JP4154256B2 - Optical information recording medium recording / reproducing apparatus and optical information recording medium recording / reproducing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical information recording medium having a recording layer for recording and reproducing information by irradiation with a laser beam or the like. the body's Recording and playback device, And optical information recording media Recording / playback To the law Related.
[0002]
[Prior art]
An optical recording medium is attracting attention as a large-capacity and high-density memory, and development of what is called an erasable type that can be rewritten is underway. As one of the erasable optical recording media, a thin film that changes phase between an amorphous state and a crystalline state is formed on a substrate as a recording layer, and information is recorded and erased by thermal energy generated by laser light irradiation. There is something.
[0003]
As a phase change material constituting this recording layer, an alloy film containing Ge, Sb, Te, In or the like as a main component, for example, a GeSbTe alloy is known. Information is often recorded by forming a mark by partially amorphizing the recording layer, and erasing is often performed by crystallization of the mark by this amorphization.
[0004]
Amorphization is performed by heating the recording layer to the melting point or higher and then cooling it at a speed equal to or higher than a certain value. On the other hand, crystallization is performed by heating the recording layer to a temperature not lower than the crystallization temperature and not higher than the melting point.
[0005]
Information recorded on the recording layer is reproduced using the difference in reflectance between the amorphous mark and the crystalline region so that the reflectance in the amorphous state is lower than the reflectance in the crystalline state. In general, a recording layer is formed.
[0006]
In general, spiral or concentric guide grooves (grooves) for tracking laser light during recording / reproduction are formed in advance on the substrate. The area between the grooves is called a land, and only one of the groove or the land is used as an information track for recording information, and the other is used as a guard band for separating adjacent information tracks. Many. This method is also used for recordable CD (CD-R) and mini-disc (MD).
[0007]
As a method of recording information on an optical recording medium, marks having different lengths are formed with various spaces, so that the length of the mark and the length of the space (that is, the front edge and the rear edge of the mark). There is a PWM recording method in which the position) carries information. In this PWM recording method, if pulse conditions such as laser pulse intensity and generation timing are inappropriate during recording, the heat generated at the front of the mark promotes the temperature rise at the rear of the mark and the front becomes narrower. The rear part has a thick and distorted mark shape, or the heat generated when the mark is formed affects the formation of the adjacent mark, the edge position of the mark fluctuates, and the signal quality decreases.
[0008]
The optimum pulse condition greatly depends on the characteristics of the optical recording medium and the recording / reproducing apparatus. Therefore, at the time of recording, when the optical recording medium is mounted on the recording / reproducing apparatus and started, a learning operation for obtaining an optimal pulse condition is required each time. In this learning operation, test recording is performed while changing the pulse conditions, and the result of measuring the quality of the reproduced signal is compared to obtain the optimum recording / reproducing conditions. Based on these conditions, optical recording is performed. The information is recorded on the formula recording medium.
[0009]
An example of such a conventional optical recording medium is shown in FIGS. FIG. 15 is a perspective view showing a conventional optical information recording medium 90, and FIG. 16 is an enlarged plan view for explaining the track pitch of tracks formed on the conventional optical information recording medium 90.
[0010]
In FIG. 15, an optical recording medium 90 includes a transparent substrate having a thickness of 1.1 mm made of polycarbonate having a central hole 2 formed in the center for mounting in a recording / reproducing apparatus. A recording layer is formed on the transparent substrate. A protective layer having a thickness of 0.1 mm is formed on the recording layer. Information is recorded / reproduced by irradiating the recording layer with laser light through this protective layer.
[0011]
On the transparent substrate, a track 6 for tracking the laser beam at the time of recording / reproducing is formed. The transparent substrate provided in the optical recording medium 90 has a read-only lead-in area in which identification information for identifying the optical recording medium 90 is recorded by embossed pits and the like, and a learning operation for obtaining an optimal pulse condition A test recording area 4 for performing recording and an information recording area 5 for recording information are arranged.
[0012]
Referring to FIG. 16, the tracks formed in the test recording area 4 and the tracks formed in the information recording area 5 are formed to have the same width and interval. The track pitch Tp1 of the track formed in the test recording area 4 and the track pitch Tp of the track formed in the information recording area 5 are set to the same width.
[0013]
Incidentally, a tracking error signal for tracking control of the laser beam on the guide groove during recording / reproduction is obtained by a detection method generally called a push-pull method.
[0014]
FIG. 17 is a block diagram showing a configuration of a conventional recording / reproducing apparatus that performs tracking control by the push-pull method. The recording / reproducing apparatus shown in FIG. 17 has a spindle motor 10 that rotates by mounting an optical information recording medium 90, a controller 11, and modulation for modulating data to be recorded on the optical information recording medium 90 into a recording signal. A laser drive circuit 13 for driving a semiconductor laser in accordance with a recording signal, the semiconductor laser, and condensing laser light from the semiconductor laser onto an optical information recording medium 90 to record information; An optical head 14 provided for obtaining a reproduction signal from the reflected light reflected by the optical information recording medium 90, and electric signals output from the light receiving portions 21 and 22 of the photodetector 20 provided in the optical head 14. The summing amplifier 15 for outputting the sum signal 15S, the binarizing circuit 17 for binarizing the sum signal 15S, and the light receiving sections 21 and 22 The data recorded on the track formed on the optical information recording medium 90 is demodulated based on the differential amplifier 16 that outputs the difference signal 16S of the electrical signal and the binarized sum signal 17S. A data demodulating circuit 18 and a tracking control circuit 19 for controlling the optical head 14 so that the laser beam appropriately scans a track formed on the optical information recording medium 90 based on the difference signal 16S are provided.
[0015]
FIG. 18 shows a cross section of a main part along the radial direction of the optical information recording medium 90 shown in FIG. 15 and a tracking error signal when the laser beam crosses the track 6 formed on the optical information recording medium 90. This is shown schematically. In order to perform stable tracking control, it is preferable that the tracking error signal has a sufficient amplitude and has a small fluctuation for each track. The amplitude of the tracking error signal depends on the width and depth of the track, the track pitch, and the reflectance, and a larger amplitude can be obtained as the track pitch is wider and the reflectance is higher.
[0016]
[Patent Document 1]
JP-A-4-19837 (Patent No. 2815673)
[0017]
[Problems to be solved by the invention]
Recently, the amount of information to be handled has increased with the improvement of the processing capability of various information devices. Therefore, a recording medium capable of recording / reproducing a larger amount of information is required. As means for increasing the capacity, there are a method for increasing the recording density by narrowing the track pitch, and a method for recording / reproducing information on each recording layer from a single side surface provided with a plurality of recording layers.
[0018]
However, if the track pitch is narrowed in order to increase the recording density, the tracking error signal becomes small, and it is easy to be affected by the reflectance change caused by recording the signal. Therefore, in the learning operation for obtaining the optimum recording condition, when test recording is performed under a laser pulse condition in which the amorphous area becomes extremely large, tracking becomes unstable, and the track cannot be accessed. For this reason, there is a problem that not only the time required for learning becomes longer, but also the test recording area is unnecessarily consumed.
