JPH10208300A - Optical information recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a disk which is seen like information are recorded on a transparent substrate up to the outer peripheral part of the substrate by covering only the recorded layer of a sticking type optical information recording medium with a first reflection layer. SOLUTION: The transparent substrate 101 provided with the surface of an information area 102 and the dummy substrate 201 provided with the surface of a dummy pit area 202 are stuck. The surface of the information area 102 have the information area 102 where is covered with a first reflection layer and where information are recorded and a non-information area 103 where is not covered with the first reflection layer and where is positioned at the outer side of the area 102 and where information are not recorded. On the surface of the dummy pit area 202, pits or grooves are formed in a prescribed range and this area is covered with a second reflection layer. Thus, dummy pits formed on the dummy substrate 201 are seen-through from the non- information area 103 of the stuck transparent substrate 101.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an optical information recording medium for recording / reproducing information by using a laser beam, and more particularly to a laminated optical information recording medium formed by laminating two substrates.

[0002]

2. Description of the Related Art A minute pit called a pit corresponding to recording information is formed on one surface of a transparent substrate, a laser beam is focused on the pit through the transparent substrate, and the recording information is reflected by a change in the amount of reflected laser light. A representative optical information recording medium is a compact disk (CD).

A CD has a diameter of 120 mm and a thickness of 1.2 mm.
A pit row having a shortest pit length of about 0.9 μm is formed at a track pitch of 1.6 μm on a transparent substrate having a constant linear velocity of about 1.2 to 1.4 m / s during reproduction, and a recording of about 650 Mbytes. It has a capacity and stores digital data such as music and video.

Conventional CDs have a maximum of 7 discs.
A 4-minute music signal can be recorded. However, not all programs use the entire recording capacity of a CD. For example, there are quite a few programs having a recording time of 40 minutes or less. However, music CDs, etc.
It is common to sell at the same price regardless of the length of the program time.

[0005] In such a program having a short recording time, C
In the case of D, there is an unrecorded area where the program is not recorded on the outer periphery of the disk. Therefore, when a reflective film is formed on an information surface having a recorded area and an unrecorded area, no pits are formed in the unrecorded area, so that the outer periphery of the disk becomes mirror-like and the appearance is impaired. was there. In addition, since it is apparent at a glance that the program time is short, the user who purchased the CD may feel that the user has lost.

In order to solve such a problem, generally, when cutting a master disc of a program having a short recording time, even after recording of necessary information is completed, the outermost periphery of a recording area (read) is required. Out), the dummy pits are recorded from the outside to the vicinity of the outer edge of the disk (approximately 116 mm in diameter).
Product value was increasing.

On the other hand, research and development of a DVD (Digital Versatile Disk) whose recording density has been increased to about 6 to 8 times that of a CD is progressing. DVDs have several different disk structures depending on the recording capacity. The most typical one is DVD-5 having only one information surface. FIG. 6 is a schematic diagram showing a cross-sectional structure of DVD-5. FIG.
As shown in FIG. 5, the DVD includes a transparent substrate 601 having a diameter of 120 mm and a thickness of 0.6 mm on which an information surface 602 is formed, and a dummy substrate 604 having a diameter of 120 mm and a thickness of 0.6 mm having no information surface. The structure is such that the bonding is performed by the adhesive layer 605 such that the surface 602 is inside.

Here, the surface of the information surface 602 is covered with a reflective layer 603 made of a metal such as aluminum which reflects most of the laser light.
1 through one side.

The specifications of the currently proposed DVD-5 are as follows:
Track pitch 0.74μm, shortest pit length 0.4μ
m, the linear velocity during reproduction is constant at about 3.5 m / s, the storage capacity is about 4.7 Gbytes on one side, and the reproduction laser beam wavelength is 635-65.
0 nm.

In the case of DVD-5, the radial position of the lead-out portion does not have to reach the outermost portion (up to about 116 mm). An unrecorded area remains on the outer periphery of the disc, and in order to maintain the aesthetic appearance of the disc, a process similar to that of a CD in which dummy pits are recorded in the unrecorded area has been performed.

