JP3162234B2 - Information recording member and recording / reproducing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an analog information signal obtained by FM-modulating a video signal and an audio signal by a recording beam such as a laser beam, and a digital information signal such as data of an electronic computer, a facsimile signal and a digital audio signal. The present invention relates to an information recording member and a recording / reproducing apparatus capable of recording information in real time, and particularly to a large capacity optical disc.

[0002]

2. Description of the Related Art In recent years, the amount of information handled in the general society has increased, and a large-capacity optical disk has been required. Also, with the diversification of information, there is an increasing demand for rewritable optical discs on which users can record and rewrite information. Methods for increasing the recording density of an optical disk include reducing the recording point size by shortening the recording laser wavelength, increasing the NA (aperture ratio) of the aperture lens, and the spot diameter of the laser beam from which information is read. There is a method that attempts to increase the density by reducing the apparent size.

In Japanese Patent Publication No. 4-4661, a substrate having a guide groove is used.
And a land / groove recording method for performing recording on both flat portions between the guide grooves and the land (land portion). However, in this method, if the groove pitch is smaller than the spot diameter of the read beam, adjacent information is read, and a crosstalk error may occur. As a method of removing the crosstalk, it has been proposed to perform reading using a three-beam optical head and an adaptive filter, or to cancel reflected light from the next by setting the guide groove to an appropriate depth.

[0004]

In the substrate used for recording the land portion and the groove portion, the groove portion is formed in a single spiral shape over the entire surface of the disk. For this reason, there is a problem that the time required to record or read a large amount of information becomes long, and when a track jump between a land portion and a groove portion is performed for each rotation of the disk, the auto focus servo and the tracking servo are not suitable. There was a problem of becoming stable.

An object of the present invention is to solve the above-mentioned problems in the prior art, and to provide an information recording member and a recording / reproducing apparatus capable of recording and reading information stably and in a short time on both a land portion and a groove portion. It is in.

[0006]

In order to achieve the above object, an information recording member and a recording / reproducing apparatus according to the present invention are provided.
Both the inside of the guide groove (groove portion) and the space between the guide grooves (land portion) formed on the surface of the substrate are used as recording tracks for recording information. A substrate in which parts appear alternately is used.

[0007] The number of switching points between the land portion and the groove portion is provided for each round of the recording track by the number represented by the following equation.
However, when counting the switching points between the land portion and the groove portion, a preformat portion in which pits indicating addresses and the like are formed in advance is considered. The preformat portion refers to a pit formation area (prepit portion) on an extension of a recording track and a portion adjacent to the prepit portion of an adjacent recording track. 2m-1 (m: 1, 2, 3, ...)

At this time, the recording track adjacent to the groove is a land, and the recording track adjacent to the land is a groove. However, the area adjacent to the pit formation area in the preformat section is not necessarily limited to the groove section. There are an odd number of switching points between the land portion and the groove portion per round of the recording track. It is preferable that the positions of the switching points be substantially aligned in the radial direction, because control during manufacturing is simplified.

[0009] The switching point depends on the use of the recording track 1
An odd number may be provided in the circumference. For example, the land part and the groove part may be switched for each sector. However, when the number of switching points in one circumference of the recording track is one (m = 1), the substrate (original) This is preferable in terms of ease of manufacturing and the stability of servo during recording and reproduction. When the number of switching points between the land and the groove is one, the pre-format part is the recording track 1
Forming every other circumference is preferable because it reduces crosstalk.

It is preferable that the groove portion has a flat portion in view of recording / erasing characteristics (C / N, erasing ratio, crosstalk, etc.). The substrate used in the present invention includes a land portion and a groove portion for recording information by a user, a pre-format portion and, in some cases, a partial ROM portion in which pits representing read-only information are formed in advance. The pre-format section or the ROM section is formed other than the groove section. In addition, the preformat portions are formed at substantially uniform positions in a predetermined range in the radial direction.