[0019]
Further, even when recording is performed under unsuitable recording conditions in the test recording, when the track pitch is set wide enough to enable stable tracking control, the information recording area recorded only under the optimal recording conditions The track pitch Tp2 is set wider than necessary. Therefore, there is a problem that the recording capacity is reduced.
[0020]
Furthermore, when recording / reproducing information on each recording layer from one side of an optical information recording medium having a plurality of recording layers, the recording layer on the back side when viewed from the side irradiated with laser light is on the near side Since the laser beam attenuated through the recording layer is irradiated, the amount of reflected light reflected by the inner recording layer is reduced. Further, since the recording layer on the laser irradiation side needs to have a sufficient light transmittance to enable recording and reproduction to the recording layer on the back side, the reflectance must be lowered. Therefore, the tracking error signal becomes small and is easily affected by the change in reflectance caused by recording the signal. For this reason, as in the case where the track pitch is narrowed, tracking becomes unstable in the learning operation for obtaining the optimum recording condition, and the track may not be accessed. For this reason, there is a problem that not only the time required for learning becomes longer, but also the test recording area is unnecessarily consumed. Further, when the track pitch is set wide enough to enable stable tracking control in the test recording, the track pitch Tp2 in the information recording area recorded only under the optimum recording condition is set wider than necessary. Become. Therefore, there is a problem that the recording capacity is reduced.
[0021]
An object of the present invention is to provide a large-capacity optical information recording medium capable of reliable tracking control during test recording. the body's Recording and playback device, And optical information recording media Recording / playback The law It is to provide.
[0022]
[Means for Solving the Problems]
Optical information recording medium according to the present invention Recording and playback device Is A recording / reproducing apparatus for recording, reproducing or erasing information by irradiating an optical information recording medium with a laser beam, wherein the optical information recording medium has a substrate and information by irradiating the laser beam. Information is recorded by irradiating the laser beam with a first recording layer formed on the substrate for recording, reproducing or erasing, a separation layer formed on the first recording layer, A second recording layer formed on the separation layer for reproducing or erasing, and at least a first test recording area for performing test recording on the surface of the substrate, and the information A first information recording area for recording, and the first test recording area and the first information recording area arranged on the surface of the substrate are arranged in a spiral shape or a concentric circle shape. A test recording track and a first information recording track are respectively formed, and at least a second test recording area for performing test recording and a second information recording area for recording the information are formed on the surface of the separation layer. Are arranged in the second test recording area and the second information recording area arranged on the surface of the separation layer, and the second test recording track and the second information arranged in a spiral shape or a concentric shape. Recording tracks are formed, the track pitch of the first test recording track is wider than the track pitch of the first information recording track, and the track pitch of the second test recording track is It is characterized by being wider than the track pitch of the information recording track, A moving means for moving the optical head along the radial direction of the information recording medium; a focus control means for focusing the laser beam on the test recording area of the target recording layer; and a laser beam on the test recording area of the recording layer. A tracking control means for tracking the test recording track after focusing, and an aberration control means for minimizing the aberration of the laser light after tracking the test recording track; Tracking in the information recording area with the aberration adjusted to the minimum It is characterized by that.
[0023]
The present invention Light Academic information recording media Recording and playback methods Is A recording / reproducing method for recording, reproducing or erasing information by irradiating a laser beam on an optical information recording medium, wherein the optical information recording medium is irradiated with a substrate and a laser beam. Information is recorded by irradiating the laser beam with a first recording layer formed on the substrate for recording, reproducing or erasing, a separation layer formed on the first recording layer, A second recording layer formed on the separation layer for reproducing or erasing, and at least a first test recording area for performing test recording on the surface of the substrate, and the information A first information recording area for recording, and the first test recording area and the first information recording area arranged on the surface of the substrate are arranged in a spiral shape or a concentric circle shape. A test recording track and a first information recording track are respectively formed, and at least a second test recording area for performing test recording and a second information recording area for recording the information are formed on the surface of the separation layer. Are arranged in the second test recording area and the second information recording area arranged on the surface of the separation layer, and the second test recording track and the second information arranged in a spiral shape or a concentric shape. Recording tracks are formed, the track pitch of the first test recording track is wider than the track pitch of the first information recording track, and the track pitch of the second test recording track is The information recording track is wider than the track pitch of the information recording track. The step of moving the optical head along the radial direction of the information recording medium, the step of focusing the laser beam on the test recording area of the target recording layer, and the focus of the laser beam on the test recording area of the recording layer After tracking the test recording track, and after tracking the test recording track, the step of minimizing the aberration of the laser light, and in a state in which the aberration of the laser light is adjusted to the minimum, Tracking in the information recording area It is characterized by that.
[0030]
DETAILED DESCRIPTION OF THE INVENTION
In the optical information recording medium according to the present embodiment, the track pitch of the test recording track is wider than the track pitch of the information recording track. Therefore, a larger tracking signal can be obtained in the test recording area than in the information recording area. Therefore, in the course of the learning operation for obtaining the optimum recording condition, stable tracking control can be performed even if test recording is performed under an inappropriate recording condition in which the amorphous area becomes extremely large.
[0031]
The information recording area preferably has a donut shape.
[0032]
It is preferable that the test recording area is disposed inside the information recording area.
[0033]
The test recording area is preferably arranged outside the information recording area.
[0034]
The test recording area is preferably arranged adjacent to the information recording area.
[0035]
It is preferable that a guard area having a mirror surface on which no track is formed is disposed between the test recording area and the information recording area.
[0036]
The depth and width of the test recording track are preferably substantially the same as the depth and width of the information recording track.
[0037]
The cross-sectional shape of the test recording track is preferably substantially the same as the cross-sectional shape of the information recording track.
[0038]
Preferably, a lead-in area in which predetermined reproduction-specific identification information is recorded is further disposed on the surface of the substrate.
[0039]
In the lead-in area, a lead-in track arranged in a spiral shape or a concentric shape is formed, and the track pitch of the lead-in track is substantially the same as the track pitch of the test recording track. It is preferable that
[0040]
The lead-in area is preferably arranged inside the information recording area.
[0041]
The lead-in area is preferably arranged inside the test recording area.
[0042]
The lead-in area is preferably arranged adjacent to the test recording area.
[0043]
The depth and width of the lead-in track are preferably substantially the same as the depth and width of the information recording track and the depth and width of the test recording track.
[0044]
The cross-sectional shape of the lead-in track is preferably substantially the same as the cross-sectional shape of the information recording track and the cross-sectional shape of the test recording track.
[0045]
In another optical information recording medium according to the present embodiment, the track pitch of the first test recording track is wider than the track pitch of the first information recording track, and the track pitch of the second test recording track is It is wider than the track pitch of the second information recording track. Therefore, it is possible to obtain tracking signals larger in the first and second test recording areas than in the first and second information recording areas, respectively. Accordingly, in the course of the learning operation for obtaining the optimum recording condition, stable tracking control can be performed even if test recording is performed under an inappropriate recording condition in which the amorphous area becomes extremely large.
