JP2006127562A - Optical recording medium and its recording and reproducing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical recording medium capable of recording user data with good signal quality in a wide range of information recording regions while suppressing an increase of the standby time unnecessary at the startup of a recording device according to the characteristics of the recording medium and its recording and reproducing method. <P>SOLUTION: The optical recording medium provided with a recording layer to be subjected to recording and reproducing of the information by irradiation with a laser beam on a substrate having information tracks consisting of spiral or concentric guide grooves for tracking the laser beam at the time of recording and reproducing is recorded with test recording region information indicating the position on the medium to be subjected to test recording for determining the irradiation conditions of the laser beam optimum for recording of the information. In use, the test recording region information is read out and whether learning of test recording conditions is performed only at the inner circumference or at both of the inner circumference and the outer communication is selected. The conditions for irradiation of the laser beam at the time of recording the user data are then determined based on the learning results in the selected test recording region. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an optical recording medium having a recording layer for recording and reproducing information by irradiation with a laser beam and the like, and a recording and reproducing method thereof.

  There is an optical recording medium as a large-capacity and high-density memory. Among them, as one of the erasable optical recording media that can rewrite information, it has a thin film that changes phase between an amorphous state and a crystalline state on a substrate as a recording layer. Some record and erase information.

  As a phase change material for the recording layer, an alloy film mainly containing Ge, Sb, Te, In, or the like, for example, a GeSbTe alloy is known. The recording layer is generally formed on the substrate by sputtering or spin coating. Information is recorded by forming a recording mark by partially amorphizing the recording layer. Information is erased by crystallizing the recording mark. Amorphization is performed by heating the recording layer to the melting point or higher and then rapidly cooling it. 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. Information reproduction is performed using the difference in reflectance between the amorphous mark and the crystal region.

  In general, spiral or concentric guide grooves (grooves) for tracking laser light during recording and reproduction are provided on the substrate in advance. 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 Blu-ray Disc (BD).

  As a method for recording information on a medium, marks having different lengths are formed by providing various spaces so that the length of the mark and the length of the space (that is, the edge positions of the front end and the rear end of the mark) can be reduced. There is a mark length recording system that carries information.

  In this mark length recording method, if the 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 and the front becomes narrower and the rear. The signal quality deteriorates due to the thick and distorted mark shape, the heat generated at the time of mark formation affects the formation of adjacent marks, and the edge position of the mark fluctuates.

  The optimum pulse condition greatly depends on the characteristics of the medium and the recording / reproducing apparatus. Therefore, at the time of recording, a learning operation for obtaining an optimum pulse condition is required each time a medium is loaded into the recording / reproducing apparatus and started. In this learning operation, test recording is performed while changing the pulse condition, and the result of measuring the quality of the reproduced signal is compared with each other to obtain the optimum pulse condition.

  An example of a conventional optical recording medium is shown in FIG. In FIG. 7, an optical recording medium 701 is provided with a recording layer on a transparent substrate having a thickness of 1.1 mm made of polycarbonate having a central hole 702 for mounting in a recording / reproducing apparatus at the center, and having a thickness of 0.1 mm. The protective layer is provided, and laser light is irradiated through the protective layer to record and reproduce information. The substrate is provided with an information track 708 for tracking laser light during recording and reproduction. The recording medium 701 records a read-only lead-in area 703 in which medium identification information and the like are recorded by embossed pits, a test recording area 704 for performing a learning operation for obtaining an optimum pulse condition, and user data. An information recording area 705 is provided. Normally, user data is recorded under the pulse conditions obtained in the test recording area 704, regardless of the recording radial position.

However, the recording characteristics may vary depending on the radial position of the recording medium. Therefore, a recording method for setting the intensity of the laser pulse at the time of recording at each radial position by performing a learning operation on both the inner and outer circumferences of the recording medium and interpolating from the result using linear approximation, etc. Has been proposed (see, for example, Patent Document 1).
Japanese Patent Laid-Open No. 9-282696

  When learning is performed not only on the inner periphery but also on the outer periphery of the recording medium, it is necessary to provide a test recording area outside the information recording area in order to maintain the recording capacity. That is, as compared with the case where the test recording area is provided only on the inner circumference, an area capable of recording / reproducing to the outer circumference side must be provided.

  However, the relationship between the radial position on the recording medium and the recording characteristics varies greatly depending on the recording medium. When the recording characteristics change gradually from the inner circumference to the outer circumference, or the recording characteristics are almost uniform from the inner circumference to the vicinity of the outer circumference. However, the recording characteristics may change suddenly at the outer peripheral edge.

