objective lens NA: 0.60

Laser diode:

Wavelength: 651.7 nm

Brightness: Rad: 0.65

Tan: 0.97

Polarization state: circularly polarized light

Speed: 3.49 m / s

Control system: focus, tracking, spindle, slide

Under the above recording / reproducing conditions, individual focus servos of the first disc 3 and the second disc 5 are allowed.

It has been confirmed that the reproduction signals from the reproduction only areas 20 and 21 of the first disc 3 and the second disc 5 have substantially the same characteristics as the reproduction signals from the DVD. Further, another fact was confirmed that the reproduction signal from the recordable area 22 of the second disc 5 satisfies the DVD format.

Second embodiment

A second embodiment of the present invention will now be described.

An example of the structure of the optical disc 101 according to the present embodiment is shown in FIG. The optical disc 101 is incorporated with the first disc 103 having the first information recording unit 102 formed on either side thereof. In addition, the optical disc 1 has a second disc 105 having a second information recording section 104 formed on either side thereof. The first disk 103 and the second disk 105 can be coupled to each other through the adhesive layer 106 so that the first information recording unit 102 and the second information recording unit 104 face each other. As shown in Figs. 12 to 15, the first disc 103 is a so-called hybrid disc having a read-only area 120 and a recordable area 121 as the first information recording unit 102. As shown in Figs. As shown in Fig. 16, the second disc 105 is a ROM type disc having a read only area 122 as the second information recording unit 104. As shown in Figs. 12 to 16, the central pit 123 is actually formed in the center of the disk. Areas without data on the disc are indicated by diagonal lines.

The first disc 103 tracks the groove 108 formed in either side of the first substrate 107 and has a pit 108 corresponding to the information. The recording layer 110, the light reflection layer 111, and the protective layer 112 are sequentially stacked on the side of the first substrate 107 on which the pits 108 and the grooves 109 are formed. In this way, the first information recording unit 102 is formed.

The first substrate 107 may be made of a known material which is usually used for constructing a substrate of the above-described type of optical recording medium. In particular, polycarbonate resins are preferably used because of the optical properties, low cost, and excellent moldability required as materials for producing DVDs. Polyolefin resin may be used.

The pit 108 and the groove 109 corresponding to the digital signals recorded on the first disk 103 are spirally formed on either side of the first substrate 107. In this way, the first information recording unit 102 is formed. When the above-mentioned resin material is used to manufacture the first substrate 107, the pit 108 and the groove 109 are transferred from the stamper to be completely formed with the first substrate 107.

The area of the first information recording unit 102 where the pit 108 is formed is the reproduction-only area 120. The read only area 120 is an area in which information is not allowed to be recorded after the first substrate 107 is molded. The portion of the first information recording unit 102 in which the groove 109 is formed is the recordable area 121. When the first substrate 107 is molded, no information is input to the above-mentioned area. After the first substrate 107 is molded, information can be recorded in the above-described area. The groove 109 is used to track the laser beam when the information is recorded. The recordable area 121 is a one-time recording area.

12 to 15, the arrangement of the read only area 121 and the recordable area 120 of the first information recording unit 102 is not limited. The arrangement may be arbitrarily determined to suit the purpose of use of the optical disc 101.

For example, as shown in Fig. 12, the recordable area 121 and the read-only area 120 may be sequentially formed from the inside thereof. As shown in FIG. 13, the read only area 120 and the recordable area 121 may be formed sequentially from the inside of the disc. As shown in Fig. 14, the read only area 120, the recordable area 121, and the read only area may be formed sequentially from the inside of the disc. As shown in Fig. 15, the recordable area 121, the read only area 120, and the recordable area 121 may be formed sequentially from the inside of the disc.

As described above, the arrangement of the read only area 120 and the recordable area 121 may be arbitrarily determined. Note that, as shown in Figs. 17 and 18, the read only area 120 and the recordable area 121 are sequentially formed. Since the pit 108 of the read only area 120 and the groove 109 of the recordable area 121 are formed in one continuous spiral, movement from the read only area 120 to the recordable area 121 is prevented. When the movement is performed or the movement from the recordable area 121 to the reproduction-only area 120 is performed, deviation of tracking can be prevented. In this way, information can be recorded and reproduced sequentially.

The recording layer 110 may be made of a light absorbing material such as, for example, an organic dye or an inorganic compound.