[0046]
The track pitch of the first test recording track and the track pitch of the second test recording track are the same, and the track pitch of the first information recording track and the track of the second information recording track The pitch is preferably the same width as each other.
[0047]
Preferably, the first test recording track and the first information recording track are arranged in a spiral shape, and the second test recording track and the second information recording track are arranged in a spiral shape.
[0048]
Preferably, the spiral direction of the first test recording track and the first information recording track and the spiral direction of the second test recording track and the second information recording track are opposite to each other.
[0049]
It is preferable that a lead-in area in which predetermined reproduction-specific identification information is recorded is further disposed on at least one surface of the substrate and the separation layer.
[0050]
In the lead-in area, a lead-in track arranged in a spiral shape or a concentric shape is formed, and the track pitch of the lead-in track is substantially the same as the track pitch of the first and second test recording tracks. Are preferably the same area.
[0051]
It is preferable that the lead-in area is disposed inside the first and second information recording areas.
[0052]
It is preferable that the lead-in area is disposed inside the first and second test recording areas.
[0053]
The lead-in area is preferably arranged adjacent to the first and second test recording areas.
[0054]
The depth and width of the lead-in track are substantially the same as the depth and width of the first and second information recording tracks and the depth and width of the first and second test recording tracks. Is preferred.
[0055]
The cross-sectional shape of the lead-in track is preferably substantially the same as the cross-sectional shape of the first and second information recording tracks and the cross-sectional shape of the first and second test recording tracks.
[0056]
In the recording / reproducing apparatus according to the present embodiment, specific information is experimentally recorded on the test recording track formed in the test recording area of the optical information recording medium according to the present embodiment. Therefore, a tracking signal larger than the information recording area can be obtained from the test recording area. Accordingly, in the course of the learning operation for obtaining the optimum recording condition, stable tracking control can be performed even if test recording is performed under an inappropriate recording condition in which the amorphous area becomes extremely large.
[0057]
In another recording / reproducing apparatus according to the present embodiment, the optical head is moved to a region where the target recording layer has a large track pitch, the laser beam is focused on the recording layer, and the information track is tracked. Adjust the aberration of the laser beam. Therefore, a tracking signal larger than the information recording area can be obtained from the test recording area having a large track pitch. Accordingly, in the course of the learning operation for obtaining the optimum recording condition, stable tracking control can be performed even if test recording is performed under an inappropriate recording condition in which the amorphous area becomes extremely large.
[0058]
Embodiments of the present invention will be described below with reference to the drawings.
[0059]
(Embodiment 1)
FIG. 1A is a perspective view showing an optical information recording medium 101 according to Embodiment 1, FIG. 1B is a cross-sectional view thereof, and FIG. 2 explains a track pitch of tracks formed on the optical information recording medium 101. It is a plane enlarged view for doing.
[0060]
The optical information recording medium 101 according to the first embodiment records and reproduces information by irradiating a laser beam with a wavelength of about 405 nm mainly collected by an objective lens having an NA of about 0.85.
[0061]
Referring to FIGS. 1A and 1B, an optical information recording medium 101 has a diameter of 120 mm and a thickness of 1 made of polycarbonate having a central hole 102 having a diameter of 15 millimeters (mm) for mounting in a recording / reproducing apparatus at the center. A 1 mm transparent substrate 1 is provided. A recording layer 2 is formed on the transparent substrate 1. A protective layer 3 having a thickness of 0.1 mm is formed on the recording layer 2.
[0062]
Information is recorded and reproduced by irradiating laser light through the protective layer 3. The recording layer 2 is made of a GeSbTe alloy, which is a phase change recording material, and forms a recording mark by partially amorphizing the recording layer 2 by irradiating a laser beam.
[0063]
On the transparent substrate 1 provided on the optical information recording medium 101, a read-only lead-in area 103 in which identification information for identifying the optical information recording medium 101 is recorded by embossed pits has a radius of about 22 mm to about 23 mm. It is arranged in a donut shape at the position.
[0064]
Outside the lead-in area 103, a test recording area 104 for performing a learning operation for obtaining an optimum pulse condition is disposed at a radius of about 23 mm to about 24 mm. Outside the test recording area 104, an information recording area 105 for recording information is arranged at a radius of about 24 mm to about 58 mm. The test recording area 104 and the information recording area 105 are configured by grooves having a depth of about 20 nanometers (nm) and a width of about 0.2 micrometers (μm), and a track 106 for tracking laser light during recording and reproduction. Is formed.
[0065]
Referring to FIG. 2, the track pitch Tp2 of the track 106 formed in the information recording area 105 arranged on the transparent substrate 1 provided in the optical information recording medium 101 is set to 0.32 μm. The track pitch Tp1 of the track 106 formed in the test recording area 104 is 0.35 μm, which is wider than 0.32 μm of the track pitch Tp2 of the track 106 formed in the information recording area 105. The width and depth of the track 106 formed in the test recording area 104 are the same as the width and depth of the track 106 formed in the information recording area 105.
[0066]
Thus, by setting the track pitch Tp1 of the test recording area 104 wider than the track pitch Tp2 of the information recording area 105, a larger tracking error signal can be obtained in the test recording area 104 than in the information recording area 105. Can do.
[0067]
The track pitch Tp1 of the track 106 formed in the test recording area 104 is wide enough to obtain a tracking error signal that is about 20% or more larger than the track pitch Tp2 of the track 106 formed in the information recording area 105. It is preferably about 3% or more wider than the track pitch Tp2.
[0068]
When the track pitch Tp1 of the test recording area 104 is about 10% wider than the track pitch Tp2 of the information recording area 105, the test recording area 104 has a tracking that is about 1.7 times larger than the information recording area 105. An error signal can be obtained.
[0069]
As described above, according to the optical information recording medium 101 according to the first embodiment, in the course of the learning operation for obtaining the optimum recording condition, the test recording is performed under an inappropriate recording condition such that the amorphous area becomes extremely large. Even so, stable tracking control is possible. Therefore, it is not necessary to set the track pitch Tp2 of the track 106 formed in the information recording area 105 recorded only under the optimum recording condition more than necessary. That is, the recording pitch of the optical information recording medium 101 can be increased by narrowing the track pitch Tp2 in the information recording area 105.
[0070]
If the width and depth of the track 106 are constant, even if the track pitch changes, the relationship between the recording conditions such as the intensity and generation timing of the laser pulse and the shape of the formed amorphous mark is substantial. Does not change. Therefore, the optimum recording condition obtained in the test recording area 104 having a relatively wide track pitch can be used in the information recording area 105.
[0071]
The boundary between the test recording area 104 and the information recording area 105 may be a mirror area where no track is formed as a guard area, or may be an area where the track pitch changes continuously.
