JP2001357527A - Optical information recording member, recording / reproducing method and apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a recording member equipped with guide grooves having a high track density and with address information, and to provide a recording/ reproducing device. SOLUTION: The optical recording member records information signals, through light irradiation on a base plate 5 equipped with rugged guide grooves having a high track density. The address information is formed by intermitting a part of the grooves G2, G3, G4 of the guide grooves; the recording position of the address information is provided in the zones X, Y which are different in the track direction between adjacent tracks; the address signals are detected by the change in reflectivity at the time when the optical beam 1 is passed over a land part; and the information signals are simultaneously recorded or reproduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information recording member capable of recording and reproducing information using a light beam, and more particularly to a recording member capable of obtaining a high track density and a recording / reproducing apparatus therefor.

[0002]

2. Description of the Related Art Conventionally, an optical disk, an optical card, or an optical tape is known as a medium on which information can be optically recorded or reproduced. Most of these recording media (recording members) use a method of recording information by irradiating a laser beam, which is finely narrowed through a lens, onto a recording thin film included in the medium. Among them, the optical disk has a circular substrate provided with a guide groove formed of concavities and convexities in a spiral or concentric shape, and a recording thin film formed thereon. In this optical disc, recording and reproduction of information are performed by irradiating a laser beam along a guide groove.

A conventional optical disk will be described with reference to FIGS. 17 and 18. Record the signal on the recording member,
Alternatively, for reproduction, it is necessary to first search a recordable area of a recording member or obtain management information indicating a recording position of a target information signal. For this reason, on the optical disk, an address area for managing an information area for recording information is provided at regular intervals of the disk. As the form of the address area, there are two types, a form in which the information signal is recorded on the convex surface of the guide groove, and a form in which the information signal is recorded on the concave surface. Here, the case where recording is performed on the convex surface of the guide groove with respect to the incident direction of the light beam is referred to as groove recording, and the case where recording is performed on the concave surface is referred to as land recording. FIG. 17 and FIG. 18 show configurations of typical examples of each mode.

FIG. 17A shows an example in which the vicinity of an address area of a recording member used for groove recording is enlarged. (B) shows an AA cross section in (a), and (c) shows a BB cross section at the center of the recording track in (a). As shown in FIG. 17A, the recording member includes an address area 2 and an information area 3.
And The address area 2 is formed on a part of the information track separated from the information area 3. FIG. 17 (b)
As can be seen from (c), the address area 2 and the information area 3 respectively have a groove 141 as a convex surface and a land 14 as a concave surface with respect to the incident direction of the light beam 1.
2 has a concavo-convex structure. The recording mark 7 corresponding to the information signal to be recorded is formed in the groove 141 of the information area 3.
Formed on top. Address pit 1 which is an address signal
43 is formed in a form in which the groove 141 is intermittent in the address area 2.

FIG. 18A shows an example in which the vicinity of an address area of a recording member used for land recording is enlarged. (B) shows the AA cross section in (a), and (c) shows the BB cross section at the center of the recording track in (a). This recording member is also separated from the address area 2 and the information area 3 respectively.
Each of the regions 2 and 3 has a concavo-convex structure including a groove 151 which is a convex surface and a land 152 which is a concave surface with respect to the incident direction of the light beam 1. In this case, the recording mark 153 is formed on the concave land 152 with respect to the laser beam 1. The address pit 154
In the address area 2, the recording mark 153 is formed on the same track as the track on which the recording mark 153 is formed as an uneven shape.

As shown in FIGS. 17 and 18, address pits 143 and 154 are formed on the center line of a track for recording an information signal in both land recording and groove recording. The demodulation of the information signal is performed by demodulating the change in the amount of reflected light due to the concave and convex pits as address information, and specifying the recording position of the information signal on the optical disk. Thereby, recording / reproduction of the information signal at a predetermined position becomes possible.

Referring to FIG. 19, a method of manufacturing a substrate provided with address pits indicating the above address signals will be described.
FIG. 19A is a flowchart showing the manufacturing process.
(B) is a schematic view showing each step in the case of manufacturing a recording member for groove recording, and (c) is a case in which a recording member for land recording is manufactured, schematically showing a step different from the case of groove recording. FIG. The manufacturing process includes a mastering process for producing a master having a shape opposite to the required substrate shape, and a replication process for forming a substrate based on the obtained master.

The mastering step will be described. First, a photoresist 162 is applied on a glass flat plate 161, and the photoresist 162 is spirally exposed by irradiating an Ar laser beam 163 while rotating the glass flat plate 161. In the case of the recording member for groove recording shown in FIG. 17, by irradiating a single Ar laser beam 163 at a constant power as shown in FIG.
A guide groove for the information recording area is formed. In the address area, an area corresponding to the address is exposed by modulating the laser power according to a predetermined pattern. In the case of a recording member for land recording, as shown in FIG. 19C, the recording member is shifted by 1/2 of the track pitch in the tracking direction.
Two laser beams 164 and 165 are used. A tracking groove is formed by the first laser beam 164, and an address pit is formed by modulating the second laser beam 165 in a predetermined pattern, thereby recording an address signal. Next, the exposed portions 166 and 16 are
7 and 168 are removed, and nickel 169 is removed by a plating process.
Is formed on the surface. Finally, the nickel 169 is separated from the glass substrate 161 to obtain a master 170 having an uneven structure on the surface.

The duplication step will be described. There are various methods depending on the material of the substrate constituting the recording member and the like, but from the viewpoint of high mass productivity, as a manufacturing process of the optical disc,
The injection molding method is mainly used. In the injection molding method, the master 170 obtained in the mastering step is mounted on a mold 171 in an injection molding machine, and a resin material 172 is injected to obtain a resin substrate 173 having predetermined concave and convex grooves. By forming the recording thin film on the resin substrate 173, an optical disk as a recordable recording member can be obtained.

[0010]

As described above, it is possible to form an address area which is management information of a recording member which can be optically recorded and reproduced. However, considering that these optical disks are widely applied to applications such as recording of large-capacity data and image information, it is necessary to further increase the recording density. As a method of increasing the recording density, it is conceivable to shorten the wavelength of the light to be irradiated or to increase the numerical aperture of a lens that collects the light. By using this method, the spot of the light to be condensed can be reduced, so that it is possible to reduce the track pitch as well as the density in the track direction during recording. In the current optical disk, the track pitch Tp is 1.6 μm, the width of the guide groove is about そ の of that, and the depth is a value near 500 nm. However, in order to cope with the high density, it is necessary to reduce the spot diameter to be condensed and to reduce the track pitch accordingly. However, for example,
Attempts to achieve near or less than 0 μm have the following problems.

By the above-mentioned mastering process, it is possible to manufacture a master having a track pitch of 1.0 μm or less. It is also possible to further increase the density by shortening the wavelength of the photoresist and the laser light for exposing the photoresist. In the case where the track pitch of the guide groove is small, the shape required for the substrate from the viewpoint of recording characteristics is to make the width of a portion where a recording mark is formed as large as possible in order to secure signal amplitude. Therefore, the groove recording substrate has a wide groove width, and the land recording substrate has a wide land width. However, in injection molding, as the track pitch becomes smaller, it becomes more difficult to maintain good transferability. The transferability indicates the degree of reproducibility of the surface shape of the master and the surface shape of the resin substrate obtained as a result of the injection molding. Injection molding
The molten resin is poured into the surface of the mold, and the shape of the master is transferred by the pressure of the injection. Therefore, when the width of the portion where the resin is pushed into the master, that is, the width of the land portion, becomes small, the transferability deteriorates.

