JPH07334867A - High density optical disc and reproducing apparatus thereof - Google Patents

Abstract

(57) [Summary] [Object] The present invention relates to an optical disc and a reproducing apparatus in which pits are formed at a density higher than that of a CD, and prevents a malfunction of the CD reproducing apparatus even when the CD is mistakenly attached to an existing CD reproducing apparatus. It is to provide a reproducing device capable of reproducing a high-density optical disc and an existing CD that can be reproduced. [Structure] The radius of the recording area of the high density optical disk is 23
This can be achieved by providing a lead-in by CD standard pits in the area of mm to 25 mm and providing a flag indicating that the optical disc is a high density optical disc in the TOC information therein. [Effect] Even when a high-density optical disc is mounted on an existing CD reproducing device, the CD reproducing device can perform operations from the start of reproduction to the end of reproduction based on a normal reproducing operation. It is possible to prevent various failures that may occur due to malfunction of the control. Further, in the high-density optical disk reproducing apparatus, the T
Since the circuit constant is changed from the OC information depending on the disc, good reproduction can be performed on both discs.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high density optical disc having pits formed at a density higher than that of a so-called compact disc (hereinafter abbreviated as CD) among optical discs having phase pits formed according to signals. In particular, the external dimensions of the disc are substantially equal to those of the CD, and therefore, when the optical disc device for existing CD reproduction (hereinafter abbreviated as CD reproduction device) is erroneously attached to the existing CD reproduction device, compatibility with the CD reproduction device is provided. The present invention relates to a high-density optical disc capable of preventing malfunction and a reproducing apparatus for the high-density optical disc.

[0002]

2. Description of the Related Art In an optical disc device such as an optical disc represented by a CD or a CD reproducing device, a laser beam emitted from a laser diode is narrowed down to its wavelength limit and a narrowed light spot is applied to a pit train on the optical disc. The digital signal is reproduced by detecting the change in the amount of reflected light. In recent years, with the shortening of the wavelength of laser diodes,
The light spot can be made smaller,
As a result, it becomes possible to reproduce a high-density optical disc having a smaller pit size and a smaller track pitch than a CD.
In such a high density optical disc, as a matter of course, for example, audio signal reproduction at the same time as a CD can be performed with a disc having a smaller size, and conversely, when the disc size is about the same as the CD, It is possible to reproduce the audio signal for a longer time. Further, due to the progress of video signal compression technology, it may be possible to reproduce a video signal for a long time even with a disc size similar to that of a CD.

On the other hand, if such a high density optical disc is the same size as a CD, it is necessary to construct the system configuration and the disc format of the optical disc device so that the high density optical disc and the CD can be discriminated. Conventionally, when there are discs having the same disc shape or the same disc cartridge shape but different disc signal formats, for example, the following method is used to determine the disc type. Has been.

The disc is provided with a pit row in which the pits of adjacent tracks are the same in a predetermined area of the innermost periphery of the disc. On the disk device side, only focus servo is performed in this area, and reproduction is performed with the tracking servo off. At this time, the light spot crosses the track diagonally depending on the amount of eccentricity of the disc. However, since the pits of adjacent tracks are equal as described above, there is some variation in the signal amplitude, but the signal reproduction Will be possible. Here, if the information about various formats of the disc is formed as pits in the area, the type of the disc can be discriminated. Regarding the discs mentioned above, IS
O Standard Document ISO / IEC JTC 1 / SC 23N (Final tex
t of DIS 9171-2).

[0005]

The above-mentioned prior art is to provide a pit in which information regarding the type of the disc is recorded in a predetermined area on the innermost circumference of the optical disc, and the above-mentioned technique is adopted when the optical disc device side mounts or reproduces the disc. A prerequisite is that the system is configured to operate. However, the CD and the CD reproducing device are not currently configured as described above. Therefore, when a high density optical disc is mounted in the CD reproducing device, even if a pit row for providing disc type discrimination information is provided in a predetermined area on the high density optical disc side, the system configuration of the CD reproducing device side is not changed. As far as it goes, the following problems occur.