[0072]
As described above, according to the first embodiment, the track pitch Tp1 of the track 106 formed in the test recording area 104 is wider than the track pitch Tp2 of the track 106 formed in the information recording area 105. Therefore, a larger tracking signal can be obtained in the test recording area 104 than in the information recording area 105. Accordingly, in the course of the learning operation for obtaining the optimum recording condition, stable tracking control can be performed even if test recording is performed under an inappropriate recording condition in which the amorphous area becomes extremely large.
[0073]
(Embodiment 2)
FIG. 3 is a perspective view showing the optical information recording medium 201 according to the second embodiment, and FIG. 4 is an enlarged plan view for explaining the track pitch of the tracks formed on the optical information recording medium 201.
[0074]
The optical information recording medium 201 in the second embodiment has a lead-in area formed by guide grooves for tracking laser light, and reproduction-only information such as identification information of the optical information recording medium 201 is recorded in the guide grooves. The structure is the same except for a part of the optical information recording medium 101 in the first embodiment described above with reference to FIGS. 1A, 1B and 2.
[0075]
Referring to FIG. 3, an optical information recording medium 201 is formed on a transparent substrate having a diameter of 120 mm and a thickness of 1.1 mm made of polycarbonate in which a central hole 202 having a diameter of 15 mm for mounting in a recording / reproducing apparatus is formed in the center. A recording layer is formed, and a protective layer having a thickness of 0.1 mm is formed on the recording layer, and laser light is irradiated through the protective layer to record and reproduce information. The recording layer is made of a GeSbTe alloy, which is a phase change recording material, and the recording layer is partially amorphized by irradiation with laser light to form a recording mark.
[0076]
The transparent substrate provided in the optical information recording medium 201 is provided at a position with a radius of about 22 mm to 23 mm, and a groove having a depth of about 20 nm and a width of about 0.2 μm is wobbled in the radial direction, and the space A read-only lead-in area 203 in which a medium information track 207 in which identification information of the optical information recording medium 201 is recorded by modulating the frequency is formed is arranged.
[0077]
Outside the lead-in area 203, a test recording area 204 is provided at a radius of about 23 mm to 24 mm for performing a learning operation for obtaining an optimal pulse condition. An information recording area 205 for recording information is arranged outside the test recording area 204 at a radius of about 24 mm to 58 mm. The test recording area 204 and the information recording area 205 are formed by grooves of the same shape having a depth of about 20 nm and a width of about 0.2 μm, and a track 206 is formed for tracking the laser beam during recording and reproduction.
[0078]
Referring to FIG. 4, the track pitch Tp2 of the tracks 206 formed in the information recording area 205 is set to 0.32 μm. The track pitch Tp1 of the track 206 formed in the test recording area 204 is 0.35 μm, which is wider than 0.32 μm of the track pitch Tp2 in the information recording area 205. The track pitch Tp3 of the medium information track 207 formed in the lead-in area 203 is 0.35 μm, which is the same as the track pitch Tp1 in the test recording area 204.
[0079]
As described above, the track pitch Tp1 of the test recording area 204 is set wider than the track pitch Tp2 of the information recording area 205 in the same manner as in the first embodiment described above. In comparison, a larger tracking error signal can be obtained.
[0080]
FIG. 5 is a main part plan view showing the shape of the medium information track 207 formed in the lead-in area 203. Referring to FIG. 5, the laser beam 208 tracked on the medium information track 207 is scanned along the direction of the arrow 209. The medium information track 207 meanders in the radial direction, and important information such as identification information of the optical information recording medium 201 is recorded by the spatial frequency. Therefore, the track pitch Tp3 of the lead-in area 203 is set in the information recording area 205 for the purpose of reducing the crosstalk between the adjacent medium information tracks 207 and increasing the reliability of the reproduced information. The formed track 206 is wider than the track pitch Tp2.
[0081]
With the above configuration, the optical information recording medium 201 in Embodiment 2 performs test recording under inappropriate recording conditions such that the amorphous area becomes extremely large in the course of the learning operation for obtaining the optimum recording conditions. However, stable tracking control is possible. Therefore, it is not necessary to set the track pitch Tp2 of the information track 206 in the information recording area 205, which is recorded only under the optimum recording condition, more than necessary. That is, the track pitch Tp2 of the information recording area 205 can be narrowed and the recording capacity can be increased. In addition, the lead-in area 203 and the test recording area 204 are arranged adjacent to each other, and the track pitch Tp3 of the lead-in area 203 and the track pitch Tp1 of the test recording area 204 are set to be the same width as each other. Since the reproduction from the in area 203 and the test recording to the test recording area 204 can be continuously performed according to the same tracking condition, the recording / reproducing apparatus can be started up smoothly.
[0082]
The boundary area between the test recording area 204 and the information recording area 205 may be a mirror area where no track is formed as a guard area, or an area where the track pitch changes continuously.
[0083]
The test recording area 204 may be arranged on the outer peripheral side of the information recording area 205. Furthermore, the recording characteristics distributed along the radial direction of the optical information recording medium 201 can be compensated by arranging the test recording area 204 on both the inner and outer peripheral sides of the information recording area 205.
[0084]
In the test recording area 204, the tracks 206 of the information recording area 205 meander (wobble) in the radial direction with a constant spatial frequency, and the rotation of the spindle motor of the recording / reproducing apparatus is rotated based on the signal obtained from this wobble. The address information obtained by frequency-modulating the wobble may be recorded on the track 206.
[0085]
(Embodiment 3)
FIG. 6 is a cross-sectional view for explaining the configuration of the optical information recording medium 301 according to the third embodiment.
[0086]
The optical recording medium 301 in Embodiment 3 has a single-sided two-layer structure including two recording layers 303 and a recording layer 305, and the recording layer 303 or the recording layer is irradiated with a laser beam 307 from the protective layer 302 side. By selectively focusing on 305, information is recorded / reproduced on the two recording layers from the same side. The recording layer 303 and the recording layer 305 are separated from each other by a separation layer 304 having a thickness of about 0.03 mm. The layers 303, 304, and 305 are separated from a substrate 306 having a diameter of 120 mm and a thickness of 1.1 mm. It is sandwiched between 0.07 mm protective layers 302.
[0087]
Similar to the second embodiment shown in FIGS. 3 and 4, the recording layer 303 and the recording layer 305 are provided with grooves having a radius of about 22 mm to 23 mm, a depth of about 20 nm, and a width of about 0.2 μm. A read-only lead-in area 203 having a medium information track 207 recorded with medium identification information and the like by being meandered (wobbled) in the radial direction and modulating the spatial frequency thereof, is provided at a radius of about 23 mm to 24 mm. A test recording area 204 for performing a learning operation for obtaining an optimum pulse condition, and an information recording area 205 provided with a radius of about 24 mm to 58 mm for recording information are arranged. The information recording area 205 includes a groove having a depth of about 20 nm and a width of about 0.2 μm, and a track 206 for tracking the laser beam during recording and reproduction. Is formed.