The problem when the track pitch is reduced will be described with reference to the sectional view of the injection molding machine shown in FIG. Here, an example of a groove recording substrate is shown. As shown in the figure, on the land portion between the grooves, that is, on the master, a narrow groove portion 17 is formed.
4 must be filled with resin. However, if the track pitch Tp is reduced while maintaining the groove width Gw for the above-described reason, there is a problem that a large facility having an extremely high injection pressure is required for filling the resin. Similarly, in a land recording-compatible substrate, when the track pitch is reduced, the width of the land areas 155 on both sides of the address pits shown in FIG. 18 is significantly reduced, and there is a problem that injection molding becomes difficult.

The present invention has been made in view of the above-mentioned problems of the prior art, and has a guide groove having a high track density;
It is an object to provide a recording member and a recording / reproducing device provided with address information.

[0014]

An optical information recording member according to the present invention comprises a first track mainly having a first surface having different optical positions with respect to an incident direction of a light beam, and a second track mainly having a second surface. A recording member having a recording thin film layer that produces a change that can be optically detected by light irradiation on a substrate having a second track on the surface thereof, wherein the first track is the first track.
An address portion having a surface isolated in accordance with a predetermined code signal, wherein a width of a region formed by the second surface in contact with the address portion in a direction perpendicular to the track is equal to a track width of the first track; As described above, the address portions are arranged at different positions in the track direction between adjacent tracks, and the information recording area is on the second track, thereby achieving the above object.

The first track adjacent to the track of the address portion in the vertical direction may have a continuous shape on the first surface.

The width of the first track vertically adjacent to the track of the address portion may be smaller than the width of the first track in a continuous area of the first surface of the adjacent track.

[0017] The first surface may be convex with respect to the incident direction of the light beam.

At the head of the address portion, there may be provided an address start zone indicating the start point of the address information, and the start zone may have the same pattern between tracks adjacent to each other.

The width of the first track may be substantially equal to the width of the second track, and the information recording area may be on the first track.

Further, the optical information recording member of the present invention has a first track mainly having a first surface having different optical positions with respect to an incident direction of a light beam, and a second track mainly having a second surface. A recording thin film layer that produces a change that can be optically detected by irradiation of light on a substrate having a track on a surface thereof, wherein the first track has a predetermined code on the first surface. An address portion formed in isolation in accordance with a signal, a width of a second surface area in contact with the address portion in a direction perpendicular to the track is equal to or greater than a track width of the first track; The address portion has at least two zones adjacent to each other in the track direction, and the address portion has at least one of the address patterns identical to that of an adjacent track, thereby achieving the above object. It is.

The width of the first track may be substantially equal to the width of the second track, and the information recording area may be on the first track.

The recording / reproducing method for an optical information recording member according to the present invention is a method for recording / reproducing an information signal by irradiating a recording member having a recording thin film layer on a substrate having a guide groove with a light beam. Irradiating the light beam to first and second address portions disposed on the recording medium on the recording medium on the left and right of the center of the recording / reproducing track and at different positions in the track direction, and reflecting the light beam Light is received by a light receiving surface divided in a direction perpendicular to the track, and the first light is received by using a differential signal output from the light receiving surface.
And demodulating the address information from the second address part,
The address of the recording / playback track is specified, thereby achieving the above object.

The address signal may be demodulated by inverting the polarity of the differential signal from one of the first and second address sections and comparing the inverted signal with a predetermined level.

Further, in the recording / reproducing method for an optical information recording member according to the present invention, a first track mainly having a first surface having a different optical position with respect to an incident direction of a light beam, and a second track mainly having a second surface. And a second track on the surface of the recording member having an address portion formed by isolating the first surface in accordance with a predetermined code signal. A method of demodulating an information signal, wherein the reflected light of the light beam is received by a light receiving surface divided in a direction perpendicular to the track, and an address signal is obtained from a differential signal output from the light receiving surface. Demodulated,
The information signal is demodulated using both the differential signal and the sum signal of the output from the light receiving surface, thereby achieving the above object.

After correcting one of the differential signal and the sum signal under predetermined conditions, the information signal may be demodulated by combining the signal with the other signal.

The recording / reproducing apparatus for an optical information recording member according to the present invention is an apparatus for recording / reproducing an information signal by irradiating a recording member having a recording thin film layer on a substrate having a guide groove with a light beam. A photodetector having a light receiving surface that divides reflected light from address pits arranged on the left and right with respect to the center of a recording / reproducing track on the recording medium, in a direction perpendicular to the track, A differential amplifier that obtains a differential signal from the output from the light receiving surface, a comparator that compares the output of the differential amplifier with a predetermined level, and a demodulator that demodulates the comparison result into an address signal. Thereby, the above object is achieved.

When the polarity for judging the polarity of one of the outputs of the differential signals from the first and second address sections is matched, the address signal may be demodulated by comparing it with a predetermined level.

According to the optical information recording member of the present invention, the information recording area for recording the information signal and the address area for recording the address information have the first surface and the second surface having different optical positions with respect to the incident direction of the light beam. Since the tracks are formed on different surfaces of the two tracks on the uneven surface, even if the track pitch is reduced, the address signal is demodulated while keeping the width of the track on which information is recorded large. be able to.

Also, the optical information recording / reproducing apparatus of the present invention
An address signal and an information signal can be respectively demodulated from the information member having the above configuration.

[0030]

FIG. 1A is an enlarged plan view of an address area of an optical information recording member according to the present invention.
FIG. 2B is a cross-sectional view of the address area of FIG. (C) shows a reproduced signal waveform obtained when the light beam 1 passes on the track T2 shown in (a), and 2
The signal waveform at the time of digitization is shown.

The surface of the substrate 5 which is optically transparent to the wavelength of the light beam 1 for recording or reproducing an information signal is provided with a guide groove made of irregularities having planes whose positions are different from each other in the direction of incidence of the light beam 1. Configuration. The shapes of the grooves G1 to G4 forming the irregularities shown here are the same as those of the substrate used for the conventional groove recording. The recording member has an address area 2 and an information area 3. The address area 2 is provided at regular intervals so that the amount of information recordable in the information area therebetween is constant. The address area 2 includes a zone X and a zone Y. The address pits 4 are formed by intermittently forming grooves in a pattern in accordance with a predetermined code signal in a zone having different positions in the track direction between adjacent tracks. In the grooves G1 and G3, an address pattern is provided in the zone X area, and between the grooves G2 and G4, the address pattern is provided in the zone Y area.

FIG. 1C shows a reproduction output obtained when the light detector 1 detects the reflected light from the light irradiating section when the light beam 1 passes on the track T2 on the land of the recording member. Shows the change in In the address area 2, as in the information area 3, on the point P1 where the grooves G2 and G3 are present on both sides, the light incident on the reproducing optical system becomes lower due to the diffraction effect of the grooves G2 and G3 on both sides. Becomes On the other hand, the point P where only one side is the groove G3
2, the amount of reflected light is less than the point P1 because the diffraction of the incident light is small.
, And a voltage V3 higher than V2 is obtained. An address signal is reproduced by demodulating the light amount change signal.

As described above, according to the present invention, an address is formed by intermittently providing a groove without forming an address pit in a land area. For this reason, a substrate corresponding to land recording can be manufactured by a mastering process using a single laser beam used in conventional groove recording. Further, even when the track pitch is reduced, the width of the land area, which is a problem during the injection molding shown in the conventional example, can be dealt with by relatively increasing the width, that is, by reducing the width of the groove Gw.