  When the recording characteristics change gradually from the inner periphery to the outer periphery, it is effective to perform the learning operation at both the inner periphery and the outer periphery and determine the recording condition at each radial position based on the result. On the other hand, when the recording characteristics change abruptly at the outer peripheral edge, the learning result at the outer peripheral edge does not reflect the recording characteristics of the information recording area. It is preferable to determine the recording conditions based on this.

  Therefore, when the learning operation is performed on both the inner periphery and the outer periphery, there is a problem that an optimum recording condition cannot be obtained depending on the medium.

  In addition, there is little difference in recording characteristics depending on the radial position in the information recording area, and it is not necessary to perform the learning operation not only on the inner periphery but also on the outer periphery for media capable of recording high-quality information under the same recording conditions. There is a problem that the waiting time when starting the recording apparatus increases.

  The present invention solves the above-described conventional problems, and selects whether to learn the recording condition only on the inner circumference or to learn the recording condition on both the inner circumference and the outer circumference according to the characteristics of the recording medium. An object of the present invention is to provide an optical recording medium capable of recording user data with a good signal quality in a wide range of information recording area and a recording / reproducing method thereof, while suppressing an unnecessary increase in standby time when the recording apparatus is activated. And

  In order to achieve the above object, the optical recording medium of the present invention provides information by irradiating a laser beam on a substrate provided with an information track comprising spiral or concentric guide grooves for tracking the laser beam during recording and reproduction. Is an optical recording medium provided with a recording layer for recording and reproducing information, and records test recording area information indicating the position on the medium for performing test recording for obtaining the optimum laser light irradiation condition for information recording It is characterized by that.

  By reading out the test recording area information at the time of use, unnecessary learning is performed by selecting whether to learn the recording condition only on the inner circumference or to learn the recording condition on both the inner circumference and the outer circumference. It is possible to record and reproduce user data with good signal quality in a wide range of information recording areas while omitting the operation and suppressing an unnecessary increase in standby time when the recording apparatus is activated.

  The test recording area information may be recorded by wobbling the guide groove in the radial direction and modulating the spatial frequency thereof, or may be recorded by uneven prepits, or in the radial direction. It may be recorded in the form of a bar code that is a set of lines.

  Further, in addition to the test recording area information, the laser recording condition at the time of user data recording at each radial position on the medium is derived from the result of the test recording performed near the inner periphery and the result of the test recording performed near the outer periphery. An interpolation coefficient may be recorded.

  This makes it possible to more accurately derive the optimum laser beam irradiation conditions at each radial position during recording, and to record and reproduce user data with better signal quality in a wide range of information recording areas.

  The recording / reproducing method of the present invention is a recording / reproducing method for recording, reproducing, or erasing information by irradiating an optical recording medium with laser light, and the optimum laser light irradiation condition for information recording is set. Test recording area information indicating the position on the medium for performing test recording for recording is recorded on the optical recording medium, the test recording area information is read, and the area indicated by the test recording area information is read It is characterized in that test recording is performed, laser light irradiation conditions at the time of user data recording are determined based on the result, and information is recorded, reproduced or erased.

  By reading out the test recording area information at the time of use, unnecessary learning is performed by selecting whether to learn the recording condition only on the inner circumference or to learn the recording condition on both the inner circumference and the outer circumference. It is possible to record and reproduce user data with good signal quality in a wide range of information recording areas while omitting the operation and suppressing an unnecessary increase in standby time when the recording apparatus is activated.

  The test recording is performed by, for example, recording a specific signal while changing the intensity of laser light, reproducing the recorded signal, and measuring any one of the amplitude, modulation degree, jitter value, or error rate of the reproduced signal. Then, the quality of the reproduced signal is evaluated, and the optimum irradiation condition of the laser beam is determined.

  Further, in addition to the test recording area information, the laser recording condition at the time of user data recording at each radial position on the medium is derived from the result of the test recording performed near the inner periphery and the result of the test recording performed near the outer periphery. The interpolation coefficient may be recorded in advance on a recording medium.

  This makes it possible to more accurately derive the optimum laser beam irradiation conditions at each radial position during recording, and to record and reproduce user data with better signal quality in a wide range of information recording areas.