[0088]
The track pitch Tp3 of the lead-in area 203 is set to 0.35 μm, the track pitch Tp1 of the test recording area 204 is set to 0.35 μm, and the track pitch Tp2 of the information recording area 205 is set to 0.32 μm. By setting the track pitch Tp1 of the test recording area 204 wider than the track pitch Tp2 of the information recording area 205, a larger tracking error signal can be obtained in the test recording area 204 than in the information recording area 205. Therefore, in the course of the learning operation for obtaining the optimum recording condition, stable tracking control can be performed even if test recording is performed under an inappropriate recording condition in which the amorphous area becomes extremely large. Therefore, it is not necessary to set the track pitch of the information track in the information recording area to be recorded only under the optimum recording condition more than necessary. That is, the track pitch of the information recording area can be narrowed and the recording capacity can be increased.
[0089]
In a multi-layer recording medium that includes a plurality of recording layers as in the third embodiment and records and reproduces information on each recording layer from one side, the recording layer on the back side is the front side when viewed from the laser beam irradiation side. The amount of reflected light is reduced because the attenuated laser light is irradiated through the recording layer, and the recording layer on the laser irradiation side has sufficient light to enable recording and reproduction to the recording layer on the back side. It is necessary to have transmittance, and the reflectance must be lowered. Since the tracking error signal has a smaller amplitude as the reflectance is lower, the effect of the present invention is more remarkable in a multilayer recording medium than in the case where there is only one recording layer.
[0090]
The lead-in area may be provided only in one of the recording layers, or medium identification information or the like may be recorded by embossed pits instead of the medium information track. The recording layer 303 and the recording layer 305 may have different track pitches, or the spiral directions of the tracks may be reversed. Furthermore, the number of recording layers may be three or more.
[0091]
In the present invention, it is important to set the track pitch of the test recording area wider than that of the information recording area. The specific values of the shape of the optical recording medium shown in the first to third embodiments, the radial position of the track, the depth, the groove width and the track pitch depend on the performance of the recording / reproducing apparatus used and the characteristics of the recording film. It can be changed as appropriate.
[0092]
(Embodiment 4)
In the fourth embodiment, a recording / reproducing apparatus and a recording / reproducing method will be described. FIG. 7 is a block diagram showing a configuration of the recording / reproducing apparatus 50 according to the fourth embodiment. The recording / reproducing apparatus 50 is loaded with the optical recording medium 301 having a plurality of recording layers described above with reference to FIG. 6 in the third embodiment. The recording / reproducing apparatus 50 includes an optical head 401.
[0093]
FIG. 8 is a block diagram showing a configuration of the optical head 401. The optical head 401 has a light source 402 constituted by a semiconductor laser having a wavelength of 405 nm. The laser light emitted from the light source 402 passes through the collimator lens 403, the optical path correction device 409 including a lens having a movable mechanism, the beam splitter 404, the quarter wavelength plate 405, and the objective lens 406. Then, the light is condensed on the optical recording medium 301.
[0094]
The laser beam condensed on the optical recording medium 301 is focused on the target recording layer formed on the optical recording medium 301 by adjusting the position of the objective lens 406 by the voice coil 407, and the optical path. By adjusting the correction device 409, the aberration is adjusted to be minimized. The laser light reflected from the recording layer passes through the objective lens 406 and the quarter-wave plate 405 again, is reflected by the beam splitter 404, enters the detector 408, and is converted into an electric signal.
[0095]
The recording / reproducing apparatus 50 shown in FIG. 7 includes a spindle motor 110 for mounting and rotating an optical recording medium 301, a controller 111, and a modulator for converting data to be recorded on the optical recording medium 301 into a recording signal. 112, a laser driving circuit 113 that drives a light source 402 constituted by a semiconductor laser according to a recording signal, and a laser beam emitted from the light source 402 is condensed on an optical recording medium 301 to record information, The optical head 401 that obtains a reproduction signal from the reflected light, the preamplifier 114 that amplifies the reproduction signal and generates an information reproduction signal 114S, a focus error signal 114F, a tracking error signal 114T, and an aberration control signal 114A, and an information reproduction signal 114S. A binarization circuit 115 for converting the signal into a binarized signal and the binarized signal A data demodulating circuit 116 that demodulates data based on the signal, a signal quality determiner 117 that determines the quality of a signal obtained by experimentally reproducing specific data recorded in a test recording area arranged in the optical recording medium 301, and A recording condition storage 118 for storing the optimum recording conditions obtained by the learning operation, a pulse condition setting unit 119 for controlling the laser pulse in accordance with the recording conditions stored in the recording condition storage 118, and the optical recording medium 301. A focus control circuit 120 for controlling the optical head 401 based on the focus error signal 114F so that the laser beam is focused on the target recording layer formed on the optical recording medium 301, and on the track formed on the optical recording medium 301. So that the laser beam is appropriately scanned based on the tracking error signal 114T. A tracking control circuit 121 for controlling, an aberration control circuit 122 for controlling the optical head 401 based on the aberration control signal 114A so as to minimize the aberration of the laser beam on the target recording layer, and an optical recording medium And moving means 123 for moving the optical head 401 along the radial direction 301.
[0096]
Here, the focus error signal 114F is generated based on a general method called an astigmatism method. The tracking error signal 114T is generated based on the push-pull method described above with reference to FIGS. The aberration control signal 114A is generated based on the reproduction signal, and is generated so that the aberration of the laser beam on the target recording layer is minimized when the intensity of the reproduction signal is maximized.
[0097]
In a multilayer recording medium such as the optical recording medium 301, the thickness from the surface on the laser beam irradiation side to each recording layer is different, so that irradiation is performed for each recording layer to be recorded / reproduced in the recording / reproducing apparatus. It is necessary to adjust the focus and aberration of the laser beam to be optimal.
[0098]
In the recording / reproducing apparatus 50 according to the fourth embodiment, when accessing each recording layer using a multilayer recording medium such as the optical recording medium 301 in which a region having a wide track pitch is arranged at a specific radial position, By moving the optical head 401 to a specific radial position by the moving means 123, the optical head 401 is arranged in a wide track pitch region in the target recording layer, and after focusing, based on a predetermined condition Thus, tracking is performed with the optical path correction device 409 substantially adjusted.
[0099]
At this time, since the intensity of the tracking error signal obtained is small in the region where the track pitch is narrow, it is difficult to track without adjusting the aberration of the laser beam to the minimum, whereas the track pitch is difficult. Since the intensity of the obtained tracking error signal is large in a wide region, stable tracking is possible if the aberration of the laser beam is generally adjusted.
[0100]
Next, the laser beam can be adjusted to minimize the aberration by adjusting the optical path correction device 409 so that the intensity of the reproduction signal of the recorded information is maximized.
[0101]
Therefore, it is not necessary to provide a special detector for detecting aberrations, and recording / reproduction on a multilayer recording medium can be performed with an optical head having a simple configuration.