[0006] In general, a CD reproducing apparatus, at the start of reproduction, has a focus servo pull-in, a tracking servo pull-in, a pit signal reproduction, and a disk rotation servo by a synchronization signal included in a reproduction signal at the lead-in area of the innermost circumference of the disk. It operates in the order of pulling in. Assuming that a high-density optical disc is mounted on such a CD reproducing device and the reproducing operation is started, the focus servo pull-in operation may be performed, but the subsequent tracking servo pull-in operation may not be performed. is there. For example, the track pitch of a high density optical disc is CD
If the track pitch is smaller than the track pitch, the degree of modulation of the tracking error signal decreases, and the tracking servo becomes unstable or impossible. If the track pitch is about the same as the CD and the pit length in the track tangential direction is smaller than the CD, tracking servo can be performed, but the reproduction signal modulation degree of the pit decreases, so that the signal can be reproduced stably. Without this, the operation of the disk rotation servo becomes unstable or impossible. As a result, the system control operation of the CD player becomes unstable, and there is a risk of causing various failures.

On the other hand, it may be possible to discriminate between a high-density optical disc and a CD by changing the system configuration of the CD reproducing apparatus, but C which has already been widely spread for consumer use.
Making changes to all D playback devices is virtually difficult.

By the way, in the reproducing apparatus for the high-density optical disc, similarly, in addition to the high-density optical disc, the existing C
It is necessary to assume that D is also attached. At this time, if each circuit constant such as the waveform equalization constant of the reproduction signal and the servo gain in the reproduction device is set to a value suitable for reproduction of the high density optical disc, a good reproduction signal cannot be obtained during CD reproduction. Conversely, if the circuit constant is set to a value suitable for reproducing a CD, a good reproduction signal cannot be obtained when reproducing a high density optical disc. Therefore, in the case of considering a reproducing apparatus capable of reproducing both optical disks, it is necessary to switch the circuit constants in accordance with the mounted optical disks to perform reproduction. However, until the loaded optical disk is played back, it cannot be detected whether it is a high density optical disk or an existing CD, so there is a problem that the circuit constants cannot be initialized at the start of playback.

In view of the above-mentioned circumstances, an object of the present invention is a music CD and a data CD-which have been widely spread for consumer use.
Each CD that plays a CD that has been applied to various applications, such as ROM or multi-session CD-ROM
To provide a high density optical disc capable of preventing a malfunction by providing compatibility with the CD reproducing device without making any change to the CD reproducing device when a high density optical disc is accidentally mounted in the reproducing device. It is in. Another object of the present invention is to provide a high-density optical disk reproducing apparatus capable of reproducing both a high-density optical disk and an existing CD and obtaining a good reproduction signal even at the start of reproduction.

[0010]

In order to achieve the above object, a high density optical disc of the present invention divides a signal recording surface into a plurality of regions in the radial direction of the disc. For example, at least the CD lead-in area (radius 23 mm to 25 mm)
Is divided into a first region including the position of 1 and a second region located on the outer periphery of the first region.

In the first region, pits having the same optical characteristics as that of the CD, that is, pits having the same depth and width of the pit and the track pitch as those of the CD are formed. In addition, the signal modulation method and the data format are made equal to those in the lead-in area of the CD,
TOC (Table Of Cont) included in the lead-in area
In the ents) information, TOC information that is completed only in the first area is recorded regardless of the data recorded in the second area. For example, in the TOC information, the subcode indicating the total playback time of the disc is 0 minutes, 0 seconds, and 0 frames, and the subcode indicating whether it is a multi-session CD-ROM is a CD that is not a multi-session CD-ROM. Make a note of the flags that exist. Furthermore, at a predetermined position of the subcode, a bit indicating that a pit not conforming to the CD standard is formed in the second area is recorded.

On the other hand, in the second area, a pit row smaller than the depth and width of the CD pits or the track pitch is formed, and the pit row is formed at an arbitrary position in the second area, for example, the innermost circumference of the area. The TOC information regarding the data in the second area is recorded in the section. Further, a bit indicating that the pit formed in the second area is out of the CD standard is recorded in the subcode of the TOC information.