The light reflection layer 111 may be composed of a gold thin film, an insulating multilayer film, or an organic dye film. In particular, the insulating multilayer film is preferably used in view of the balance between light absorption and light reflectance. When a thin metal film is used, a multilayer structure such as an insulating multilayer film is not necessary. The light reflection layer 111 may be composed of only one layer. Therefore, the cost can be reduced.

The protective layer 112 protects the recording layer 110 and the light reflection layer 111. The light reflection layer 111 may be composed of an inorganic film or a polymer film.

The second disk 105 is incorporated with a pit 108 formed on either side of the second substrate 113, which is a substrate through which light can pass, and the pit 108 corresponds to information. The light reflecting layer 114 is formed on the side of the second substrate 113 on which the pit 108 is formed. In this way, the second information recording unit 104 is formed.

The second substrate 113 is made of an optically transparent resin. The second substrate 113 may be made of a known material which is usually used to constitute a substrate of the above-described type of optical recording medium. In particular, polycarbonate resins are preferably used because of the optical properties, low cost, and excellent moldability required as materials for producing DVDs. Polyolefin resin may be used. The refractive index of the second substrate 113 is approximately 1.55 ± 0.1.

Spiral pits 108 corresponding to the digital information recorded on the second disc 105 are formed on either side of the second substrate 113. In this way, the second information recording section 104 is constructed. The pit 108 is formed by transferring information from the stamper so as to be completely formed with the second substrate 113 when the second substrate 113 is manufactured by molding the above-described resin material. The second information recording unit 104 is a reproduction-only area 122 that stops recording of information after the second substrate 113 is molded.

The light reflection layer 114 may consist of a thin metal film, an insulating multilayer film, or an organic dye film.

As described above, in the optical disc 101 according to the present embodiment, the first disc 103 and the second disc 105 are coupled through the adhesive layer 106, thereby providing the first information recording unit 102 or the second information recording unit. Sides with 104 are configured to face each other. The position of the first information recording section 102 and the position of the second information recording section 104 preferably coincide with each other when the first disk 103 and the second disk 105 are coupled to each other. Note that it does not always have to match.

The adhesive layer 106 may be made of a material such as an optically transparent adhesive sheet, a photocurable resin, or a thermosetting resin.

The thickness of the adhesive layer 106 is adjusted in such a manner that the first disc 103 and the second disc 105 satisfy the DVD standard. For example, the predetermined interval is about 55 ± 15 μm. The refractive index of the adhesive layer 106 is approximately (refractive index ± 0.1 of the first substrate 107).

As shown in Figs. 19 and 20, the optical disc 101 has the structure described above so that information is recorded and reproduced about the application of the laser beam to the substrate surface of the first disc 103. As shown in Figs. The optical system 130 for recording and reproducing information on the optical disc 101 is equipped with a laser beam generating means 131, a half mirror 132, an objective lens 133, and a gray light detecting means 134. . The laser beam emitted from the laser beam generating means 131 passes through the half mirror 132 to be projected onto the objective lens 133. The laser beam projected onto the objective lens 133 is collected by the objective lens 133 in one point in order to focus on the optical disk 101.

When information is reproduced from the first disc 103, the laser beam is focused on the light reflection layer 111 of the first disc 103. As shown in Fig. 20, when information is reproduced from the second disk 105, the laser beam is focused on the light reflection layer 114 of the second disk 105. As shown in FIG.

The light returned from the optical disc 101 passes through the objective lens 133 to enter the half mirror 132. The laser beam incident on the half mirror 132 is reflected by the half mirror 132 to be incident on the gray detecting means 134. In this way, an information signal is detected.

As shown in FIG. 19, when information is recorded on the first disk 103, the laser beam is focused on the recording layer 110 of the first disk 103. As shown in FIG. A portion of the recording layer 110 composed of light absorbing organic pigments is heated to deform. Reflectance difference occurs. In this way, pit 108 is formed.

According to this embodiment, the optical disc 101 having the above-described structure is characterized in that the first disc 103 having the first information recording unit 102 and the second disc 105 having the second information recording unit 104 are mutually different. It is prepared by combining with. Therefore, a large capacity can be obtained when compared with an optical record medium composed of only one disc. Since the optical disc 101 is provided with the read only areas 120 and 122 and the recordable area 121, the required disc can be configured to meet the needs.

The optical disc 101 according to the present embodiment is a medium in which a computer program having a large capacity can be recorded by a user. Therefore, it is possible to prevent the program from being deleted undesirably.

The optical disc 101 according to the present embodiment has a large capacity and allows information of pre-recorded sounds, images or characteristics, and information recorded by a user to be stored in one medium.