[0102]
The aberration control signal is a signal obtained from the wobble of the track, and the aberration is minimized by adjusting the optical path correction device 409 so that the intensity of the reproduction signal of the recorded information is maximized. The laser beam may be adjusted. Further, the optical path correction device 409 may be constituted by a liquid crystal element or the like.
[0103]
In the multilayer recording medium used in the recording / reproducing apparatus 50 according to the fourth embodiment, when the position on the multilayer recording medium for switching the recording layer to be accessed is predicted in advance, the position for switching the recording layer is the test recording. Even in an area not used for the purpose, it is preferable to set the track pitch at the position where the recording layer is switched to be wider than the normal track pitch in the information recording area.
[0104]
In the fourth embodiment, the optical head 401 is moved to a predetermined radial position so that the optical head is arranged in a region where the track pitch of the recording medium 301 is wide. However, the radius of the region where the track pitch is wide is shown. Information indicating the position is recorded on the recording medium 301, information indicating the radial position of the area with a wide track pitch is read out at startup, and stored in the controller 111, and the information indicating the radial position of the area with a wide track pitch is stored. Based on this, the optical head 401 may be moved.
[0105]
(Embodiment 5)
Embodiment 5 relates to a recording / reproducing method using an optical recording medium according to the present invention. FIG. 9 is a block diagram showing an example of a recording / reproducing apparatus 60 using the optical recording medium 101 according to the present invention, and shows a state in which the optical recording medium 101 described above with reference to FIGS. 1A and 1B is mounted. ing.
[0106]
The recording / reproducing apparatus 60 includes a spindle motor 10 that rotates by mounting an optical recording medium 101, a controller 11, a modulator 12 that modulates data to be recorded on the optical recording medium 101 into a recording signal, A laser driving circuit 13 for driving a semiconductor laser in accordance with a recording signal, and an optical head having the semiconductor laser, condensing the laser beam on the optical recording medium 101, recording information, and obtaining a reproduction signal from the reflected light 14, a summing amplifier 15 that outputs a sum signal 15S of electrical signals output from the light receiving units 21 and 22 provided in the photodetector 20 of the optical head 14, and a binarization circuit that binarizes the sum signal 15S 17, a differential amplifier 16 that outputs a difference signal 16S of electrical signals output from the light receiving units 21 and 22, and a binarized sum signal 17S. The data demodulating circuit 18 that demodulates the data recorded on the track formed on the optical recording medium 101 and the specific data recorded in the test recording area arranged on the optical recording medium 101 are tested. A signal quality determiner 19 for determining the quality of the reproduced signal, a recording condition storage 21 for storing the optimum recording condition obtained by the learning operation, and a pulse condition setting unit 22 for controlling the laser pulse in accordance with the recording condition. And a tracking control circuit 19 for controlling the optical head 14 so that the laser beam appropriately scans the track formed on the optical recording medium 101 based on the difference signal 16S.
[0107]
FIG. 10 is a flowchart showing a recording / reproducing method using the recording / reproducing apparatus 60 shown in FIG.
[0108]
First, the recording / reproducing apparatus 60 is activated (step S501). Specifically, after the optical recording medium 101 is mounted on the spindle motor 10 and rotated, the optical recording medium 101 is irradiated with laser light for information reproduction by the optical head 14, and the optical recording medium 101 is The lead-in area 103 placed in the lead-in area 103 is accessed, and the identification information of the optical recording medium 101 recorded in the lead-in area 103 is read out. Reading of the identification information or the like is a signal obtained by binarizing the sum signal 15S obtained from the reflected light from the optical recording medium 101 by the binarization circuit 17 set to a predetermined binarization slice level. 17S is demodulated by the data demodulator 18 and taken into the controller 11.
[0109]
Next, a learning operation for obtaining optimum recording / reproduction conditions is performed (step S502). This learning operation is performed according to the following procedure. First, the optical head 14 is moved to form a track having the same depth and width as the information recording area 105 with a track pitch wider than the track pitch of the track formed in the information recording area 105 for recording information. The test recording area 104 is accessed. The controller 11 sets the pulse condition setting unit 22 to a predetermined specific condition or a condition specified by the identification information of the optical recording medium 101. Next, the specific data output from the controller 11 is modulated into a laser drive signal by the modulator 12, and the laser drive circuit 13 drives the semiconductor laser provided in the optical head 14 in accordance with the laser drive signal. The light emitted from the semiconductor laser is condensed on the optical recording medium 101 by the optical head 14, and a test signal is recorded in the test recording area 104 arranged on the optical recording medium 101.
[0110]
In this way, a jitter value of the signal obtained by binarizing the reproduction signal obtained by reproducing the test signal recorded in the test recording area 104 by the binarization circuit 17 (a fluctuation amount of the reproduced signal position with respect to the reference clock) is obtained. The signal quality is determined by the signal quality determiner 39 and compared with a predetermined determination criterion to determine the signal quality. If the jitter value satisfies the criterion, the learning operation is terminated. When the jitter value does not satisfy the determination criterion, the pulse condition is sequentially changed to determine the test recording of the specific data and the signal quality of the test signal recorded by the test recording. By repeating this operation until the jitter value satisfies the criterion, the optimum recording condition is obtained.
[0111]
Next, the optimum recording condition obtained by the learning operation in step S502 is stored in the recording / reproducing condition storage 21 (step S503), the pulse condition is set based on the optimum recording condition, and the information is recorded in the information recording area. 105 (step S504).
[0112]
In this way, by performing test recording in an area where the track pitch is set wider than the information recording area for recording information, a larger tracking error signal can be obtained during test recording than when information is recorded.
[0113]
Therefore, in the course of the learning operation for obtaining the optimum recording condition, stable tracking control can be performed even if test recording is performed under an inappropriate recording condition in which the amorphous region becomes extremely wide. Therefore, it is not necessary to set the track pitch of the information track formed in the information recording area recorded only under the optimum recording condition more than necessary. That is, it is possible to narrow the track pitch in the information recording area 105 arranged on the optical recording medium 101 and increase the recording capacity.
[0114]
The optimum recording conditions obtained by the recording / reproducing apparatus 60 when the optical recording medium 101 is used for the first time are recorded on the optical recording medium 101, and the recording medium 101 is used when the recording medium 101 is used again. The optimum recording conditions recorded in the above may be read out and stored in the recording / reproducing condition storage 21 for use. In this case, the learning operation for obtaining the optimum recording / reproducing condition every time the recording medium 101 is loaded into the recording / reproducing apparatus 60 and activated can be omitted or shortened.
[0115]
(Embodiment 6)
In the sixth embodiment, a method for manufacturing the optical information recording medium 101 described above with reference to FIGS. 1A, 1B, and 2 in the first embodiment will be described. FIG. 11A to FIG. 11D are cross-sectional views for explaining a procedure for creating an optical disc master in the method of manufacturing the optical information recording medium 101 according to the sixth embodiment.
[0116]
Referring to FIG. 11A, first, a disk-shaped glass substrate 1 on which a positive photoresist is uniformly applied is prepared.