Here, for example, when reading the contents of the preformat portion corresponding to the land portion information, there is no crosstalk from the neighbor since there is no preformat portion corresponding to the groove portion information on both sides. However, since there is no pre-format part corresponding to the groove part information, information such as the address of the groove part cannot be known. Therefore, when the light spot tries to move on the groove, the reflected light change expressed by the preformat sections on both sides appears as crosstalk at the foot of the light spot, and these sum signals correspond to the central groove section Corresponding to the information (address information, servo information, and the like) that the preformat section should have. Thereby, both information corresponding to the land portion and the groove portion can be read stably. At this time, there is no problem even if pre-pits (for example, sector marks or VFOs) other than pre-pits (for example, track addresses) representing different information for each track are formed in the groove portion.

Such a method of obtaining information corresponding to the contents of the central preformat portion from the crosstalk signals from the preformat portions on both sides is such that lands and groove portions are provided alternately along the recording track. Instead of the substrate, the groove portion is connected by a single line from the inner circumference to the outer circumference, and the preformat portion is highly effective even on a substrate formed every other recording track and other than the groove portion.

Further, by forming the pit forming area of the preformat section so as not to be adjacent to the pit forming area of the preformat section of the adjacent recording track in a direction perpendicular to the recording track, the pit forming area of the adjacent recording track may be slightly reduced. Crosstalk from the preformat section of the recording track can be eliminated. In the information recording member of the present invention, the lands and the groove portions always appear alternately when following the spiral recording track, so that the recording / reproducing apparatus used in the present invention sets the switching point between the land portions and the groove portions. It has means for predicting and switching the way of autofocus servo. There is also provided a means for predicting a switching point between the land portion and the groove portion and switching a method of applying tracking servo. In this way, by predicting the switching point between the land portion and the groove portion on the recording track, by switching the method of applying the auto focus servo or the tracking servo, the information of the land portion and the groove portion can be continuously recorded without jumping the track. Can be read.

Further, a wobble pit may be provided on the substrate to provide a sample servo type information recording member having a groove portion. The information recording member of the present invention can perform more stable reading by providing a mask layer that generates an area that does not contribute to the change in the reflected light amount in the beam spot using a dye such as phthalocyanine or a low-melting inorganic substance. . That is, the spot diameter of the laser beam is equivalently reduced using this mask layer.

A mask effect can also be obtained when a magneto-optical recording film is used as the recording film. For example, the magnetic layer has a structure of two or more layers, and one of the layers is used as a mask for making an adjacent region invisible. When reading information recorded on a recording track, first, all recording points are temporarily covered by using an initialization magnetic field. Next, the mask is removed only at one recording point smaller than the laser spot diameter by using the heat generated by the reading light, and the signal is read. In this way, portions of the read beam spot that are unnecessary for reading the recording points are masked, and the apparently effective beam spot diameter is reduced.

As the recording film, a perforated recording film,
A crystal-amorphous phase-change optical recording film capable of high-speed crystallization, a recording film utilizing an amorphous-amorphous change, and a crystal-crystal phase-change recording such as a change in a crystal system or a crystal grain size. A film and a magneto-optical recording film are preferred, but other recording films may be used. Also,
The recording medium is not limited to a disk shape, and can be applied to other forms of recording media such as a card shape.

[0017]

According to the present invention, recording can be performed on both the land portion and the groove portion, so that recording at a higher density than before can be performed. Further, since land portions and groove portions are alternately formed on one circumference of the recording track, information on both the land portion and the groove portion can be recorded without jumping between adjacent land portions and groove portions. Recording can be performed continuously, and information on both the land portion and the groove portion can be continuously read. As a result, related information can be collectively recorded and reproduced in a certain area,
The recording time and the access time can be reduced.