The present invention has a remarkable effect under a narrow track condition in which the track pitch is 1.2 μm or less. This effect will be described with reference to FIG. FIG. 2 shows the track pitch dependence of the transferability of the substrate obtained by injection molding.
The transferability is indicated by the ratio of the groove depth after injection molding to the groove depth of the master. In FIG. 2, (a), (b), (c)
Are the relationship between the groove width Gw and the land width Lw, respectively, Gw = Lw + 0.1 (μm), Gw = Lw, Gw =
The measurement results when Lw-0.1 (μm) are shown.
(A) corresponds to the conventional groove recording, and has a configuration in which the width of the track for recording information is kept large even when the track pitch is reduced. (C) shows a case where the present invention is applied, in which the width of a groove for forming an address is set to be small and the width of a land for recording information is set to be large.

Here, the substrate was formed by injection molding a polycarbonate resin, and a master was produced by a mastering process using an exposure apparatus using a single Ar laser light source as shown in the conventional example. In general, when the refractive index of a material used for injection molding is n and the wavelength of light used for recording / reproducing is λ, the groove depth d is made substantially equal to λ / (8n). This is because the servo signal used for the tracking control is maximized at this depth, which is preferable. Specifically, the wavelength of the light used was 780 nm, the refractive index of the polycarbonate resin was 1.6, and the groove depth of the master was 50 nm.

Referring to FIG. 2, for example, when the comparison is made on the basis of the transferability of 95%, the conventional groove recording shown in FIG. In the present invention, the track pitch is 1.
It can be seen that molding up to 0 μm is possible. As described above, the present invention exhibits a remarkable effect under the track condition in which the track pitch is 1.2 μm or less. This tendency becomes more remarkable when the difference between the groove width Gw and the land width Lw is further increased.

An identifier for identifying the recording member according to the present invention from the conventional recording member is provided in a specific area of the disk. When the present recording member is mounted on the recording / reproducing apparatus, it is possible to determine the tracking polarity by checking the identifier. As the method of forming the identifier, firstly, the same method as that for the address pits is provided on the inner side or the outer side of the information area on the optical disk. An identifier may be provided by a pit pattern. With this identifier, it is confirmed that the address of the recording member is formed in a pattern different from that of the conventional groove recording or land recording, that the address area is composed of a plurality of zones, and that the land side is an information track. Is done.

Although the method of forming address pits by intermittently forming a groove having a convex surface in the light incident direction has been described here, conversely, by forming intermittent lands, address pits are formed, and information is recorded on the groove. The same effect can be obtained also when recording.

By equalizing the groove width and the land width in the above configuration, it is also possible to simultaneously record signals on both tracks while demodulating the address signal on both tracks of the groove and land. Becomes The present invention will be described in detail by showing a specific configuration example.

(Embodiment 1) As a substrate material, polycarbonate, polymethyl methacrylate (PMM)
A), a material such as glass, which is optically transparent to the wavelength of the light beam used for recording and reproduction, is desirable. Here, a substrate having the configuration shown in FIG. 1 is formed using polycarbonate for the substrate 5. The groove has a track pitch pitch T
p = 1.1 μm, groove width Gw = 0.4 μm, depth d
= 50 nm. A master is prepared by a mastering process using an exposure apparatus using a single Ar laser light source as shown in the conventional example, and a substrate having the above configuration is formed by an injection molding machine. On the surface, a dielectric layer made of ZnS-SiO ₂ is provided.
10 nm, the phase change recording layer made of GeSbTe is 25 n
The recording layer 6 is provided by sequentially laminating m, a dielectric layer made of ZnS-SiO ₂ at 20 nm, and a reflective layer made of Au at 50 nm. The initial reflectance from the recording layer 6 is 30%, and when the recording mark 7 is formed, the reflectance is 10%.

FIG. 3 shows the configuration of a signal recording / reproducing apparatus formed according to the present invention. This recording / reproducing apparatus includes a laser drive circuit 20, a laser light source 21 (wavelength 780 nm),
The optical system includes an objective lens 22 (NA = 0.55). The rotating recording member 23 is irradiated with a light beam by this optical system. Specifically, the laser light source 21 emits a constant output (1 mW) light beam by the laser drive circuit 21, and the emitted light beam is condensed by the objective lens 22 and is irradiated on the recording member 23.

The recording / reproducing apparatus further includes a photodetector 24
And a differential amplifier 25 to which an output of the photodetector 24 is input.
And a tracking control unit 26 to which the output of the differential amplifier 25 is input, and the amplifier 2 to which the output of the photodetector 24 is input.
7, a comparator 28 connected to an amplifier 27, and a comparator 2
8 and a system controller 30 connected to the demodulator 29. Photodetector 24
Is divided into two in the vertical direction with respect to the track, and detects reflected light from the recording member 23. Photodetector 24-2
The difference between the two outputs is amplified by the differential amplifier 25, and the tracking control unit 26 is operated based on the differential signal, whereby the light beam can be tracked on the land of the recording member 23. . As a result, it is possible to detect a change in the amount of reflected light from a specific track.
The photodetector 24 is further divided according to the focus servo method. On the other hand, the photodetector 24
Is amplified by an amplifier 27, whereby a change in the amount of reflected light corresponding to the recording mark 7 is obtained from the information area 3 as shown in FIG.
, A change in the amount of reflected light corresponding to the address pit 4 is obtained, and as a result, a reproduction signal S27 is obtained as an output signal.

The information area 3 shows a change between the output V2 corresponding to the unrecorded reflected light and the output V1 corresponding to the recording mark 7 when grooves are present on both sides. By demodulating this level change, the information signal recorded in the information area 3 can be reproduced. On the other hand, from the address area 2, the signal level of the reproduced signal S27 is
By comparing the value with the reference value Vs1, the binary signal S28 is obtained. The reference value Vs1 is set to an intermediate level between the voltage V2 when a groove exists on both sides and the voltage V3 when only one side has a groove. Since the binarized signal S28 includes information of the address pits 4 of the grooves G2 and G3 on both sides of the track, the demodulator 29 demodulates the address information for each of the zones X and Y.
The address of the track T2 is specified by comparing or adding the two demodulated signals by the system controller 30. For example, when using addition, the groove G2
Is "10", groove G3 is "11", groove G4
Is "12", the track T2 becomes "2".
1 and track T3 are obtained as address information of 23. By irradiating a predetermined track with light whose intensity is modulated by the semiconductor laser light source 21 on the basis of the obtained address information, information can be recorded. And the recorded information can be reproduced.

Although the case where the phase-change material is used for the recording member has been described here, the present invention can be applied to all recording members having a recording state that can be optically detected. It does not limit the invention. Further, although the shape of the groove, particularly the groove depth, the angle of the slope area at the boundary between the land and the groove, and the like have not been described in detail, these do not limit the present invention. However, in consideration of the quality of the signal to be recorded, especially the signal amplitude and crosstalk,
It is possible to choose each value optimally.

As a method of detecting an address signal, a method of comparing a reproduced signal with a fixed reference level is used.
Detection using a differentiating circuit is also possible. Most of the signal demodulation is shown by a configuration using an analog circuit. However, the signal immediately after the photodetector is converted into a digital signal by an A / D converter. It is also possible to obtain signals and information signals.

(Embodiment 2) In Embodiment 1, address pits are formed only on one side of a track composed of lands. Compared with the conventional groove recording shown in FIG. 18, the signal amplitude in the address area 2 is smaller. small. Therefore, in a second embodiment, a method of forming address pits having the same pattern in grooves on both sides of a land in order to keep the signal amplitude of the address signal large will be described. Note that conditions other than the address pattern are basically the same as those in the first embodiment.