  According to the optical recording medium and the recording / reproducing method of the present invention, depending on the characteristics of the recording medium, whether to learn the recording condition only at the inner circumference or to learn the recording condition at both the inner circumference and the outer circumference. It is possible to record and reproduce user data with good signal quality in a wide range of information recording areas while selecting and suppressing an unnecessary increase in standby time when the recording apparatus is activated.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 shows an optical recording medium according to Embodiment 1 of the present invention. The recording medium in the present embodiment records and reproduces information by irradiating laser light with a wavelength of about 405 nm mainly focused by an objective lens having an NA of about 0.85.

  In FIG. 1, an optical recording medium 101 is provided with a recording layer on a transparent substrate having a diameter of 120 mm and a thickness of 1.1 mm made of polycarbonate having a central hole 102 having a diameter of 15 mm for mounting in a recording / reproducing apparatus. In this structure, a protective layer having a thickness of 0.1 mm is provided, and information is recorded and reproduced by irradiating a laser beam through the protective layer. The recording layer is made of a GeSbTe alloy or an organic dye, which is a phase change recording material, and forms recording marks by irradiating laser light.

  The recording medium 101 is a read-only lead-in area 103 provided at a radius of about 22 mm to 23 mm, and provided at a position of a radius of about 23 mm to 24 mm, which is an optimum pulse for recording information at the inner peripheral position. A first test recording area 104 for performing a learning operation for obtaining a condition, provided at a position of a radius of about 24 mm to 58 mm, an information recording area 105 for recording information, provided at a position of a radius of about 58 mm to 58.5 mm; A second test recording area 106 is provided for performing a learning operation for obtaining an optimum pulse condition for recording information at the outer peripheral position. The test recording areas 104 and 106 and the information recording area 105 are formed with grooves having a track pitch of about 0.32 μm and are provided with information tracks 107 for tracking laser light during recording and reproduction.

  In the lead-in area 103, grooves having a track pitch of about 0.35 μm are wobbled in the radial direction, and the spatial frequency is modulated, so that at least only the first test recording area 104 performs test recording, A medium information track 108 on which test recording area information indicating whether test recording is performed in both the first test recording area 104 and the second test recording area 106 is provided. For example, when the test recording area information is represented by 1-bit information α and test recording is performed only in the first test recording area 104, α = 0, and the first test recording area 104 and the second test recording area In the case where test recording is performed in both cases, α = 1.

  Further, in addition to the test recording area information α, the result of the test recording performed in the first test recording area 104 and the result of the test recording performed in the second test recording area 106 are used for each radial position in the information recording area 105. An interpolation coefficient β for deriving the laser light irradiation condition at the time of user data recording is recorded.

  For example, the interpolation coefficient β is represented by 2-bit information, the first bit represents the interpolation method, and the second bit represents the application start position of the interpolation method. Then, the laser pulse intensity Pn in the nth radial position range from the inner circumference when the radial position of the information recording area 105 is divided into 16 ranges is obtained in the first test recording area 104. It is obtained from the intensity P0 of the pulse and the intensity P1 of the laser pulse obtained in the second test recording area 106.

At this time, up to the radial position indicated by the second bit of β,
Pn = P0
Pn is obtained from the relational expression indicated by the first bit of β on the outer peripheral side.

For example, when the first bit of β is “0”, on the outer peripheral side than the radial position indicated by the second bit of β,
Pn = P1
And When the first bit of β is “1”, interpolation is performed by linear approximation on the outer peripheral side from the radial position indicated by the second bit of β, and when the second bit of β is “9”,
Pn = P0 + (P1-P0) x (n-9) / (16-9)
And

  FIG. 4 is a plan view of the main part showing the shape of the track in the lead-in area 103. In the figure, a laser beam 402 tracked on a track 401 is scanned in the direction of an arrow 403. Since the track 401 meanders in the radial direction and contains important information in its spatial frequency, information recording is performed for the purpose of reducing crosstalk with adjacent tracks and increasing the reliability of reproduced information. A track pitch larger than that of the area 105 is set. In addition, the information track 107 in the test recording areas 104 and 106 and the information recording area 105 is modulated at a constant frequency and wobbled in the radial direction to record address information, and recorded based on a signal obtained from this wobble. Used to control the rotation of the spindle motor of the playback device.

  With the above configuration, the optical recording medium of the present invention reads the test recording area information α and the interpolation coefficient β when in use, and learns recording conditions only on the inner circumference, or records on both the inner circumference and the outer circumference. Good signal quality in a wide range of information recording area while suppressing unnecessary increase in waiting time when starting the recording device by omitting unnecessary learning operation by selecting whether to learn conditions Thus, user data can be recorded and reproduced.