The optical disc 101 according to the present embodiment is a medium for storing entertainment lists such as music or games, a medium for storing documents formatted for use in an office, or a medium for storing programs such as a weed processor. Alternatively, it may be used as a medium for storing educational materials or as a medium for electronic publishing. In the case described above, the comparison (simultaneous reproduction) between the user information and the distributed information, and the change or recording of the information distributed by the user (to suit personal preferences, addition of information by the user and recording of the reproduction frequency, etc.) Is allowed.

When the person distributing a large amount of information uses the recordable area 121, the serial number and password of the disc can be recorded personally. Therefore, illegal copying or illegal use of information can be prevented. In addition, the number of readings of information may be limited.

Information necessary when the recording operation is performed by the user, for example, the optimum value of the recording laser power and the adjustment of the pulse length of the laser beam to be applied are recorded in the read only areas 120 and 122 in advance. In this way, the user can record information under optimal conditions.

The manufacturing process of the optical disc 101 will now be described. Note that the present invention is not limited to the specific values of the film thickness and the conditions for forming the film described below by way of example. The value may be arbitrarily changed within the scope of the present invention.

First, the first disc 103 is manufactured as follows.

First, the polycarbonate resin is injection molded by using a stamper to manufacture the first substrate 107. When the first substrate 107 is molded, a pit 108 is formed at a portion to be provided as the first information recording unit 102, and the pit 108 is formed completely with the first substrate 107. At this time, the pitch of the track is 0.74 占 퐉, the ratio of the width of each pit to the land is 0.12 ± 0.01, and the depth of each pit is 125 nm.

When the first substrate 107 is molded, a groove 109 for tracking the laser beam is formed in the portion of the second information recording portion 102 to be formed as the recordable area 121. At this time, the pitch of the track is 0.74 占 퐉, the ratio of the width of each pit to the land is 0.54, and the depth of each pit is 150 nm.

At that time, a recording layer 110 made of an organic dye film is formed on the first substrate 107 where the pits 108 and the grooves 109 are formed. The organic pigment is NK-4288 (manufactured by Nihon Photosensitive Color Matter) having the structure represented by the formula (2). While the first substrate 107 is rotating at 2000 rpm, an organic dye film is formed by spin coating a tetrafluoropropanol solution (0.4 wt%) of NK-4288. The organic dye film is formed on the entire surface of the first substrate 107 irrespective of the read only area 120 and the recordable area 121. The organic dye film is formed in the recordable area 121 provided as the recording layer 110.

Then, the recording is executed to the sputtering surface of the layer 110 being _{Al 2 O 3 (100㎚) /} MgF 2 (118㎚) / ZnS (71㎚) / MgF 2 (118㎚) The recording layer in this order ( Stacked on the surface of 110). In this way, a light reflection layer 111 composed of four insulating layers 111 is formed.

At that time, while the first substrate 107 on which the light reflection layer 111 is formed is rotated at 2000 rpm, the polyvinyl alcohol solution (1.0 wt%) is spin coated. In this way, a protective layer 112 composed of polyvinyl alcohol is formed.

Thus, the first disc 103 having the first information recording unit 102 composed of the read only area 120 and the recordable area 121 is manufactured.

At that time, the second disk 105 is manufactured as follows.

First, the polycarbonate resin is injection molded by operating the stamper to manufacture the second substrate 113. When the second substrate 113 is molded, a pit 108 corresponding to the information is formed at the site where the second information recording unit 104 is to be formed, and the pit 108 is completely formed with the second substrate 113. Is formed. At this time, the pitch of the track is 0.74 占 퐉, the ratio of the width of each pit to the land is 0.10 ± 0.01, and the depth of each pit is 125 nm.

The DVD coat 2000 is operated to sputter gold on the surface of the second substrate 113 on which the pits 108 are formed at a power of 1.5 mW per 9.0 seconds. In this way, a light reflection layer 114 having a thickness of approximately 200 nm is formed by depositing the gold thin film.

Thus, the second disk 105 having the second information recording unit 104 constituted by the read only area is manufactured.

By positioning the first disk 103 and the second disk 105 manufactured in this manner, side surfaces having the first information recording unit 102 or the second information recording unit 104 are formed to face each other. Optically transparent ultraviolet curable resins are used to bond the first disk 103 and the second disk 105 to each other in a conventional manner. In this way, the optical disc 101 is manufactured.

