JP2001291281A - Recording disk and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain adequate information from pits and information quality from guide grooves existing in recording regions and address signals of adequate quality from the respective regions by adding recording information of pit shapes as universal information to a recording disk. SOLUTION: The recording disk has guide grooves 101 for recording, reproduction-only bit strings 103, first land prepits 104 formed with the address information adjacently to the bit strings 103 and second land prepits 102 formed with the address information contacted with the guide grooves 101. The base surfaces of the guide grooves 101, the bit strings 103, the first land prepits 104 and the second land prepits 102 exist on the same plane.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recordable disc and a method for manufacturing the same, and more particularly to a recordable disc having both a recordable / reproducible area and a reproducible area and having address information formed in a land prepit shape.

[0002]

2. Description of the Related Art Conventionally, recordable discs can be classified into a type capable of recording only once and a type capable of recording many times by repeating recording and erasing from the form thereof. The medium used varies from organic materials to inorganic materials.

The structure of a recordable disc capable of performing such recording includes, for example, recording conditions for specifying the amount of laser light for recording, the type of the disc, and recorded information such as the name of the manufacturer of the recordable disc, or the disc. Address information and the like for searching for a recordable area therein are recorded in the disc in advance.

[0004] A disc on which various kinds of information are recorded in advance is devised so that it can be used immediately after purchase. For example, in the case of recording conditions, the conditions may be formed as embossed pits when cutting the master disc, or when the disc is shipped, the pits or marks may be initially recorded in the disc lead-in area or near the disc by a recording machine. It is recorded in the area to be reproduced.

For example, the above-mentioned address information is formed as land pre-pits by increasing the width of a portion having a guide groove in a recording area where information on the disk is recorded, and the address information is recorded here. . In order to control the number of rotations of the disk, a wobble in which the guide groove is slightly shaken is also formed. Among them, the type of optical disc,
Pure universal information that does not depend on the production lot of the disc, such as the manufacturer, is inefficient if it is recorded on a disc-by- disc basis when the disc is shipped. It is created at the same time as the formation of the disk substrate by using the one engraved as.

[0006] The pits in the metal matrix are generally prepared as follows. First, a photosensitive resist having a thickness corresponding to a desired depth of a recording guide groove is applied on a smooth polished glass disk. For example, in the case of a DVD-RW type optical disk, the optical resist is applied to a thickness of about 30 nm. The glass disc coated with the photo resist is carried by a cutting machine. This cutting machine is equipped with a recording laser device, and further has a light control device that changes the light emitted from the laser device into intermittent light or sways right and left. Then, by mounting a resist board at a desired position of the light control device, information necessary as an optical disk is recorded on the optical resist by laser light. At this time,
Pits are formed by using laser light as intermittent light, and recording guide grooves are formed by using laser light as continuous light. Further, two laser beams are used, a guide groove is formed by one laser beam, and another laser beam is intermittently formed to form a land prepit.

[0007] Recorded information such as the type of disc, the manufacturer name, and recording conditions is recorded as pits by intermittent laser light. After cutting, the resist disc is developed to change its shape and information is deposited. A conductive thin film is coated on the resist board, and the shape information on the resist board is transferred to the plating board using electroplating. This plating board is processed into a desired size, formed into a matrix, and transferred as a shape change onto a plastic substrate using an injection molding machine or the like, thereby forming an optical disk substrate.

The place where the shape change on the optical disk substrate is transferred is called an information surface. A functional film for recording is formed on this information surface, and the recording type is formed through various post-processing. An optical disk is created. In some cases, after the optical disc is created, recording conditions and the like may be recorded on the optical disc information surface before shipment. In such a process, a guide disc and a pit are produced as a disc having the same depth in one optical disc.

Here, since the grooves for recording on the recordable disc are formed for guiding during recording, if the signal from the recording mark recorded at the time of reproduction is to be taken out to the utmost, the recording groove must be formed. The phase difference of the reflected light resulting from the step causes a decrease in reflectivity, which is a problem. For example, in land / groove recording as employed in DVD-RAM disks, the guide groove is made as deep as possible to reduce the stroke between tracks between land / grooves. However, in general, the depth of the groove is the depth at which the guide signal from the guide groove is most efficiently taken out (1 of the reproduction wavelength).
/ 8 wavelength). Then, the tracking operation to the guide groove is performed by the push-pull method.