FIG. 4A is an enlarged plan view showing the vicinity of the address area of the optical information recording member of the present invention, and FIG.
Shows a signal waveform S27 of a reproduction output obtained when the light beam 1 passes over the track T22 and a signal waveform obtained in the process of binarization. This recording member has an address area 2 and an information area 3 for groove recording. Here, the recording mark 7 on the information area 3 shown in the first embodiment is omitted for simplification of description.

The address area 2 has a zone X, a zone Y and a zone Z which are adjacent on the groove. The address pits 4 are formed by intermittently forming grooves in any two zones in a pattern according to a predetermined code signal. The groove G21 has an address pattern P1x
And P1z. The adjacent groove G22 is P
A region adjacent to 1x has P2x having the same pattern as the pattern of P1x, and has P2y arranged in a region not adjacent to P1x and P1z. Similarly, groove G23
Thereafter, as shown in the drawing, address patterns having the same pattern as the adjacent tracks are sequentially arranged.

The reading operation of the address signal by the recording member will be described with reference to the circuit diagram of FIG. 5 together with FIG. The reproduction signal S27 obtained when the light spot 1 passes through the track T22 on the recording member is shown in FIG.
As shown in the figure, at the point P1 where the grooves G22 and G23 exist on both sides, the output V2 is shown, and the groove G is provided only on one side.
At the point P2 where 23 exists, the output V3 is shown. At the point P3 where there is no groove on both surfaces, the diffraction by the groove disappears, and the incident light is reflected by the light according to the reflectance of the substrate surface, the light amount increases, and the output V4 is obtained. In the present embodiment, the address information is detected using a reproduction signal from an area sandwiched by P2y and P3y having the same pattern. That is, a signal amplitude equivalent to that of the conventional address pit 4 can be obtained from the address area 2 of the present embodiment.

The demodulation of the address signal is performed by selecting a signal in a zone where address pits 4 of the same pattern are present on both sides and binarizing the signal. The circuit configuration for this demodulation can be obtained by replacing the comparator 28 shown in the first embodiment with a circuit having the configuration shown in FIG. This circuit includes a comparator 3 to which the reproduction signal S27 is input.
1, 36, and LPF (Low Pass Filt)
er) 33, a gate generator 32 to which the output signal S31 of the comparator 31 is input, a comparator 34 to which the output of the LPF 33 is input, and a selector to which the outputs of the gate generator 32 and the comparator 34 are input. 35, a selector 35 and a comparator 36
And an AND circuit 37 to which the output of is input.

The operation of demodulating an address signal will be described below. First, the binary signal S31 is obtained by the comparator 31 which compares the level of the reproduction signal S27 with the reference value Vs1.
The reference value Vs1 is set to a value between the level of the output V2 of the reproduction signal S27 and the level of the output V3. Preferably, the level is set to a value substantially intermediate between the two levels as in the present embodiment in consideration of the level fluctuation of the reproduction signal S27 and the like. The gate generator 32 outputs the gate signals S32 of the time widths W21, W22, and W23 corresponding to the widths of the zones X, Y, and Z of the address area 2 formed on the substrate at intervals D.
21, which occurs at D22. As shown in FIG. 4B, the gate signal S32 is generated by the gate generator 32 in synchronization with the rise of the binarized signal S31.

On the other hand, by passing the reproduction signal S27 through the LPF 33, a signal S33 as shown in FIG. 4B is obtained. The comparator 34 has a reference value Vs3, specifies the zone where the address pits 4 are present on both sides using the reference value Vs3, and outputs "1". This is because in the zone where the address pits 4 exist on both sides, the average reflected light amount is
This is possible because the average reflected light amount is larger than the average reflected light amount in the zone where the address pits 4 do not exist on one or both sides.
3 is set between the highest level of the signal S33 in the zone where the address pits 4 exist on both sides and the highest level of the signal S33 in the zone where the address pits 4 exist only on one side. Preferably, it is set to a value approximately halfway between the two levels.

The selector 35 receives the signal from the gate generator 32
The gate when the output of the comparator 34 indicates "1" is selected from the two gates, thereby selecting the gate signal S35.
Get. Further, the reproduced signal S27 is converted by the comparator 36 having the reference value Vs2 into a signal S36 as shown in FIG.
Get. This reference value Vs2 is the address pit 4 on both sides.
Is set to the level of about 1/2 of the output voltage V4 in the case where is present. The AND circuit 37 outputs a binary signal S28 from the selection gate signal S35 and the signal S36. In this way, an address signal from a zone having address pits 4 on both sides can be obtained.

As described above, the comparator 36 for obtaining the binarized address signal uses the reference value Vs1 of the first embodiment.
Since it can be set so as to operate at a higher reference value Vs2, it is possible to ensure high reliability with respect to the level fluctuation of the reproduction signal or the level fluctuation of the reference value.

(Third Embodiment) In the second embodiment, an address signal having a large amplitude is obtained by dividing the address area 2 into three zones. A method for specifying an address signal will be described. FIG. 6A shows a plan view near the address area, and FIG. 6B shows a reproduction signal and a binarized signal obtained when the light beam passes over the track T32. The address area 2 includes two adjacent zones X and Y. Each groove G31, G32, G33, G
Numeral 34 is arranged so that the zones are alternately changed for each track so that the pattern of the address pits 4 of any one of the zones X or Y becomes the same pattern as the adjacent groove. The shape of each groove is the same as that of the first embodiment.

The reproduced signal S27 obtained when reproducing the track T32 of the recording member shows a large amplitude change from the zone Y because the pattern of the address pits 4 on both sides is the same as in the second embodiment. Can be Zone X
Since the address patterns on both sides are different,
Cannot be obtained as large as the change in the amplitude. Using the difference, the zone Y in which the address information corresponding to the track T32 is recorded is specified.

However, also in the zone X, a large amplitude change is observed in a region where the planes of the adjacent grooves G32 and G33 overlap. Therefore, an erroneous pulse 31 also occurs in the binary signal S28. However, these erroneous pulses are determined as an error address area in an error correction stage in the process of demodulating the address information, and can be ignored. For example, when the address pits 4 are provided with a plurality of pieces of address information and parity for error correction, when the address information is reproduced, the parity error amount is compared, and a zone having a small error amount is selected. It is possible to specify a target address zone.

As described above, according to the present embodiment, it is possible not only to obtain an address reproduction signal having a large amplitude change as in the second embodiment, but also to reduce the width of the address area 2 and to reduce the width of the recording member. The area of the information area 3, that is, the recording capacity can be increased.

(Embodiment 4) Here, in order to improve the accuracy of demodulation of an address signal divided into a plurality of zones,
Prior to the address area, a recording member having an area indicating the start of the address area and a reproducing method thereof will be described.
FIG. 7A shows a plan view near the address area of the recording member, and FIG. 7B shows a reproduction signal and a binarized signal. The recording member of the present embodiment has an address start zone 5 formed by intermittent grooves G51 to G54 at the front of the address area 2.
One. In the address start zone 51, the same pattern as the pattern of the adjacent grooves G51 to G54 is always formed. The pattern of the subsequent address pits 4 can be applied to any of the first to third embodiments. Here, the pattern of the first embodiment is shown.