Although injection molding was performed to manufacture the first substrate 107 and the second substrate 113 in the above-described method, the present invention is not limited to the above-described method. As an alternative to injection molding, a photopolymer method may be used in which an ultraviolet curable resin is deposited on a surface of a glass plate or the like in order to irradiate ultraviolet rays to cure the ultraviolet curable resin while the stamper is pressed against the ultraviolet curable resin.

The second disk 105 may have a protective layer for protecting the light reflection layer 114, and the protective layer is formed on the light reflection layer 114. The protective layer may be composed of an inorganic film or a polymer film. An interference layer or the like may be formed between the light reflection layer 114 and the protective layer.

In the above-described embodiment, the first disk 103 and the second disk 105 are coupled to each other. An ultraviolet curable resin is used to join the first disk 103 and the second disk 105. The present invention is not limited to the method described above. An optically transparent double-sided adhesive film (for example, having a thickness of 50 μm) may be used to bond the first disc 103 and the second disc 105 to each other.

The characteristics of the optical disc 101 having the structure described above were examined. The result is as follows.

Optical properties

The optical characteristics of the irradiated first disc 103 and the second disc 105 are light transmittance and reflectance. Transmittance and reflectance were measured using spectrometer U-3210 (manufactured by Hitachi) with the addition of a 5 degree specular measurement unit. The test sample was manufactured in the same manner as mentioned above except for the structure in which the grooves 109 and the pit 108 were omitted.

In order to evaluate the light transmittance of the light reflecting layer 111 of the first disk 103, it is made of the same material as the first substrate 107, and has the same thickness and protection on the light reflecting layer 111 on a substrate having a flat surface. Layer 112 is stacked. At that time, the test sample is manufactured by laminating the adhesive layer 106 on the protective layer 112. The test sample has 52% transmittance and 27% reflectance for light with a wavelength of 650 nm.

In order to evaluate the light transmittance of the light reflection layer 114 of the second disk 105, the light reflection layer 114 is made of the same material as the second substrate 113, and the gold is applied to a substrate having the same thickness and flat surface. It is formed by depositing. The test sample is thus prepared. For light with a wavelength of 650 nm, the test sample has a reflectance of 0% and a light reflectance of 92%.

The test sample of the first disk 103 and the test sample of the second disk 105 are usually coupled to each other by using optically transparent ultraviolet curable resin. For light with a wavelength of 650 nm, the reflectance is as follows: the reflectance from the combined first substrate 107 is 27% and the reflectance from the second substrate 113 is 25%.

Record / Playback Characteristics

The recording / reproducing characteristics of the double-layer optical disc 101 produced by combining the first disc 103 and the second disc 105 with each other were evaluated by the following recording / reproducing conditions.

Recording condition (second disc 105)

Objective lens 133NA: 0.70

Laser diode:

Wavelength: 640.9 nm

Brightness: Rad: 0.31

Tan: 0.52

Polarization state: circularly polarized light

Speed: 3.49 m / s

Record signal: EFM +

Recording method: set randomly

Control system: focus, tracking, spindle, slide

System Clock: 26.16 MHz

Playback conditions (first disc 103 and second disc 105)

Objective lens NA: 0.60

Laser diode:

Wavelength: 651.7 nm

Brightness: Rad: 0.65

Tan: 0.97

Polarization state: circularly polarized light

Speed: 3.49 m / s

Control system: focus, tracking, spindle, slide

Under the above recording / reproducing conditions, individual focus servos of the first disc 103 and the second disc 105 are allowed.

It has been confirmed that the reproduction signals from the respective read only areas 120 and 122 of the first disc 103 and the second disc 105 have substantially the same characteristics as the reproduction signals from the DVD. Further, another fact was confirmed that the reproduction signal from the recordable area 121 of the first disc 103 satisfies the DVD format.

According to the present invention, an optical recording medium equipped with a reproduction-only area in which data is recorded and a user can record information, and an area suitable for playback for a DVD can be realized at low cost. Since the present invention has a structure in which two optical recording media are coupled to each other, an optical recording medium having a large capacity equal to that of a DVD having two recording layers can be realized.

Although the present invention has been described in its specific form and with its preferred form and structure, the preferred form of this specification is directed to the following claims that the combination, arrangement and configuration of the parts may be made without departing from the spirit and scope of the invention. can be changed.