On the other hand, a DVD which is a read-only optical disk
In the case of a ROM disk, the pit depth is set near the depth at which diffraction by light is efficiently performed so that a reproduction signal as large as possible can be obtained when reproducing this disk (1/4 of the reproduction wavelength). near). For this reason, if the tracking operation is a push-pull method for the guide groove, a signal necessary for tracking cannot be sufficiently obtained, and thus tracking is performed by a phase difference method. As described above, the depth of the guide groove is set so that the recording disk can operate efficiently, and the depth of the guide groove that is convenient for reproduction is set for the reproduction type disk.

[0011]

Here, when an attempt is made to reproduce a recordable disc by using a read-only disc reproducing apparatus, information indicating the type and manufacturer of the disc is written in a pit state near the lead-in area of the disc. Even if the recording is performed, the recording type disc is set to a depth such that the guide groove can be detected at the time of cutting and the recorded signal can be reproduced efficiently (for a DVD-RW, the depth is about 30 nm). ), The reproduced signal output obtained when trying to read the pit diffracted light by the phase difference method is small and cannot be read, and a read-only disc reproducing apparatus may malfunction even if a disc is inserted. There was danger.

Although it may be considered that the type and manufacturer name of the disk should be recorded in advance for each optical disk, there is a problem in that recording for each disk is too costly. Also, if recording is performed in the same recording state as normal recording, the user may accidentally erase the recording, and when the erased disc is inserted into a playback-only disc playback device There is a danger of malfunction, indicating that the above method does not solve the fundamental problem.

From the viewpoint of reliability and cost, in order to make erasure impossible and to record the same information on a disc, it is desirable to record it as a pit row. This was not possible with recording disks, and only disks with poor reliability could be produced.

Considering that a recordable disc is to be reproduced by a disc recording / reproducing apparatus, a notch called a land prepit is formed on a recording guide groove, and the state of the notch is read out as an address signal (DVD).
-R disc, DVD-RW disc) reproduces a land pre-pit address signal necessary for recording when reproducing the disc. If this is not reproduced, when the recording / reproducing apparatus shifts to the recording operation, it becomes difficult to know from which address to start recording. Since the pit row in the area where the disc information is recorded is formed deeper than the guide groove, the address signal output of the land pre-pit embedded on the side of the pit row becomes relatively large, and the address When performing information processing, the difference between the address pit output in the guide groove portion and the address pit output in the pit row portion becomes large, and there is a drawback that normal address signal processing is hindered.

Further, in a recordable disc, it is determined that a lead-out signal indicating the end of the record information is recorded after the end of the information. However, a large amount of information to be recorded is recorded on one disc. When recording is not possible, some recording devices record too much information up to the outer periphery of the disc, and it is no longer possible to secure a sufficient area for recording the lead-out signal. Some recording devices have a reproduction state that is unstable in some sections. In addition, the transferability of the outermost portion of the disk is insufficient due to molding or the film configuration deviates from the optimum value due to film formation. Even if a lead-out signal is recorded on the outermost portion of the disk, sufficient signal quality is obtained. There was something that could not be recorded.

In order to solve these problems, the thickness of the resist in the resist process is set to be equal to or greater than the deepest pit or groove formed by cutting, and the laser power at the time of cutting is controlled. There is a method of forming different pits and guide groove depths on a single resist disk by exposing the resist in the entire direction without exposing the resist during development (FIG. 4). However,
Since the resist is not exposed in the entire thickness direction, the depth of the pits and guide grooves fluctuates due to fluctuations in the amount of laser light from the cutting device. Due to the instability of the groove shape during recording,
There is a problem that the recorded signal quality is poor.

[0017]

In order to solve the above-mentioned problems, a recording guide groove 101 for recording information is provided.
And recording conditions such as the maker name of the recordable disc, the amount of laser light at the time of recording, lead-in information indicating a lead-in area of the disc, and lead-out information indicating a lead-out area of the disc. A read-only pit string 103 in which information is recorded in advance, a first land pre-pit 104 formed adjacent to the pit string with address information indicating a recording address of a recordable area of the recordable disc, A second land pre-pit 102 formed by contacting the guide groove with address information indicating a recording address of a recordable area of the recordable disc.
And the guide groove 10
1. There is provided a recording type disc wherein the heights of the bottom surfaces of the pit row 103, the first land pre-pits 104, and the second land pre-pits 102 are on the same plane.

A recording guide groove 101 for recording information, a maker name of a recordable disc, recording conditions indicating a laser light amount at the time of recording, and lead-in information indicating a lead-in area of the disc. A read-only pit string 103 in which recording information such as lead-out information indicating a lead-out area of the disc is recorded in advance,
A recordable disc having address information indicating a record address of a recordable area of the recordable disc and a second land pre-pit formed in contact with the guide groove, wherein A recordable disc is provided, wherein the heights of the bottom surfaces of the pit row 103 and the second land pre-pits 102 are on the same plane.