Further, the pit formation area of the preformat section is made not to be adjacent to the pit formation area of the preformat section of the adjacent recording track, or the crosstalk signals from the preformat sections on both sides make the preformat section of the groove section. By obtaining information corresponding to the content of
Crosstalk can be reduced. Furthermore, by providing a mask layer that generates a region that does not contribute to the change in the amount of reflected light in the beam spot, higher density and stable reading can be achieved.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to embodiments. Embodiment 1 FIG. 1 schematically shows an example of the arrangement of land portions and groove portions on a disk.

In this embodiment, both the groove 1 and the land 2 formed on the substrate surface are used as recording tracks for recording information. The recording track is formed in a single spiral shape on the substrate, and if the recording track is advanced without track jumping, the groove portions 1 and the land portions 2 appear alternately, and the groove portion 1 and the land portion 2 are switched. The number of points A is provided for one round of the recording track by the number represented by the following equation. 2m-1 (m: 1, 2, 3, ...)

FIG. 1 shows a case where there are five switching points A between the groove portion 1 and the land portion 2 (m = 3). In this figure, the preformat section is omitted. When counting the switching points between the land portion and the groove portion, the preformat portion is excluded. The recording tracks on both sides of the groove 1 along the track direction are the lands 2, and the recording tracks on both sides of the lands 2 are the grooves 1. However, the portion adjacent to the preformat portion is not necessarily limited to the groove portion. The switching point A is formed substantially aligned in the radial direction. An odd number of switching points A may be provided for one round of the recording track depending on the application. For example, a land portion and a groove portion may be switched for each sector.

As shown in FIG. 1, a substrate in which lands and grooves alternately appear on one circumference of a recording track was manufactured as follows. First, a positive photoresist is applied to an optically polished glass disk, and exposure is performed by irradiating an argon laser beam having a wavelength of 457.9 nm while rotating the glass disk (cutting). Here, at least a preformat portion such as an address and a groove portion for recording information by a user are formed. At this time, a recording track is formed in a spiral shape by moving the beam spot in the radial direction of the disk by an amount corresponding to the recording track pitch during one rotation of the glass disk while irradiating with argon laser light. The exposed portion becomes a groove portion, and the unexposed portion becomes a land portion. That is,
While moving the beam spot in the radial direction, the argon laser light is turned on and off at a position (switching point) determined during one rotation of the glass disk, and this operation is repeated for each rotation of the disk (of course, In the preformat part, turn on the argon laser light according to the signal,
OFF). When the number of switching points is one, it is sufficient to switch ON / OFF of the argon laser light only once at a predetermined position every time the glass substrate makes one rotation (the number of ON / OFF operations in the preformat portion). Is excluded).

The exposed portion is dissolved and removed by developing the cut glass disk with a developing solution to form a master. Further, a nickel layer is formed on the master by a sputtering method. Then, using this nickel layer as an electrode, nickel plating is performed to a thickness of about 200 μm.
Mold (nickel stamper) is obtained. Using the nickel stamper as a mold, a substrate used in the present invention was produced by injection molding of polycarbonate. In this example, both the width of the groove portion and the width of the land portion are about 0.8 μm, and the groove portion is a U-shaped groove having a flat portion at the bottom. On the substrate on which the groove portion is formed in this way, when the recording track is followed, the land portion and the groove portion appear alternately on one circumference as shown in FIG.

Next, a method of manufacturing a disk will be described with reference to FIG. First, the recording track pitch produced as described above is 0.8 μm in diameter, 13 cm in diameter, and 1.2 mm in thickness.
about 125 nm in thickness on a polycarbonate substrate 3 having a thickness of about 125 nm by magnetron sputtering.
An O ₂ protective layer 4 was formed. Was then formed to a thickness of the recording film 5 of about 25nm of the composition of Ge ₂₂ Sb ₂₂ Te ₅₅ Co ₁ on the ZnS-SiO ₂ protective layer 4. Next, to form a ZnS-SiO ₂ intermediate layer 6 in a thickness of about 225 nm. Further, an Al-Ti reflection layer 7 was formed thereon to about 100 nm. These films were formed sequentially in the same sputtering apparatus.
Thereafter, an ultraviolet curable resin layer 8 was applied thereon, and then adhered tightly to another disk having the same structure with a hot melt adhesive 9.