[0117]
11B, the track pitch Tp1 of the test recording region 104 is made larger than the track pitch Tp2 of the information recording region 105 by a laser recording device (LBR) 202 using a deep ultraviolet laser having a wavelength of 248 nanometers (nm). The pregroove pattern is exposed so that it becomes wider.
[0118]
The laser recording device 202 is equipped with an encoder for detecting the amount of movement of the glass substrate 1 along the radial direction. The laser recording device 202 can calculate the movement amount based on the number of pulses detected by the encoder and a predetermined pulse interval. The laser recording device 202 moves based on a predetermined pulse interval and the number of pulses detected by the encoder in accordance with the track pitch Tp1 of the test recording area 104 and the track pitch Tp2 of the information recording area 105.
[0119]
The laser recording apparatus 202 exposes the pre-groove pattern according to a set value of a pulse corresponding to the track pitch Tp1 of the test recording area 104. Then, when moving to the information recording area 105, the pre-groove pattern is exposed by switching to a pulse setting value corresponding to the track pitch Tp2 of the information recording area 105.
[0120]
As a result, a pre-groove pattern having a track pitch Tp2 is formed in the information recording area 105, and a pre-groove pattern having a track pitch Tp1 wider than the track pitch Tp2 is formed in the test recording area 104.
[0121]
11C, a latent image 203 having a desired groove pattern is formed on the glass substrate 201 in this manner. Next, referring to FIG. 11D, while the glass substrate 1 is rotated, a developing solution is discharged from the developing nozzle 204 to develop the latent image 203 formed on the glass substrate 201.
[0122]
12A to 12F are cross-sectional views for explaining a step of creating a stamper in the method of manufacturing the optical information recording medium 101 according to Embodiment 6.
[0123]
Referring to FIG. 12A, when the glass substrate 1 on which the latent image 203 has been developed is dried, a master disc 206 on which a desired groove pattern 205 is formed is created. Then, referring to FIG. 12B, a nickel film 401 is formed on the disk master 206 so as to cover the groove pattern 205. Next, referring to FIG. 12C, a nickel thin plate 402 is formed by performing nickel plating using the nickel film 401 as an electrode. Referring to FIG. 12D, the nickel thin plate 402 is peeled from the disc master 206 and the resist is removed to remove the resist, thereby transferring the desired groove pattern to a thickness of about 0.3 mm (mm). 403 is created.
[0124]
Then, referring to FIG. 12E, nickel plating is performed again on the father 403, the nickel plating is peeled off from the father 403, and a nickel thin plate having a thickness of about 0.3 mm to which a desired groove pattern formed on the father 403 is transferred ( Mother) 404 is created. Next, referring to FIG. 12F, after the back surface of the mother 404 is polished, a die (stamper) 405 in which a desired groove pattern is formed is formed by punching into a desired shape.
[0125]
13A to 13F are cross-sectional views for explaining a process for manufacturing the optical information recording medium 101 based on the stamper 405.
[0126]
Referring to FIG. 13A, a stamper 405 is attached to an injection molding machine (not shown), and injection molding is performed using polycarbonate as a material to produce a transparent substrate 1 having a thickness of approximately 1.1 mm onto which a desired groove pattern is transferred. Referring to FIG. 13B, a phase change recording layer 2 containing Ge—Sb—Te as a main component is laminated on the surface of the transparent substrate 1 to which a desired groove pattern has been transferred by a sputtering method.
[0127]
Next, referring to FIG. 13C, a polycarbonate sheet 503 having a thickness of about 90 micrometers (μm) is prepared. Then, an ultraviolet curable resin 504 is dropped onto the polycarbonate sheet 503 on the spin coater. Thereafter, the transparent substrate 1 is overlaid on the polycarbonate sheet 503 so that the surface on which the phase change recording layer 2 is formed faces the polycarbonate sheet 503.
[0128]
Referring to FIG. 13D, the spin coater is rotated to shake off the excess UV curable resin 504, and when the thickness of the UV curable resin 504 reaches about 10 μm, the spin coater stops rotating. Next, referring to FIG. 13E, the ultraviolet curable resin 504 is cured by irradiating the ultraviolet curable resin 504 with ultraviolet rays from the ultraviolet source 505. Referring to FIG. 13F, the ultraviolet curable resin 504 and the polycarbonate sheet 503 constitute the protective layer 3, and thus the optical information recording medium 101 is manufactured.
[0129]
14A to 14C are cross-sectional views for explaining a process of manufacturing the optical information recording medium 301 including the two recording layers 303 and 305 described in the third embodiment. Referring to FIG. 14A, first, the recording layer 305 is formed on the substrate 306 by a process similar to the process described above with reference to FIGS. 13A and 13B. Then, after polishing the back surface of a father substrate (not shown), a stamper punched into a desired shape is used to perform injection molding using a polycarbonate as a material, thereby creating a transfer substrate 601 on which a desired groove pattern is formed. To do. Next, an ultraviolet curable resin 504 is applied on the recording layer 305. Thereafter, the transfer substrate 601 is overlaid on the ultraviolet curable resin 504 so that the surface on which the desired groove pattern is formed faces the ultraviolet curable resin 504.
[0130]
Referring to FIG. 14B, the ultraviolet curable resin 504 is cured by irradiating the ultraviolet curable resin 504 with ultraviolet rays from the ultraviolet ray source 505 from the transfer substrate 601 side.
[0131]
Referring to FIG. 14C, after that, the transfer substrate 601 is peeled from the ultraviolet curable resin 504, and a groove pattern is formed on the ultraviolet curable resin 504. Then, a phase change recording layer 303 is formed by sputtering. The ultraviolet curable resin 504 constitutes the separation layer 304 described above with reference to FIG. Next, a protective layer 302 made of polycarbonate is formed by a process similar to that described above with reference to FIGS. 13C to 13F.
[0132]
【The invention's effect】
As described above, according to the present invention, a large-capacity optical information recording medium capable of reliable tracking control at the time of test recording, a recording / reproducing apparatus, a recording / reproducing method, and a method for manufacturing the optical information recording medium are provided. be able to.
[Brief description of the drawings]
1A is a perspective view showing an optical information recording medium according to Embodiment 1. FIG.
1B is a cross-sectional view of the optical information recording medium according to Embodiment 1. FIG.
FIG. 2 is an enlarged plan view for explaining the track pitch of tracks formed on the optical information recording medium according to the first embodiment.
3 is a perspective view showing an optical information recording medium according to Embodiment 2. FIG.
4 is an enlarged plan view for explaining the track pitch of tracks formed on the optical information recording medium according to Embodiment 2. FIG.
5 is an enlarged plan view of a main part of a track formed in a lead-in area of an optical information recording medium according to Embodiment 2. FIG.
6 is a cross-sectional view for explaining a configuration of an optical information recording medium according to Embodiment 3. FIG.
7 is a block diagram showing a configuration of a recording / reproducing apparatus according to Embodiment 4. FIG.