2. The method of manufacturing a recording disk according to claim 1, wherein the guiding step is performed by changing the intensity of two laser beams arranged in parallel in the cutting step. A second land pre-pit formed in contact with the groove and the guide groove, or a first land pre-pit formed adjacent to the pit row and the pit row is simultaneously formed. A method for manufacturing a disk is provided.

Further, in the method of manufacturing a recordable disk according to claim 2, wherein the intensity of two laser beams arranged in parallel is changed in the cutting step. A method of manufacturing a recording disk, wherein a guide groove and a second land prepit formed in contact with the guide groove are simultaneously formed.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a recording disk according to the present invention and a method for manufacturing the same will be described with reference to the drawings.
An optical disk which is a recordable disk according to the present invention is prepared by the following steps.

First, a glass disk having a smooth surface is prepared, and a resist is applied to the surface of the glass disk to a thickness corresponding to the depth having the deepest shape. The glass master thus processed is referred to as a resist board 14. The resist board 14 is carried to a cutting device as shown in FIG. The cutting device has two laser beams, and further has an optical deflector 6 for slightly oscillating one laser beam A left and right, and an optical modulator 8 for changing the laser beam intensity. ing. Further, the cutting device is provided with an optical modulator 5 for changing the laser intensity of another laser beam B.

An objective lens 13 for condensing the laser beam is provided on the resist board 14, and the two laser beams A and B are incident on the objective lens 13 side by side in the radial direction of the track where they are recorded. . Resist board 1
4 is mounted on a rotating turntable 15,
It rotates with the turntable 15. Then, the laser beam is focused by the objective lens 13 on the rotating resist board 14.

In a part of the area of the resist disc 14 which becomes a lead-in area when the disc is formed, identification information that the disc is a recordable disc is provided with laser intensity (PA1) suitable for recording pits. ) Is recorded using the laser beam A. At this time, the pit row is recorded with a predetermined frequency and slightly wobble (there is no need to wobble). Then, a first land prepit suitable to be adjacent to the pit row to be recorded by the laser beam A is recorded by a laser beam B having a laser beam intensity (PB1) necessary for forming the first land prepit ( (Fig. 2). At this time, if a pit is formed next to the first land pre-pit, the pit and the first land pre-pit are integrally formed in contact with each other. In some cases, the first land prepit adjacent to the pit row need not be formed.

Further, a guide groove is recorded following the pit row.
At this time, recording is performed with a laser beam A having a laser intensity (PA2) suitable for exposing the entire resist in the thickness direction, but the guide groove is recorded with a predetermined frequency and a slight wobble. Then, a second land prepit suitable for contacting the guide groove beside the guide groove recorded by the laser beam A is formed by a laser beam B having a laser beam intensity (PB2) necessary for forming the second land prepit. Record. At this time, the depth of the second land prepit is equal to the depth of the guide groove. The intensity of the laser beam B is for exposing the resist to a desired thickness. After recording the guide groove up to the radius of the predetermined area, the lead-out area is formed.

In the lead-out area, pits are recorded again. At this time, lead-out information is recorded under the same conditions as the pit formation in the lead-in area. That is, recording is performed using a laser beam A having a laser intensity (PA1) suitable for recording pits and suitable for exposing the entire resist thickness direction. At this time, the pit row is recorded with a predetermined frequency and slightly wobble (the wobble may not be necessary). The laser beam B forms a first land pre-pit suitable for contacting the side of the pit row with a laser intensity (PB) suitable for forming the first land pre-pit.
Record in 1). Thus, one resist board 1
4 is recorded as a latent image (FIG. 2).

Then, in the next development step, the latent image is precipitated as a shape change and carried to a metal master forming step. In the metal master forming process, a conductive film such as nickel is coated on the resist master 14, and a nickel film is formed thereon by nickel plating or the like. Thereafter, the metal master made of nickel is peeled off from the resist board 14. The peeled metal master is cleaned and processed into a size that can be mounted on a molding die. The metal master after processing is called a matrix. A mother disk is mounted on a molding die, and a plastic disk substrate is formed by molding. FIG. 3 is a cross-sectional view showing a plastic disc substrate of the recordable disc according to the present invention.

A recording type film is formed on a disk substrate, and a protective film is applied thereon, or a substrate called a dummy substrate is bonded thereto to produce a recording type disk. Depending on the recording method, there are various types of recordable disks, such as a magneto-optical disk, a phase change recording disk, and a write-once recording disk using a dye film. In the case of phase change recording, the disk is shipped after initialization of the disk. In the case of a recordable disk, the minimum format is performed for each disk, so that the disk can be used as a recording disk immediately after purchase.

Next, the recording disk of the present invention and the method of manufacturing the same will be described in more detail. 200mm diameter
The resist was applied to a glass disk having a smooth surface with a thickness of 70 nm, and the resist was dried to prepare a resist disk 14. The resist disk 14 was mounted on a cutting device. The cutting device is equipped with a krypton laser. An emission filter (ND filter) 2 for changing the intensity of the laser light is provided at a laser light emission opening of the laser light source 1, and a semi-transparent mirror 3 for dividing the laser light into two is provided behind the filter. Equipped.
The laser beam A among the two split laser beams is reflected by the mirror 4 and passed through the optical modulator 6 to the optical polarizer 9. Another laser beam B passes through the optical modulator 5. Each laser beam A,
B denotes separate beam expanders 7, 1 so that a laser spot of a predetermined size can be obtained during cutting.
0 (laser beam A is reflected by mirror 9 before passing through beam expander 10). Thereafter, the laser beam A and the laser beam B are converted into two parallel laser beams by the translucent mirror 11 and guided to the objective lens 13 of the cutting device via the mirror 12.

Then, the turntable 15 on the cutting device is rotated at a desired number of revolutions, and cutting of the guide groove is performed under the following condition 1.

Condition 1: A laser beam was applied to a position of 42 mm in diameter on the resist board 14 to cut the guide groove and the second land prepit (FIG. 2). The laser beam A contains a wobble signal. The wobble signal has an amplitude of 15 nm on the resist board 14 so that the optical deflector 6
Is shaking the laser light left and right. The width of the guide groove to be cut was 0.3 μm, and the intensity of the laser beam was set so as to expose the entire resist in the thickness direction (PA
2). On the other hand, the laser beam B has a laser beam intensity (PB2) at which a desired second land prepit is formed, and the laser beam intensity is such that the resist thickness remains about 30 nm except when the land prepit is formed. Set. The cutting was performed at a constant linear velocity.

Next, pit row cutting was performed under the following condition 2.

Condition 2: Cutting of the pit row was performed from the position of the disk having a diameter of 45 mm. Laser beam A
Increases the intensity of laser light by the light modulator 8 so that a pit having a depth of 70 nm can be formed (PA1),
Further, an operation for generating an intermittent light according to the pit information signal is performed to cut the pit. At this time, the wobble signal is continuously superimposed.

On the other hand, the laser beam of the laser beam B has the intensity (PB1) of the laser beam for forming the desired first land prepit, and the depth of the first land prepit to be cut is about 50 nm. It is set to be. In this state, cutting was performed up to a position of about 48 mm in diameter.

The guide groove was cut from the position of the resist disc 14 having a diameter of 48 mm to the position of 117 mm in diameter again according to the contents of the condition 1.

Next, a pit row was prepared under the condition 2 from the position of the resist board 14 having a diameter of 117 mm to the position of a diameter of 119 mm.

The resist plate 14 thus cut is completed as a master through a development process, a conductive film formation and a plating process. The master mold is attached to the mold of the injection molding machine and has a diameter of 12 mm using polycarbonate resin.
An optical disk substrate having a thickness of 0 mm and a thickness of 0.6 mm was obtained. A phase-change recording medium having a four-layer structure of a protective layer, a recording layer, a protective layer, and a reflective layer was formed on the optical disk substrate. The substrate thus processed and a dummy substrate having the same size as this substrate are bonded together with an ultraviolet curable resin to produce a final disk. Then, the disk is subjected to an initialization process by an initialization device, and a label is printed on the recording / reproducing surface opposite to the laser incident light surface to complete the disk.
In the recordable disk according to the present invention, the read-only pit row is formed as uneven pits and cannot be erased.

When a signal was recorded on the recordable disk manufactured as described above, better recording / reproducing characteristics could be obtained as compared with a recordable disk in which the bottom surface of the guide groove was not smooth.

FIG. 3 is a diagram showing a cross-sectional shape of a recording type disk according to the present invention. The guide groove 101 formed on the disk 100 has a depth of 1, and the guide groove 101 and the guide groove 101 And a second groove formed in contact with the guide groove.
Of land pre-pit 102 has the same depth 1 as guide groove 101
Having. The pit 103 has a depth of 2 and a first land pre-pit 1 formed adjacent to the pit 103.
04 has a depth of three. At this time, the depth 1, the depth 2, and the depth 3 are different depths.

The depth of the guide groove 101 is preferably 24 nm or more and 45 nm or less, and the depth of the pit 103 is preferably 60 nm or more and 100 nm or less. When the depths of the guide groove 101 and the pit 103 are determined as described above, the depth of the first land pre-pit 104 becomes 24
It is preferably larger than 100 nm and smaller than 100 nm. Moreover, considering the signal output from the first land pre-pit 104, when the depth of the first land pre-pit 104 is 100 nm (actually, a very small value less than 100 nm), When the depth of the first land pre-pits 104 is 60 nm so that the width is about 0.1 μm, the width is 0.15 μm.
If the depth of the first land pre-pit 104 is 30 nm so that the width is set to μm, it is preferable that the width is set to 0.3 μm.

In the above-described embodiment, the pit 103 and the first land pre-pit 104 are formed integrally. However, actually, the pit 103 and the first land pre-pit 104 are positioned adjacent to each other in cross section. And the first land prepit 1 adjacent to a position where no pit exists.
04 may be formed.

The recording medium according to the present invention is not limited to a phase change optical disk, but may be a magneto-optical recording medium or a write-once medium using a dye or the like.

[0043]

As described above in detail, according to the recordable disc and the method for manufacturing the same according to the present invention, pit-shaped record information as universal information is added to the recordable disc.
There is an effect that appropriate information from the pits and appropriate information quality from the guide groove in the recording area can be obtained, and an address signal of appropriate quality can be obtained from each area. In addition, since the lead-out signal by the pit string is set in the disk lead-out area, it is not necessary to input the lead-out signal after the recording of the disk is completed, and it is possible to prevent signals other than the lead-out signal from being accidentally input to the lead-out area. In addition, a highly reliable disk can be obtained. Furthermore, while the depth of the pits and guide grooves is constant,
Since the bottom surface of the recording guide groove is flat, the quality of the recorded signal is improved.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an example of a cutting device used in a method of manufacturing a recordable disc according to the present invention.

FIG. 2 is a diagram showing an example of a recordable disc according to the present invention and the light intensity of a laser beam during cutting.

FIG. 3 is a sectional view showing an example of a recordable disc according to the present invention.

FIG. 4 is a cross-sectional view showing an example of a conventional recordable disc.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Laser light source 2 ND filter 3,11 Translucent mirror 4,9,12 Mirror 5,8 Optical modulator 6 Optical polarizer 7,10 Beam expander 13 Objective lens 14 Resist board 15 Turntable 100 Disk 101 Guide groove 102 Second Land pre-pit 103 pit 104 first land pre-pit

Continuation of the front page F term (reference) 5D029 JB09 KB03 WA27 WA30 WB19 WD12 WD13 WD22 5D090 AA01 BB11 CC14 DD01 EE16 FF02 GG10 5D121 AA02 BB22 BB26 BB38

Claims (4)

[Claims] 1. A recording guide groove for recording information, a maker name of a recordable disc, recording conditions indicating a laser light amount at the time of recording, lead-in information indicating a lead-in area of the disc, A read-only pit string in which recording information such as lead-out information indicating a lead-out area of the disc is recorded in advance, and address information indicating a recording address of a recordable area of the recordable disc are adjacent to the pit string. And a second land prepit formed by contacting the guide groove with address information indicating a recording address of a recordable area of the recordable disc. A recordable disc, wherein the heights of bottom surfaces of the guide groove, the pit row, the first land prepit, and the second land prepit are the same. Recording disc, characterized in that in the plane. 2. A recording guide groove for recording information, a maker name of a recordable disc, recording conditions indicating a laser light amount at the time of recording, lead-in information indicating a lead-in area of the disc, A read-only pit string in which recording information such as lead-out information indicating a lead-out area of the disc is recorded in advance, and address information indicating a recording address of a recordable area of the recordable disc are brought into contact with the guide groove. And a second land pre-pit formed by the following method: wherein the height of the guide groove, the row of pits, and the bottom surface of the second land pre-pit are in the same plane. Recordable disc. 3. The method of manufacturing a recording disk according to claim 1, wherein the guiding is performed by changing the intensity of two laser beams arranged in parallel in a cutting step. A second land pre-pit formed in contact with the groove and the guide groove, or a first land pre-pit formed adjacent to the pit row and the pit row is simultaneously formed. Disc manufacturing method. 4. The method of manufacturing a recording disk according to claim 2, wherein said guiding is performed by changing the intensity of two laser beams arranged in parallel in a cutting step. A method for manufacturing a recordable disk, comprising simultaneously forming a groove and a second land prepit formed in contact with the guide groove.