In this embodiment, the wavelength 78 is used for recording and reproducing information.
Since a 0 nm semiconductor laser was used, the groove depth of the substrate was set to 78 nm. As a result, the crosstalk from the signal of the adjacent recording track could be reduced to -30 dB or less, and the information of the land portion and the groove portion could be stably reproduced.

Embodiment 2 FIG. 3 shows an example of a substrate having a ROM section. The substrate used in the present invention includes, in addition to a land portion and a groove portion for recording information by a user, a pre-format portion and, in some cases, a ROM portion in which pits representing read-only information are formed in advance. The format portion or the ROM portion is formed in a portion other than the groove portion, such as the flat portion, which is the same as the land portion, in consideration of the easiness of manufacturing the substrate and the stability of the servo during recording and reproduction. FIG.
5 schematically shows an example of a substrate in which the ROM section 10 and the recordable track, that is, the groove sections 1 are alternately arranged when there is one switching point. However, the preformat section is not shown.

[Embodiment 3] FIG. 4 shows an example of the arrangement of a preformat section. In this embodiment, the preformat portion of each track is formed so as not to be adjacent to the preformat portion of the adjacent recording track. FIG.
Is an example in which the number of switching points is one, that is, the case where the groove portion 1 and the land portion 2 are switched by one rotation of the disk. In the present invention, when counting the switching points between the land portion and the groove portion, the preformat portion is excluded, so that one switching point A is used for both the switching points A ′ and A ″.
Count as In addition, there are actually four or more preformat sections per track, and the preformat sections are simplified and shown larger. A groove may be provided next to the preformat, but it is preferable that the groove is not a groove in order to obtain a large reproduction signal. The preformat portion of each track is formed so as not to be adjacent to the preformat portion of the adjacent recording track. In this example, the preformat portion is formed every other turn of the recording track. Further, the pre-format portion may be formed substantially in the radial direction from the inner circumference to the outer circumference as in the present embodiment, but for example, MCAV (Modified Constan
As in the case of the “t Linear Velocity” method, they may be formed substantially uniformly within a predetermined range in the radial direction. In the case of the logical track format, the preformat portion may be formed to be largely shifted in the radial direction.

Assuming that recording and reproduction are performed in the clockwise direction in the figure, when reading the contents of the preformat section 11 having the information of the land section 2, there is no preformat section on both sides in the radial direction. There is no problem with crosstalk. However, since there is no pre-format section having the information of the groove section 1, the address of the groove section 1 is unknown.

Therefore, in this embodiment, in order to obtain the preformat information of the groove portion 1, the sum signal of the change in the reflected light amount expressed by the preformat portions 11 and 11 'on both sides having the information of the land portion is at the center. It corresponds to the address information of the groove section 1. That is, when the beam spot is located at the center between the preformat sections 11 and 11 ', the foot portion of the beam spot is irradiated to the preformat sections 11 and 11' on both sides in this embodiment. Information of the preformat units 11 and 11 'can be read as a talk signal. The information on the groove section 1 is determined from these pieces of information.

As a simple example, the address inside the preformat portion of interest (in the radial direction) is 100 in binary code.
0101, when the outer address is 1000110, and when the reproduction signal becomes 1 only when both are 1, the address of the preformat portion corresponding to the groove portion of interest can be read as 1000100. Thus, the address need not be incremented by one from the inner track to the outer track, or vice versa, but may be incremented by one. As a result, the contents of the preformat portions of both the land portion and the groove portion could be read stably.

Similar effects can be obtained by forming prepits (for example, sector marks and VFOs) other than prepits (for example, track addresses) representing different information for each track in the preformat section corresponding to the groove section 1. Was done. At this time, the prepits representing the same information for each track may be smaller than the prepits representing different information for each track, depending on the reproduction method.

In the present embodiment, the preformat portion corresponds to the information of the land portion. Conversely, the preformat portion is formed so as to correspond to the content of the groove portion.
Information corresponding to the contents of the land format part can be obtained from the crosstalk signals from the preformat parts on both sides. Further, the method of obtaining information corresponding to the contents of the central format portion from the crosstalk signals from the preformat portions on both sides is not limited to a substrate in which land portions and groove portions come alternately as in this embodiment. Also, the effect was large even in a conventional substrate in which the groove portion was connected by one piece from the inner circumference to the outer circumference.
In this case, it is preferable that grooves are provided on both sides of the preformat from the viewpoint of manufacturing a substrate.

[Embodiment 4] FIG. 5 shows another example of the arrangement of the preformat section. In this embodiment, the pit formation area of the preformat section 11 is formed so as not to be adjacent to the pit formation area of the preformat section 12 of the adjacent recording track in a direction perpendicular to the recording track.

By forming the preformat portion as in the present embodiment and reproducing the data by the conventional method, the sum signal of the change in the amount of reflected light expressed by the preformat portions on both sides corresponds to the preformat information at the center. The occurrence of crosstalk can be avoided without using a reproducing method. That is, according to the present embodiment, although the recording capacity is somewhat reduced, since there is no pit formation area of the preformat portion on both adjacent recording tracks, the problem of crosstalk does not occur.

FIG. 5 shows an example in which the number of switching points is five and both sides of the pit forming area of the preformat portion are not grooves. However, the number of switching points is not limited to five, and the number of pits in the preformat portion is not limited to five. Both sides of the formation region may be grooves.
In this embodiment, the same effect is obtained even if the pit formation areas of the preformat sections 11 and 11 'corresponding to the land section 2 and the preformat sections 12 and 12' corresponding to the groove section 1 are reversed. .

[Embodiment 5] FIG. 6 shows another arrangement example of the preformat section. In this embodiment, as in FIG. 5, the pit formation area of the preformat section 11 is not adjacent to the pit formation area of the preformat section 12 of the adjacent recording track in a direction perpendicular to the recording track.
Only one information different for each track is recorded in one of the adjacent preformat sections.

In the reproduction, the preformat sections 11 and 11 'corresponding to the land section 2 are reproduced by tracking the center of the preformat section as in the prior art, and the information corresponding to the groove section 1 is different for each track. A pre-pit representing information, for example, a pre-format section 12 'having only a track address is reproduced by a conventional method, and other information such as a sector mark and VFO is expressed by a pre-format section 11, 11' corresponding to a land section subsequent thereto. Information may be extracted from the sum signal of the change in the amount of reflected light. Of course, the preformat part corresponding to the groove part is not limited to the address relation as described above,
Conversely, the preformat portion corresponding to the land portion can be associated only with the address.

According to this embodiment, the occurrence of crosstalk can be avoided without reducing the recording capacity as compared with the case shown in FIG. In this embodiment, the same effect is obtained even if the pit formation areas of the preformat sections 11 and 11 'corresponding to the land section 2 and the preformat sections 12 and 12' corresponding to the groove section 1 are reversed. .

[Embodiment 6] The information recording member of the present invention comprises:
Since the lands and the grooves always appear alternately when following the spiral recording track, the recording / reproducing apparatus of the present invention predicts the switching point between the lands and the grooves, and performs automatic focus servo and tracking servo control. A means for switching how to call is provided.

As a method of predicting the switching point between the land and the groove, for example, as shown in FIG. 7, a PLL obtained based on a clock signal extracted from an RF signal is used.
(Phase Locked Loop) The channel clock signal of the circuit can be used. In addition, a seal may be attached on the disk substrate or a synchronization signal for controlling the disk rotation motor, and a signal from the seal may be used. Further, a switching mark (pre-pit) for directly predicting a switching point may be provided on the substrate of the disk. In this case, it may be provided in the ID section of each preformat section. In particular, in the case where the number of switching points between the land portion and the groove portion is one in one rotation of the disk, only the ID portion of the preformat portion immediately before the switching point from the land portion to the groove portion or from the groove portion to the land portion is used. A switching mark may be provided.
Further, a track number or a sector number of the ID section may be read and used as a reference.