Further, the high density optical disk reproducing apparatus of the present invention comprises a waveform equalizing circuit capable of switching the waveform equalizing constant of the reproduced signal, a servo circuit capable of switching the servo gain of the optical pickup, a data strobe timing and the like. A switchable data strobe circuit is provided so that constants of each circuit can be switched by a control signal from the system controller.

[0014]

In a general CD reproducing apparatus, at the start of reproduction, first, the focus servo pull-in operation is performed with the target of the disk radius of 23 mm to 25 mm, and then the series of operations described above is started. Here, in this high-density optical disc,
In the first region including the range of 23 mm to 25 mm in radius, pits having the same pit depth and width as the CD and the track pitch are formed. It is possible to operate the rotary servo in exactly the same manner as during CD reproduction.

Here, since 0 minutes 0 seconds 0 frames are recorded in the data indicating the total reproduction time of the disc in the TOC information in the lead-in area formed in the first area, the reproduction operation thereafter is performed. Is not done. Furthermore, since a flag indicating that the disc is not a multi-session CD-ROM is recorded, a multi-session CD
Even if the high-density optical disc is played back by the CD playback device compatible with ROM, the operation of searching the next lead-in area after the lead-in area in the first area is not played back.

By the above operation, a high density optical disc is
Since compatibility with the D playback device can be provided, even if the high density optical disc is accidentally loaded into the CD playback device, it is possible to prevent malfunction of the CD playback device.

In the high density optical disc reproducing apparatus, the circuit constants of the waveform equalizing circuit, the servo circuit and the data strobe circuit are initially set to values suitable for reproducing CD standard pits, and the optical disc is mounted. When the subsequent reproduction is started, reproduction is performed within the range of the disk radius of 23 mm to 25 mm. High density optical disc and existing C
Regardless of D, pits are formed according to the CD standard on both optical discs, so that a good reproduction signal can be obtained by setting each circuit constant. If a bit indicating that a pit not conforming to the CD standard is formed in the second area is recorded at a predetermined position of the subcode data of the TOC information obtained by reproducing the area, the system controller In response to this, the values of the circuit constants are switched to constants suitable for reproducing the pit train in the second area, and then the second area is reproduced. Further, when the bit at the predetermined position of the subcode data indicates that there is no area where pits out of the CD standard are formed, each circuit constant is not changed and reproduction is continued as it is. . With the above operation, good reproduction can be performed on either optical disk, whether the optical disk mounted is a high density optical disk or an existing CD.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A high density optical disk and a high density optical disk reproducing apparatus according to the present invention will be described below.

FIG. 1 is a sectional view of a high density optical disc showing a first embodiment of the present invention. FIG. 1 (a) is a sectional view of a disc recording surface, and FIG. 1 (b) is a diagram in (a). It is an enlarged view of A area | region and B area | region. In the figure, 1 is a high density optical disc, 2 is a transparent substrate with pits formed therein, and 3 is a reflective film layer formed of a material such as aluminum.
Note that (b) shows the case of a cross section in which all the tracks have pits. Further, the protective film layer is omitted for simplification of the drawing.

FIG. 2 is a view showing the pit shapes in the A area and the B area formed on the high density optical disk 1 in a disk parallel plane.

The inner radius r ₁ and the outer radius r ₅ of the high density optical disc 1 are, for example, r ₁ = 7.
5 mm and r ₅ = 60 mm. The information recording area in which the pits are formed is divided into two areas, for example, an area A having a radius r ₂ to a radius r _{3 and} an area B having a radius r ₃ to a radius r ₄ . Phase A pits having a track pitch p ₁ and a depth d ₁ are formed in the area A, and pits having a track pitch p ₂ and a depth d ₂ are formed in the area B.

Here, the radius r ₂ and the radius r ₃ are set so that the range of the area A includes the range of the lead-in area in the CD.
Are r ₂ ≦ 23 mm and r ₃ ≧ 25 mm, respectively. In the area A, the track pitch p ₁ and the phase pit depth d ₁ are set to, for example, p ₁ ≈1.6 μm, d so that various signals can be detected by the light spot of the CD reproducing device.
₁ ≈ 0.11 μm. In addition, at least in the region A, the reflectance of the reflective film layer 3 is 70% or more. The data bit string recorded as a pit string in the area A is made to conform to the signal format of the CD standard including the data modulation method.