  The contents and the notation method of the test recording area information α and the interpolation coefficient β shown in the present embodiment are merely examples, and are not limited to this, and can be freely selected according to the characteristics of the recording medium and the design contents of the recording apparatus. Can be set to For example, α may indicate whether or not test recording can be performed on the outer periphery.

  Further, when the recording condition is not learned on the outer periphery, the interpolation coefficient β may be omitted, and the second test recording area 106 may not be provided.

  Further, the interpolation coefficient β may be a coefficient for calculating the laser light irradiation condition at the time of user data recording at each radial position in the information recording area 105 only from the result of the test recording performed on the inner circumference.

  Further, the test recording areas 104 and 106 are not provided as independent areas, but a part of the information recording area 105 can be used as needed.

  The recording of the test recording area information α and the interpolation coefficient β in the medium information track 108 may be performed by forming uneven prepits instead of meandering the grooves. Further, recording / reproduction conditions recommended by the manufacturer of the medium may be recorded in the lead-in area 104.

(Embodiment 2)
FIG. 2 shows an optical recording medium according to Embodiment 2 of the present invention. The optical recording medium in the present embodiment is a recording of test recording area information in the form of a bar code that is an aggregate of radial lines, and the optical recording medium in the first embodiment described with reference to FIG. It is the same structure except for a part.

  In FIG. 2, an optical recording medium 201 is provided with a recording layer on a transparent substrate having a diameter of 120 mm and a thickness of 1.1 mm made of polycarbonate having a central hole 202 having a diameter of 15 mm for mounting in a recording / reproducing apparatus. In this structure, a protective layer having a thickness of 0.1 mm is provided, and information is recorded and reproduced by irradiating a laser beam through the protective layer. The recording layer is made of a GeSbTe alloy or an organic dye, which is a phase change recording material, and forms recording marks by irradiating laser light.

  The recording medium 201 is provided at a position with a radius of about 21 mm to 22 mm, an identification information area 203 in which identification information of the recording medium is recorded, and a read-only lead-in area provided at a position with a radius of about 22 mm to 23 mm. 204, a radius of about 23 mm to 24 mm, a first test recording area 205 for performing a learning operation for obtaining an optimum pulse condition for recording information at the inner circumferential position, and a radius of about 24 mm to 58 mm An information recording area 206 is provided for recording information, and is provided at a radius of about 58 mm to 58.5 mm, and a second test recording for performing a learning operation for obtaining an optimal pulse condition for recording information at the outer peripheral position. An area 207 is included. The test recording areas 205 and 207 and the information recording area 206 are formed with grooves having a track pitch of about 0.32 μm and are provided with information tracks 208 for tracking laser light during recording and reproduction.

  In the identification information area 203, a test indicating whether at least test recording is performed only in the first test recording area 205 or whether test recording is performed in both the first test recording area 205 and the second test recording area 207. The recording area information α is recorded in a barcode shape that is a set of radial lines.

  Further, in addition to the test recording area information α, the result of the test recording performed in the first test recording area 205 and the result of the test recording performed in the second test recording area 207 are determined at each radial position of the information recording area 206. An interpolation coefficient β for deriving the laser light irradiation condition at the time of user data recording is recorded.

  The contents of the test recording area information α and the interpolation coefficient β are the same as those of the optical recording medium in the first embodiment, and detailed description thereof is omitted.

  In the lead-in area 204, grooves having a track pitch of about 0.35 μm meander (wobble) in the radial direction, the spatial frequency is modulated, and information for reproduction only is recorded. Further, the information track 208 in the test recording areas 205 and 207 and the information recording area 206 is modulated at a constant frequency and wobbled in the radial direction to record address information, and recorded based on a signal obtained from this wobble. Used to control the rotation of the spindle motor of the playback device.

  With the above configuration, the optical recording medium of the present invention reads the test recording area information α and the interpolation coefficient β when in use, and learns recording conditions only on the inner circumference, or records on both the inner circumference and the outer circumference. Good signal quality in a wide range of information recording area while suppressing unnecessary increase in waiting time when starting the recording device by omitting unnecessary learning operation by selecting whether to learn conditions Thus, user data can be recorded and reproduced.

  Note that the recording of the identification information area 203 can be performed by partially erasing, deforming, or changing the color of the recording film by, for example, laser light irradiation. Therefore, the present invention can be applied to the case where recording media having different characteristics are manufactured using a common substrate. Further, after evaluating the recording characteristics of the completed recording medium, it is possible to individually record the test recording area information and the interpolation coefficient based on the evaluation result.

  Further, when the recording condition is not learned on the outer periphery, the interpolation coefficient may be omitted or the second test recording area 207 may not be provided.