The same circuit may be used for the auto focus servo in the land portion and the groove portion. However, if there is a possibility that the focus may be largely deviated between the land portion and the groove portion, the auto focus circuit for the groove portion may be used. And the autofocus circuit for the land portion may be used separately, and the switching of this circuit may be performed at the switching point between the land portion and the groove portion. Even if the tracking servo uses a tracking circuit for the groove section and a tracking circuit for the land section separately and executes switching of this circuit at a switching point between the land section and the groove section, the same circuit is used for the land section. The switching may be performed by inverting the tracking polarity in the groove portion.

As described above, by switching the method of applying the auto focus servo and the tracking servo while predicting the switching point between the land and the groove on the recording track, the track jumps to both the adjacent land and the groove. It was possible to record continuously without performing. Of course, it is also possible to read out the information of the land portion and the groove portion continuously. In addition, a wobble pit is provided on the substrate to provide an information recording member compatible with a sample servo system with a groove portion.

[Embodiment 7] Next, an embodiment using a recording member provided with a mask layer for producing a region which does not contribute to the change in reflected light amount in the beam spot will be described in detail. As the disk substrate, a substrate in which land portions and groove portions alternately appear on one circumference of a recording track as used in the above-described embodiment was used.

FIG. 8 shows an example of a sectional view of the structure of the disk of this embodiment. First, on a polycarbonate substrate 20 having a diameter of 6.4 cm and a thickness of 1.1 mm in which both the width of the groove portion and the land portion are about 0.5 μm and the recording track pitch is 0.5 μm, the magnetron sputtering method is used. to form a ZnS-SiO ₂ lower protective layer 21 of approximately 125 nm. This ZnS-SiO ₂ protective layer 2
A recording film 22 of Ge ₂₂ Sb ₂₆ Te ₅₀ Co ₂ composition having a high melting point (melting point: up to 650 ° C.) was formed on
m. Then the intermediate layer 2 of ZnS-SiO ₂
3 was formed to a thickness of about 210 nm. Further, an organic material layer 24 containing a naphthalocyanine dye is laminated as a mask layer to a thickness of 300 nm, and a Ni-Cr reflective layer 25 is
00 nm. Further, an ultraviolet curable resin protective layer 26 was provided thereon. Thereafter, the resultant was bonded to another disk having the same structure via an adhesive layer 27 thereon.

Next, the principle of recording and reproduction will be described. In this example, there is heat resistance, like a naphthalocyanine dye,
When a laser beam having an intensity exceeding a certain threshold is irradiated, the dye in the ground state disappears, and after that, a dye having an absorption saturation property in which light is not absorbed is used. First, the light beam emitted from the semiconductor laser passes through the substrate 20 and is irradiated on the recording film 22. Further, the light beam transmitted through the recording film 22 is applied to the mask layer 24 containing a dye.
At this time, the transmittance at the center of the light beam spot, which exceeds the threshold at which absorption saturation occurs, increases. Then, the beam that has passed through the portion where the transmittance has increased is reflected by the reflection layer 25 and returns to the recording film side to cause multiple reflection. as a result,
The size of a recording point formed on the recording film 22 is determined by the size of a portion where absorption saturation occurs in the mask layer 24 containing a dye. That is, the density can be increased by reducing the size of the portion where absorption saturation occurs.