FIG. 3 is an area division diagram in which the area A is further divided, and the area A in FIG. 1 is enlarged. In the figure, the areas A1 to A3 have a data structure in the CD signal format as shown below. That is, the A1 area is the lead-in area format,
The A2 area has a program area format, and the A3 area has a lead-out area format. Also, r6 is A1
The radius of the disc that separates the area and the A2 area.
8 mm ≦ r6 ≦ 25 mm. As described above, if attention is paid only to the area A, the high-density optical disc 1 is no different from the CD in the optical characteristics of the disc such as the pit shape, the signal format and the data structure.

As a result, the high-density optical disc 1 is replaced with the existing C
When mounted on the D playback device and played back, at least in the area A, normal operation can be performed,
The reproduction operation of the B area, which has a risk of malfunction of the system, is not performed. Further, here, the length of the A2 area is zero to
If it is set to about several seconds, it is possible to end the reproducing operation immediately after starting the reproducing operation.

By the way, in a CD reproducing apparatus capable of reproducing a so-called multi-session CD in which the next lead-in, program and lead-out areas are further present on the outer peripheral side of the lead-out area, the lead-out information in the A3 area is recorded. Even after the reproduction, the operation of further searching for the next lead-in area on the outer peripheral side of the disc is performed. In order not to perform this operation, in the sub-code of the lead-in information recorded in the A1 area, a flag bit indicating whether or not it is a multi-session CD is set to multi-session C.
Set not to be D. As a result, even when the high-density optical disc 1 is played back by a CD playback device compatible with multi-session, it is possible to end the playback operation in the area A alone, and it is possible to play back the area B in which there is a risk of malfunction of the system. Absent.

In this embodiment, the area A is defined as the areas A1 to A.
Although the data of the lead-in area format, the program area format, and the lead-out area format are divided into three areas and respectively recorded, the present invention is not particularly limited to this, and for example, the above-mentioned A1 area to A3. In the area, the lengths of the A2 area and the A3 area may be zero, that is, the A area may be composed of only the A1 area. In this case, subcode data indicating that the total time of the program area is 0 minutes 0 seconds 0 frames is recorded in the TOC information included in the lead-in of the A1 area. As a result, the CD reproducing device does not shift to the reproducing operation of the program area after the lead-in reproduction, and does not execute the reproducing operation of the B area.

The data structure of the area A is not limited to the above example, and any data string may be used as long as the reproduction operation of the existing CD reproducing device in the area A is completed.

By the way, as the lead-in subcode data of the A1 area, for example, an empty bit (a bit not defined) in the CD signal format is used as a bit indicating the following information. That is, 1) a bit indicating that data is recorded in the B area by a pit string and a track pitch other than the standard value of CD. 2) a bit indicating information of a waveform equalization constant for a reproduced signal in the B area. By doing so, when reproducing the high density optical disc 1, by reproducing the area A, it is possible to determine that the data is recorded in the area B, for example, by a high density pit string. Further, since the constants for waveform equalization are shown, it is possible to set the optimum waveform equalization constant when the reproduction operation of the B region is started, and it is possible to obtain a good reproduced waveform.

On the other hand, in the region B, for example, the outer radius r ₅ is r ₅ =
When 60 mm, the radius r ₃ and the radius r ₄ are r ₃ ≧
25 mm and r ₄ <58 mm. Further, in the B region, the track pitch p ₂ and the pit depth d ₂ are set to values smaller than the standard values p ₁ and d _{1 of the} CD, respectively, so as to be suitable for reproduction by a small-diameter light spot. For example, the wavelength of the light source is λ = 530 nm, and the numerical aperture of the objective lens is NA.
Values suitable for reproduction on an optical disk device having an optical head of = 0.55 are p ₂ ≈0.9 μm and d ₂ ≈0.075 μm.
Becomes In this case, the recording density in the area B is about three times the recording density of the area A, that is, the CD, including the increase in the recording density in the track tangential direction.