Claims (14)

In the optical recording medium, A first information recording member formed on either side of the optically transparent first substrate and having a first information recording section on which a reproduction-only area is mounted; A second information recording member formed on one surface of the second substrate and having a second information recording section on which a read only area and a recordable area are mounted; The first information recording member and the second information recording member are coupled to each other through an optically transparent adhesive layer so that the side surfaces on which the first information recording portion and the second information recording portion are formed face each other. And information is recorded and reproduced optically when a laser beam is incident on the first substrate. The method of claim 1, The first information recording member is mounted with a light reflection layer formed on the first substrate, Pits corresponding to the information signal are formed in the first substrate portion formed as the reproduction-only area, And said pits are formed completely with said first substrate when said first substrate is molded. The method of claim 1, The second information recording member has a structure in which a light reflection layer made of a light absorbing material and a recording layer are sequentially stacked on the second substrate, Pits corresponding to information signals are formed in the second substrate portion to be formed as the reproduction-only area, A groove is formed in the second substrate portion to be formed as the recordable area, And the pit and the groove are formed completely with the second substrate when the second substrate is molded. The method of claim 3, wherein And the light absorbing material is an organic pigment. The method of claim 3, wherein And a protective layer is formed on the recording layer. In the optical recording medium, A first information recording member formed on either side of the first optically transparent substrate and having a first information recording section mounted thereon with a read only area and a recordable area therein; A second information recording member formed on one surface of the second substrate and having a second information recording section on which a read only area is mounted; The first information recording member and the second information recording member are coupled to each other through an optically transparent adhesive layer so that the side surfaces on which the first information recording portion and the second information recording portion are formed face each other, and the information is lasered. And optically recorded and reproduced when a beam is incident on the first substrate. The method of claim 6, The first information recording member has a structure in which a recording layer and a light reflection layer made of a light absorbing material are sequentially stacked on the second substrate, Pits corresponding to information signals are formed in the first substrate portion to be formed as the reproduction-only area, A groove is formed in the first substrate portion to be formed as the recordable area, And the pit and the groove are formed completely with the first substrate when the first substrate is molded. The method of claim 7, wherein And the light absorbing material is an organic pigment. The method of claim 7, wherein And a protective layer is formed on the recording layer. The method of claim 6, The second information recording member has a structure in which a light reflection layer is formed on the second substrate, Pits corresponding to the information signal are formed in the second substrate portion formed as the read only area, And said pits are formed completely with said second substrate when said second substrate is molded. In the manufacturing method of the optical recording medium, Forming a first optically transparent substrate, and forming a pit corresponding to an information signal on either side of the first substrate to form the first substrate completely with the first substrate; A first information recording member manufacturing step for forming a first information recording member by forming at least one light reflection layer on the side of the first substrate formed in the first substrate forming step in which the pit is formed; Forming a second substrate, and forming a groove and a pit corresponding to an information signal in either side of the second substrate, thereby forming the second substrate and the second substrate forming the second substrate; Manufacturing a second information recording member by sequentially laminating at least one light reflection layer and a recording layer made of a material which absorbs light on the side of the second substrate formed in the second substrate forming step in which the grooves and pits are formed. A manufacturing step of the second information recording member for The groove is formed by coupling the first information recording member manufactured in the manufacturing step of the first information recording member and the second information recording member manufactured in the manufacturing step of the second information recording member to each other through an optically transparent adhesive layer. And a joining step in which sides of the pits are formed to face each other. The method of claim 11, And a method of manufacturing the second information recording medium, wherein an organic dye is used as the light absorbing material. In the manufacturing method of the optical recording medium, Forming an optically transparent first substrate and forming a groove and a pit corresponding to an information signal in either side of the first substrate so that the groove and the pit are completely formed with the first substrate. Steps, First information recording by sequentially stacking at least one recording layer and a light reflection layer made of a material absorbing light on the side of the first substrate formed in the forming step of the first substrate on which the groove and the pit are formed; A manufacturing step of the first information recording member for forming the member; Forming a second substrate and forming a pit corresponding to the information signal so that the pit is formed completely with the second substrate; A step of manufacturing a second information recording member for manufacturing a second information recording member by forming at least one light reflection layer on the side of the second substrate formed in the second substrate forming step in which the pit is formed; The groove is formed by coupling the first information recording member manufactured in the manufacturing step of the first information recording member and the second information recording member manufactured in the manufacturing step of the second information recording member to each other through an optically transparent adhesive layer. And a joining step in which sides of the pits are formed to face each other. The method of claim 13, And an organic dye is used as the material for absorbing light by performing the manufacturing step of the first information recording medium.