FIG. 8 is a block diagram showing a configuration of an optical head 401 provided in a recording / reproducing apparatus according to a fourth embodiment.
FIG. 9 is a block diagram showing a configuration of a recording / reproducing apparatus according to Embodiment 5;
FIG. 10 is a flowchart showing a procedure of a recording / reproducing method executed by the recording / reproducing apparatus according to the fifth embodiment.
FIG. 11A is a cross-sectional view for explaining a procedure for creating an optical disc master in the method for manufacturing an optical information recording medium according to Embodiment 6;
FIG. 11B is a cross-sectional view for explaining a procedure for creating an optical disc master in the method for manufacturing an optical information recording medium according to Embodiment 6;
FIG. 11C is a cross-sectional view for explaining a procedure for creating an optical disc master in the method for manufacturing an optical information recording medium according to Embodiment 6;
FIG. 11D is a cross-sectional view for explaining a process of creating an optical disc master in the method for manufacturing an optical information recording medium according to Embodiment 6;
12A is a cross-sectional view for explaining a step of creating a stamper in the method for manufacturing an optical information recording medium according to Embodiment 6. FIG.
12B is a cross-sectional view for explaining a step of creating a stamper in the method for manufacturing an optical information recording medium according to Embodiment 6. FIG.
12C is a cross-sectional view for explaining a step of creating a stamper in the method for manufacturing an optical information recording medium according to Embodiment 6. FIG.
12D is a cross-sectional view for explaining a step of creating a stamper in the method for manufacturing an optical information recording medium according to Embodiment 6. FIG.
12E is a cross-sectional view for explaining a step of creating a stamper in the method for manufacturing an optical information recording medium according to Embodiment 6. FIG.
12F is a cross-sectional view for explaining a step of creating a stamper in the method for manufacturing an optical information recording medium according to Embodiment 6. FIG.
FIG. 13A is a cross-sectional view for explaining a process for manufacturing an optical information recording medium based on a stamper in the method for manufacturing an optical information recording medium according to Embodiment 6;
13B is a cross-sectional view for explaining a process of manufacturing an optical information recording medium based on a stamper in the method of manufacturing an optical information recording medium according to Embodiment 6. FIG.
13C is a cross-sectional view for explaining a process of manufacturing an optical information recording medium based on a stamper in the method of manufacturing an optical information recording medium according to Embodiment 6. FIG.
13D is a cross-sectional view for explaining a process of manufacturing an optical information recording medium based on a stamper in the method of manufacturing an optical information recording medium according to Embodiment 6. FIG.
13E is a cross-sectional view for explaining a process of manufacturing an optical information recording medium based on a stamper in the method of manufacturing an optical information recording medium according to Embodiment 6. FIG.
13F is a cross-sectional view for explaining a process for manufacturing an optical information recording medium based on a stamper in the method for manufacturing an optical information recording medium according to Embodiment 6. FIG.
14A is a cross-sectional view for explaining a process of manufacturing another optical information recording medium based on a stamper in the method for manufacturing an optical information recording medium according to Embodiment 6. FIG.
14B is a cross-sectional view for explaining a process of manufacturing another optical information recording medium based on a stamper in the method for manufacturing an optical information recording medium according to Embodiment 6. FIG.
14C is a cross-sectional view for explaining a process of manufacturing another optical information recording medium based on a stamper in the method for manufacturing an optical information recording medium according to Embodiment 6. FIG.
FIG. 15 is a perspective view showing a conventional optical information recording medium.
FIG. 16 is an enlarged plan view for explaining the track pitch of tracks formed on a conventional optical information recording medium.
FIG. 17 is a block diagram showing a configuration of a conventional recording / reproducing apparatus.
FIG. 18 is a schematic diagram for explaining a tracking error signal reproduced from a conventional optical information recording medium.
[Explanation of symbols]
1 Substrate
2 Recording layer
3 Protective layer
104 Test recording area
105 Information recording area
106 tracks

Claims (2)

A recording / reproducing apparatus for recording, reproducing or erasing information by irradiating a laser beam onto an optical information recording medium,
The optical information recording medium is
A substrate,
A first recording layer formed on the substrate for recording, reproducing or erasing information by irradiating a laser beam;
A separation layer formed on the first recording layer;
A second recording layer formed on the separation layer for recording, reproducing or erasing information by irradiating the laser beam,
On the surface of the substrate, at least a first test recording area for performing test recording and a first information recording area for recording the information are disposed,
In the first test recording area and the first information recording area arranged on the surface of the substrate, a first test recording track and a first information recording track arranged in a spiral shape or a concentric shape are formed, respectively. ,
On the surface of the separation layer, at least a second test recording area for performing test recording and a second information recording area for recording the information are disposed,
In the second test recording area and the second information recording area arranged on the surface of the separation layer, a second test recording track and a second information recording track arranged in a spiral shape or a concentric shape are formed, respectively. And
The track pitch of the first test recording track is wider than the track pitch of the first information recording track,
The track pitch of the second test recording track is wider than the track pitch of the second information recording track,
The recording / reproducing apparatus comprises:
Moving means for moving the optical head along a radial direction of the optical information recording medium;
A focus control means for focusing the laser beam on the test recording area of the target recording layer;
Tracking control means for tracking the test recording track after focusing the laser beam on the test recording area of the recording layer;
An aberration control means for minimizing the aberration of the laser beam after tracking the test recording track;
A recording / reproducing apparatus that performs tracking in an information recording area in a state in which the aberration of the laser beam is adjusted to a minimum. A recording / reproducing method for recording, reproducing or erasing information by irradiating a laser beam onto an optical information recording medium,
The optical information recording medium is
A substrate,
A first recording layer formed on the substrate for recording, reproducing or erasing information by irradiating a laser beam;
A separation layer formed on the first recording layer;
A second recording layer formed on the separation layer for recording, reproducing or erasing information by irradiating the laser beam,
On the surface of the substrate, at least a first test recording area for performing test recording and a first information recording area for recording the information are disposed,
In the first test recording area and the first information recording area arranged on the surface of the substrate, a first test recording track and a first information recording track arranged in a spiral shape or a concentric shape are formed, respectively. ,
On the surface of the separation layer, at least a second test recording area for performing test recording and a second information recording area for recording the information are disposed,
In the second test recording area and the second information recording area arranged on the surface of the separation layer, a second test recording track and a second information recording track arranged in a spiral shape or a concentric shape are formed, respectively. And
The track pitch of the first test recording track is wider than the track pitch of the first information recording track,
The track pitch of the second test recording track is wider than the track pitch of the second information recording track,
The recording / reproducing method includes:
Moving the optical head along a radial direction of the optical information recording medium;
Focusing the laser beam on the test recording area of the target recording layer;
Tracking the test recording track after focusing the laser beam on the test recording area of the recording layer;
And after tracking to the test recording track, the step of minimizing the aberration of the laser beam,
A recording / reproducing method, wherein tracking in an information recording area is performed in a state in which the aberration of the laser beam is adjusted to a minimum.

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