In the present embodiment, the mask layer 24 containing the dye is formed between the intermediate layer 23 and the reflective layer 25. However, by forming the mask layer 24 between the inorganic layers, the mechanical strength is increased and Possible times increased. For example, in the disk structure of this embodiment, the noise level did not increase even after the rewriting was performed 100,000 times, but when the mask layer 24 containing the dye was formed on the substrate 20, the noise level was increased 10,000 times. The noise level increased by about 5 dB by rewriting. It is considered that the cause is that the mask layer 24 containing the dye was deformed by rewriting. Further, as in this embodiment, the reflection layer 2
5 is provided in contact with or in proximity to, that is, through another thin layer, the heat generated in the mask layer 24 containing the dye rapidly escapes to the reflective layer 25 side because the heat Thus, there is an effect that layer deformation and structural destruction due to high temperature during recording or the like are reduced. In particular, the mask layer 24 containing a dye is
5 was more effective.

In the dye used in this example, the portion where the absorption and saturation occurred was about 0.5 μmφ, and the influence of crosstalk from information on the adjacent recording track was eliminated.
Also, the record information on the same track to be read next is not read. For this reason, the recording point density was improved twice as compared with the related art. In this embodiment, a phase-change optical recording film having a high melting point was used as a recording film, but the same effect was obtained with a magneto-optical recording film.

[Embodiment 8] The structure of the disk of this embodiment is basically the same as that of the above-mentioned Embodiment 7. However, instead of the organic layer containing the naphthalocyanine dye, Te ₂₀
It has a structure in which a Se ₈₀ phase change mask layer is laminated to a thickness of 25 nm.
Next, the principle of reproduction will be described. In the present embodiment, Te ₂₀ Se
_An inorganic layer having a low melting point of 250 ° C. and a relatively large change in the refractive index when the film is melted, such as the ₈₀ phase change mask layer, is used. First, a reproduction light beam (continuous light) emitted from a semiconductor laser passes through a PC substrate and passes through Ge ₂₂ Sb ₂₆ Te ₅₀ Co _2.
The recording film is irradiated. Further, the reproducing light beam transmitted through the recording film is applied to the Te ₂₀ Se ₈₀ phase change mask layer. At this time, if the disk is rotating, the temperature becomes highest in the portion behind the center of the light beam spot, and Te ₂₀ Se
The refractive index and the extinction coefficient of the portion exceeding the melting point of the ₈₀ phase change mask layer film become small. Then, the beam passing through the portion where the refractive index and the extinction coefficient have decreased is reflected by the reflection layer, and further returns to the recording film side to cause multiple reflection, and the reflectance decreases. As a result, it is possible to read only a recording point existing in a minute portion where the light spot and the portion where the Te ₂₀ Se ₈₀ phase change mask layer is not melted overlap, and a large reproduction signal is obtained.

The lower protective layer and the recording film are selected so that the reproduction light reflectance at the portion where the mask layer does not melt is particularly low, and the recording points existing at the portion where the mask layer melts and in the area within the light spot are selected. May be read. The reproduction light is
Pulse light may be used instead of continuous light. Inorganic substances having a low melting point include, in addition to Te-Se, Pb-Sn and B
i-Sn system, Bi-Ga system, Sn-Zn system, Ga-Sn
Those having a melting point of 300 ° C. or less, such as a system, are preferable.

For example, by forming a mask layer of such an inorganic material between inorganic layers such as an Al alloy reflective layer and a ZnS-based material protective layer, the mechanical strength is increased and the mask layer is deformed even if it is rewritten many times. Can be suppressed. Further, by forming the inorganic mask layer on the reflection layer side of the recording film, heat generated in the inorganic mask layer can be released to the reflection layer side, and damage of the inorganic mask layer due to heat is reduced. As a result, layer deformation due to high temperature during recording etc.
Structural damage is reduced. At this time, it is preferable to use a reflective layer having a high thermal conductivity because heat is quickly released. It is more preferable that the inorganic mask layer is formed in contact with the reflection layer because the heat diffusion effect is further increased.

In this embodiment, a high-melting-point phase-change optical recording film was used as the recording film, but the same effect was obtained with a magneto-optical recording film. As in the second embodiment, there is no influence of crosstalk from information on an adjacent recording track, and recording information on the same track to be read next is not read.
The recording point density was doubled as compared with the related art.