  Further, the interpolation coefficient β may be a coefficient for calculating the laser light irradiation condition at the time of user data recording at each radial position in the information recording area 206 only from the result of test recording performed on the inner circumference.

  Further, the test recording areas 205 and 207 are not provided as independent areas, but a part of the information recording area 206 can be used as needed.

  Further, in the identification information area 203, in addition to the test recording area information and the interpolation coefficient, copyright information, medium individual identification information, and the like may be recorded. In the identification information area 203 or the lead-in area 204, recording / reproducing conditions recommended by the manufacturer of the medium may be recorded.

(Embodiment 3)
FIG. 3A shows an optical recording medium according to Embodiment 3 of the present invention. The optical recording medium 301 in this embodiment has a single-sided two-layer structure including two recording layers 303 and 305, and the first recording layer 303 or the second recording layer 303 is irradiated with a laser beam 307 from the protective layer 302 side. By selectively focusing on the recording layer 305, information is recorded on and reproduced from the two recording layers from the same side. The recording layers 303 and 305 are separated from each other by a separation layer 304 having a thickness of about 0.03 mm. These layers 303, 304 and 305 have a substrate 306 having a diameter of 120 mm and a thickness of 1.1 mm and a thickness of 0.1 mm. It is sandwiched between a protective layer 302 of 07 mm.

  Details of the recording layer 305 are shown in FIG. As in the first embodiment shown in FIG. 1, the recording layer 305 is a read-only lead-in area 308 provided at a radius of about 22 mm to 23 mm and a radius of about 23 mm to 24 mm. A first test recording area 309 for performing a learning operation for obtaining an optimal pulse condition for recording information at a position, provided at a position of a radius of about 24 mm to 58 mm, and an information recording area 310 for recording information, a radius of about 58 mm And a second test recording area 311 for performing a learning operation for obtaining an optimum pulse condition for recording information at the outer peripheral position.

  The test recording areas 309 and 311 and the information recording area 310 are provided with information tracks 312 which are constituted by grooves having a track pitch of about 0.32 μm and track laser light during recording and reproduction.

  In the lead-in area 308, grooves having a track pitch of about 0.35 μm are wobbled in the radial direction, and the spatial frequency is modulated, so that at least only the first test recording area 309 performs test recording, A medium information track 313 in which test recording area information α indicating whether to perform test recording in both the first test recording area 309 and the second test recording area 311 is provided.

  Furthermore, in addition to the test recording area information α, the result of the test recording performed in the first test recording area 309 and the result of the test recording performed in the second test recording area 311 at each radial position of the information recording area 310. An interpolation coefficient β for deriving the laser light irradiation condition at the time of user data recording is recorded.

  The contents of the test recording area information α and the interpolation coefficient β are the same as those of the optical recording medium in the first embodiment, and detailed description thereof is omitted.

  The recording layer 303 has the same configuration as the recording layer 305 except that it does not include a medium information track.

  With the above configuration, the optical recording medium of the present invention reads the test recording area information α and the interpolation coefficient β when in use, and learns recording conditions only on the inner circumference, or records on both the inner circumference and the outer circumference. Good signal quality in a wide range of information recording area while suppressing unnecessary increase in waiting time when starting the recording device by omitting unnecessary learning operation by selecting whether to learn conditions Thus, user data can be recorded and reproduced.

  Also, in the case of a multi-layer recording medium having a plurality of recording layers as in this embodiment and recording / reproducing information on each recording layer from one side, test is performed at the test recording position and at both the inner and outer circumferences. When recording is performed, a method for deriving the irradiation condition of the laser beam at the time of user data recording at each radial position of the information recording area from the result can be designated for each recording layer. Therefore, a learning operation suitable for each recording layer can be performed on a multilayer recording medium having recording layers with different characteristics, such as mixing an erasable recording layer and a write-once recording layer, and only one recording layer is available. The effect of the present invention becomes more significant than in the case of.

  When the recording condition is not learned on the outer periphery, the interpolation coefficient β may be omitted, and the second test recording area 311 may not be provided.

  Further, the interpolation coefficient β may be a coefficient for calculating the laser light irradiation condition at the time of user data recording at each radial position in the information recording area 310 only from the result of the test recording performed on the inner periphery.

  Further, the test recording areas 309 and 311 are not provided as independent areas, but a part of the information recording area 310 can be used as needed.

  The recording of the test recording area information α and the interpolation coefficient β in the medium information track 313 may be performed by forming uneven prepits instead of meandering the grooves. Further, recording / reproduction conditions recommended by the manufacturer of the medium may be recorded in the lead-in area 308.