The signal reproduction from the recording member will be described with reference to the circuit shown in FIG. 8 and the signal waveform shown in FIG. Note that the address demodulation can be performed by changing only the function of the comparator 28 in FIG. 3 of the first embodiment, and FIG. 8 shows only the contents of the circuit to be changed. This circuit is the amplifier 2
The two comparators 6 receiving the reproduction signal S27 from the
1, 62, a gate generator 63 to which an output signal S61 of the comparator 61 is input, a comparator 62 and a gate generator 6
AND circuit 6 to which the output signals S62 and S63 of FIG.
And 4.

As shown in FIG. 7B, the track T52
Address reproduction signal S27 when light beam 1 passes above
Shows a large optical output V4 in the address start zone 51 because both sides are flat, and the subsequent address area 2 shows a change in the amplitude of the optical output V3 in a portion where one side is flat. The comparator 61 has an intermediate level Vs between the optical output V3 and the optical output V4.
Set the reference voltage to 2. As a result, from the comparator 61, only the portion corresponding to the address start zone 51 is obtained.
A binarized signal S61 is output. In response to the rise of S61, the gate generator 63 generates gate signals G1 and G2 having a predetermined width from the timing delayed by a predetermined delay time D1 from S61. This delay time D1,
The times of the gate signals G1 and G2 and the gate interval D2 can be dealt with by setting them in advance in the gate generator 63 in accordance with the setting conditions of the zone of the address area used in the mastering process of the recording member.

On the other hand, the comparator 62 sets the reference signal Vs1 to an intermediate value between V2 and V3 as in the first embodiment, and as a result, a binary signal S62 is obtained. Next, the AND circuit 6
4, the signal S28 is obtained by taking the logical product of the signal S61 and the signal S62. The signal S28 has the same pattern as the binary signal S26 of the first embodiment, and the address signal can be subsequently demodulated by the same circuit.

With the above configuration, the address start zone 5
From No. 1, the reproduction is always performed at the same position and the same timing with respect to the rotation of the recording member, and the pattern of the adjacent track is also the same, so that the position of the address area can be detected stably. As a result, as in the present invention, it is possible to demodulate address signals generated from different zones at a plurality of locations with high accuracy. Although not described in detail here, it is clear that the same effect can be obtained for patterns corresponding to the second and third embodiments.

(Embodiment 5) As shown in FIG. 9A, in the address pattern shown in Embodiments 1, 2, and 4,
There are zones where one side of the track is a continuous groove. For this reason, the differential output S25 from the differential amplifier 25 used for the tracking control shown in FIG. 3 is, in the address area 2, as shown in FIGS. Indicates a level change depending on whether or not the address pit 4 exists. However, since there is a frequency band that can be followed by the control system, a malfunction does not easily occur when the rotation speed of the optical disk is high. However, in the case of a low rotation speed, the signal change of the address area 2 approaches the control frequency band and becomes a control signal as shown in FIG. 9C, and the tracking control may malfunction.

In order to cope with this, in the present embodiment, as shown in FIG. 9D, the groove G of the zone G75x adjacent to the zone G74x where the address pit 4 exists is provided.
The groove width Gw2 of 75 is made smaller than the groove width Gw of the information area 3. That is, when one side is a continuous groove and the other side is a zone where address information is recorded,
The effects of diffraction from the grooves G74 and G75 of both sides can be made equal. When the light beam 1 passes on the track T74 provided with such an address area 2, the differential signal S25 changes minutely around the OV as shown in (e). Since the change of the signal S25 is a change that cannot be followed in the band of the tracking servo, the control signal has a small change as shown in FIG. 9F. As a result, a stable tracking servo operation becomes possible.

The address area 2 obtained in this case is
, The signal level obtained from the address pits 4 is lower than in the first and second embodiments.
This case can be dealt with by relatively lowering the reference level. As another method, stable tracking control can be performed by the address pits 4a having the pattern shown in FIG. In this method, the width Gw3 of the address pit 4a is set larger than the width Gw of the groove G78,
Thereby, the address pit 4a and the address pit 4a
And the increase in the amount of reflected light at the point P7 is canceled. That is, in a portion where the wide address pit 4a exists, the amount of reflected light decreases due to the diffraction effect of the light beam 1, and
The increase is canceled by the decrease.

Although the method of forming address pits based on the pattern of the first embodiment has been described here, the method of forming address pits of the same pattern on adjacent tracks as described in the second embodiment is also applicable. Applicable. In the case of the second embodiment, the present invention is applied to a portion in which one side of the address pit is a continuous groove. Any of the methods of making the width larger than the width can be applied.

(Embodiment 6) In the above-described embodiment and the conventional optical disk, the address area and the information area are recorded in a circumferentially separated manner. A method for recording and reproducing information in the address area and the information area will be described. FIG. 11A shows a configuration diagram of the optical disc of the present embodiment, and FIG. 11B shows a reproduced signal waveform.

As shown in FIG. 11A, the address pattern of the optical disk substrate of the present embodiment is the same as that of the first embodiment, and the information area 3 for recording the information signal overlaps with the address area 2. The only difference is that the recording marks 7 are continuously formed on the lands. The process of irradiating the track T81 with the light beam 1 and demodulating the reproduction signal obtained as a result will be described using the signal demodulation system of FIG. 12 and the signal waveform of FIG. 11B. The input signal in FIG. 12 uses the amplifier output S27 of the sum signal of the photodetector 24 divided in the vertical direction of the track shown in FIG. 3 and the differential amplifier output S25.

As shown in FIG. 11 (b), the amplified signal S27 of the sum signal has a waveform in which the change in reflectivity by the recording mark 7 and the diffraction effect by the address pit pattern are combined. On the other hand, the differential amplifier output S25 shows a change corresponding to the presence or absence of the address pit 4 adjacent to the track T81.
Are formed, the polarity is inverted.

FIG. 12 is a block diagram of a demodulation circuit for an address signal and an information signal. This demodulation circuit includes an attenuator 90 to which the amplifier output S27 is input, a differential amplifier 91 to which the output of the attenuator 90 and the differential amplifier output S25 are input, and an absolute input to which the output of the differential amplifier 91 is input. A value circuit 92 and a comparator 96 to which the output of the absolute value circuit 92 is input
And a differential amplifier 97 to which the amplifier output S27 and the output of the absolute value circuit 92 are input, and a comparator 98 to which the output of the differential amplifier 97 is input. The operation of the demodulation circuit having such a configuration will be described below.

The operation amplification signal S25 is affected by waveform distortion due to a reflectance difference caused by the presence or absence of the recording mark 7. In order to reduce this effect, the differential amplifier 91 uses the signal S90 and the differential signal S25, which are obtained by attenuating the sum signal S27 by the attenuator 90 exhibiting a constant attenuation rate in accordance with the degree of the change in the reflectance. The signal S91 is obtained. Differential signal S9
1 is converted into an amplitude change only in the positive direction by the absolute value circuit 92 to obtain a signal S92. More specifically, the absolute value circuit 9
In No. 2, the two diodes 93a and 93b make the amplitude only change in one direction, the negative amplitude is inverted by the differential amplifier 94, and the output signal S93a of the diode 93a and the output signal S94 of the differential amplifier 94 are inverted by the amplifier 95. A signal S92 is obtained by amplifying the sum of This signal S9
2, the comparator 96 compares the level with a predetermined reference value in the same manner as in the first embodiment to obtain a binary signal S96. Based on this signal S96,
The track can be specified by demodulating the address signal.