[0030] Incidentally, the pit row formed on the B region, where is shown as an example specific values as a track pitch p ₂ and pit depth d ₂ is the p _2, d ₂ in the present embodiment The value is not particularly limited. Further, even if the values of p ₂ and d ₂ are the same as those of the CD, for example, since the data modulation method of the data bit string, the pit shape, etc. are different from those of the CD, a normal reproducing operation is performed in the CD reproducing device. It also includes pit rows that are not performed.

FIG. 4 is an area division diagram in which the area B is further divided, and the area B in FIG. 1 is enlarged. In the figure, the B1 area is a lead-in area including so-called TOC information indicating the contents of the data recorded in the B2 area,
The B2 area is a program area, and the B3 area is a so-called lead-out area which indicates the outer peripheral edge of the disk for recording data. Here, as subcode data to be recorded in the TOC information of the B1 area, a bit indicating the following information is provided. That is, 1) a bit indicating that data is recorded in the B area by a pit row and a track pitch other than the standard value of CD 2) a bit indicating the information of a waveform equalization constant for a reproduced signal in the B area 3) B It is a bit indicating the information of the disc reflectivity and the reproduction signal modulation degree in the area. By doing so, when reproducing the B area of the high density optical disc 1, it can be determined that the pit string being reproduced is a pit string other than the CD standard, for example, a high density pit string. Further, since the constants for waveform equalization are shown, it is possible to set an optimum waveform equalization constant and obtain a good reproduced waveform. Further, since the disk reflectance and the reproduction signal modulation degree are obtained as data, the gain of the servo system,
It is possible to optimally set the signal slice level and the like of the reproduction signal, and as a result it is possible to obtain reproduction data with few errors.

FIG. 5 is a circuit block diagram of a high density optical disk reproducing apparatus according to the present invention. In the figure, 7 is a waveform equalization circuit whose waveform equalization constant can be switched by a control signal 105, 8 is a data strobe circuit whose data slice level and data strobe timing can be switched by a control signal 106, and 9 is a control signal 107. A demodulation circuit whose demodulation method can be switched by, 11 is a control signal 1
This is a servo circuit in which the servo gain can be switched by 04. The operation of the present high density optical disc reproducing apparatus will be described below.

At the beginning of the reproducing operation, the waveform equalizing circuit 7, the data strobe circuit 8, the demodulating circuit 9 and the servo circuit 11 are all set to values suitable for reproducing the CD, and the optical pickup 5 A disk radius of 23 mm to 25 mm by an optical pickup moving means (not shown).
Located in. At this position, the optical pickup traces a light spot on a pit row formed on the disk by a known servo technique, and reproduces a signal corresponding to the pit. The reproduced RF signal is input to the demodulation circuit 9 via the waveform equalization circuit 7 and the data strobe circuit 8. Subcode data 103 is obtained from the demodulation circuit 9 and input to the system controller 10. When reproducing the program area, the digital data 102 is obtained from the demodulation circuit 9 and converted into an audio signal or the like. When the loaded optical disc is the high-density optical disc 1 according to the present invention, the subcode data 10 is added as described above.
3 shows that data is recorded in the B area by a pit row and a track pitch other than the standard value of CD, and accordingly, the system controller 10 receives the data.
A control signal 108 for moving the pickup in the outer peripheral direction is output to the pickup moving means. Servo circuit 1
In No. 1, for example, the tracking error signal amplitude during movement of the optical pickup is detected, and when it falls below a predetermined value, the area boundary detection signal 109 is output. As will be described later,
At this time, if a so-called mirror portion is provided between the area A and the area B of the high density optical disc 1, the area boundary can be easily detected. When the system boundary detection signal 109 is input, the system controller 10 stops the optical pickup moving means and shifts to the reproduction operation of the B area. Since the information of the waveform equalization constant for the reproduction signal of the B area has already been obtained from the subcode 103 at the time of reproducing the A area, the waveform equalization circuit 7 is provided before the system controller 10 shifts to the reproduction operation of the B area. , The data strobe circuit 8, the demodulation circuit 9, and the servo circuit 11 are output as control signals 104 to 107 so as to set the constants and the like suitable for the reproduction of the B area. As a result, a good reproduced waveform can be obtained.