  The medium information track need only be provided in one of the recording layers, but may be provided in both recording layers. Further, the number of recording layers may be three or more.

  Further, as in the second embodiment shown in FIG. 2, the test recording area information may be recorded in a barcode shape that is an aggregate of radial lines.

  Specific numerical values such as 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 are the characteristics of the recording / reproducing apparatus used and the characteristics of the recording film It can be set appropriately according to

(Embodiment 4)
In the present embodiment, a recording / reproducing method will be described.

  FIG. 6 is a block diagram schematically showing an example of a recording / reproducing apparatus using the optical recording medium in the present invention, and shows a state in which the optical recording medium 101 shown in FIG. 1 is mounted. In the present embodiment, as an example, the test recording area information is represented by 1-bit information α, and α = 0 when the test recording is performed only in the first test recording area 104, and the first test recording area 104 In the case where test recording is performed in both the first test recording area 106 and the second test recording area 106, a case where α = 1 is described.

  The recording / reproducing apparatus shown in FIG. 6 includes a spindle motor 602 for mounting and rotating a recording medium, a controller 603, a modulator 604 for converting data to be recorded into a recording signal, and a laser driving circuit 605 for driving a semiconductor laser in accordance with the recording signal. , Having a semiconductor laser, condensing the laser beam on a medium, recording information, optical head 601 for obtaining a reproduction signal from reflected light, amplifying the reproduction signal, information reproduction signals 606S and 606P, focus error signal 606F, a preamplifier 606 that generates a tracking error signal 606T, a binarization circuit 617 that converts the information reproduction signal 606P into a binary signal, a reproduction dedicated information demodulation circuit 618 that demodulates the reproduction dedicated information from the binary signal, and information reproduction A binarization circuit 607 that converts the signal 606S into a binarized signal A data demodulating circuit 608 for demodulating data, a signal quality judging circuit 609 for judging the quality of a signal obtained by recording and reproducing specific data in a test recording area of the recording medium 101, and a recording condition obtained by a learning operation. Recording condition storage circuit 610 to perform, test recording area information storage circuit 611 to store test recording area information read from the recording medium 101, interpolation coefficient storage circuit 612 to store interpolation coefficients read from the recording medium 101, recording conditions and interpolation coefficients A pulse condition setting circuit 613 for controlling the laser pulse according to the above, a focus control circuit 614 for controlling the optical head 601 based on the focus error signal 606F so that the laser beam is focused on the target recording layer of the recording medium 101, and the laser beam Properly runs the track of the recording medium 101 Tracking control circuit 615 for controlling the optical head 601 based on the tracking error signal 606T so that, a moving means 616 for moving the optical head 601 in the radial direction of the recording medium 101.

  Here, the focus error signal 606F is generated by a general method called an astigmatism method. The tracking error signal 606T is generated by a general method called a push-pull method.

  FIG. 5 is a flowchart showing a recording / reproducing method using the recording / reproducing apparatus of FIG. 6, and will be described together with FIG.

  First, in S501, the controller 603 activates the recording / reproducing apparatus. Specifically, after rotating the recording medium 101 mounted on the spindle motor 602, the optical head 601 irradiates the recording medium 101 with laser light for information reproduction. Further, the focus control circuit 614 and the tracking control circuit 615 are driven, the laser beam is focused on the recording layer, the lead-in area 103 is accessed, and the laser beam is tracked on the medium information track 108. As a result, read-only information such as identification information of the recording medium 101, test recording area information α, and interpolation coefficient β stored in the lead-in area 103 is read.

  Here, the read-only information is read by binarizing the information reproduction signal 606P obtained from the reflected light from the recording medium 101 by the optical head 601 by the binarization circuit 617 and demodulating the binarized signal. This is performed by demodulating by the circuit 618 and taking in the controller 603.

  Next, in S502, the controller 603 stores the test recording area information α and the interpolation coefficient β in the test recording area information storage circuit 611 and the interpolation coefficient storage circuit 612, respectively.

  Next, in S503, a learning operation for obtaining an optimum recording condition is performed in the first test recording area 104 arranged on the inner peripheral side of the recording medium 101. The learning operation is performed according to the following procedure.

  First, the controller 603 moves the optical head 601 to access the test recording area 104. The controller 603 sets the pulse condition setting circuit 613 to a predetermined specific condition or a condition specified by identification information.

  Next, specific data (test recording data) for learning operation output from the controller 603 is converted into a laser drive signal by the modulator 604. The laser drive circuit 605 drives a semiconductor laser provided in the optical head 601 in accordance with a laser drive signal. The light emitted from the semiconductor laser by the optical head 601 is collected on the recording medium 101 and a test signal is recorded in the test recording area 104.

  The test-recorded data is reproduced by the preamplifier 606 and the binarization circuit 607. Further, the signal quality determination circuit 609 measures the jitter value of the reproduced signal (the amount of fluctuation of the reproduced signal position with respect to the reference clock), and compares it with a predetermined criterion to determine the signal quality. .

  When the jitter value satisfies the criterion, the learning result is sent to the controller 603, and the learning operation is terminated.

  When the jitter value does not satisfy the determination criterion, the controller 603 sequentially changes the pulse condition of the pulse condition setting circuit 613 to perform test recording of specific data and signal quality of the test recorded data. By repeating this operation until the jitter value satisfies the criterion, the optimum recording condition in the test recording area 104 is obtained.

  Next, in S504, the recording condition obtained by the controller 603 in S503 is stored in the recording condition storage circuit 610.

  Next, in S505, based on the test recording area information α, it is determined whether or not a learning operation for obtaining an optimal recording condition in the second test recording area 106 is performed. When α = 1, the process is subsequently executed in the order of S506, S507, S508, S509, and S510, and when α = 0, the process is subsequently executed in the order of S508, S509, and S510.

  In S506, the controller 603 performs a learning operation for obtaining an optimal recording condition in the second test recording area 106 arranged on the outer peripheral side of the recording medium 101 in the same procedure as in S503.

  In S507, the recording condition obtained by the controller 603 in S506 is stored in the recording condition storage circuit 610.

  In S508, the controller 603 responds to each radial position of the information recording area 105 based on the optimum recording condition in the first test recording area 104, the optimum recording condition in the second test recording area 106, and the interpolation coefficient β. Recording conditions for recording user data. This recording condition is determined by the following method, for example.

  The interpolation coefficient β is represented by 2-bit information, the first bit represents the interpolation method, and the second bit represents the application start position of the interpolation method. Then, the laser pulse intensity Pn in the nth radial position range from the inner circumference when the radial position of the information recording area 105 is divided into 16 ranges is obtained in the first test recording area 104. It is obtained from the intensity P0 of the pulse and the intensity P1 of the laser pulse obtained in the second test recording area 106.

At this time, up to the radial position indicated by the second bit of β,
Pn = P0
Pn is obtained from the relational expression indicated by the first bit of β on the outer peripheral side.

When the first bit of β is “0”, on the outer peripheral side than the radial position indicated by the second bit of β,
Pn = P1
And When the first bit of β is “1”, interpolation is performed by linear approximation on the outer peripheral side from the radial position indicated by the second bit of β, and when the second bit of β is “9”,
Pn = P0 + (P1-P0) x (n-9) / (16-9)
And

  In step S509, the recording condition for user data obtained by the controller 603 in step S508 is stored in the recording condition storage circuit 610.

  Next, in S510, the controller 603 sets a pulse condition suitable for the recording condition for user data in the pulse condition setting circuit 413, and records the user data in the information recording area.

  Here, the pulse condition includes the intensity, length, and generation timing of the laser pulse, and is set in accordance with the length and interval of the mark to be recorded.

  As described above, the test recording area information α and the interpolation coefficient β recorded on the medium are read, and whether the recording condition is learned only on the inner circumference or the recording condition is learned on both the inner circumference and the outer circumference. By selecting, it is possible to record / reproduce user data with good signal quality in a wide range of information recording areas while suppressing unnecessary increase in standby time by omitting unnecessary learning operations. .

  In this embodiment, in the learning operation, the test recorded data is reproduced, and the jitter value of the reproduced signal is measured to determine the pulse condition. However, the error rate of the data, the amplitude of the reproduced signal are determined. Alternatively, the pulse condition may be determined by measuring the modulation degree. Further, when measuring the amplitude or degree of modulation of the reproduction signal, it is preferable to use the information reproduction signal 606S that is not binarized.

  Further, learning in the second test recording area 106 may be simplified as compared with learning in the first test recording area 104. For example, in the first test recording area 104, a multi-level learning operation such as the intensity, length and generation timing of the laser pulse is performed, and in the second test recording area 106, the learning operation is performed only for the intensity of the laser pulse. Is also possible.

  The recording / reproducing method of the present invention can also be applied to the case where the recording medium to be recorded is a recording medium having a plurality of recording layers as described in the third embodiment.

  Further, the test recording area information α and the interpolation coefficient β may be recorded in a barcode shape that is a set of radial lines as in the recording medium in the second embodiment.

  In the first to fourth embodiments, the recording medium may be an erasable type capable of rewriting information, or may be a write-once type recording medium capable of recording only once.

  The recording medium and the recording / reproducing method according to the present invention select whether to learn the recording condition only on the inner circumference or to learn the recording condition on both the inner circumference and the outer circumference according to the characteristics of the recording medium, Information recording apparatus that has an effect of recording and reproducing user data with a good signal quality in a wide range of information recording area while suppressing an increase in unnecessary waiting time at the time of starting the recording apparatus, and requires a large recording capacity Etc. are useful.

1 is a perspective view showing an example of an optical recording medium in Embodiment 1 of the present invention. The perspective view which shows an example of the optical recording medium in Embodiment 2 of this invention Sectional drawing and perspective view which show an example of the optical recording medium in Embodiment 3 of this invention FIG. 2 is an enlarged plan view of a main part showing an example of an optical recording medium according to Embodiment 1 of the present invention. The flowchart which shows an example of the recording / reproducing method in Embodiment 4 of this invention The block diagram which shows the structure of one Embodiment of the recording / reproducing apparatus of this invention A perspective view showing a conventional optical recording medium

Explanation of symbols

101, 201, 301 Optical recording medium 103, 204, 308 Lead-in area 104, 106, 205, 207, 309, 311 Test recording area 105, 206, 310 Information recording area 107, 208, 312 Information track 108, 313 Medium Information track 203 Identification information area 601 Optical head 603 Controller 610 Recording condition storage circuit 611 Test recording area information storage circuit 612 Interpolation coefficient storage circuit 613 Pulse condition setting circuit

Claims (10)

An optical recording medium in which a recording layer for recording and reproducing information by irradiating a laser beam is provided on a substrate having an information track formed of a spiral or concentric guide groove for tracking a laser beam during recording and reproduction. An optical recording medium having recorded therein test recording area information indicating a position on a medium on which test recording is performed in order to obtain an optimum laser light irradiation condition for information recording. The test recording area information is code information indicating selection of whether to perform test recording only near the inner periphery of the medium or to perform test recording near both the inner periphery and the outer periphery of the medium. Item 5. The optical recording medium according to Item 1. It is characterized by recording an interpolation coefficient that guides the irradiation condition of laser light at the time of user data recording at each radial position on the medium from the result of test recording performed near the inner periphery and the result of test recording performed near the outer periphery. The optical recording medium according to claim 2. 2. The optical recording medium according to claim 1, wherein the test recording area information is recorded by wobbling the guide groove in a radial direction. The optical recording medium according to claim 1, wherein the test recording area information is recorded by uneven prepits. 2. The optical recording medium according to claim 1, wherein the test recording area information is recorded in a bar code shape that is a set of radial lines. A recording / reproducing method for recording, reproducing or erasing information by irradiating a laser beam on an optical recording medium, on a medium for performing test recording for obtaining an optimum laser beam irradiation condition for information recording Test recording area information indicating the position is recorded on the optical recording medium, the test recording area information is read, test recording is performed in the area indicated by the test recording area information, and based on the result A recording / reproducing method characterized in that a laser beam irradiation condition at the time of user data recording is determined, and information is recorded, reproduced or erased. In the test recording, a specific signal is recorded at least while changing the intensity of the laser beam, the recorded signal is reproduced, and the amplitude, modulation degree, jitter value or error rate of the reproduced signal is measured. 8. The recording / reproducing method according to claim 7, wherein the quality of the reproduced signal is evaluated to determine the irradiation condition of the laser beam at the time of user data recording. The test recording area information is recorded as code information indicating selection of whether to perform test recording only near the inner periphery of the medium or to perform test recording near both the inner periphery and the outer periphery of the medium, 8. The recording / reproducing method according to claim 7, wherein the recording area information is read and test recording is performed in an area indicated by the test recording area information. In addition to the test recording area information, the interpolation for deriving the laser light irradiation condition at the time of user data recording at each radial position on the medium from the result of the test recording performed near the inner periphery and the result of the test recording performed near the outer periphery The coefficient is recorded, the test recording area information and the interpolation coefficient are read out, test recording is performed in the area indicated by the test recording area information, and the user data recording time is recorded from the test recording result and the correction coefficient. 10. The recording / reproducing method according to claim 9, wherein the laser light irradiation condition is determined, and information is recorded, reproduced or erased.

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