On the other hand, the sum signal S27 corresponding to the change in the reflectance of the recording mark 7 causes a waveform distortion due to the influence of the adjacent address signal. This waveform distortion can be suppressed by subtracting the absolute value circuit output S95 from the sum signal S27 using the differential amplifier 97. That is, the amount of diffraction of light when grooves are present on both sides is larger than the amount of diffraction when the address pits 4 are present.
It can be said that it is proportional to the difference between the amounts of light on the two photodetectors. The output signal S97 obtained as a result shows a reproduction amplitude corresponding to the shape of the recording mark 7, with the amplitude change due to the address pit being suppressed. Next, S97 is passed through a comparator 98 having a reference level VS4 intermediate the voltages V1 and V2,
A binary signal S98 corresponding to the pattern of the recording mark 7 is obtained. In order to remove the influence of the address pits 4 more precisely, the amplitude of S95, which is an input signal to the differential amplifier 97, can be finely adjusted in accordance with the groove shape.

As described above, the address signal and the reproduction signal from the recording mark 7 are independently demodulated in the recording member where the address area 2 and the recording area 3 overlap with each other by the substrate and the reproduction system of this configuration. Becomes possible.

(Embodiment 7) In Embodiments 1 to 6, the method of recording a signal only on a land portion is described. Here, a method of recording information on both a land and a groove will be described. FIG. 13A is an enlarged plan view showing the vicinity of the address area of the optical information recording member of the present invention, and FIG.
3A is a cross-sectional view of the address area 2 in FIG. FIG. 13C shows that the light beam 1 is on the track L on the land.
10 shows a signal waveform of a reproduction output obtained when the signal passes over the track 102 and a signal waveform obtained when the signal is binarized. On the contrary, the reproduction output from the track G103 of the groove portion and the binarized signal are shown in FIG. Shown in The shape of the guide groove shown here has the same pattern as that of FIG. 1, but the width Gw of the groove portion and the width Lw of the land portion in the direction perpendicular to the track are set to be substantially equal. The grooves G101 and G103 provide an address pattern in the zone X area, and the grooves G102 and G104 therebetween provide an address pattern in the zone Y area.

In address area 2, land L102
When the light beam 1 passes above, the point P10 where the grooves G102 and G103 exist on both sides as in the information area 3.
1 has a diffraction effect of the grooves on both sides, and the reproduced signal SL119
Becomes the voltage V102. On the other hand, only one side has a groove G1.
On the point P102 where 02 does not exist, since one side is a flat surface, the diffraction of the incident light is reduced, the light amount is increased, and the voltage V103 is obtained. By comparing the light amount change signal with a reference voltage, address information from the two zones X and Y is obtained, and by demodulating the address information, the address of the track L102 through which the light beam 1 passes is specified. be able to.

On the other hand, when the light beam 1 passes over the groove, a change in the amount of reflected light corresponding to the address pit 104 is observed as in the conventional groove recording. That is, the area where the address pits 104 are present has the same amount of reflected light as that of the groove portion, and the reproduction signal SG119 is at the voltage V105, whereas in the plane area where the address pits 104 are not present, the amount of reflected light is increased and the voltage V106 is increased. can get.
The address information is reproduced by demodulating the light amount change signal.

With the above configuration, even when reproducing the address from the land portion, the address information can be obtained by detecting the change in the amount of diffraction of the reflected light by the address pit 104 formed by the intermittent groove. Obtainable. Therefore, a substrate corresponding to land recording can be created by a mastering process using a single laser beam used in conventional groove recording.

As described above, the configuration of the guide groove is as follows.
It is desirable that the groove width Gw in the vertical direction of the track and the land width Lw be substantially equal. That is, when the land portion and the groove portion are irradiated with the light beam 1 and the reflected light is measured, the value changes depending on the groove width. By making the widths of both portions equal, it is possible to keep the amount of reflected light on the photodetector constant. Therefore, it is possible to obtain the same signal amplitude from signals recorded in any of the land and the groove. From the above viewpoints, it is desirable that Gw / Lw is in the range of 0.7 to 1.3 as the range of the groove width.

As described above, the depth d of the guide groove is generally set to be near λ / (8n) or an odd multiple thereof so as to maximize the tracking signal. However, when an information signal is recorded on both the land and the groove, a change in the adjacent recording mark 107 affects the reproduction signal from the recording mark 107 recorded on both (also called crosstalk). It is necessary to set the depth d so as to minimize the amount of talk. As a result of an experiment of the amount of this crosstalk using a substrate in which the groove depth d was changed,
In the vicinity of λ / (5n) between λ / (8n) and λ / (4n), there was a tendency that the recording signal was large and the crosstalk amount was small. As described above, when recording signals on both the land and the groove, it is necessary to make the width of both grooves the same and to select the groove depth optimally, as compared with the case of recording on the groove on one side. , They can experimentally determine the optimum value according to the required signal quality.

For the substrate having the structure shown here, a master was prepared by a mastering process using an exposure apparatus using a single Ar laser light source as shown in the conventional example, and the substrate having the above structure was formed by an injection molding machine. . On the surface, a thin film corresponding to a recording method in which the optical properties of the thin film are changed by irradiation of light shown in the conventional example, for example, deformation recording, phase change recording, magneto-optical recording, photon mode recording, etc. can be applied. The recording member shown in FIG. 13 is an example in which a phase change thin film capable of reproducing a signal by a change in reflectivity is provided as a recording layer, and a recording mark 107 obtained by laser irradiation is different from the initial state in comparison with the initial state. The reflectivity decreases.

FIG. 14 shows the configuration of a signal recording / reproducing apparatus formed according to the present invention. The configuration and operation of the recording / reproducing apparatus will be described below. The recording / reproducing apparatus includes a laser light source 110, an objective lens 111 for converging a light beam from the laser light source 110 to a recording member 112,
An optical system including a photodetector 113 for detecting reflected light from the recording member 112, a voice coil 116 supporting the objective lens 111, and a differential amplifier 114 to which an output of the photodetector 113 is input; An inverter 118 to which an output of the differential amplifier 114 is input, a tracking control unit 115 to which an output from the inverter 118 is input, and a system controller 117 are provided.

The optical system irradiates light to a rotating recording member 112 using a laser light source 110 and an objective lens 111, and focuses and tracks the reflected light using a photodetector 113 having a plurality of light receiving surfaces. I do. The tracking control uses output signals from the light receiving surface divided in the vertical direction with respect to the track of the photodetector 113, amplifies the level difference between these output signals by the differential amplifier 114, and A voice coil 116 for instructing the objective lens 111 by the tracking control unit 115
Is operated, the light beam is tracked to the guide groove on the recording member 112. It should be noted that whether to perform tracking control on the land or groove of the guide groove of the recording member is determined by driving the inverter 118 for inverting the polarity of the output of the differential amplifier 114 in accordance with the setting of the system controller 117. Selected.

This recording / reproducing apparatus has an amplifier 119 to which an output from the photodetector 113 is input, a comparator L120 and a comparator G122 to which the output of the amplifier 119 is input.
And a demodulator L121 and a demodulator G12 to which outputs from the comparator L120 and the comparator G122 are respectively input.
3 is further provided.

The sum signal of the output of the photodetector 114 is
In the case of a land, the signal is amplified as shown in FIG.
3C, a change in the amount of reflected light corresponding to the recording mark 107 from the information area 3 and a change in the amount of reflected light corresponding to the address pit 104 are obtained from the address area 2 as shown in FIG.