If the loaded optical disk is not the high density optical disk 1 but an existing CD, the subcode data 103 obtained during the reproduction with the disk radius of 23 mm to 25 mm includes the CD in the B area. Since there is no flag indicated when data is recorded with a pit string or track pitch other than the standard value, the system controller 10 does not change the control signals 104 to 107 in response to this. Therefore, the settings of the waveform equalization circuit 7, the data strobe circuit 8, the demodulation circuit 9, and the servo circuit 11 all continue to be values suitable for CD reproduction, and the existing C
It is assumed that the same operation as the D playback device is performed. As a result, the existing CD can be played back, and so-called upper compatibility can be secured.

FIG. 6 is a sectional view of a high density optical disc showing a second embodiment of the present invention. FIG. 6 (a) is a sectional view of the disc recording surface, and FIG. 6 (b) is a diagram in (a). Area A,
It is an enlarged view of B area | region and C area | region. In the figure,
The same parts as those in are denoted by the same reference numerals, and the description thereof will be omitted here. The difference between FIG. 6 and FIG. 1 is that the C region in which no pit is formed is provided in the radius r ₃ to the radius r ₇ between the A region and the B region. Further, FIG. 7 is a view showing a pit shape formed on the high density optical disc 1 according to FIG. 6 in a disc parallel plane. As described above, by using the C area as a so-called mirror portion, the boundary between the areas can be easily detected in the access operation performed when the A area and the B area are alternately reproduced.

FIG. 8 is an enlarged sectional view of a disk showing another example of the enlarged sectional view (b) of the high density optical disk 1 shown in FIGS. 1 and 5. In the figure, the same parts as those in FIGS. 1 and 6 are designated by the same reference numerals, and the description thereof will be omitted here.
The difference between FIG. 8 and FIGS. 1 and 6 is that the pits formed in the A region and the B region have the same depth (d ₃ ). The pit depth d ₃ may be equal to the above-mentioned depth d ₂ or may be equal to d ₁ . By doing so, it is not necessary to change the pit depth in each region, and there is an advantage that the manufacturing process of the high density optical disc 1 is simplified. However, when d ₃ = d ₂ , for example, the amplitude of the reproduction signal is slightly reduced when reproducing the area A in the existing CD reproducing device, compared with the pit depth d ₁ , for example d ₃ = d ₁
In that case, compared with the pit depth d ₂ , a problem such as a slight decrease in the amplitude of the reproduction signal occurs in the reproduction of the B area in the high density optical disk reproducing apparatus. Therefore, the pit depth d ₃ may be set to an appropriate value of d ₂ <d ₃ <d ₁ so that the degree of the obstacle is assigned as evenly as possible.

By constructing the high-density optical disc as described above, even if the high-density optical disc 1 is accidentally mounted in the existing CD reproducing device and the reproducing operation is started, the CD is reproduced.
The playback device can normally perform focus, tracking, and disc rotation control, and can prevent a failure due to a malfunction of the system control of the CD playback device. In addition, in the area of the disk radius 23mm ~ 25mm,
As the subcode data of the TOC information, pits other than the CD standard pit string are formed in the outer peripheral portion, and the constant of waveform equalization is shown. It is possible to detect and obtain a good reproduction waveform when reproducing the high density area.

[0038]

According to the present invention, in a high density optical disc in which a pit row in which the pit depth, track pitch, etc. are different from the CD value is formed, the area of radius 23 mm to 25 mm conforms to the CD standard. By forming a pit string and recording the lead-in and lead-out information of the CD standard as a data bit string, even if the high-density optical disc is accidentally mounted in an existing CD reproducing device, the existing CD in the area is It is possible to cause the playback device to perform operations from the start of playback to the end of playback based on normal playback operations. As a result, it is possible to prevent various troubles that may occur due to the unstable system control operation in the CD reproducing device.

In the high density optical disk reproducing apparatus according to the present invention, the radius of the mounted disk is 23 mm to 25 mm.
Area is reproduced with initializing circuit constants such as waveform equalization constants and servo gains suitable for reproducing existing CDs.
From the subcode included in the OC information, it is determined whether the optical disc is a high density optical disc or an existing CD. In the case of an existing CD, by continuing the circuit constant, and in the case of a high density optical disc, by setting the circuit constant to a value suitable for reproduction of the high density area at the same time as accessing the high density area. Good reproduction can be performed on both discs.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a high density optical disc according to the present invention.

FIG. 2 is a diagram showing pits formed on the high density optical disc of FIG.

FIG. 3 is a disk cross-sectional view showing an area division of an A area.

FIG. 4 is a cross-sectional view of a disk showing an area division of an area B.

FIG. 5 is a circuit block diagram of a high density optical disc reproducing apparatus according to the present invention.

FIG. 6 is a disc cross-sectional view showing another example of the high-density optical disc according to the present invention.

7 is a diagram showing pits formed on the high-density optical disc of FIG.

FIG. 8 is an enlarged cross-sectional view of a disc showing another example of the high-density optical disc according to the present invention.

[Explanation of symbols]

1 ... High-density optical disc, 2 ... Transparent substrate, 3 ... Reflective film layer,
5 ... Optical pickup, 7 ... Waveform equalization circuit, 8 ... Data strobe circuit, 9 ... Demodulation circuit, 10 ... System controller, 103 ... Subcode data

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akio Fukushima 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Stock Information Media Division, Hitachi, Ltd.

Claims (9)

[Claims] 1. An optical disc in which phase pits are formed according to a signal, a signal recording surface is divided into at least two areas, a first area and a second area, and the phase pits are provided in the first area. Row spacing is 1.6 μm, phase pit length is 0.8
forming a first phase pit row having a size of μm or more, and forming a second phase pit row different from the phase pit row interval, the phase pit length or the data modulation method in the first area in the second area, The first area is at least the disc radius 2
A high density optical disc including a range of 3 mm to 25 mm. 2. The high density optical disc according to claim 1, wherein the subcode data of the TOC information formed in the first area has data formed by a second phase pit string in the second area. A high-density optical disk characterized by allocating a bit indicating and a bit indicating information on a waveform equalization constant used for signal reproduction of the second phase pit train. 3. The high density optical disc according to claim 1, wherein the sub-code data of the TOC information formed in the second area has data formed by a second phase pit string in the second area. Bit, information indicating a waveform equalization constant used for signal reproduction of the second phase pit train, disc reflectance in the second area, and reproduction signal modulation degree of the second phase pit train. A high-density optical disc characterized by allocating a bit indicating 4. The high density optical disc according to claim 1, wherein the first and second phase pit rows are different on the disc outer peripheral side than the first region and on the disc inner peripheral side than the second region. A high density optical disc comprising a third region in which a third phase pit row is formed. 5. A high density optical disc, wherein no phase pits are formed in the third region according to claim 4. 6. The high-density optical disc according to claim 1, wherein the relationship between the first phase pit depth of the first phase pit row and the second phase pit depth of the second phase pit row is:
(First phase pit depth)> (Second phase pit depth)
A high-density optical disc characterized in that 7. The high-density optical disc according to claim 1, wherein the relationship between the first phase pit depth of the first phase pit row and the second phase pit depth of the second phase pit row is:
(First phase pit depth) = (Second phase pit depth)
A high-density optical disc characterized in that 8. A servo circuit capable of switching a tracking servo gain of an optical pickup, a waveform equalization circuit capable of switching a waveform equalization constant of a reproduction RF signal, and a data strobe circuit capable of switching a data strobe timing of a reproduction signal. In an optical disc reproducing device having a disc radius of 23 mm to 25 m of the loaded optical disc.
A high-density optical disk reproducing apparatus characterized in that when reproducing a range of m, a first servo gain, a first waveform equalization constant, and a first data strobe timing are set, respectively. 9. The high density optical disk reproducing apparatus according to claim 8, wherein when a bit at a predetermined position of subcode data obtained when reproducing a disk radius of 23 mm to 25 mm indicates a predetermined value. , The servo circuit is switched to a second servo gain, the waveform equalization circuit is switched to a second waveform equalization constant, and the data strobe circuit is switched to a second data strobe timing to reproduce the second area. A high-density optical disk reproducing device characterized by carrying out.