[0052]

According to the present invention, both land portions and groove portions formed on the surface of a substrate are used as recording tracks for recording information, and land jumps are made between adjacent land portions and groove portions without a track jump. Continuous recording and continuous reproduction can be performed on both the section and the groove section, and an information recording member and a recording / reproducing apparatus capable of recording and reading in a stable and short time can be realized.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of an arrangement of a groove portion and a land portion.

FIG. 2 is a structural sectional view of an example of a disk.

FIG. 3 is a diagram illustrating an example of a substrate having a ROM portion.

FIG. 4 is a diagram showing an example of the arrangement of a preformat unit.

FIG. 5 is a diagram showing another example of the arrangement of a preformat unit.

FIG. 6 is a diagram showing another example of the arrangement of a preformat unit.

FIG. 7 is a circuit block diagram of an example of a unit for obtaining a signal for predicting a switching point.

FIG. 8 is a structural sectional view of an example of a disk having a mask layer.

[Explanation of symbols]

1 ... groove portion 2 ... land portions 3, 3 '... polycarbonate substrate 4, 4' ... ZnS-SiO ₂ protective layer _{5,5 '... Ge 22 Sb 22 Te} 55 Co 1 recording layer 6,6' ... ZnS-SiO ₂ Intermediate layer 7, 7 'Al-Cu reflective layer 8, 8' UV-curable resin protective layer 9 Hot melt adhesive layer 10 ROM section 11, 11 'Preformat section corresponding to land section 12, 12' preformat portion 20, 20 '... polycarbonate substrate 21, 21' ... ZnS-SiO ₂ protective layer _{22,22 '... Ge 22 Sb 22 Te} 50 Co 2 recording layer 23, 23' ... ZnS-SiO ₂ which corresponds to the groove portion Intermediate layer 24, 24 ': Organic layer containing naphthalocyanine dye 25, 25': Ni-Cr reflective layer 26, 26 ': UV curable resin protective layer 27: Hot melt adhesive layer

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Motoyasu Terao Inventor, Central Research Laboratory, Hitachi, Ltd. 1-280, Higashi-Koigabo, Kokubunji-shi, Tokyo (72) Inventor Masahiro Ojima 1-1280, Higashi-Koigabo, Kokubunji-shi, Tokyo Hitachi, Ltd. Central Research Laboratory (72) Inventor Akemi Hirone 1-280 Higashi Koigakubo, Kokubunji-shi, Tokyo Central Research Laboratory, Hitachi, Ltd.

Claims (2)

(57) [Claims] An information recording member for recording information using a groove portion and a land portion formed on the surface of a disk-shaped substrate as recording tracks , wherein the tracks are provided in a spiral shape and follow the tracks. forward and appear the land portions and groove portions are alternately the lands and grooves are
Show at least radial position information at the switching point
<br/> preformat portion by the user, which is configured to include a pit row does not record information is provided substantially aligned position in the radial direction of the substrate, pit arrays provided on the preformat portion in the radial direction An information recording member, which is arranged so as not to be adjacent to a pit row and a recording track of an adjacent preformat section in a direction perpendicular to a recording track, in a circumferential direction. And a track provided in a spiral shape on the surface of the disk-shaped substrate. When the track is followed by the track without jumping, a land portion and a groove portion appear alternately. A pre-format part, which includes at least a pit row representing position information in the radial direction at a position where the groove part is switched, and in which a user does not record information, is provided at a position substantially aligned in a radial direction of the substrate, and the pre-format part is provided. The land portion and the groove portion of the information recording member which are arranged in the circumferential direction so as not to be adjacent to the pit line of the preformat portion radially adjacent to the recording track in the direction perpendicular to the recording track. And an information recording / reproducing apparatus for performing recording / reproducing with respect to the information recording / reproducing apparatus.