When the light beam 1 scans on the land L2, a signal SL119 corresponding to the change in the amount of reflected light is obtained from the amplifier 119 as shown in FIG. In the information area 3, the voltage V102 corresponding to the reflectance when the groove exists on both sides and the output V10 corresponding to the recording mark 107.
The change from 1 is shown. From the address area 2, the reproduction signal SL
119 is compared with the reference value VS by the comparator L120.
Compare with 101. This reference value VS101 is set to an intermediate level between the voltage V102 when a groove exists on both sides and the voltage V103 when one side has a groove. 2
Since the digitized signal S120 includes information of the address pits 107 of the grooves G102 and G103 on both sides of the track L102, the address information is demodulated by the demodulator L121 for each of the zones X and Y, and the two demodulated signals are processed by the system controller. In step 117, the address of the land L102 is specified by comparison or addition. For example, when the addition is used, the groove G102 is set to “1”.
0 ", groove G103 is" 11 ", groove G104
Is "12", the land L102 is "2".
1 "and the land L103" 23 "are obtained as address information.

On the other hand, the reproduction signal SG1 of the groove G102
19 shows a change between the output V105 for the unrecorded reflected light on the groove and the output V104 corresponding to the recording mark 107 in the information area 3 as shown in FIG.
By demodulating this level change, the information signal from the information area 3 can be reproduced. On the other hand, a binary signal S122 is obtained from the address area 2 by comparing the signal level of the reproduction signal SG119 with the reference value Vs102 by the comparator G122, and the demodulator G123 based on this signal. Demodulate the address signal.

The current position of the light beam 1 is specified from the obtained address information, and the position of the light beam 1 is moved by the tracking driving means in accordance with the difference from the target track. It is possible to follow. The semiconductor laser light source 11
It is possible to record an information signal by modulating the intensity of 1, or to reproduce an information signal recorded in advance. That is, from the recording mark 107 formed on the land L102, the signal SL119 is compared and demodulated using a third comparator using the intermediate level between the voltage V101 and the voltage V102 as a reference level and demodulated. Can be played. The information on the groove can be reproduced by the same method.

As described above, the address can be specified from the track on either the land or the groove, and information can be recorded or reproduced on an arbitrary track.

(Embodiment 8) In the case where the address pits are alternately provided in different zones on the groove as in the embodiment 7, the address reproduction amplitude when tracking the land is equal to that when reproducing the groove. It is smaller than. In the present embodiment, a method of forming address pits having the same pattern in the grooves on both sides of the land in order to keep the signal amplitude of the address signal large even during groove reproduction will be described. Note that conditions other than the address pattern are basically the same as those in the seventh embodiment.

FIG. 15A is an enlarged plan view showing the vicinity of the address area of the optical information recording member of the present invention, and FIG.
Shows a signal waveform of a reproduction output and a binarized signal waveform obtained when the light beam 1 passes over the land L122;
(C) shows a reproduction output obtained when the light beam 1 passes over the groove G123 and a binarized signal waveform. Here, the recording marks in the information area 3 are omitted for the sake of simplicity.

The address area 2 has a zone X, a zone Y and a zone Z which are adjacent on the groove. The address pits 104 are formed by intermittently forming grooves in any two zones in a pattern according to a predetermined code signal. The groove G121 has the address pit 104 in the zone X and the zone Z. The adjacent groove G122 has an address pit 104 in the zone X in the same pattern as that of the zone X of the G121.
Has an address pit 104 of a new address pattern. Zone Z is a continuous groove. Similarly, groove G12
As shown in the figure, the address patterns of the same pattern as the tracks adjacent to each other are sequentially arranged in the third and subsequent tracks as well.

For demodulating the address signal, a signal having substantially the same configuration as that of the seventh embodiment is used. The reproduced signal SL119 from the land L122 of the recording member shows the same output V102 as the information area 3 at the point P101 where the grooves G122 and G123 exist on both sides, and the groove G is provided only on one side.
An output V103 is shown from a point P102 where 123 is present. At the point P103 where no groove exists on both sides, diffraction by the groove disappears, and the incident light is reflected by the light according to the reflectance of the substrate surface, the light amount increases, and the output V107 increases.
Becomes In the land L122, the address information is detected using the reproduction signal from the point P103, that is, from the zone Y. From the address area 2, if the address pit width is equal to the land width, a signal amplitude equivalent to that of a groove can be obtained.

For this reason, when demodulating the address reproduction signal SL119, the comparator L120 is set to operate at the higher reference value Vs103 than in the seventh embodiment, whereby
A value signal S120 is obtained. Further, in the case of the substrate having this configuration, by using the comparators L120 and G122 as independent comparators and setting the reference level Vs103, it is possible to binarize the address signals from the lands and the grooves.

Note that the reproduction signal S is obtained by using the reference value Vs103.
Although L119 is binarized, it is conceivable that the amplitude of the address pit 104 on one side becomes larger than this value due to the formation state of the address pit 104 or fluctuation of the reproducing apparatus. In order to solve this, as in the second embodiment, the address pits 10 are placed on both sides immediately after the amplifier 119.
A gate selection circuit for selecting only the zone where 4 exists can be provided. This gate selection circuit sets a time of 3 corresponding to the width of the zone used in advance in the mastering process of the substrate.
A gate generator for generating two gates, a phase lock circuit for matching the timing of the gate signal to the amplitude of the reproduction signals SL119 and SG119, and comparing the amplitude of the reproduction signal in each gate to determine the gate exhibiting the maximum amplitude. The configuration is specified. The obtained reproduced signal in the gate is compared with a comparator L12.
By inputting 0 and G122, a highly accurate address signal can be obtained from a plurality of address pit signals.

On the other hand, the address reproduction signal of the groove G123 is obtained from the zone Y and the zone Z where the address pits 104 are present. The address of the track can be specified by the same calculation as in the case of the land.

(Embodiment 9) Embodiment 8 is a method in which an address area is divided into three zones to obtain an address signal having a large amplitude from a land portion. Here, a method using two zones will be described. State. FIG.
(A) shows a plan view near the address area, and (b) shows a reproduced signal and a binarized signal obtained when the light beam 1 passes over the land L132. Address area 2 is
It is composed of two adjacent zones X and Y. Each groove is arranged so that the zone changes alternately for each track so that the pattern of the address pits 104 in one of the zones X and Y becomes the same pattern as the adjacent groove. The shape of each groove was the same as in the seventh embodiment.

The reproduced signal SL119 obtained when the land L132 is reproduced has a large amplitude change from the zone Y because the pattern of the address pits 104 on both sides is the same as in the eighth embodiment. In Zone X,
Since the address patterns on both sides are different, an amplitude change as large as the amplitude change in zone Y cannot be obtained. Using the difference, the zone Y in which the address information corresponding to the track T132 is recorded is specified.

However, also in the zone X, a large amplitude change is observed in a region where the planes of the adjacent grooves G132 and G133 overlap. For this reason, the binary signal S12
Even at 0, an erroneous pulse 121 is generated. However, these erroneous pulses 121 are determined as an error address area in an error correction stage of a process of demodulating address information,
It can be ignored.

The address reproduction signal of the groove G132 is
It is obtained corresponding to two zones as in the eighth embodiment,
By demodulating the two addresses and calculating the demodulated result by the system controller 117 in the same manner as in the case of the land of the seventh embodiment, the address of the track can be specified.

As described above, according to the present embodiment, it is possible to secure the same high address reproduction signal and to reduce the width of the address area, as compared with the eighth embodiment.
The area of the information area of the recording member, that is, the recording capacity can be increased.

Although not described in the seventh to ninth embodiments,
The method of providing an area indicating the start of the address area prior to the address area described in the fourth embodiment can be similarly applied to a method of recording signals on both lands and grooves. Further, the method of reducing the groove width of the continuous groove adjacent to the address pit or the method of making the width of the address pit larger than the width of the groove shown in the fifth embodiment records signals on both the land and the groove. The same method can be applied.