[0011]

However, in the above-mentioned method, the outermost periphery (lead-out portion) of the recording area is kept even after necessary information is recorded in the cutting step.
Since the dummy pits must be recorded from the outside of the disk to the vicinity of the outer peripheral end (about 116 mm in diameter) of the disk, there is a problem that a long cutting time is required.

That is, the shorter the program time of the disc, the longer the time for recording the dummy pits.
Originally, the cutting process could be performed in a short time, but extra cutting time had to be spent, which was a factor of delaying the production cycle and increasing the production cost.

[0013]

An optical information recording medium according to the present invention is an optical information recording medium comprising a substrate on which information is recorded, such as a DVD-5, and a dummy substrate on which no information is recorded, are bonded together. The medium has been made to solve the above problems, and the invention according to claim 1 of the present invention includes a transparent substrate having an information surface and a dummy substrate having a dummy pit surface, The information surface of the transparent substrate and the dummy pit surface of the dummy substrate are bonded together via a transparent adhesive layer, and the information surface is covered with a first reflective layer and a recording area where information is recorded and the An unrecorded area, which is not covered by the first reflective layer and is located outside the recording area and on which the information is not recorded, wherein the dummy pit surface has a predetermined outer periphery at least from the innermost position of the outermost periphery of the recording area. Range of position Oite pits or grooves are formed, the area where pits or grooves are formed in the dummy pit surface is an optical information recording medium, characterized in that is covered by the second reflecting layer.

According to a second aspect of the present invention, there is provided a transparent substrate having an information surface, and a dummy substrate having a dummy pit surface, wherein the information surface of the transparent substrate and the dummy substrate of the dummy substrate are provided. The pit surface is bonded via a transparent adhesive layer, and the information surface is covered with a first reflective layer and a recording area where information is recorded and a recording area which is not covered with the first reflective layer and is outside the recording area. An unrecorded area where the information is not recorded, wherein the dummy pit surface has a display made of characters or patterns in the same radius area as the unrecorded area. is there.

According to the first aspect of the present invention, only the recording area of the transparent substrate on which the short program is recorded is covered with the reflective layer, and the substrate on which the dummy pits are recorded and the reflective layer is formed is bonded. The dummy pits formed on the dummy substrate,
It is possible to manufacture a disk that can be seen through an unrecorded area of the bonded transparent substrate and that looks as if information is recorded on the transparent substrate up to the outer peripheral portion.

Here, if dummy pits are formed on the entire area corresponding to the recording area defined by the DVD standard and a large number of dummy substrates covered with a reflective layer are produced, a disc having various program times can be obtained. Therefore, the production cost can be reduced and the production cycle can be speeded up.

According to the second aspect of the present invention, only the recording area of the transparent substrate on which the short program is recorded is covered with the reflective layer, and is recorded in the recording area on the outer periphery of the dummy substrate. Since the display of the content related to the information is performed by characters, pictures, prints, or the like formed by the dummy pits, the display can be seen through the unrecorded area, and the added value of the disc can be increased. .

Therefore, according to the first and second aspects of the present invention, it is not necessary to record dummy pits after the recording of the recording area is completed when cutting the master, unlike the related art.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an optical information recording medium of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic view showing one embodiment of a transparent substrate having an information surface before bonding the optical information recording medium of the present invention. In the figure, 101 is a transparent substrate, 102 is an information area, 103 is a non-information area, 104
Is a central hole. The transparent substrate 101 has a diameter of 120 mm,
The thickness is 0.6 mm, and the diameter of the center hole 104 is 15 mm.
It is.

The transparent substrate 101 has an information area 102 in which information is recorded as pits, and the inner diameter of the information area 102 is about 45 mm. Information area 102
The outer diameter depends on the amount of recorded information,
Since the optical information recording medium of the present invention is intended for a medium having a small capacity of recorded information, it is assumed that the outer diameter of the information area 102 does not exceed about 116 mm.

Outside the information area 102 of the transparent substrate 101, a mirror-like non-information area 103 having no pits is formed.
It has become. In the optical information recording medium of the present invention, only the information area 102 of the transparent substrate 101 is covered with a reflective film of aluminum, gold, or the like, and the non-information areas 103 inside and outside the information area 102 are covered with a reflective film. Not done.

FIG. 2 is a schematic view showing an embodiment of a dummy substrate before bonding an optical information recording medium according to the present invention. In the figure, 201 is a dummy substrate, 202 is a dummy pit area,
203 is a center hole. The dummy substrate 201 has a diameter of 12
The diameter of the center hole 203 is 0 mm, the thickness is 0.6 mm, and the diameter of the center hole 203 is 15 mm.

The dummy substrate 201 has a dummy pit region 202 in which pits or pregrooves similar to the pits recorded in the information region 102 of the transparent substrate 101 in FIG. 1 are formed. Dummy pit area 202
Has an outer diameter of about 116 mm. Here, the outer diameter of the dummy pit area 202 only needs to be inside the outer diameter of the information area 102 of the transparent substrate 101 bonded to the dummy substrate 201.

However, as the dummy substrate 201, the inner diameter of the dummy pit region 202 is about 45 mm, and the outer diameter is about 116 m.
If one kind of m is manufactured in large quantities, the amount of information recorded in the information area 102 of the transparent substrate 101 to be bonded can correspond to any kind of information. Various types of dummy substrates 2
01 is not required, and the manufacturing cost can be reduced. The dummy pit region 202 of the dummy substrate 201 is covered with a reflection film (not shown) made of aluminum, gold, or the like. The reflective film needs to be thick enough to identify the dummy pits when viewed from the reflective film side.
A film thickness of about 50 to 100 nm is preferred.

FIG. 3 is a schematic diagram showing a relative relationship when a transparent substrate and a dummy substrate are bonded. In the figure, the same parts as those shown in FIGS. 1 and 2 are denoted by the same reference numerals. The surface of the transparent substrate 101 on which the information area 102 is formed and the surface of the dummy substrate 201 on which the dummy pit area 202 is formed are bonded via a transparent adhesive layer (not shown) made of an ultraviolet curable resin or the like.

FIG. 4 is a schematic view showing a first embodiment of the optical information recording medium of the present invention. In the figure, the same parts as those shown in FIGS. 1 and 2 are denoted by the same reference numerals. FIG. 4 shows a state in which the transparent substrate 101 and the dummy substrate 201 are bonded together as viewed from the transparent substrate 101 side.

In the transparent substrate 101, only the information area 102 is covered with a reflective film, and the non-information area 103 outside the information area 102 is smooth and transparent. A dummy pit area 202 covered with a transparent adhesive layer and the non-information area 103 can be seen through. Therefore, the user feels as if the information area of the transparent substrate 101 is recorded up to the outer peripheral portion (about 116 mm), and it is possible to provide a good-looking optical information recording medium.

FIG. 5 is a schematic diagram showing a second embodiment of the optical information recording medium of the present invention. In the figure, the same parts as those shown in FIGS. 1 and 2 are denoted by the same reference numerals. FIG. 5 shows a state in which the transparent substrate 101 and the dummy substrate 201 are bonded together as viewed from the transparent substrate 101 side.

The difference between the first embodiment and the first embodiment is that a portion of the dummy pit area 202 of the dummy substrate 201 which is visible from the non-information area of the transparent substrate 101 is provided with a pit or pre-groove called a pit art. That is, a display 501 indicating a character or a pattern depending on the presence or absence is formed. Here, the display 501 is a character or a pattern related to the information recorded in the information area 102 of the transparent substrate 101, and is, for example, a trademark of a manufacturer / seller, a title of the recorded information, an artist name, or the like. is there.

The pit art will be described. For example, since no pits or pre-grooves are formed at a portion corresponding to the display 501 in FIG. 5, the display 501 can be visually recognized by the light interference effect.

As a method of producing the pit art, when recording the dummy pit area of the master disk of the dummy substrate 201, only the portion corresponding to the display 501 is turned off so that the recording laser beam is turned off so that no pit or pre-groove is formed. do it.

According to the second embodiment of the present invention, the dummy pit region 202 in which the display 501 is formed by being covered with the reflection film of the dummy substrate 201 bonded to the transparent substrate 101 is formed.
Can be seen through the transparent adhesive layer and the non-information area 103. Therefore, since the area outside the information area 102 of the transparent substrate 101 is not mirror-shaped and has a display using pit art, it is possible to provide an optical information recording medium having good appearance and added value. it can.

[0033]

According to the optical information recording medium of the present invention, only the recording area of the transparent substrate on which the short program is recorded is covered with the reflective layer, and the substrate on which the dummy pits are recorded and the reflective layer is formed is bonded. Pits formed on the dummy substrate can be seen through the unrecorded area of the bonded transparent substrate, as if information were recorded on the transparent substrate up to the outer periphery. Can be produced.

According to the optical information recording medium of the present invention,
Only the recording area of the transparent substrate on which the short program is recorded is covered with the reflective layer, and the contents of the information related to the information recorded in the recording area are displayed on the outer periphery of the dummy substrate with characters or patterns formed by dummy pits. Or, because it is applied by printing etc., those displays can be seen through the unrecorded area,
The added value of the disc can be increased.

Further, according to the optical information recording medium of the present invention, it is not necessary to record the dummy pits after the recording of the recording area is completed when cutting the master, unlike the related art, so that the production cost can be reduced. In addition, the speed of the production cycle can be increased.

[Brief description of the drawings]

FIG. 1 is a schematic view showing one embodiment of a transparent substrate having an information surface before bonding an optical information recording medium of the present invention.

FIG. 2 is a schematic view showing one embodiment of a dummy substrate before bonding the optical information recording medium of the present invention.

FIG. 3 is a schematic diagram showing a relative relationship when a transparent substrate and a dummy substrate are bonded.

FIG. 4 is a schematic view showing a first embodiment of the optical information recording medium of the present invention.

FIG. 5 is a schematic view showing a second embodiment of the optical information recording medium of the present invention.

FIG. 6 is a schematic diagram showing a cross-sectional structure of DVD-5.

DESCRIPTION OF SYMBOLS 101 Transparent substrate 102 Information area 103 Non-information area 104 Center hole 201 Dummy substrate 202 Dummy pit area 203 Center hole 501 Display 601 Transparent substrate 602 Information surface 603 Reflective layer 604 Dummy substrate 605 Adhesive layer

Claims (2)

[Claims] A transparent substrate having an information surface; and a dummy substrate having a dummy pit surface, wherein the information surface of the transparent substrate and the dummy pit surface of the dummy substrate are interposed via a transparent adhesive layer. The information surface is covered with a first reflective layer, and a recording area where information is recorded is not covered with the first reflective layer, and the information located outside the recording area is not recorded. An unrecorded area, wherein the dummy pit surface is formed with pits or grooves at least in a range of a predetermined outer peripheral position from the innermost peripheral position of the recording area, and the pits or grooves of the dummy pit surface are formed. An optical information recording medium, wherein the area covered is covered with a second reflective layer. 2. A transparent substrate having an information surface, and a dummy substrate having a dummy pit surface, wherein the information surface of the transparent substrate and the dummy pit surface of the dummy substrate are interposed via a transparent adhesive layer. The information surface is covered with a first reflective layer, and a recording area where information is recorded is not covered with the first reflective layer, and the information located outside the recording area is not recorded. An optical information recording medium, comprising: an unrecorded area, wherein the dummy pit surface has a display composed of characters or patterns in the same radius area as the unrecorded area.