[0103]

As is apparent from the above description, according to the optical information recording member of the present invention, a guide groove having a high track density and address information can be realized.
According to the recording / reproducing apparatus of the present invention, information can be recorded on such a recording member, and the address information and the recorded information can be reproduced stably from the recording member.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a configuration near an address area of an optical information recording member according to a first embodiment of the present invention and a diagram illustrating a reproduced signal waveform.

FIG. 2 is a characteristic diagram showing a track pitch dependency of the first embodiment.

FIG. 3 is a block diagram showing a configuration of a recording / reproducing apparatus according to the first embodiment.

FIG. 4 is a diagram showing a configuration near an address area of an optical information recording member according to a second embodiment and a diagram showing a reproduced signal waveform;

FIG. 5 is a block diagram showing a configuration of a comparison circuit of the recording / reproducing apparatus according to the second embodiment;

FIG. 6 is a diagram showing a configuration near an address area of an optical information recording member according to a third embodiment and a diagram showing a reproduced signal waveform;

FIG. 7 is a diagram showing a configuration near an address area of an optical information recording member according to a fourth embodiment and a diagram showing a reproduced signal waveform;

FIG. 8 is a block diagram showing a configuration of a comparison circuit of the recording / reproducing apparatus according to the fourth embodiment.

FIG. 9 is a diagram illustrating a configuration near an address area of an optical information recording member according to a fifth embodiment and a diagram illustrating a reproduced signal waveform.

FIG. 10 is a diagram showing a configuration near an address area of an optical information recording member according to a fifth embodiment and a diagram showing a reproduced signal waveform.

FIG. 11 is a diagram showing a configuration near an address area of an optical information recording member according to a sixth embodiment and a diagram showing a reproduced signal waveform;

FIG. 12 is a block diagram showing an address detection circuit and a data detection circuit of the recording / reproducing apparatus according to the sixth embodiment;

FIG. 13 is a diagram showing a configuration near an address area of an optical information recording member according to a seventh embodiment and a diagram showing a reproduced signal waveform.

FIG. 14 is a block diagram illustrating a configuration of a recording / reproducing apparatus according to a seventh embodiment.

FIG. 15 is a diagram illustrating a configuration near an address area of an optical information recording member according to an eighth embodiment and a diagram illustrating a reproduction signal waveform.

FIG. 16 is a diagram showing a configuration near an address area of an optical information recording member according to a ninth embodiment and a diagram showing a re-signal waveform;

FIG. 17 is a diagram showing a configuration near a conventional groove recording address area and a waveform of a reproduced signal.

FIG. 18 is a diagram showing a configuration near a conventional land recording address area and a waveform of a reproduced signal.

FIG. 19 is a flowchart showing a conventional manufacturing process of a grooved substrate.

FIG. 20 is a sectional view showing a state of injection molding of a substrate having a narrow groove.

[Explanation of symbols]

 Reference Signs List 1 light beam 2 address area 3 information area 4 address pit 7 recording mark

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Eiji Ono 1006 Kadoma Kadoma, Osaka Pref. Matsushita Electric Industrial Co., Ltd. Terms (Reference) 5D029 KB08 PA03 WA31 WB11 WD10 5D090 AA01 BB05 CC05 DD03 FF11 FF15 FF45 GG10 GG28

Claims (14)

[Claims] 1. A substrate provided with a first track mainly on a first surface and a second track mainly on a second surface, which are different in optical position with respect to an incident direction of a light beam, on a substrate. A recording member comprising a recording thin-film layer that produces a change that can be detected optically by light irradiation, wherein the first track has an address portion formed by isolating the first surface in accordance with a predetermined code signal. A width in a direction perpendicular to the track in a region formed by the second surface in contact with the address portion is equal to or greater than a track width of the first track; An optical information recording member, wherein the optical information recording member is disposed at a different position from the first track, and the information recording area is on the second track. 2. The optical information recording member according to claim 1, wherein the first track vertically adjacent to the track of the address portion has a continuous shape on the first surface. 3. The optical device according to claim 2, wherein the width of the first track vertically adjacent to the track of the address portion is smaller than the width of the first track in the continuous area of the first surface. Information recording member. 4. The optical information recording member according to claim 1, wherein the first surface is convex with respect to the incident direction of the light beam. 5. The optical information according to claim 1, further comprising an address start zone indicating a start point of the address information at a head of the address portion, wherein the start zone has the same pattern between tracks adjacent to each other. Recording member. 6. The optical information recording member according to claim 1, wherein the width of the first track is substantially equal to the width of the second track, and the area on the first track is an information recording area. 7. A substrate having on its surface a first track mainly having a first surface and a second track mainly having a second surface whose optical positions are different from each other in an incident direction of a light beam. A recording member comprising a recording thin-film layer that produces a change that can be detected optically by light irradiation, wherein the first track has an address portion formed by isolating the first surface in accordance with a predetermined code signal. A width of a second surface area in contact with the address portion in a direction perpendicular to the track is equal to or greater than a track width of the first track;
An optical information recording member, wherein at least one of the address portions has the same address pattern as an adjacent track. 8. The optical information recording member according to claim 7, wherein the width of the first track is substantially equal to the width of the second track, and the information recording area is on the first track. 9. A method for recording / reproducing an information signal by irradiating a recording member provided with a recording thin film layer with a light beam on a substrate provided with a guide groove, wherein a center of a recording / reproducing track on the recording medium is provided. Irradiating the light beam to the first and second address portions arranged right and left and at different positions in the track direction, and reflected light of the light beam is divided in a direction perpendicular to the track. Receiving light by a light receiving surface, demodulating address information from the first and second address units using a differential signal output from the light receiving surface, and specifying an address of the recording / reproducing track; A recording / reproducing method for an optical information recording member. 10. The address signal is demodulated by inverting the polarity of a differential signal from one of the first and second address units and comparing the inverted signal with a predetermined level. Optical recording and reproducing method. 11. A first track mainly having a first surface and a second track mainly having a second surface whose optical positions are different from each other with respect to the incident direction of the light beam are provided on the surface. A method for demodulating address information and an information signal on a second track of a recording member having an address portion in which the first surface is formed so as to be isolated in accordance with a predetermined code signal; Reflected light is received by a light receiving surface divided in a direction perpendicular to the track, an address signal is demodulated from a differential signal output from the light receiving surface, and the differential signal and the output from the light receiving surface are demodulated. An optical recording / reproducing method characterized in that an information signal is demodulated by using both of the sum signal and the sum signal. 12. The optical recording according to claim 11, wherein one of the differential signal and the sum signal is corrected under a predetermined condition, and then the information signal is demodulated by combining with the other signal. Playback method. 13. An apparatus for recording / reproducing an information signal by irradiating a recording member having a recording thin film layer with a light beam on a substrate having a guide groove, wherein a center of a recording / reproducing track on the recording medium is provided. A photodetector having a light receiving surface that divides reflected light from address pits arranged on the left and right in a direction perpendicular to the track; and a differential that obtains a differential signal from an output from the light receiving surface. A recording / reproducing apparatus for an optical information recording member, comprising: an amplifier; a comparator for comparing an output of the differential amplifier with a predetermined level; and a demodulator for demodulating the comparison result into an address signal. 14. When the polarity for judging the polarity of one of the outputs of the differential signal from the first and second address sections is matched, the address signal is demodulated by comparing with a predetermined level. The optical recording / reproducing apparatus according to claim 13, wherein: