JPWO2011125160A1 - Information recording medium, information recording apparatus and method, and information reproducing apparatus and method - Google Patents

Abstract

In a multilayer recording type information recording medium, high-accuracy tracking servo is performed while adopting the CLV method, and a specific type of processing such as high-precision tilt detection is performed while increasing the information recording density. The CLV-type information recording medium (11) includes a guide layer (12) in which tracks (TR) are formed in advance, and a plurality of recording layers (13) stacked on the guide layer. In the track, a plurality of guide regions (22) each having a physical structure for carrying guide information for guide are discretely and arranged in a radial direction at an arrangement interval equal to or less than a predetermined distance set in advance in the track direction. The plurality of adjacent tracks are arranged so as to be shifted between the plurality of tracks. In addition, a group of a plurality of track portions so that a specific type of pattern signal can be detected at least at the center track portion located near the center in the radial direction among the plurality of track portions adjacent to each other in the radial direction. A plurality of signal detection areas (23) each having a predetermined pattern (23a) are arranged.

Description

  The present invention relates to an information recording medium such as a multilayer type or multilayer recording type optical disc, a recording apparatus and method for recording information on the information recording medium, and an information reproducing apparatus and method for reproducing information from the information recording medium. Related to the field.

  In this type of information recording medium, a plurality of or many recording layers are formed on a single guide layer on which tracks are formed in advance, and recording and reproduction are performed on the recording layer using the guide layer. (For example, see Patent Documents 1 to 3).

  Specifically, at the time of recording and reproduction, a first light beam for tracking (for example, a guide light beam or a servo light beam made of a red laser as in the case of DVD) is irradiated and condensed on the guide layer through the recording layer. Is done. Thereby, tracking for each recording layer becomes possible. That is, the focus servo for the guide layer and the tracking servo using the track previously formed on the guide layer can be performed.

  In parallel with such a tracking operation, a second beam for information recording / reproduction having a fixed or known positional relationship with the first beam, such as using the same optical pickup or via the same objective lens ( For example, a main light beam composed of a blue laser as in the case of Blu-ray) is typically irradiated in a form concentrically superimposed on the first beam, and focused on one recording layer to be recorded or reproduced. The As a result, information can be recorded and reproduced on each recording layer. That is, focus servo and information writing or reading can be performed on each recording layer.

  In addition, recording and reproduction of this type of information recording medium can be performed on the optical pickup by a so-called “tilt correction” by a correction mechanism that corrects the disc tilt or simply tilt (typically, the tilt of the optical disc surface). It is executed while being applied. More generally, in addition to tilt correction, various processes such as disc eccentricity correction, disc surface tilt correction, optical system aberration correction, light beam phase difference correction and distortion correction, light absorption correction, and strategy setting, etc. Recording and reproduction are executed while the above is performed.

JP-A-4-301226 JP 2003-67939 A International Publication WO2009 / 037773

  However, in the technique disclosed in the patent document, the diameter of each beam on the disk is different between the first beam for irradiating the guide layer and the second beam for irradiating the recording layer. In this case, the tracking accuracy of the guide layer is controlled by the track pitch calculated from the first beam diameter having a relatively large diameter, and the tracking of the recording layer is performed based on the track pitch. For this reason, it becomes coarser than the tracking accuracy that can be calculated from the second beam diameter, which is relatively small, and the characteristics are deteriorated due to an increase in crosstalk or the like from an adjacent track due to high-density recording.

  Further, when high density recording is performed in which the track pitch of the guide layer is substantially equal to the track pitch of the recording layer, the first beam irradiates a plurality of track regions of the guide layer at a time and follows the target track. There is a technical problem that makes it extremely difficult.

  In particular, when a CLV (Constant Linear Velocity) method is employed, it is extremely difficult to increase the utilization efficiency on the disk surface and achieve high-density recording. In other words, when the CLV method is adopted in a multilayer type information recording medium, tracking servo is executed with high precision or high resolution capable of corresponding to the high density recording that is the original purpose of the multilayer type, tilt correction, etc. There is a technical problem that it is extremely difficult to practice the various processes. Also, the address configuration method of the guide layer is not disclosed.

  In particular, in the case of a multi-layer type optical disk and the like, since it is multi-layered, it is extremely important to appropriately perform a specific type of processing such as tilt correction on each recording layer, and it is further important for further increasing the density. It becomes important.

  The present invention has been made, for example, in view of the above-described problems, and enables high-accuracy tracking servo while adopting the CLV method, while increasing information recording density, for example, high-accuracy tilt detection, etc. Multi-layered information recording medium enabling execution of specific types of processing, recording apparatus and method for recording information on such information recording medium, and information reproducing apparatus and method for reproducing information from such information recording medium It is an issue to provide.

  In order to solve the above problems, an information recording medium of the present invention is a CLV-type information recording medium, and includes a guide layer in which tracks are formed in advance, and a plurality of recording layers laminated on the guide layer. In the track, (i) a plurality of guide regions each having a physical structure carrying guide information for guides are discretely arranged at an arrangement interval equal to or smaller than a predetermined distance set in advance in the track direction along the track. And a plurality of tracks adjacent to each other in the radial direction intersecting with the tracks, being shifted between the plurality of tracks, and (ii) a plurality of adjacent to each other in the radial direction intersecting with the tracks. A set of locations across the plurality of track portions so that a specific type of pattern signal can be detected at least in the center track portion located near the center in the radial direction of the track portions. A plurality of signal detection areas each having a fixed pattern are arranged.

  In order to solve the above problems, an information recording apparatus of the present invention is an information recording apparatus for recording data on the above-described information recording medium of the present invention, wherein the guide layer is irradiated with a first light beam for tracking. A light irradiating means capable of condensing and irradiating and condensing a second light beam for data recording onto one of the plurality of recording layers; and the guide layer Receiving the first light based on the irradiated and condensed first light beam from the first light beam, obtaining the carried guide information based on the received first light, and receiving the received first light. Each of the plurality of signal detection areas indicated by the acquired guide information functioning as mark information indicating that a corresponding one of the plurality of signal detection areas will be provided later. And An acquisition / detection means for detecting a tone signal, a tracking servo means for controlling the light irradiation means so as to apply a tracking servo in a predetermined band to the track based on the acquired guide information, and the detected Processing means for performing a specific type of processing on the light irradiation means based on the pattern signal, and the second light on the one recording layer in a state where the processing is performed when the tracking servo is applied. Data recording control means for controlling the light irradiation means so as to record the data by irradiating and condensing the beam.

  In order to solve the above-described problem, the information recording method of the present invention can irradiate and focus the tracking layer with the first light beam for tracking on the information recording medium of the present invention described above. An information recording method for recording data using a light irradiating means capable of irradiating and condensing a second light beam for data recording onto one recording layer among a plurality of recording layers, Receiving a first light based on the irradiated and condensed first light beam from the guide layer, obtaining the carried guide information based on the received first light, and receiving the received first light; Based on one light, the plurality of signal detection areas indicated by the acquired guide information functioning as mark information indicating that a corresponding one of the plurality of signal detection areas comes later At each An acquisition / detection step for detecting a pattern signal; a tracking servo step for controlling the light irradiation means to apply a tracking servo in a predetermined band to the track based on the acquired guide information; A processing step of performing a specific type of processing on the light irradiation means based on the pattern signal, and the second light on the one recording layer in a state where the processing is performed when the tracking servo is applied. A data recording control step of controlling the light irradiation means so as to record the data by irradiating and condensing the beam.

  In order to solve the above problems, an information reproducing apparatus of the present invention is an information reproducing apparatus for reproducing data from the above-described information recording medium of the present invention, and irradiates the guide layer with a first light beam for tracking. A light irradiating means capable of condensing and irradiating and condensing a second light beam for data reproduction to one of the plurality of recording layers; and the guide layer Receiving the first light based on the irradiated and condensed first light beam from the first light beam, obtaining the carried guide information based on the received first light, and receiving the received first light. Each of the plurality of signal detection areas indicated by the acquired guide information functioning as mark information indicating that a corresponding one of the plurality of signal detection areas will be provided later. Said An acquisition / detection means for detecting a turn signal; a tracking servo means for controlling the light irradiation means so as to apply a tracking servo in a predetermined band to the track based on the acquired guide information; and the detected A processing unit that performs a specific type of processing on the light irradiation unit based on a pattern signal; and the irradiation from the one recording layer in a state in which the processing is performed when the tracking servo is applied; Data acquisition means for receiving second light based on the condensed second light beam and acquiring the data based on the received second light.

  In order to solve the above-described problem, the information reproducing method of the present invention can irradiate and collect the first light beam for tracking on the guide layer from the above-described information recording medium of the present invention. An information reproducing method for reproducing data using a light irradiating means capable of irradiating and condensing a second light beam for data reproduction to one recording layer among a plurality of recording layers, Receiving a first light based on the irradiated and condensed first light beam from the guide layer, obtaining the carried guide information based on the received first light, and receiving the received first light; Based on one light, the plurality of signal detection areas indicated by the acquired guide information functioning as mark information indicating that a corresponding one of the plurality of signal detection areas comes later Each An acquisition / detection step for detecting the pattern signal, a tracking servo step for controlling the light irradiation means to apply a tracking servo in a predetermined band to the track based on the acquired guide information, and the detected A processing step of performing a specific type of processing on the light irradiation means based on the pattern signal, and the irradiation from the one recording layer in a state where the processing is performed when the tracking servo is applied. And a data acquisition step of receiving second light based on the condensed second light beam and acquiring the data based on the received second light.

  Such an operation and gain of the present invention will be clarified from the embodiments described below.

It is a typical perspective view which shows the basic composition of the information recording medium based on the Example of this invention. FIG. 3 is a schematic partial enlarged cross-sectional view showing an objective lens for focusing a first beam for guide and a second beam for recording (or reproduction) and an information recording medium in an example. It is a partially expanded perspective view of the guide layer in an Example. It is a partially expanded perspective view of the same meaning as FIG. 3 in the comparative example of an Example. FIG. 3 is a partially enlarged perspective view having the same concept as in FIG. 2 when an example of prepits is provided in the embodiment. FIG. 3 is a partially enlarged perspective view having the same concept as in FIG. 2 in the case where another example of the prepit in the embodiment is included. It is a typical partial enlarged plan view showing a track for low density recording. It is a typical partial enlarged plan view showing a track for high density recording. It is a conceptual diagram which shows the structure of the track | truck with which three area | regions are arrange | positioned and the structure in each of three area | regions provided in a guide layer in an Example. It is a typical top view which shows the structure of the track | truck with which three area | regions of the guide layer in an Example are arrange | positioned. It is a conceptual diagram which shows the structural example of the data preformatted so that a tracking signal and a tilt signal can be generated in a guide area in an Example. It is a conceptual diagram which shows one structural example of the various data recorded in each slot in an Example. It is a conceptual diagram which shows the other structural example of the various data recorded in each slot in an Example. It is a conceptual diagram which shows the structural example of the various data recorded in each slot in an Example. It is a block diagram of the information recording / reproducing apparatus in an Example. FIG. 16 is a block diagram illustrating a configuration of a tilt detection system included in the information recording / reproducing apparatus of FIG. 15. FIG. 17 is a timing chart of various signals used in the tilt detection system of FIG. 16. 5 is a flowchart of an information recording / reproducing method in the embodiment. 6 is a flowchart of a recording method for a new disk in the embodiment. 5 is a flowchart illustrating an example of a playback method for a new disc in the embodiment. It is a conceptual diagram which shows the structural example (when the presence information of "B Slot" is superimposed on "A Slot") of the various data recorded in each slot in an Example. It is a block diagram of the circuit part which performs tracking servo among the information recording / reproducing apparatuses of an Example. FIG. 23 is a characteristic diagram illustrating an operation of sampling a tracking error of a sampler included in the circuit portion of FIG. In an Example, it is a characteristic view which shows the phase rotation which prescribes | regulates the arrangement | positioning space | interval of the two guide area | regions which adjoin along a track | truck. In an Example, it is a characteristic view which shows the frequency characteristic of the gain in tracking servo which prescribes | regulates the arrangement | positioning space | interval of the two guide area | regions which adjoin each other along a track | truck. It is a typical enlarged plan view which shows the structure of the guide area | region in an Example. It is a typical expanded plan view which shows the structure in a guide area | region in another modification. It is a typical expanded plan view which shows the structure in a guide area | region in another modification. It is a typical expanded plan view which shows the structure in a guide area | region in another modification. It is a typical perspective view of the same meaning as FIG. 1 of the optical disk in another modification.

Hereinafter, as the best mode for carrying out the invention, embodiments according to a driving device will be described in order.
(Information recording medium)

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In order to solve the above problems, the information recording medium of the present embodiment is a CLV-type information recording medium, and includes a guide layer in which tracks are formed in advance, and a plurality of recording layers laminated on the guide layer. (I) a plurality of guide regions each having a physical structure carrying guide information for guides are discretely arranged at an arrangement interval equal to or less than a predetermined distance set in advance in the track direction along the track. And (ii) a plurality of adjacent to each other in the radial direction intersecting the track, and (ii) a plurality of adjacent to each other in the radial direction intersecting the track. A group of the plurality of track portions so that a specific type of pattern signal can be detected at least in the center track portion located near the center in the radial direction. A plurality of signal detection areas each having the predetermined pattern are arranged.

  According to the information recording medium of the present embodiment, typically, a plurality of recording layers stacked on or below the guide layer by using a track provided on the guide layer for guiding or tracking. Information can be optically recorded by a CLV (Constant Linear Velocity) method along the track. Furthermore, information can be optically reproduced by the CLV method from a desired recording layer that has been recorded, with or without using the track for guiding.

  Here, the “guide layer” is typically a position in the recording surface related to each recording layer (ie, a radial position along the recording surface) at least when recording or writing information to each recording layer. And a position in the track direction) means a layer for guiding or guiding a first light beam for guiding or tracking (hereinafter simply referred to as “first light beam”). The “guide layer” is typically a layer in which a track configured to generate a tracking error signal (or a wobble signal or a prepit signal as a source thereof) is physically created in advance.

  The “track” formed in the guide layer means a trajectory in which the first light beam is traced or followed at least during information recording, and typically, for example, wobbled, or in addition to or Instead, it is physically built in advance in the guide layer or on the guide layer as a groove track or land track in which pits are formed. It should be noted that the information track formed after recording in the recording layer is constructed in advance here in that it is constructed as an array or arrangement of recorded information pits on the recording surface where no track was originally present. It is clearly distinguished from the “track”.

  Information recording is typically performed at each position on the information track after recording in a desired recording layer corresponding to each position of the first light beam on the track in the guide layer guided in this manner. Information recording is performed using a second light beam for writing or information writing (hereinafter simply referred to as “second light beam”).

  Typically, only one guide layer is required for all the recording layers. However, a plurality of guide layers, for example, two layers may be provided, and each may be appropriately used or assigned a role. Absent. In any case, the guide layer and the plurality of recording layers are provided as separate layers.

  The plurality of recording layers, such as 16 layers, can be configured to record information independently of each other and to be reproducible. Each of the plurality of recording layers preferably has a structure as simple as possible, for example, a straight groove, a straight land, or a mirror surface in an unrecorded state. This is because it is preferable in manufacturing that alignment between a plurality of recording layers and alignment with the guide layer are hardly or practically unnecessary. The structure of the recording layer is such that the transmittance and reflectance of each recording layer are within a predetermined range so that the light beam can reach the recording layer or guide layer on the back side as viewed from the irradiation side of the light beam. It is configured to be able to record with various recording methods set to fit.

More specifically, at the time of information recording, for example, it is obtained when a first light beam (for example, a red laser that forms a light spot having a relatively large diameter) is focused on a track existing in the guide layer. From the reflected light, a tracking error signal (or a wobble signal as a source thereof and a pre-pit signal in addition thereto) can be detected. According to the tracking error signal, tracking or tracking servo can be executed as a kind of guide operation. With this tracking being performed or the tracking servo being closed, a second light beam (for example, a blue laser that forms a relatively small-diameter light spot on the desired recording layer on the upper layer or lower layer side of the track) ) Is collected, information is recorded. In other words, when recording information in a desired recording layer which is another layer in which no track or track exists in advance (for example, mirror state) with reference to the position of a track formed in advance in the guide layer In-plane positioning is performed. (Note that focusing is performed separately when condensing.)
Here, if the optical system for irradiating the first and second light beams in the optical pickup or the like is fixed, the positional relationship of the light spots formed by them is also fixed. For this reason, performing a guide operation such as a tracking servo on the position of the first light beam (ie, the position of the light spot on the track formed thereby) is formed by the second light beam (ie, formed thereby). The guide operation is also performed with reproducibility on the position of the light spot in the recording surface. In other words, it is possible to track or guide the second light beam in the recording surface where no track exists in advance by using the first light beam on the track that exists in advance.

  If such a recording method is adopted, the alignment in the direction along the recording surface between the tracks between the guide layer and each recording layer, or between the plurality of recording layers, which are laminated with each other, is performed. There is little or no practical need to do. This is extremely advantageous in manufacturing.

  On the other hand, when reproducing information, the track may be used for guiding as well, or when reproducing this information, the guide layer is changed by following the information already written on the recording layer. Reproduction can also be performed by performing a tracking operation on the recorded information track without using it for the guide (typically for tracking).

  In the track formed in the guide layer, a plurality of guide regions each having a physical structure carrying guide information are arranged. Here, the “guide information” is information for guiding or guiding or following the first light beam. Typically, the “guide information” is optically a tracking error signal (or a wobble signal that is a source thereof and an addition thereto). Information for generating a pre-pit signal). Furthermore, the guide information can be rephrased as “mark information” in the sense that it becomes a mark for positioning the tracking light beam.

  Alternatively, such guide information can also serve as “marking information” according to the present invention described in detail later.

  The physical structure carrying such guide information is typically wobble and prepit structures (ie, land prepits, groove prepits, etc.), wobbles, This is realized by an arrangement or a series of prepits on a partially cut-out structure, a surface (for example, a mirror surface) without a groove and a land. Here, the “physical structure” means a physically existing structure, unlike a logical structure or a conceptual or virtual structure constructed by simple data. The physical structure is already built on the guide when the information recording medium is completed.

  Here, as a result of research by the present inventor, for a specific purpose such as performing a guide operation such as tracking in a predetermined band, it is necessary to be able to detect guide information in any track. On the other hand, it has been found that a special device for detecting the guide information, such as a track in a conventional or existing optical disc, can be achieved without being continuously formed in the track direction. That is, the guide information arrangement interval (that is, the arrangement pitch) corresponding to the time interval at which the guide information is detected is smaller than the minimum distance necessary for enabling the guide operation (for example, the tracking servo has a predetermined bandwidth). As long as it is set to less than the maximum distance that can be operated with the above, it has been found that the above objective can be achieved even if such a special mechanism is not applied to the entire area along the track. . At the same time, as for a plurality of adjacent tracks, it is not necessary to arrange such special devices in each of a plurality of positions or regions aligned in the radial direction, that is, in a regular manner in a row in the radial direction. It has been found that the above object can be achieved without arranging (or aligning) special devices.

  Therefore, in the present invention, the plurality of guide regions have a predetermined distance or less than a predetermined distance in the track direction along the spiral or concentric track (in other words, the tangential direction of the track). These are arranged discretely as arrangement intervals (that is, arrangement pitch). Here, the “predetermined distance” is typically the longest distance at which the guide or the guide operation can function, which is a tracking or tracking operation in a predetermined band (for example, the tracking operation is stably executed in the predetermined band). This is a short distance with a slight margin (the longest distance at which the tracking signal can be generated continuously or continuously with a frequency of making it possible). The “predetermined band” means a band specific to a data format or data standard in which a tracking operation is performed, which is determined in relation to a band used at the time of information recording.

  For such a predetermined distance, a guide operation (typically, a tracking operation in a predetermined band) functions on a guide layer in a specific information recording medium in advance by experiment, experience, simulation, or the like. It may be set by obtaining the limit distance and determining an appropriate margin. If the guide areas are discretely arranged at an arrangement interval (that is, arrangement pitch) longer than a predetermined distance, for example, tracking is performed with a frequency that enables stable tracking servo in a predetermined band, for example. A stable guide operation cannot be executed, for example, an error signal cannot be generated.

  Note that “discretely” refers to other planes such as a mirror surface, a buffer region, and a region other than the guide region between the recording layers of each recording layer as viewed in plan on the recording surface. It means that the region is interposed.

  The plurality of guide regions are arranged so as to be shifted between the plurality of tracks in the radial direction (that is, the radial direction) intersecting the tracks over a plurality of adjacent tracks. Here, “across a plurality of tracks” includes two or more tracks adjacent to each other in a plan view on the recording surface of each recording layer and a region that occupies a gap between them. , Meaning across or across them. In addition, “shifted in a radial direction between a plurality of tracks” means that a plurality of tracks in the radial direction (that is, the radial direction) have the same phase (for example, an angle on the disk) or a position corresponding to the same phase (for example, , Or an angular position on the disk) or not on the same radius. At this time, the plurality of guide regions that are arranged relatively close to each other in the radial direction do not need to be completely separated (that is, with a gap between them). Typically, the information is recorded or reproduced. It is sufficient that the phase in the radial direction is shifted to such an extent that the tracking servo light beam in (1) does not simultaneously reach the plurality of guide regions (for example, over five tracks). Alternatively, it is sufficient that signals and information that can be read from the plurality of guide regions are shifted to some extent by the light beam so that they can be distinguished from each other.

  For this reason, even if the track density is increased until the spot of the light beam straddles two or more adjacent tracks or track portions (for example, up to 5 tracks), the guide region corresponds to the above. As long as the guide information is shifted as described above, the guide information is overlapped in both the track direction and the radial direction (or the signal information from other guide regions affects as noise), that is, the detected guide information. It is possible to avoid a situation in which the guide information cannot be detected due to the crosstalk. Thus, even if the track density is increased, guiding or tracking is possible, and the original function of generating a tracking signal, typically as a guide layer, is guaranteed.

  Therefore, while the track pitch is narrowed with respect to the diameter of the first light beam to such an extent that the first light beam is simultaneously irradiated to a plurality of adjacent tracks in the guide layer, for example, reflection caused by the first light beam. By sampling a push-pull signal obtained from light, etc., it is possible to stably and continuously generate a tracking error signal or a wobble signal as a source thereof and guide information such as a pre-pit signal in addition to this. Become. That is, a guide operation such as a stable tracking operation in a predetermined band can be executed. Alternatively, when control information (for example, servo mark or address information) is included in the guide information, it can be reliably read as information based on reflected light or the like caused by the first light beam. Become. That is, the preformat information can be acquired stably.

  This is particularly effective when the first light beam (for example, a red laser) has a larger beam diameter than that of the second light beam (for example, a blue laser), and a relatively small light spot of the second light beam is effectively used. This is extremely advantageous when the recording density in recording information on the recording layer is increased to the limit (that is, depending on the size). That is, when a narrow-pitch track corresponding to a narrow-pitch recording area that becomes a track after recording in the recording layer is previously built in the guide layer, the first light inevitably increased with respect to such a track. The light spot of the beam has the technical property that it is simultaneously irradiated over a plurality of tracks (for example, a large number of tracks such as 5 tracks). For this reason, it is necessary to perform a guide operation such as a tracking operation corresponding to a recording layer with a narrow pitch by using the first light beam that forms a relatively large light spot.

  Even when the diameter of the first light beam is smaller than that of the second light beam, or when the diameter of the light beam is larger than the track pitch, the diameter of the light beam is larger than the track pitch. As long as the guide operation is appropriately performed, the unique configuration in the present embodiment as described above has a corresponding effect.

  As described above, with respect to the guide track, the pitch (for example, in the recording layer) is maintained while maintaining a guide function such as enabling tracking servo in a predetermined band or reading preformat information. An information track constructed by recording and having an information track commensurate with the beam diameter of the second light beam has a narrow pitch (to the same extent as the narrow pitch) (i.e., narrower than inappropriate for the first light beam). Pitch).

  In addition, since the CLV method is adopted, the angular velocity increases toward the inner circumference side (in other words, the angular velocity decreases toward the outer circumference side). The arrangement relationship of the guide information recorded in advance is arbitrary according to the radial position. For example, as is possible with the CAV (Constant Angular Velocity) method, it is fundamentally impossible to arrange information having a specific length in a line in a radial direction over a plurality of tracks. Then, if no measures are taken in the CLV method, when the first light beam forms a light spot extending over a plurality of tracks, the track portion entering the light spot becomes arbitrary depending on the radial position. (In other words, any information of a specific length is shifted in the track direction according to the radial position), and the acquisition of the guide information has to be extremely unstable depending on the radial position.

  However, the guide regions are consciously or positively shifted between the plurality of tracks in the radial direction as described above. For this reason, regardless of the radial position (that is, near the inner periphery or the outer periphery), a predetermined band corresponding to the high-density track pitch and recording linear density for realizing high-density recording. The guide operation such as tracking servo can be executed stably. In other words, assuming that the CLV method is used, there is no problem even if the CLV method is used if a predetermined distance and a shifting method are defined in advance according to the radial position.

  Moreover, in the present embodiment, in particular, a plurality of signal detection regions are arranged on the track provided in the guide layer having such a guide function. Each of the plurality of signal detection regions has a set of predetermined patterns straddling a plurality of track portions adjacent to each other in the radial direction so that a specific type of pattern signal can be detected in the center track portion. Here, the “center track portion” is at least near the center in the radial direction, such as being located at the center, center, or center line in the radial direction among a plurality of track portions adjacent in the radial direction in each signal detection region. The part of the track that is located. For example, if the plurality of track portions are odd numbers such as 3, 5, 7,..., The center track portion is preferably the center track portion.

  On the other hand, the track portion other than the center track portion is intentionally excluded from the detection target of the pattern signal even when the center of one light spot by the first light beam is directly on the track portion. That is, some signal or noise resulting from the predetermined pattern may be detected in the track portion other than the center track portion, but such signal or noise is not detected as noise from the beginning, or is discarded as noise after detection. The

  The plurality of signal detection regions are typically discretely arranged in the track direction and discretely arranged in the radial direction. For this reason, even if the track density is increased until the spot of the light beam straddles two or more adjacent tracks or track portions (for example, up to 5 tracks, 7 tracks, etc.), the detected pattern signal A situation in which the pattern signal cannot be detected due to the crosstalk can be avoided.

  For example, a predetermined pattern is typically created in advance so that a tilt detection signal such as a tilt error signal can be generated as a pattern signal, or can be recorded at an arbitrary time after the start of use. For example, when a tilt occurs, a large signal change in the pattern signal can be obtained, which is extremely useful in practice.

  Specifically, for example, if the tilt is in the radial direction (that is, radial direction), a predetermined line-symmetric pattern with the center track as the center line is formed so as to have a surface spread in a direction across a plurality of tracks. In this case, it is possible to generate a tilt detection signal having excellent sensitivity with respect to the tilt in the radial direction. Alternatively, if the tilt is in the track direction (that is, the tangential direction), a predetermined line-symmetric pattern with a line segment orthogonal to the track as a center line has a surface spread in a direction across a plurality of tracks. If formed, it is possible to generate a tilt detection signal with excellent sensitivity to the tilt in the track direction. Alternatively, in the case of tilt in an oblique direction, a predetermined line-symmetric pattern with a line segment obliquely intersecting the track as a center line may be formed so as to have a surface spread in a direction across a plurality of tracks. Therefore, it is possible to generate a tilt detection signal having excellent sensitivity with respect to tilt in an oblique direction.

  In addition to the tilt detection signal for tilt correction, the eccentric signal for disc eccentricity correction, the tilt signal for disc surface tilt correction, the aberration signal for optical system aberration correction, and the phase difference for optical beam phase difference correction The predetermined pattern may be configured such that various signals such as a signal, a distortion signal for correcting distortion, a light absorption signal for correcting light absorption, and a strategy signal for setting a strategy are detected as pattern signals.

  The predetermined pattern is, for example, each part of a plurality of tracks in an annular (that is, a hollow type) or a solid (that is, a centering type) planar region in which the outer ring shape is a circle, a rectangle, or the like so as to straddle a plurality of tracks. In addition, a plurality of pits and a plurality of minute optical special portions are formed. In other words, the predetermined pattern is composed of a series or a set of a plurality of pits, a plurality of minute optical special portions, and the like.

  Here, as a result of research by the inventors of the present application, for example, a specific type of processing based on a pattern signal such as tilt correction based on a tilt detection signal can be executed. It has been found that even though it is necessary to be able to detect the signal, it is possible to achieve it without forming pattern signals such as tilt detection signals continuously on all tracks. It is rather rare for a particular type of processing to be carried out continuously on an equal basis. That is, depending on the frequency or period of time when a specific type of processing is performed such that the tilt detection signal is detected once every time the tilt correction is held at a constant value (in other words, the period during which the tilt servo is locked). If the pattern signal such as the tilt detection signal is detected, it has been found that the specific purpose can be achieved.

  Therefore, on the other hand, in the case of a plurality of adjacent tracks, if pattern signals are detected every two or more tracks, in practice, predetermined processing based on the pattern signals is executed completely or almost completely. Is possible. On the other hand, for the area along the track, if the pattern signal is detected at some interval or at any phase (for example, an angle on the disk), it is practically complete or almost complete. It is possible to carry out a predetermined process based on the pattern signal. In the end, for example, if a pattern signal is obtained intermittently at the center track portion representing each of a plurality of tracks such as every five or seven tracks, it is sufficient in practice. Further, the phase position (for example, the angular position on the disk) where the pattern signal is detected may be aligned or may not be aligned.

  Therefore, in the present embodiment, for the signal detection region, an opportunity that the center of the light spot of the first light beam is on the center track portion is captured as a pattern signal detection opportunity. The track portion other than the center track portion is intentionally excluded from the opportunity to detect the pattern signal even if the center of one light spot by the first light beam is on the track portion.

  This is particularly effective when the first light beam (for example, a red laser) has a larger beam diameter than that of the second light beam (for example, a blue laser), and a relatively small light spot of the second light beam is effectively used. This is extremely advantageous when the recording density in recording information on the recording layer is increased to the limit (that is, depending on the size). That is, when a narrow-pitch track corresponding to a narrow-pitch recording area that becomes a track after recording in the recording layer is previously built in the guide layer, the first light inevitably increased with respect to such a track. The light spot of the beam has a technical property that it is irradiated simultaneously over a plurality of tracks (for example, multiple tracks such as 5 tracks and 7 tracks).

  For this reason, it is very convenient to detect a set of predetermined patterns across a plurality of track portions adjacent in the radial direction by using the first light beam that forms a relatively large light spot. It can also be said that a large light spot with respect to the track pitch, which tends to detract from disadvantages, is effectively used.

  Even when the diameter of the first light beam is smaller than that of the second light beam, or when the diameter of the light beam is larger than the track pitch, the diameter of the light beam is larger than the track pitch. As long as a predetermined pattern is to be detected, the unique configuration of the present embodiment as described above has a corresponding effect.

  As described above, since a plurality of signal detection areas each having a predetermined pattern are arranged on the track, the degree of freedom in arrangement of a specific type of pattern signal such as a tilt detection signal is remarkably increased. In addition, since a plurality of signal detection areas can be arranged independently of each other, that is, discretely, the information recording medium as a whole can be arranged with flexibility. By providing a plurality of types of pattern signals corresponding to a plurality of specific types of processing, it is also possible to appropriately execute a plurality of types of processing.

  As a result, while adopting the CLV method, the track pitch and recording linear density (for example, linear recording density, pit pitch or information transfer speed (that is, recording linear density × movement speed)) that can be recorded or reproduced in the recording layer are Stable and efficient acquisition of pattern signals such as tilt detection signals in a guide layer separate from the recording layer while increasing to the extent that it can be said to be the “high density recording” that is the original purpose in a multilayer information recording medium For example, specific types of processing such as high-precision tilt detection and high-precision tilt correction can be performed.

<2>
In one aspect of the information recording medium of the present embodiment, guide information relating to at least one guide area disposed in front of the center track portion in the track direction among the plurality of guide areas is the plurality of signals. It is also configured to function as mark information indicating that a corresponding one of the detection areas will come later.

  According to this aspect, guide information functions as landmark information. That is, for each of the plurality of signal detection areas, a mark area carrying mark information indicating that a corresponding one of the plurality of signal detection areas comes after the center track portion in the track direction is arranged. ing. The mark information is, for example, information reproduced as the above-described guide information, or by a wobble signal or a prepit signal.

  Therefore, the pattern signal can be read easily and reliably based on the arrival of the mark information. In particular, with respect to the same phase position (for example, the same angular position on the disk), even at the phase position where the signal generation region exists, the center track portion arrives only at every fifth or seventh (for example, every other position) There is no opportunity to detect the pattern signal). In other words, in many cases, only the track portion other than the center track portion arrives, and the signal generation region does not arrive.

  Therefore, it becomes extremely advantageous to detect the arrival fact of the center track portion in the near future by detecting the mark information because the detection of the pattern signal and the like can be performed easily and stably. For example, after detection of the mark information, it is possible to start preparation for starting detection of a pattern signal and further to start preparation for starting a specific type of processing based on the pattern signal. For example, by predefining the phase relationship and interval between the pattern signal and the mark information, the sampling timing for detecting the predetermined pattern can be easily specified from the mark information. Alternatively, if the mark information has an address position where the pattern signal is recorded, the sampling timing at which the predetermined pattern should be detected can be easily specified.

  In this case, the plurality of signal detection regions are discretely arranged so as not to be adjacent to or overlap each other in the radial direction and the track direction, and the mark information is the plurality of signal points in the center track portion. May be arranged in front of each of the signal detection regions. “Before” includes both the meaning of “before” without intervening other regions, and “before” via a buffer region, a mirror surface region, and other regions.

<3>
In another aspect of the information recording medium of the present embodiment, the track is formed in a spiral shape from the inner periphery to the outer periphery or from the outer periphery to the inner periphery in the information recording medium, and the mark area is the track direction. It is arranged immediately before the center track portion in FIG. 5 and indicates that a corresponding one of the plurality of signal detection regions immediately follows.

  According to this aspect, at the time of recording or reproduction, it is first determined that the mark information is detected in the mark area, and then the pattern signal arrives without delay. For this reason, it becomes possible to prepare the detection of the pattern signal in advance, and the pattern signal can be detected stably and reliably. Furthermore, according to the detection of the mark information, it is possible to prepare for execution of a specific type of processing based on the detected pattern signal, and the specific type of processing can be executed stably and reliably.

  Note that “immediately before” means before without any other region in between, and without any region other than the buffer region and the specular region in between (that is, only through the buffer region and the specular region). And) both meanings before.

  Alternatively, the track is formed in a spiral shape from the inner periphery to the outer periphery or from the outer periphery to the inner periphery in the information recording medium, and the mark information should sample the corresponding one that comes after (i) The timing or (ii) the corresponding one coming later may be indicated by indicating the address position from the inner circumference to the outer circumference or from the outer circumference to the inner circumference along the track direction. Good.

  On the other hand, the physical structure may carry address information indicating address positions from the inner periphery to the outer periphery or from the outer periphery to the inner periphery along the track direction as the guide information for the guide.

  With this configuration, the guide layer exhibits not only one guide function, for example, tracking by generation of a tracking error signal, but also a guide function by providing address information instead of or in addition to this. If address information can be acquired from a track formed in advance in the guide layer, the operation of recording information on the recording layer while being guided by the track can be facilitated, and the reliability and stability of the recording operation can be improved.

<4>
In another aspect of the information recording medium of the present embodiment, the physical structure includes the length in the track direction of the guide information and the length in the track direction of the minimum structural unit of data recorded in each of the plurality of recording layers. And the predetermined pattern has a length in the track direction of the minimum structural unit of the pattern signal, and a length in the track direction of the minimum structural unit. Is defined to be a predetermined integer ratio.

  According to this aspect, the length of the guide information in the guide layer in the track direction and the minimum structural unit (in other words, the format of the data (eg, user data, content data)) to be recorded in each recording layer The length of the structural unit) in the track direction is a predetermined integer ratio. Here, the “minimum structural unit” means a structural unit conforming to the data format, such as an error correction unit such as an ECC (Error Correction Code) block or an ADIP (Address In Pre-groove) unit, Typically, the unit is handled when a predetermined type of processing is performed during information recording or information reproduction.

  For this reason, the occurrence frequency of guide information such as a tracking error signal and the period of recording information on the recording layer at the recording surface position corresponding to the track are constant regardless of the radial position or the track position. The relationship can be maintained. In particular, since the CLV method is used, a stable guide operation can be performed at an arbitrary radial position even though the angular velocity changes depending on the radial position.

  Moreover, the length in the track direction of the minimum structural unit of the pattern signal in the guide layer and the length in the track direction of the minimum structural unit of data (for example, user data, content data) to be recorded in each recording layer Is a predetermined integer ratio.

  For this reason, the occurrence frequency of the pattern signal such as the tilt detection signal and the period of recording data on the recording layer at the recording surface position corresponding to the track are constant regardless of the radial position or the track position. The relationship can be maintained. In particular, when the CLV method is employed, it is possible to execute a specific type of stable process based on the detected pattern signal at an arbitrary radial position, even though the angular velocity changes depending on the radial position.

<5>
In another aspect of the information recording medium of the present embodiment, the plurality of guide regions are each configured as slots having the same length in the track direction, and the guide information is the plurality of tracks in the radial direction. The slots are arranged in the slots so as not to be adjacent to each other.

  According to this aspect, the plurality of guide regions are one in a plurality of slots that are not adjacent to each other in the track direction and are not adjacent to each other across the plurality of tracks in the radial direction. It is arranged one by one.

  Here, the “slot” is a logical section or section obtained by dividing a track in the track direction, or a physical section or section. The slots are typically arranged continuously without gaps in the track direction and arranged without gaps or adjacent to each other in the radial direction. However, the slots may be arranged with a slight gap in at least one of the track direction and the radial direction. In other words, a track is constructed from an arrangement or a series of slots in a plurality of slots that are preliminarily arranged in the track direction in the guide layer.

  The guide areas are not adjacent to each other in the track direction and are arranged one by one in a plurality of slots that are not adjacent to each other across a plurality of tracks in the radial direction, so that they can be detected from a plurality of guide areas. It is possible to reliably reduce or eliminate crosstalk between various guide information. In addition, in the guide layer, grooves, lands, pre-pits, etc. need only be created in the slot where the guide area is arranged, and it is not necessary to create these continuously throughout the track. In addition, the presence or absence of the slot (for example, the difference between the slot and the mirror surface) is easily and clearly distinguished physically, so that it is easy to detect, so that the guide information can be easily read and stably executed. This is very advantageous in practice.

  On the other hand, for the plurality of slots in the recording layer, unlike the guide layer, individual recording for recording content data, user data, etc. in all the continuous slots in both the track direction and the radial direction. An area may be placed. Since any slot in the recording layer can correspond to the slot in which the guide area in the guide layer is arranged, tracking servo in a predetermined band can be executed indirectly on the recording layer. In other words, with respect to the recording layer, information can be recorded in all slots at a high density up to the readable limit by the light spot formed by the second light beam.

  In addition, since the plurality of slots have the same length, the guide information can be read very easily and stably. At the same time, it is very easy to associate the guide information with the data to be recorded in the recording layer and the recorded data.

  In this case, the plurality of slots may have the same length in the track direction and may be arranged without a gap in the track direction. With this configuration, slots may be arranged in the guide layer and the recording layer, and in which slot of the guide layer may be disposed, and in which slot the guide area may not be disposed. Or such an arrangement rule can be determined relatively easily.

<6>
In this aspect, each of the plurality of signal detection regions is configured as another slot having the same length as the slot, and the predetermined pattern is not adjacent to each other between the plurality of tracks in the radial direction and The plurality of guide regions may be arranged in each of the slots so as not to overlap each other.

  With this configuration, the plurality of signal detection regions are not adjacent to each other in the track direction and are not adjacent to each other across the plurality of tracks in the radial direction, like the guide information. One is arranged in each of the plurality of slots.

  The plurality of signal detection regions are arranged one by one in a plurality of slots that are not adjacent to each other in the track direction and are not adjacent to each other in the radial direction across the plurality of tracks. It is possible to reliably reduce or eliminate crosstalk between pattern signals that can be detected from the detection region.

<7>
In this case, the physical structure further includes a length in the track direction of the slot and a length in the track direction of a structural unit of a data format to be recorded in each of the plurality of recording layers. The guide information is carried so as to be a ratio, and the predetermined pattern is a length of the other slot in the track direction and a unit of a format unit of data to be recorded in the plurality of recording layers, respectively. The length in the track direction may be configured to have a predetermined integer ratio.

  With this configuration, the length in the track direction of the slot in the guide layer and the length in the track direction of the format unit of data (for example, user data, content data, etc.) to be recorded in each recording layer Is a predetermined integer ratio. Here, “format unit” means a unit conforming to the data format, such as an error correction unit such as an ECC block or ADIP unit, and is typically used for information recording or information reproduction. Sometimes it becomes a unit that is handled when performing a predetermined type of processing.

  In addition, the length in the track direction of the other slots in which the signal detection areas are arranged and the length in the track direction of the structural unit of the data format to be recorded in each recording layer are a predetermined integer ratio. Become.

  For this reason, the generation frequency of guide information such as tracking error signals and the generation frequency of pattern signals such as tilt detection signals and the period of recording information on the recording layer at the recording surface position corresponding to the track are shifted to the radial position. It is possible to maintain a certain relationship without depending on the track position. In particular, because of the CLV method, a stable guide operation can be executed at an arbitrary radial position and a specific type of stable process is executed based on the detected pattern signal, even though the angular velocity changes depending on the radial position. It becomes possible. In addition, for this purpose, the length of the slot in the track direction may be defined in advance according to the length of the structural unit of the data format.

<8>
In another aspect of the information recording medium of the present embodiment, the plurality of guide areas and the plurality of signal detection areas are mixedly arranged with mutually different arrangement rules.

  According to this aspect, at the time of recording, the guide information is read according to the predetermined rule corresponding to the guide region arrangement rule. Then, it becomes difficult to read the pattern signal from the signal detection area arranged according to another arrangement rule. Conversely, at the time of recording or reproduction, the pattern signal is read according to a predetermined rule corresponding to the arrangement rule of the signal detection area. Then, it becomes difficult to read the guide information from the guide area arranged according to another arrangement rule. That is, the crosstalk between the guide information and the pattern signal can be reduced according to the arrangement rule or the difference in the predetermined rule when reading. Therefore, the guide region and the signal detection region can be mixed with little or no practical concern about the crosstalk. Accordingly, at least one of the guide information and the pattern signal can be appropriately read at an arbitrary position in the entire area of the guide layer or in the vicinity of the arbitrary position. Therefore, it is compatible to perform a guide operation such as a stable tracking servo over the entire area of the information recording medium and to perform a specific type of processing such as stable tilt detection and highly accurate tilt correction.

<9>
In another aspect of the information recording medium of the present embodiment, the plurality of guide regions and the plurality of signal detection regions are separated with a buffer region interposed therebetween so as not to be adjacent to each other in the radial direction. ing.

  According to this aspect, the guide region and the signal detection region are separated with the buffer region interposed therebetween so as not to be adjacent to each other in the radial direction. Here, “not adjacent to each other in the radial direction” includes not only the meaning that it is not arranged on the immediately adjacent track, but also the meaning that it is not arranged on a plurality of tracks separated from each other. The “buffer region” is a region having a mirror surface, a straight groove or a straight land structure. This “mirror surface” means a plain raw surface in which no information is embedded, and is the surface having the highest light reflectance in the guide layer. The “straight groove or straight land structure” means a straight groove (groove) in which no wobble or pit is formed or a bank (land) between the grooves. Note that the groove and the land are relative irregularities, and any of them may be concave and convex as viewed from the direction in which the first and second light beams are irradiated. For example, the groove is concave with respect to the main body substrate constituting the information recording medium, and the land is convex. In this case, the groove is convex and the land is concave as viewed from the direction in which the first and second light beams are irradiated.

  Therefore, at least when the guide information is read from the guide area at the time of recording, it is difficult to read the pattern signal from the signal detection areas that are separated by the buffer area. Conversely, when the pattern signal is read from the signal detection area at the time of recording or reproduction, it is difficult to read the guide information from the guide areas that are separated by interposing the buffer area. That is, crosstalk between the guide information and the pattern signal can be reduced according to attributes such as the size of the buffer area. Therefore, the guide region and the signal detection region can be mixed while interposing the buffer region with little or no concern about the crosstalk. Accordingly, at least one of the guide information and the pattern signal can be appropriately read at an arbitrary position in the entire area of the guide layer or in the vicinity of the arbitrary position. Therefore, it is compatible to perform a guide operation such as a stable tracking servo over the entire area of the information recording medium and to perform a specific type of processing such as stable tilt detection and highly accurate tilt correction.

<10>
In another aspect of the information recording medium of the present embodiment, the physical structure includes at least one of a wobble and a prepit structure, and a wobble and a partially cutout structure.

  According to this aspect, each of the plurality of guide regions has a physical structure including at least one of a wobble and a pre-pit structure and a wobble and a partially-notched structure that carries guide information for guide. Here, the “wobble and prepit structure” means a structure in which a wobbled or wobbled groove or land track is formed, and a prepit is formed in the groove or land. Further, the “pre-pit” means a convex or concave pit or phase pit formed to be narrower than the groove width or land width in or on the groove or on the track on or in the land. In other words, the prepit may be a land prepit or a groove prepit.

  On the other hand, “wobble and partially cutout structure” means that a wobbled or wobbled groove or land track is formed, and a notch equivalent to the groove width or land width is provided in the groove or land. Means the structure. A case where a part of a land existing between adjacent grooves is notched, a case where a part of a groove present between adjacent lands is notched, and a combination thereof are conceivable. In other words, the physical structure may be configured to include a broad-defined prepit that is partially notched, and the broad-defined prepit may be a broad-purpose land prepit or a broad-defined groove prepit. Further, in addition to such a structure, the above-mentioned narrowly-defined prepits (that is, prepits not accompanied by a notch structure) can be formed together.

  In this way, the track is pre-constructed in the guide layer as a groove track or land track wobbled and formed with pits, or as a groove track or land track in which a part of the land or groove is cut out. Therefore, the construction is relatively easy, and finally, a highly reliable and stable guide operation is possible.

<11>
In another aspect of the information recording medium of the present embodiment, the track is a guide track for tracking servo, and the physical structure generates the tracking servo signal that constitutes at least part of the guide information. Each of the plurality of guide regions is a servo region for generating the tracking servo signal, and the predetermined distance is preset to a distance at which the tracking servo can operate in a predetermined band. The plurality of servo areas are shifted and arranged between the plurality of tracks based on the diameter of the tracking servo light beam so that the light beam is not simultaneously irradiated.

  According to this aspect, the guide layer can generate a tracking error signal or the like in order to track the position in the recording surface related to each recording layer with the first light beam at least when recording information on each recording layer. This is the layer in which the structured track is built.

  More specifically, at the time of information recording, a tracking error signal or the like can be detected from reflected light obtained when the first light beam is condensed on a track existing in the guide layer. According to the tracking error signal, tracking or tracking servo can be executed as a kind of guide operation.

  Here, in the present embodiment, in particular, the plurality of servo areas are arranged in the track direction so as to be separated from each other by a distance within which a preset tracking servo can operate in a predetermined band. In other words, the distance between two servo areas adjacent to each other in the track direction is within the longest distance at which tracking signals can be generated continuously or continuously from the servo area at a frequency at which tracking operations can be performed stably. Are arranged discretely.

  In addition, the plurality of servo areas are arranged so as to be shifted between the plurality of tracks based on the diameter of the first light beam for tracking servo so that the light beam is not irradiated simultaneously.

  For this reason, even if the track density is increased until the spot of the first light beam straddles two or more adjacent track portions, the servo area is shifted correspondingly as described above. In addition, the tracking error signal (or the wobble signal that is the source) overlaps in both the track direction and the radial direction (or the tracking error signal component from other servo areas affects crosstalk noise). As a result, a situation in which the tracking error signal cannot be detected can be avoided. That is, even if the track density is increased in this way, tracking becomes possible, and the original function of generating a tracking signal as a guide layer is guaranteed.

  Therefore, while narrowing the track pitch, for example, a push-pull signal obtained from reflected light or the like caused by the first light beam is sampled, or a phase difference signal is sampled by a phase difference method (DPD). Thus, the tracking error signal can be generated stably and continuously. That is, a guide operation such as a stable tracking operation can be executed.

<12>
In another aspect of the information recording medium of the present embodiment, the predetermined pattern is configured to detect a tilt detection signal for tilt detection as the pattern signal.

  According to this aspect, if a predetermined pattern is typically created in advance so that a tilt detection signal can be generated, or if it is recorded at an arbitrary time after the start of use, a tilt can be generated. Since a large signal change in a tilt detection signal such as a tilt error signal can be obtained, it is extremely useful in practice. Thereby, tilt correction can be performed with high accuracy.

  In the information recording medium of the above-described embodiment, the plurality of guide areas include (i) a buffer area having a mirror surface, a straight groove, or a straight land structure in the track direction, and (ii) a mirror surface, a straight groove, or a straight land structure. You may arrange | position at least one among the mirror surface areas to have on both sides. If comprised in this way, in the guide layer, the structure where a buffer area | region, a guide area | region, and a mirror surface area | region will be arranged in order suitably along a track | truck is built beforehand. Here, the “mirror surface” means a plain raw surface in which information is not embedded, and is the surface having the highest light reflectance in the guide layer. The “straight groove or straight land structure” means a simple straight groove (groove) in which no wobbles or pits are formed or a bank (land) between the grooves. Note that the groove and the land are relative irregularities, and any of them may be concave and convex as viewed from the direction in which the first and second light beams are irradiated. For example, the groove is concave with respect to the main body substrate constituting the information recording medium, and the land is convex. In this case, the groove is convex and the land is concave as viewed from the direction in which the first and second light beams are irradiated.

  Further in this case, the buffer area is disposed adjacent to each other in front of the head and behind the last in each of the plurality of guide areas in the track direction, and the mirror area is in the track direction. The buffer region disposed adjacently behind the rearmost part of one guide region of the plurality of guide regions, and before the leading portion of the other guide region next to the one guide region of the plurality of guide regions. You may arrange | position between the said buffer area | regions arrange | positioned adjacently.

  With this configuration, the buffer areas are provided before and after each guide area in the track direction, so to speak, a “guide area with a buffer area” is constructed. Further, since the mirror surface area is arranged between them, it is easy to find the guide area along the track, and the guide information can be detected stably and reliably. Thereby, a stable guide operation can be executed.

  In the same slot where one guide area is arranged, a buffer area adjacently arranged in front of the leading portion of the one guide area may also be arranged. Alternatively, in addition to or in addition to this, a buffer region adjacently disposed behind the rearmost portion of the one guide region may be disposed in the same slot.

  In addition, in the information recording medium of the embodiment described above, preferably, the plurality of slots in which the guide regions are arranged are (i) irradiated and condensed on the track at the time of information recording on at least the recording layer. The diameter of the light spot formed on the track, (ii) the radial pitch of the track, and (iii) adjacent to each other in the radial direction for each turn according to the CLV method. Based on the displacement amount shifted along the track direction compared to the case where the relative position between the two slots is based on the CAV method, and (iv) the length of the slot in the track direction, It is selected as a plurality of slots that are not simultaneously included in the light spot.

With this configuration, a plurality of slots that are not simultaneously included in the light spot can be determined by arithmetic operation from the diameter of the light spot, the pitch of the track, the amount of displacement, and the length of the slot in the track direction. In the narrow sense, “not included” in the narrow sense means that two slots are located within the light spot at a part such as an edge or a corner when viewed in plan on the main surface of the guide layer, that is, the recording surface of the recording layer. Is not included in In a broad sense, it means that two slots may be included in the light spot at the same time for some portions as long as the guide information can be detected without crosstalk. If the guide area is arranged only in the slot thus selected, it is possible to realize a guide area having a slot arrangement that can be relatively easily and surely prevented from generating crosstalk between the guide information.
(Information recording device)

<13>
In order to solve the above-described problem, the information recording apparatus of the present embodiment is an information recording apparatus that records data on the information recording medium of the above-described embodiment (including various aspects thereof), and the information recording apparatus includes: It is possible to irradiate and condense the first light beam for tracking and to irradiate and condense the second light beam for data recording to one of the plurality of recording layers. And receiving the first light based on the irradiated and condensed first light beam from the guide layer and obtaining the carried guide information based on the received first light. In addition, based on the received first light, the acquired guide information functioning as mark information indicating that a corresponding one of the plurality of signal detection regions is to be followed is indicated. Said compound And an acquisition / detection means for detecting the pattern signal in each of the signal detection areas, and the light irradiation means is controlled so as to apply tracking servo to the track in a predetermined band based on the acquired guide information. Tracking servo means, processing means for performing a specific type of processing on the light irradiation means based on the detected pattern signal, and in the state where the processing is performed when the tracking servo is applied, Data recording control means for controlling the light irradiation means to record the data by irradiating and condensing the second light beam to one recording layer.

  According to the information recording apparatus of this embodiment, the first light beam is irradiated and condensed on the guide layer by, for example, light irradiation means that is an optical pickup including two types of semiconductor lasers. As described above, the first light beam may be a light beam having a relatively large spot diameter such as a red laser light beam. That is, the light beam may be a light beam that is relatively large and has a large luminous flux that forms a large light spot that is irradiated over a plurality of tracks.

  Then, the first light that is reflected light, scattered light, refracted light, transmitted light, etc. from the guide layer based on the first light beam is received by the light receiving means. Here, the light receiving means includes, for example, a photodetector or a light receiving element such as a two- or four-divided CCD (Charged Coupled Device) that is formed integrally with the light irradiation means and at least partially shares an optical system such as an objective lens. Is done. For example, the light receiving unit is configured to receive the first light through a prism, a dichroic mirror, a dichroic prism, or the like in an optical path different from the second light and the first and second light beams.

  Subsequently, based on the received first light, guide information carried by the physical structure of the guide region is acquired by an acquisition / detection unit including, for example, a processor, an arithmetic circuit, a logic circuit, and the like.

  Subsequently, based on the obtained guide information, the tracking servo means such as a tracking servo circuit, for example, an optical pickup or the like is used to apply the tracking servo in a predetermined band to the track or to close the tracking servo. The light irradiation means is controlled. For example, an actuator for tracking control in the light irradiation means is controlled by feedback control or feedforward control, and the light beam formed by the first light beam follows the track. At this time, in particular, in order to perform tracking servo in a predetermined band, it is not necessary to arrange guide areas capable of generating guide information in all slots along the track. That is, it is sufficient that the slots including the guide region are discretely arranged in both the track direction and the radial direction according to a predetermined band.

  The first light received from the signal detection area indicated by the guide information acquired by the acquisition / detection means before or after the execution of such tracking servo is indicated by the guide information acquired by the acquisition / detection means. Based on the light, a pattern signal is detected. Here, the guide information functions as mark information indicating that “a corresponding one of the plurality of signal detection areas will follow”. Note that it is not necessary for all guide information to function as landmark information. Among all guide information, one or a plurality of guide information arranged at a predetermined position (for example, in front of a signal detection area) is used as landmark information. It only has to function.

  Subsequently, based on the detected pattern signal, a specific type of processing is performed on the light irradiation unit by a processing unit including, for example, a processor, an arithmetic circuit, a logic circuit, and the like. Here, the “specific type of processing” is, for example, tilt correction when the pattern signal is a tilt detection signal. That is, for example, according to the tilt detection signal, an actuator for tilt correction provided in a light irradiation means such as an optical pickup is driven by feedback control or feedforward control, and the irradiation angle of the first light beam is corrected. After the correction, it is fixed until the next tilt detection signal is detected (that is, the tilt servo is locked until the next opportunity).

  Other specific types of processing include disk decentration correction, disk surface tilt correction, optical system aberration correction, light beam phase difference correction and distortion correction, light absorption correction, and strategy setting. In either case, the processing is performed according to the type of pattern signal.

  Here, if the optical system for irradiating the first and second light beams in the optical pickup or the like is fixed, the positional relationship of the light spots formed by them is also fixed. For this reason, performing a specific type of processing such as tilt correction using the first light beam means that the specific type of processing is also performed with reproducibility for the second light beam. . In other words, by using the first light beam on the pre-existing track, the necessary or preferable specific type of processing can be indirectly performed on the second light beam in the recording surface where the track does not exist in advance. It is a translation.

  Thus, in a state where the tracking servo is applied in a predetermined band or the tracking servo is closed and a specific type of processing is performed (for example, the tilt servo is locked or tilt correction is performed). In the meantime, under the control of data recording control means such as a processor, the second light beam modulated in accordance with the information to be recorded is irradiated and condensed by the light irradiation means. . The second light beam may be a light beam having a relatively small spot diameter such as a blue laser light beam as described above, aiming at high-density recording of information recording. From the viewpoint of increasing the recording information density, it is desirable that the second light beam is a thinner light beam.

  Then, in the desired recording layer, data is sequentially recorded in an area that becomes an information track corresponding to the track in the guide layer. At this time, if data is recorded on the recording layer in units corresponding to the slots, for example, an integral multiple of the slots, the recording operation becomes simple and stable.

As described above, the information to be recorded, such as content information and user information, is preferably recorded on the recording layer in the information recording medium of the above-described embodiment with high accuracy under the execution of a specific type of processing such as tilt correction. Recording is possible at high density.
(Information recording method)

<14>
In order to solve the above-described problem, the information recording method of this embodiment irradiates the guide layer with the first light beam for tracking on the information recording medium of the above-described embodiment (including various aspects thereof) and Data can be collected using a light irradiating means capable of condensing and irradiating and condensing a second light beam for data recording onto one of the plurality of recording layers. An information recording method for recording, comprising: receiving a first light based on the irradiated and condensed first light beam from the guide layer; and carrying the carried guide information based on the received first light. And, based on the received first light, the fact that the corresponding one of the plurality of signal detection areas will be followed by the acquired guide information functioning as mark information indicating that the corresponding one will come later. Indicated The acquisition / detection step of detecting the pattern signal in each of the plurality of signal detection areas, and the light irradiation means so as to apply tracking servo to the track in a predetermined band based on the acquired guide information A tracking servo step for controlling the light, a processing step for performing a specific type of processing on the light irradiation means based on the detected pattern signal, and a state in which the processing is performed when the tracking servo is applied. And a data recording control step of controlling the light irradiation means so as to record the data by irradiating and condensing the second light beam to the one recording layer.

According to the information recording method of the present embodiment, it operates in the same manner as the information recording apparatus of the above-described embodiment, and finally, for example, content is suitably applied to the recording layer in the information recording medium of the above-described embodiment. Information to be recorded such as information and user information can be recorded with high accuracy and high density under the execution of a specific type of processing such as tilt correction.
(Information playback device)

<15>
In order to solve the above problems, the information reproducing apparatus of the present embodiment is an information reproducing apparatus for reproducing data from the information recording medium (including various aspects thereof) of the above-described embodiment, and the information reproducing apparatus It is possible to irradiate and condense the first light beam for tracking and to irradiate and condense the second light beam for data reproduction to one of the plurality of recording layers. And receiving the first light based on the irradiated and condensed first light beam from the guide layer and obtaining the carried guide information based on the received first light. In addition, based on the received first light, the acquired guide information functioning as mark information indicating that a corresponding one of the plurality of signal detection regions is to be followed is indicated. Above Acquisition / detection means for detecting the pattern signal in each of a plurality of signal detection areas, and the light irradiation means for applying tracking servo to the track in a predetermined band based on the acquired guide information. Tracking servo means for controlling, processing means for performing a specific type of processing on the light irradiation means based on the detected pattern signal, and in a state where the processing is performed when the tracking servo is applied, Data acquisition means for receiving second light based on the irradiated and condensed second light beam from the one recording layer, and acquiring the data based on the received second light;

  According to the information reproducing apparatus of the present embodiment, the first light beam is irradiated and condensed on the guide layer by, for example, light irradiation means that is an optical pickup including two types of semiconductor lasers. As described above, the first light beam may be a light beam having a relatively large spot diameter such as a red laser light beam. That is, the light beam may be a light beam that is relatively large and has a large luminous flux that forms a large light spot that is irradiated over a plurality of tracks.

  Then, the first light that is reflected light, scattered light, refracted light, transmitted light, etc. from the guide layer based on the first light beam is received by the light receiving means.

  Subsequently, based on the received first light, guide information carried by the physical structure of the guide region is acquired by an information acquisition unit including, for example, a processor, an arithmetic circuit, a logic circuit, and the like.

  Subsequently, based on the obtained guide information, the tracking servo means such as a tracking servo circuit, for example, an optical pickup or the like is used to apply the tracking servo in a predetermined band to the track or to close the tracking servo. The light irradiation means is controlled. At this time, in particular, in order to perform tracking servo in a predetermined band, it is not necessary to arrange guide areas capable of generating guide information in all slots along the track. That is, it is sufficient that the slots including the guide region are discretely arranged in both the track direction and the radial direction according to a predetermined band.

  The first light received from the signal detection area indicated by the guide information acquired by the acquisition / detection means before or after the execution of such tracking servo is indicated by the guide information acquired by the acquisition / detection means. Based on the light, a pattern signal is detected.

  Subsequently, based on the detected pattern signal, a specific type of processing is performed on the light irradiation unit by a processing unit including, for example, a processor, an arithmetic circuit, a logic circuit, and the like.

  Thus, in a state where the tracking servo is applied in a predetermined band or the tracking servo is closed and a specific type of processing is performed (for example, the tilt servo is locked or tilt correction is performed). In the meantime, under the control of a data acquisition means such as a processor, the second light beam is irradiated onto the desired recording layer and condensed by the light irradiation means. The second light beam may be a light beam having a relatively small spot diameter such as a blue laser light beam as described above, aiming at high-density reproduction of information recording.

  Then, recorded information is reproduced in a desired recording layer. At this time, if the recording of data on the recording layer at the time of recording is performed in units corresponding to the slots, for example, an integral multiple of the slots, the reproducing operation becomes simple and stable.

  In this way, the recorded information in the information recording medium of the above-described embodiment is preferably paired with the recorded information such as content information and user information with high accuracy under the execution of a specific type of processing such as tilt correction. It becomes possible to reproduce at high density.

It is to be noted that tracking is performed on an information track composed of an array or a series of recorded recording information by using only the second light beam without using tracking by the guide layer, that is, without using the first light beam. It is also possible to reproduce information from the information track. That is, when reproducing information, only the second light beam is used, and when recording information, both the first and second light beams are used. It is also possible to construct. Since only the second light beam is used during information reproduction, reproduction is performed with relatively low power consumption and simple control (that is, compared with the case where the first light beam is also used during reproduction). It becomes possible. In particular, if the information reproducing apparatus is realized as an “information recording / reproducing apparatus” having a recording function that selectively uses a light beam for information recording and information reproducing, it is very advantageous in practice.
(Information playback method)

<16>
In order to solve the above-described problem, the information reproducing method of this embodiment irradiates the guide layer with the first light beam for tracking from the information recording medium of the above-described embodiment (including various aspects thereof) and Data can be collected using a light irradiating means capable of condensing and irradiating one of the plurality of recording layers with a second light beam for data reproduction and condensing. An information reproducing method for reproducing, wherein the first guide light based on the irradiated and condensed first light beam from the guide layer is received, and the carried guide information is based on the received first light. And, based on the received first light, the fact that the corresponding one of the plurality of signal detection areas will be followed by the acquired guide information functioning as mark information indicating that the corresponding one will come later. Indicated An acquisition / detection step of detecting the pattern signal in each of the plurality of signal detection regions, and the light irradiation means so as to apply tracking servo to the track in a predetermined band based on the acquired guide information A tracking servo step for controlling the light, a processing step for performing a specific type of processing on the light irradiation means based on the detected pattern signal, and a state in which the processing is performed when the tracking servo is applied. Receiving a second light based on the irradiated and condensed second light beam from the one recording layer, and acquiring the data based on the received second light.

  According to the information reproducing method of the present embodiment, it operates in the same manner as in the information reproducing apparatus of the above-described embodiment, and finally, for example, content information is preferably selected from the recording layer in the information recording medium of the above-described embodiment. In addition, recorded information such as user information can be reproduced with high accuracy and high density under the execution of a specific type of processing such as tilt correction.

  Such an operation and other advantages of the present embodiment will be clarified from examples described below.

  As described above, according to the information recording medium according to the present embodiment, the CLV method includes the guide layer and the plurality of recording layers, and the plurality of signal detection areas and the guide areas are arranged on the track. In this way, high-precision recording is possible under the execution of a specific type of processing such as tilt correction, and the track pitch and recording linear density that can be recorded or reproduced on the recording layer can be increased.

  The information recording apparatus according to the present embodiment includes a light irradiation unit, an acquisition / detection unit, a tracking servo unit, a processing unit, and a data recording control unit. Since the detection process, the tracking servo process, the processing process, and the data recording control process are provided, information to be recorded such as content information and user information is preferably recorded on the recording layer in the information recording medium of the above-described embodiment. Recording can be performed with high accuracy and high density.

  The information reproducing apparatus according to the present embodiment includes a light irradiation unit, an acquisition / detection unit, a tracking servo unit, a processing unit, and a data acquisition unit. According to the information reproduction method according to the present embodiment, the acquisition / detection is performed. Since the process, the tracking servo process, the processing process, and the data acquisition process are provided, recorded information can be suitably reproduced with high accuracy and high density from the recording layer in the information recording medium of the above-described embodiment.

Hereinafter, various embodiments of the present invention will be described with reference to the drawings. Hereinafter, an example in which the information recording medium according to the present invention is applied to a multilayer recording type optical disc will be described.
<Example of information recording medium>
First, with reference to FIGS. 1 to 15, an embodiment of a multilayer recording type optical disc as an example of an information recording medium according to the present invention will be described.

  First, the basic configuration (mainly the physical structure) and the basic principle of the optical disc 11 according to this embodiment will be described with reference to FIGS.

  In FIG. 1, an optical disc 11 is a multi-layer recording type, and includes a single guide layer 12 and a plurality of recording layers 13. Here, FIG. 1 shows a plurality of layers constituting one optical disk 11 shown on the left half surface in the drawing, and the right half surface in the drawing is spaced from each other in the stacking direction (vertical direction in FIG. 1). It is a typical perspective view made easy to see each layer by opening and disassembling.

  For the optical disk 11, at the time of recording, it is used for tracking servo and the first beam LB1 as an example of the “first light beam” according to the present invention, and “second light” for information recording and according to the present invention. The second beam LB2 as an example of the “beam” is irradiated at the same time. During the reproduction, the first beam LB1 and the second beam LB2 for information reproduction are simultaneously irradiated. During information reproduction, the second beam LB2 can be used as a single light beam for tracking servo and information reproduction (that is, the first beam LB1 is not used). .

  The optical disk 11 is a CLV system and is pre-recorded on a concentric or spiral track TR, and a tracking error signal (or a wobble signal that is a source thereof) detected at the time of information recording or reproduction, address information (or its) The original pre-pit signal) is arranged along the track in accordance with the CLV system. As shown in the right half of FIG. 1, the first beam LB1 is focused on the guide layer 12 and tracking-controlled so as to follow the track TR (that is, the guide track).

  As shown in FIG. 2, the second beam LB <b> 2 is focused on one desired recording layer 13 that is a recording target or a reproduction target among the plurality of recording layers 13 stacked on the guide layer 12. The second beam LB2 is a blue laser beam having a relatively small diameter, for example, like a BR (Blu-ray) disc. On the other hand, the first beam LB1 is a red laser beam having a relatively large diameter, for example, like DVD. The diameter of the light spot formed by the first beam LB1 is, for example, about several times the diameter of the light spot formed by the second beam LB2.

  The plurality of recording layers, such as 16 layers, are configured such that information can be optically recorded and reproduced independently of each other. More specifically, each of the plurality of recording layers 13 is composed of, for example, a translucent thin film containing a two-photon absorption material. For example, as a two-photon absorption material, a fluorescent type using a fluorescent material in which the fluorescence intensity in a region where two-photon absorption occurs is changed, a refractive index changing type using a photorefractive material in which the refractive index is changed by electron localization, etc. However, it can be adopted. The use of photochromic compounds, bis (aralkylidene) cycloalkanone compounds, etc. is promising as refractive index changing type two-photon absorption materials.

  As an optical disk structure using a two-photon absorption material, (i) a bulk type in which the entire optical disk 11 is made of a two-photon absorption material and (ii) a recording layer of two-photon absorption material and a spacer layer of another transparent material are alternately arranged. There are stacked layer structure types. The layer structure type has an advantage that focus servo control can be performed using light reflected at the interface between the recording layer 13 and the spacer layer. The bulk type has an advantage that the manufacturing cost can be suppressed because there are few multilayer film forming steps.

  As the material of the recording layer 13, recording can be performed by changing the optical characteristics such as refractive index, transmittance, absorption rate, and reflectance in response to at least one of the wavelength and intensity of the second beam LB2. At the same time, any stable material may be used. For example, a light-transmitting or translucent photosensitive material such as a photopolymer that causes a photopolymerization reaction, a photo-anisotropic material, a photorefractive material, a hole burning material, a photochromic material that absorbs light and changes its absorption spectrum, Conceivable. For example, as the recording layer 13, a phase change material, a two-photon absorption material, or the like that is sensitive to the second beam LB2 having the wavelength λ2 and is not sensitive to the first beam LB1 having the wavelength λ1 (λ2 <λ1) is used.

  Each of the plurality of recording layers 13 may be, for example, a dye material in addition to the above-described two-photon absorption material and phase change material. In each of the plurality of recording layers 13, in the unrecorded state, the track TR is not formed in advance, and for example, the entire region is a mirror surface or a flat surface without unevenness.

  With respect to the optical disc 11 in which such a plurality of recording layers 13 are laminated on the guide layer 12, at least at the time of information recording, these diameters and depths of focus are different through a common objective lens 102L included in the optical pickup. The first beam LB1 and the second beam LB2 are irradiated almost or coaxially in practice.

  In FIG. 1 and FIG. 2, the tracking operation for the second beam LB2 is performed by the tracking operation for the track TR of the guide layer 12 by the first beam LB1 (in particular, no track exists on the recording layer 13 during recording). Made indirectly. That is, the first beam LB1 and the second beam LB2 are irradiated through a common optical system such as the objective lens 102L (in other words, an optical system in which the positional relationship between the irradiated light beams is fixed). . Therefore, the positioning of the first beam LB1 in the plane of the optical disc 11 can be used as the positioning of the second beam LB2 in the plane of the optical disc 12 (that is, in the recording plane of each recording layer 13).

  The track TR of the guide layer 12 includes a plurality of servo areas each having a physical structure carrying a tracking error signal (or a signal for generating a tracking error such as a wobble signal as a source thereof) and a pre-pit signal. Has been placed. Here, the tracking error signal and the pre-pit signal constitute an example of “guide information for guide” according to the present invention. The plurality of servo areas constitute one example of “a plurality of guide areas” according to the present invention.

  Here, the physical structure of the guide layer 12 will be described in detail with reference to FIGS. 3 to 6 each show an enlarged view of the track portion of the guide layer 12 on which wobbling has been performed. In particular, FIG. 3 shows a track portion where wobbling is simply performed in the embodiment, and FIG. 4 shows a guide layer 12 in a comparative example in which grooves, lands, etc. are formed without gaps over the entire area of each track. Indicates the track part. FIG. 5 shows a track portion having “wobble and partially cutout structure” in the embodiment and wobbling, and FIG. 6 has “wobble and narrow land pre-pit” in the embodiment and wobbling. The applied track part is shown.

  As shown in FIG. 3, the guide layer 12 has a groove track GT corresponding to a specific example of the track TR in FIG. In the groove track GT, for example, a reflective film 12a, which is a thin film made of a light-reflective material, is formed on a transparent film 12c as a substrate on which concave and convex grooves are formed, and further a transparent or opaque film as a protective film It is formed by being filled with 12b. In the meaning of the groove dug in the transparent film 12c as the base material located on the upper side in FIG. 3, the groove track GT or the groove is formed in a convex shape on the upper side in FIG. Or conversely, the groove track GT is formed by forming the reflective film 12a on the transparent or opaque film 12b as the base material on which the concave and convex grooves are formed, and further filling with the film 12c as the protective film. The

  The groove track GT has a wobble WB on the side wall. In other words, the groove track GT is formed such that the side wall wobbles (meanders) along the track direction.

  In FIG. 3, the grooves are provided only locally, but each groove track GT indicated by a one-dot difference line is recorded information formed by recording information that the recording layer 13 (see FIG. 1) has after recording. They are arranged at a track pitch corresponding to the track pitch of the track. Here, the arrangement on the recording layer 13 of the recorded information along the track TR that has already been recorded along the track TR of the guide layer 12 will be simply referred to as “recorded information track” as appropriate. The information-recorded track is physically formed on the recording surface of the recording layer 13 by irradiation of the second beam LB2 at the time of recording, the portion where the fluorescence intensity is changed, the portion where the refractive index is changed, the phase change portion, the dye It can be said that it is a series of ridges along the track TR of the guide layer 12, such as a changed portion. That is, in FIG. 3, the groove is formed at a frequency at which a tracking error can occur at a predetermined frequency even for the groove track GT in which no groove is formed. That is, at the radial position and the track direction position not shown in FIG. 3, grooves are appropriately formed on the groove track GT, and the groove track GT on which no groove is formed over the circumference is Basically does not exist.

  In FIG. 4, in the comparative example, the recording layer 13 (see FIG. 1) after recording has a track pitch corresponding to the track pitch of the recorded information track formed by the recording information, and covers the entire track direction and radial direction. Thus, grooves and lands are formed. In a traditional DVD, BR disc, etc., the groove track GT is because the recording layer also serves as the guide layer or because the recorded information track of the recording layer and the guide track of the guide layer have a one-to-one correspondence. The guide layer is also configured as in the comparative example of FIG.

  On the other hand, in the specific example of FIG. 3, the groove is not formed over the whole area along the track direction on the groove track GT. The grooves are not formed on the groove tracks GT adjacent to each other in the radial direction. A quantitative description of such an arrangement (more specifically, an arrangement interval in the track direction and the radial direction) and the operation and effect thereof will be described in detail later with reference to FIGS.

  As shown in FIG. 5, a groove notch GN1 having a partially cut structure may be formed in the groove track provided in the guide layer 12 (see FIG. 1). A notch is a mirror surface that is cut out over one track width of a groove track.

  Alternatively, as shown in FIG. 6, a land prepit LPP1 may be formed in the land part LP. Note that the land prepit LPP1 is also formed in the comparative example of FIG. The groove notch GN1 in FIG. 5 and the LPP1 in FIG. 6 have the same effect although appearing in the opposite direction when the guide layer is reproduced.

  In addition, in FIG. 6, the prepits may be appropriately formed for the land part LP in which no prepits are formed.

  Here, referring to FIG. 7 and FIG. 8, attention should be paid when the track TR of the guide layer 12 builds a physical structure in which the track TR carries the tracking error signal (or the wobble signal that is the source) in the track TR. Add consideration.

  As shown in FIG. 7, it is assumed that the light spot SP1 is not relatively large with respect to the track pitch and tracking for low density recording is performed. In this case, the light spot SP1 has a diameter of about 1 μm (relative to the track pitch of 0.5 μm), and has little or no influence as a noise of signals on the tracks TR1 and TR3 other than the track TR2 that is focused and followed by itself. Not received at all in practice. That is, with respect to all the tracks TR1, TR2, TR3,..., There are no gaps in the radial direction and the track direction, a groove structure or a wobble structure (see FIG. 3), a partially cut-out structure (see FIG. 5), Even if a pre-pit structure (see FIG. 6) is provided, no crosstalk occurs in the tracking error signal (or the wobble signal that is the source). For this reason, tracking can be executed.

  As shown in FIG. 8, it is assumed that the light spot SP1 is relatively large with respect to the track pitch and tracking for high density recording is performed. In this case, the light spot SP1 has a diameter of about 1 μm (relative to the track pitch of 0.25 μm), and is used as noise of signals on the tracks TR1, TR2, TR4, and TR5 other than the track TR3 that is focused and followed by itself. It is significantly affected. That is, if a groove structure or a wobble structure (see FIGS. 3 to 6) is given to all the tracks TR1, TR2, TR3,. Crosstalk occurs remarkably. This makes tracking impossible.

  In particular, in the case of the CLV method as in this embodiment, unlike the CAV method, the address positional relationship (address difference) on a plurality of adjacent tracks TR changes depending on the radial position. Even if tracking is possible at this location, there is a significant possibility that tracking will be impossible at other locations (that is, at locations where the degree of proximity of other signal generation regions adjacent in the radial direction increases).

  This is the same when the land pre-pit LPP1 exists in the vicinity as shown in FIG. That is, the pre-pit signal recorded in the land pre-pit LPP1 surrounded by a broken-line circle in the figure provided for the other track TR5 with respect to the land pre-pit LPP1 provided for the track TR3 to be tracked. (That is, the land pre-pit signal) affects as noise. As a result, the land prepit LPP1 cannot be detected at any position, or the land prepit LPP1 cannot be detected depending on the radial position or the track direction position. In other words, it becomes impossible to detect address information or the like by the pre-pit signal. In this way, an arrangement that reduces not only adjacent tracks but also crosstalk between tracks separated by two tracks or more is required.

  The situation as shown in FIG. 8 uses the second beam LB2 (for example, a blue laser similar to the BR disc) corresponding to high-density recording on the recording layer 13 so that the information recording track has a narrow pitch after recording. When the narrow-pitch track TR is formed in the guide layer 12 in advance and the first beam LB1 (for example, red laser as in the DVD) corresponding to the low density recording is used for the guide layer 12, it is inevitable. Will occur. In other words, when the first beam LB1 is used for the guide layer 12 and the second beam LB2 having a smaller diameter than the first beam is used for the recording layer 13, the technically generated technically occurs. It can be said that this is a serious restriction. If the track TR having a pitch corresponding to the first light beam LB1 is formed on the guide layer 12, it does not help at all for performing tracking for high-density recording in the recording layer 13.

  However, the specific purpose of tracking in a predetermined frequency band is to generate a tracking error signal at any timing in any track TR, but a wobble structure for detecting a tracking error signal Alternatively, the pre-pit structure (see FIGS. 3 to 6) can be achieved without continuously forming on the track TR in the track direction. That is, a tracking error signal is generated in the entire area along the track direction on the track TR if the arrangement interval (that is, the arrangement pitch) is equal to or less than the longest distance at which the tracking servo can operate in a predetermined frequency band. Thus, it is not necessary to apply a wobble structure or the like (see FIGS. 3 to 6). In addition, for a plurality of adjacent tracks TR, in order to achieve this specific purpose, positions aligned in the radial direction (that is, positions or regions having the same phase or the same phase, in other words, the same angle on the optical disc 11). Alternatively, it is not necessary to align the wobble structure that generates a tracking error at each of the positions or regions having the same angle.

  In addition, not only the tracking error signal but also a specific purpose of detecting a prepit signal constituting control information for other recording control or reproduction control such as address information using a prepit such as the land prepit LPP1. Therefore, it is not necessary to make a wobble structure or a pre-pit structure (see FIGS. 3 to 6) in the entire region along the track direction on the track TR. For example, it is possible to detect control information without recording all information in advance in the track direction and the radial direction as if stuffing bits are packed in an unrecorded track.

  Therefore, in the present embodiment, in particular, in order to achieve the specific purpose of mainly enabling tracking on the track TR, a plurality of servo areas are discrete in both the track direction and the radial direction as described below. Provided.

  Next, with reference to FIG. 9 and FIG. 10, the physical configuration of three regions in the guide layer 12, that is, a groove region, a mark region, and a pattern region will be described in detail.

  As shown in FIG. 9, the guide layer 12 has a mirror area 21 as “area 1” and a “servo area” as “area 2”, and a mark area 22 that can generate mark information of a detection pattern. As a “region 3”, a pattern region 23 having a predetermined pattern 23a capable of generating a tilt detection signal is arranged.

  Here, a straight groove or a straight land may be formed in the mirror surface region 21. In this case, the mirror surface region 21 may be referred to as a “groove region”. Alternatively, if attention is paid to the buffering action when reading the other mark area 22 or the pattern area 23 in the mirror surface area 21, the mirror surface area 21 can also be referred to as “buffer area”. This is an example of a “buffer area”.

  As shown in FIG. 10, on the guide layer 12, seven adjacent tracks TR are set as one group GR, and the center track thereof is set as a center track 23TR for tilt detection. The mark area 22 and the pattern area 23 are arranged in succession on the center track 23TR. The mark area 22 also functions as a guide area or a servo area for detecting a tracking error signal, and is therefore provided in a track TR other than the center track 23TR. The pattern region 23 has a predetermined pattern 23a that spans seven adjacent tracks TR (that is, seven tracks TR constituting one group GR).

  In FIG. 9, the mirror surface region 21 is an example of the “buffer region” according to the present invention, and is a region having a straight groove. The mirror surface area 21 is adjacently arranged in front of the head portion and behind the last portion in each of the plurality of mark areas 22 in the track direction.

  The buffering action in the mirror surface area 21 provides a preparation period for signal detection from the mark area 22 in the servo system during information recording or the like. In particular, the first beam LB1 is allowed to enter the mark area 22 while tracking is on during information recording. That is, the mirror surface area 21 arranged on the leading side of the mark area 22 gives a very effective preparation period for stable operation of the tracking servo.

  9 and 10, a mark area 22 is an area in which a wobble structure or a prepit structure is formed in advance as shown in FIGS. 3 to 5, that is, an area where a tracking error signal or a prepit signal can be detected. The mark areas 22 are discretely arranged in the track direction (left and right direction in FIG. 9) as arrangement intervals (that is, arrangement pitch) with a predetermined distance or a distance less than the predetermined distance. In addition, the plurality of mark regions 22 are positively or actively left and right between the plurality of tracks TR across the plurality of adjacent tracks TR in the radial direction (that is, in the vertical direction in FIG. 9) ( That is, they are arranged shifted along the track direction.

  The mark information is arranged immediately before the pattern area 23 on the center track 23TR, and indicates that the pattern area 23 comes immediately after. Therefore, when mark information is first detected in the mark area 22 during recording or reproduction, it is found that the pattern signal in the pattern area 23 arrives without delay thereafter. Alternatively, the mark information indicates a timing at which the subsequent pattern area 23 should be sampled on the center track 23TR or an address position from the inner periphery to the outer periphery or from the outer periphery to the inner periphery along the track direction of the subsequent pattern area 23. . Therefore, when mark information is first detected in the mark area 22 at the time of recording or reproduction, it is subsequently determined at which timing or at which address position the pattern signal arrives.

  If the first light beam is not on one central track composed of a plurality of tracks, the wobble signal detected by the push-pull signal is detected with an offset in the pattern area 23. Therefore, it can be recognized whether or not the first light beam is on the center track 23TR.

  9 and 10, the pattern area 23 is an example of the “signal detection area” according to the present invention, and is a center track 23TR (a track indicated by an alternate long and short dash line in FIG. 9). In order to detect a specific type of pattern signal, a set of predetermined patterns 23a extending over seven tracks adjacent in the radial direction (vertical direction in FIG. 9) are provided.

  On the other hand, the track portion other than the center track 23TR is intentionally excluded from the detection target of the pattern signal even when the center of the first light spot LS1 by the first light beam is directly on the track portion.

  The pattern areas 23 are discretely arranged in the track direction (left and right direction in FIG. 9), and are also discretely arranged in the radial direction (up and down direction in FIG. 9). For this reason, even if the track density is increased until the spot of the light beam straddles seven adjacent tracks, a situation in which the pattern signal cannot be detected due to the crosstalk of the detected pattern signal can be avoided. .

  Since the predetermined pattern 23a is prepared in advance so that a tilt detection signal such as a tilt error signal can be generated as a pattern signal, a large signal change in the tilt detection signal can be obtained when a tilt occurs.

  The predetermined pattern 23a is formed from a plurality of short pits, embosses, or emboss pits formed on a groove or land that is notched shortly having local unevenness, or on a groove track or land track. For example, when straddling seven tracks, it is composed of a set of ten embossed pits, etc., with five on one side and both sides. The predetermined pattern 23a is formed so as to substantially match the outer ring shape of the light spot LS1, and has a shape that substantially follows the bright ring LS1a when it occurs. The wobble may be combined with the predetermined pattern 23a.

  In addition to the tilt detection signal, the predetermined pattern 23a in the pattern area 23 includes an eccentric signal for correcting the eccentricity of the disc, an inclination signal for correcting the tilt of the disc surface, an aberration signal for correcting the aberration of the optical system, and an optical beam. Various signals such as phase difference signal for phase difference correction, distortion signal for distortion correction, light absorption signal for light absorption correction, strategy signal for strategy setting are configured to be detected as pattern signal It's okay.

  Here, the specific purpose of enabling the tilt correction based on the tilt detection signal is to detect the tilt detection signal in any track TR, but the tilt detection signal is applied to all the tracks TR. Even if it does not form continuously, it can be achieved. That is, if the tilt detection signal is detected according to the frequency or period of tilt correction such that the tilt detection signal is detected once every period during which the tilt servo is locked, the specific purpose is achieved. Is possible.

  Therefore, on the other hand, if a tilt detection signal can be obtained for every seven tracks of one GR, tilt correction can be executed. On the other hand, with respect to the region along the track TR, tilt correction can be executed if a tilt detection signal can be obtained with some interval or at any phase (for example, an angle on the disk). In the end, it is sufficient if the tilt detection signal is obtained intermittently at the center track 23TR representing them every seven tracks of one group GR.

  In this embodiment, the first beam LB1 (for example, a red laser) has a larger beam diameter than the second beam LB2 (for example, a blue laser), so that one group GR is configured using the first beam LB1. It is extremely convenient to detect a set of predetermined patterns 23a across the seven tracks TR.

  Thus, the pattern region 23 having the tilt detection pattern can be arranged with a degree of freedom. In addition, by providing pattern signals other than the tilt detection signal in correspondence with processes other than tilt correction, it is possible to execute other processes in parallel or appropriately with tilt correction.

  Moreover, in this embodiment, in particular, a mark area 22 that carries mark information indicating that the pattern area 23 comes after the center area 23TR in the track direction of the pattern area 23 is disposed. The mark information is information reproduced by a wobble signal or a prepit signal corresponding to wobbles or prepits that are discretely formed in the mark area 22.

  For this reason, the tilt detection signal can be read easily and reliably based on the arrival of the mark information. For example, after detection of the mark information, it is possible to start preparation for starting detection of a tilt detection signal and further start preparation for starting tilt correction based on the tilt detection signal. For example, by predefining the phase relationship and interval between the tilt detection signal and the mark information, the sampling timing for detecting the tilt detection signal can be easily specified from the mark information. Alternatively, if the mark information has an address position where the tilt detection signal is recorded, the sampling timing for detecting the tilt detection signal can be easily specified.

  In the present embodiment, the length of the tilt detection signal on the track TR in the track direction and the format of the data to be recorded on the recording layer 13 are, for example, ECC blocks, RUBs (Recording Unit Blocks), ADIP units, and the like. The length of the structural unit in the track direction may be configured to have a predetermined integer ratio. In this way, the occurrence frequency of the tilt detection signal and the period for recording data on the recording layer 13 at the recording surface position corresponding to the track TR are constant regardless of the radial position or the track position. It is easy to maintain the relationship. In particular, when the CLV method is employed, stable tilt correction can be performed based on the detected tilt detection signal at an arbitrary radial position, even though the angular velocity changes depending on the radial position. Even when the zone CAV method is employed, stable tilt correction can be executed based on the detected tilt detection signal without any problem for each zone.

  Next, specific data structures of the mark area 22 and the pattern area 23 in the guide layer 12 will be described in detail with reference to FIGS.

  In this example, the signals recorded in the mark area 22 and the pattern area 23 are arranged in units of slots. Here, the “slot” is a logical section or section obtained by dividing the track TR in the track direction, or a physical section or section. The slots are typically arranged continuously without gaps in the track direction and arranged without gaps or adjacent to each other in the radial direction. In this case, since control such as tracking servo and tilt servo is indirectly performed by the guide layer 12, the data format in the recording layer 13 can be controlled easily by having a certain relationship with the slot.

  FIG. 11 shows a specific example of the preformat in the mark area 22 and the pattern area 23 in the guide layer 12.

  In FIG. 11, one RUB is configured corresponding to a BD-R (Blue ray Disc-Recordable: Blu-ray disc that can be recorded once) format.

  Specifically, one RUB is physically composed of (248 × (2 × 28)) physical clusters, and logically three ADIP words (ADIP word NO. 1 to NO.3).

  One ADIP word is composed of 83 ADIP units (ADIP units). One ADIP unit is composed of 56 wbl (wobble), which corresponds to two recording frames (Recording frames). Data to be recorded is a unit of 15 code words, that is, 9 nibbles. Therefore, one RUB is a section corresponding to 13944 wobbles.

  In the present embodiment, six (that is, No. 1 to No. 6) address words (Address words) included in one RUB are respectively 86 (that is, A1 to A86) address subunits (Address). sub-unit). A zero unit (Zero unit) is arranged at the head of each address word.

  Furthermore, each address subunit is composed of six slots, and the first five slots (A Slot) are assigned to address slots (ie, “preformat address slots”). A subsequent slot (B Slot) is assigned to a tilt detection slot (ie, a tilt detection pattern slot). That is, one address sub-unit corresponds to a total of 7 slots of 5 A Slots and 1 B Slot, and thus is composed of 9 × 6 = 54 wbl in total.

  Therefore, in this example, the length of one RUB corresponds to 13944 wbl from 2 {(54 × 86) × 3 + (4 × 3)} = 13944. In this example, the length D of one wobble located at the head of each slot is D = 1 wbl> 1.2 μm (the maximum diameter of the light spot).

  In this way, with regard to the pre-address configuration example, a 6-address configuration is provided for one RUB, and each address is composed of 86 units. The address data (1 slot data) × 86 units = 2 bits × 86 units = 172 bits.

  Thus, according to the configuration example in units of 1 RUB, when the recording data format to the other recording layer 13 is based on, for example, the BD-R format, the wobble period provided in the mark area 22 is the recording layer 13. The unit of the data format is in a relationship of a predetermined integer ratio. The section of the pattern area 23 and the position to be arranged are also arranged so as to have a predetermined relationship with the wobble cycle. Therefore, a predetermined position of the pattern area 23 can be specified from the wobble signal detected from the mark area of the mark area 22. Therefore, the recording / reproducing apparatus described later can easily create the timing for sampling the specific parameter detection error detection.

  In particular, even if measures are taken to solve a new problem that occurs because the first beam LB1 for reading on the guide layer 12 has a lower density than the reading beam for the BD-R format, the preformat for recording is used. As a result, data such as necessary pre-addresses can be formed in a desired amount of information. Since one unit is provided with 5 slots and a buffer area D (that is, a part of the mirror surface area 21) for removing the influence of the beam diameter, a mark placed on the adjacent track when acquiring the preformat data. The influence of the area 22 and the pattern area 23 can be removed, the influence of the beam diameter of the pickup 102 can also be removed, and the preformat information can be acquired stably.

  In FIG. 12, a wobble is formed in the mark area 22 as slot information in slot units. The sample servo marks 300S are also widely distributed in the left area of the mark area 22 (mark area 22 also serving as a servo area) in the mark area 22, and in each track TR (Track 1 to Track 7), the track direction (in FIG. 9, It is formed in slot units discretely in the left-right direction) and spaced by two tracks in the radial direction (up-down direction in the figure).

  In the mark area 22, slots 300 </ b> A (that is, “A Slot (see FIG. 11)”) are arranged in such a manner that the sample servo marks 300 </ b> S are widely distributed according to a predetermined rule. The slots 300B (that is, “B Slot (see FIG. 11)) are arranged so as to be substantially aligned in the radial direction. Before and after the pattern area 23, only three wobbles are secured as an overlapping area 400. Yes.

  In FIG. 12, in the pattern region 23, a tilt detection pattern is formed in slot units as a pattern signal in the slot 300B. In the pattern area 23, one pattern is constructed as a tilt detection pattern so as to straddle seven tracks. In the present example, the upper half of the outer ring circumference of the light spot LS1 (that is, the bright ring LS1a) is immediately after the mark region 22, as shown as a pattern region 23 shown in a rectangle on the lower right in the drawing. A pattern for covering is formed, and subsequently, a pattern for covering the lower half of the outer ring circumference of the light spot LS1 (that is, the bright ring LS1a) is formed at a slight distance. One tilt detection pattern is constructed from these two patterns.

  Here, with reference to FIG. 12, the condition required for the slot 300B is examined in relation to the slot 300A.

As shown in FIG. 12, first, since the lengths of adjacent tracks differ by 2ΠP (P: track pitch), adjacent portions in CLV are shifted by 2ΠP. Here, if P = 0.32 [μm],
X = 2ΠP≈2.01 [μm] (generally, X = 2Π (r + P) −2Πr).

On the other hand, the length of one wobble wave equivalent to the BD format is
W _L = 69 (Channel bit) × 0.0745 [μm] = 5.1405 [μm].

Because of the tilt detection pattern arrangement, if 7 tracks are grouped together, the amount of deviation from the center track corresponds to the amount of deviation (Δl) that is 3 tracks away.
Δl = 2ΠP × 3≈6.03 μm.

  Therefore, in relation to the predetermined pattern 23a that is a tilt detection pattern arranged in the slot 300B, it is necessary to separate the front and rear by an amount Δl in the slot 300B.

In this embodiment, the wobble frequency is set to twice the BD, so
(W _L /2)=5.1405 [μm] /2=2.57 [μm], so that three wobbles (> Δl) may be secured as an overlapping area.

  Therefore, the slot 300B requires at least 7 locations (in this embodiment, 9 locations are required).

  Subsequently, the condition of the number of slots in the slot 300B (that is, “B Slot (see FIG. 11)) is generalized.

First, when generalizing the conditions described above, the track direction of the spread T tracks (T = 2k-1, where k is an integer) of the tilt detection pattern and, if the length of one wobble wave and W _W,
(Δl / W _W ) = (2ΠP × k) / W _W = m remainder S The remainder is rounded up to secure (m + 1) wobble as an overlapping area.

Therefore, it is necessary to secure at least {2 × (m + 1) +1} as the number of locations in slot B. In this embodiment, K = 2 and m = 2. Next, with reference to FIG. 13, the conditions required for the slot 300A are examined. FIG. 13 shows an example of adaptive arrangement within one unit of the slot 300A (that is, “A Slot (see FIG. 11)”).

  As shown in FIG. 13, one unit includes nine locations, and the mark area 22 is adaptively arranged in at least one slot. As a condition for arranging the mark area 22, it does not overlap with the mark area 22 already arranged one track before (inner adjacent track) and two tracks before (inner adjacent track before one track) in the radial direction. Thus, for example, the slot 300A-1 may be adaptively arranged from the slot “Slot 1” to the slot “Slot 3” as indicated by the dotted arrow from there. For example, the slot 300A-2 may be adaptively arranged from the slot “Slot 1” to the slot “Slot 5” as indicated by the dotted arrow from there.

  As described above, the mark area 22 (that is, the area having the wobble and land pre-pit structure) and the pattern area 23 (that is, the area having a predetermined pattern across a plurality of tracks) are expressed in units of one wobble period. As an integral multiple, the slot 300A has a 5-slot configuration including 9 wobbles, and the slot 300B has a 1-slot configuration including 9 wobbles. Therefore, these two types of slots can be arranged in a predetermined repetition, and these two types of slots can be independently configured in a form that satisfies different conditions.

  In particular, the slot 300A (that is, “A Slot”) has a 5-slot configuration so as to satisfy the conditions for allocating preformat address data. On the other hand, the slot 300B (that is, “B Slot”) is configured so as to satisfy the conditions for arranging the tilt detection pattern.

  Here, the A slot has a 5-slot structure, and a desired preformat address is set so that address data is not arranged at a position adjacent to an adjacent track and a track one track away (a track adjacent to an adjacent track). Data is adaptively arranged by selecting one of the five slots. Thereby, it arranges so that the preformat data from another track of the track which follows may not be read simultaneously.

  On the other hand, the slot 300B (that is, “B Slot”) is arranged to form a predetermined tilt detection pattern with 7 tracks as one group as a 1-slot configuration. Here, since the track has a CLV configuration, the length of one round is different, so that the positions of adjacent slots are shifted. For this reason, the slot 300B has three locations in the present embodiment before and after the center slot in which the tilt detection pattern is arranged so as not to be affected by the slot when the preformat data of the slot 300A is acquired. A mirror surface area 21 is provided as a “buffer area”.

  By arranging the slot 300A and the slot 300B in the relationship shown in FIG. 12 and FIG. 13, the format arranged under different conditions is not affected. Therefore, these two types of slots can be used appropriately for data creation and recording in accordance with the respective purposes.

  11 to 13, the wobble period in the mark area 22 is set to have a relationship of a predetermined integer ratio with the structural unit of the data format recorded in the recording layer 13. In this embodiment, the mark area 22: 1RUB = 9: 13944 × 2 is set. The relationship between the mark area 22 and the pattern area 23 is also set to a predetermined integer ratio. In this embodiment, the mark area 22: pattern area 23 = 1: 1.

  The mark information is arranged in the mark area 22 immediately before the center track 23TR of the pattern area 23. If the mark information is configured to indicate the address position of the pattern area, the sampling timing, or the arrival timing, not only immediately before the center track 23TR of the pattern area 23, the sample servo mark 300S is arranged in FIG. It can be arranged at any position.

  In the pattern area 23, a predetermined specific parameter detection pattern of the pattern area 23 is formed so that a desired tilt error can be detected in the center track 23TR with 7 tracks as one group GR (see FIG. 12). . Therefore, when the center track 23TR of the pattern area 3 is followed, a predetermined specific parameter detection error at that position can be detected.

  In FIG. 12, when a plurality of tracks are grouped into one group GR, the number of tracks on the guide layer surface of the first beam LB1 when the disc is tilted with respect to the track pitch, the beam diameter of the first beam LB1, and the pickup. As a result determined in consideration of the spread in the example, there are 7 tracks in this embodiment. Since the tilt detection pattern formed in the pattern region 23 is detected symmetrically with respect to the track TR, the number of tracks is generally an odd number.

  As described above, the mark area 22 is arranged immediately before the center track TR in which the specific parameter detection error can be detected by the specific parameter detection pattern among the seven tracks TR belonging to the pattern area 23. It can be recognized that the first beam LB1 is located on the center track TR capable of detecting the specific parameter detection error. Therefore, the sample timing for detecting the specific parameter detection error can be easily created.

  On the other hand, when the first beam LB1 is not on the center track TR of one collective pattern area 23 composed of a plurality of tracks, the wobble signal detected by the push-pull signal is detected with an offset. Therefore, it can be recognized that the first beam LB1 is not on the center track TR.

  In addition, in this embodiment, since the sample servo marks 300S are arranged in the spaced slots in both the track direction and the radial direction (see FIG. 12), the track TR of the guide layer 12 is followed by the first beam LB1. When recording data on the recording layer 13, a continuous tracking error signal is stably generated by sampling the push-pull signal or by sampling the phase difference signal by the phase difference method (DPD). be able to. For example, if a high frequency component of a push-pull signal that is a difference from the left and right divided detectors is removed by LPF (Low Pass Filter), it is possible to remove a wobble component and an unnecessary high frequency noise component. Here, by sampling the tracking error signal including the eccentric component from the inner periphery to the outer periphery, it becomes possible to obtain continuously, and it can be used as a tracking error signal when recording on the recording layer 13.

  As shown in FIG. 14, in an example of data assignment (assignment) in one slot, the first 2 bits or 3 bits out of 9 bits in each slot can detect a SYNC signal (that is, a tracking error signal). Assigned to the sync signal). The subsequent 3 bits are assigned to a slot number (Slot No.), and the subsequent 2 bits are assigned to data (that is, control data, address data, etc.). For example, the data values (Data) “0” to “3” (when the next slot number is “5”) are expressed as bit arrays as shown in the lower half of the figure by the 2-bit data, respectively. Is done.

  Incidentally, for the configuration of the ECC block, for example, 160 bits in 172 bits (= 8 bits × 20) are used, and 10 bytes are used as 10 bytes raw data, and 10 bytes are used as an ECC code.

For example, Reed-Solomon codes are generated for the codes C ₀ ,..., C ₁₉ (Parity C ₁₀ ,..., C ₁₉ ) as follows.

＝{Ｉ(Ｘ)・Ｘ}ｍｏｄ{Ｇ_Ｅ(Ｘ)}

= {I (X) · X } mod {G E (X)}

Ｇ_ｐ(ｘ)＝Ｘ^８＋Ｘ^４＋Ｘ^３＋Ｘ^２＋１
なお、本例では、１ウォブルは、６９×２＝１３８チャネルビットとされている。各スロットの最初の１つのウォブル（言い換えれば、１ビット）が、鏡面領域２１（図９参照）に割り当てられてよい。

G _p (x) = X ⁸ + X ⁴ + X ³ + X ² +1
In this example, one wobble is 69 × 2 = 138 channel bits. The first one wobble (in other words, one bit) of each slot may be assigned to the mirror area 21 (see FIG. 9).

  As described above in detail with reference to FIGS. 1 to 15, according to the track forming method of the present embodiment (see FIG. 6), the recorded information track of the recording layer 13 is continuous from the inner periphery toward the outer periphery. In addition, the track TR of the guide layer 12 is formed by, for example, sample servo marks (see FIGS. 12 and 13) discretely arranged at positions corresponding to recorded information tracks so as to be formed in a spiral shape. In this case, the mark area 22 and the pattern area 23 are discretely formed at predetermined positions or intervals (see FIG. 7). For this reason, a specific parameter detection error can be detected anywhere on the entire surface of the optical disc 11 by a recording / reproducing apparatus described later. As a result, the track pitch and recording linear density (for example, linear recording density, pit pitch, or information transfer speed (that is, recording linear density × movement speed)) that can be recorded or reproduced in each recording layer 13 are set in the multilayer optical disk 11. Highly accurate tilt detection and high accuracy by stable and efficient acquisition of the tilt detection signal in the guide layer 12 different from the recording layer 13 while increasing to the extent that it can be said to be “high density recording” which is the original purpose. The tilt correction can be performed.

  In particular, in the embodiment shown in FIGS. 12 and 13, since the sample servo mark 300S is disposed in the slot which is separated in both the track direction and the radial direction, the track TR of the guide layer 12 is followed by the first beam LB1. When recording data on the recording layer 13, a continuous tracking error signal is stably generated by sampling the push-pull signal or by sampling the phase difference signal by the phase difference method (DPD). be able to. For example, if a high frequency component of a push-pull signal that is a difference from the left and right divided detectors is removed by LPF (Low Pass Filter), it is possible to remove a wobble component and an unnecessary high frequency noise component. Here, by sampling the tracking error signal including the eccentric component from the inner periphery to the outer periphery, it becomes possible to obtain continuously, and it can be used as a tracking error signal when recording on the recording layer 13.

  In particular, as shown in FIG. 14, in this embodiment, SYNC, data, etc. are allocated to the bits in each slot, and it is assumed that a prepit is formed or not for one wobble wave. Partial information necessary for the preformat address configuration can be adaptively arranged in a desired slot as the servo mark 300S. This pre-pit is used to determine presence / absence, and in the optical disc 11 as in the present embodiment, no data is recorded on the guide layer 12, so it is sufficient that LPP can be detected in the initial state. For this reason, it becomes easy to detect the pre-pit signal in a recording apparatus or reproducing apparatus described in detail later.

  In particular, in the embodiment shown in FIGS. 12 and 13, one slot including the mark region 22 or the sample servo mark 300S is not only the adjacent track one track before, but the mark region 22 or sample arranged two tracks before. It is adaptively arranged so as not to overlap with other slots including the servo mark 300S. Therefore, even when the first beam LB1 (for example, a red laser) for reading the guide layer 12 is for a lower density than the second beam LB2 for the BD-R format, it is adjacent when detecting wobbles and prepits. The influence by the mark area | region 22 arrange | positioned to several track | truck TR which was made can be avoided. Therefore, good preformat data can be acquired.

In this embodiment, the mark area 22 is an area where mark information is arranged. The mark area also serves as a “guide area” or a “servo area” according to the present invention. That is, information for tracking servo such as guide information or sample servo marks is also recorded in the mark area 22. In this sense, the mark area 22 can also be referred to as a “servo area 22”. The mark area 221 is an area having both functions by arranging both mark information and guide information in a mixed manner.
<Example of Information Recording / Reproducing Apparatus and Method>
Next, embodiments of the information recording / reproducing apparatus and method according to the present invention will be described with reference to FIGS.

  In FIG. 15, a recording / reproducing apparatus 101 is configured as a disk drive as an example of an “information recording apparatus” and an “information reproducing apparatus” according to the present invention, and is connected to a host computer 201.

  The recording / reproducing apparatus 101 includes an optical pickup 102, a signal recording / reproducing unit 103, a spindle motor 104, a bus 106, a CPU (drive control unit) 111, a memory 112, and a data input / output control unit 113. During recording, the first beam LB1 and the second beam LB2 are irradiated through an objective lens 102L (see FIG. 2) of the optical pickup 102. During reproduction, a tracking light beam is also transmitted through the objective lens 102L. Only the second beam LB2 serving as the same, or both the first beam LB1 and the second beam LB2 are irradiated.

  The host computer 201 includes an operation / display control unit 202, operation buttons 202, a display panel 204, a bus 206, a CPU 211, a memory 212, and a data input / output control unit 213. At the time of recording, data to be recorded is input from the data input / output control unit 213, and at the time of reproduction, the reproduced data is output from the data input / output control unit 213.

  The optical pickup 102 includes a red semiconductor laser that emits the first beam LB1, a blue semiconductor laser that emits the second beam LB2, and a combining / separating optical system including a prism, a mirror, and the like including the objective lens 102L. The optical pickup 102 is configured to irradiate the first beam LB1 and the second beam LB2 coaxially and with different focus (see FIGS. 1 and 2) via a common objective lens 102L.

  Furthermore, the optical pickup 102 receives the reflected light from the optical disk 11 caused by the first beam LB1 via the objective lens 102L, and a light receiving element such as a two-divided or four-divided CCD, and the second beam LB2. And a light receiving element such as a two-part or four-part CCD that receives reflected light from the optical disk 11 through the objective lens 102L. The optical pickup 102 is configured to be able to modulate the second beam LB2 with a relatively high recording intensity during recording and to be set to a relatively low reproducing intensity during reproduction.

  The optical pickup 102 and the signal recording / reproducing unit 103 generate a tracking error signal by, for example, a push-pull method or a phase difference method (DPD) based on a light receiving signal from a light receiving element that receives reflected light from the guide layer 12 at least during recording. In addition, the pre-pit signal or the address information can be reproduced.

  The optical pickup 102 and the signal recording / reproducing unit 103 generate a tracking error signal by, for example, a push-pull method or a phase difference method based on a light receiving signal from a light receiving element that receives reflected light from the recording layer 13 during reproduction. A data signal is generated as a signal corresponding to the amount of light.

  Alternatively, the optical pickup 102 and the signal recording / reproducing unit 103 generate a tracking error signal based on a light receiving signal from a light receiving element that receives reflected light from the guide layer 12 during reproduction, and receive the reflected light from the recording layer 13. A data signal is generated by a light reception signal from the light receiving element.

  The memory 112 and the memory 212 are (i) a computer for controlling each element such as the CPU 111 in the recording / reproducing apparatus 101 and each element such as the CPU 211 in the host computer 201 so that the recording / reproducing operation described below is performed. Program and (ii) various data such as control data, in-process data, processed data, etc. necessary for recording / reproduction operations are used appropriately to temporarily or permanently hold data via the bus 106, bus 206, etc. It is done.

  Particularly in this embodiment, the recording / reproducing apparatus 101 further includes a correction mechanism 105. The correction mechanism 105 is an example of the “processing unit” according to the present invention, and is typically a tilt correction mechanism. The correction mechanism 105, in addition to or in place of the tilt correction mechanism, is an eccentricity correction of the optical disk 11, a disk surface inclination correction mechanism, an optical system aberration correction mechanism, a light beam phase difference correction or distortion correction mechanism, and a light absorption correction. Various correction mechanisms such as a mechanism and a strategy setting mechanism may be used. A specific type of processing (typically tilt correction) is performed on the optical pickup 102 based on the pattern signal (typically tilt detection signal) detected from the guide layer 12 by the correction mechanism 105. For example, in the case of tilt correction, it is performed every time a tilt detection signal is detected, and the tilt servo is locked during the period until the next tilt detection signal is detected.

  Here, with reference to FIG. 16 and FIG. 17, the details of the portion related to the correction performed by the correction mechanism 105 in the recording / reproducing apparatus 101 will be described.

  In FIG. 16, the correction mechanism includes an LPF (low-pass filter) 121, a sample & hold & smoothing circuit 122, an operation (subtraction) & integration & hold circuit 123, an LPF 131, a wobble detector (132), an oscillator 133, and a sample. A timing generation circuit 134 is provided.

  First, a push-pull signal (Push-pull signal) from the light receiving element of the optical pickup 102 is input to the LPF 121 and the LPF 131, respectively, and high frequency noise is cut.

  Subsequently, on the other hand, the output signal from which the high frequency noise has been cut by the LPF 131 is subjected to wobble detection by the wobble detector (132), and is transmitted from the transmitter 133 at a frequency corresponding to the detected wobble. .

  As shown in FIG. 17, a rectangular wave corresponding to the wobble in the disk track shape is output from the transmitter 133 here.

  In FIG. 16, a sample timing signal is generated by the sample timing generation circuit 134 in accordance with this transmission output. As shown in FIG. 17, the sampling timing signal is a rectangular pulse for closing the sampling switch located at the center of the output pulse of the transmitter 133.

  On the other hand, the output signal from which the high-frequency noise has been cut by the LPF 121 is sampled, held, and further smoothed by the sample & hold & smoothing circuit 122. At this time, the sampling timing follows the sample timing signal generated by the sample timing generation circuit 134. As shown in FIG. 17, according to the sample timing signal, a pattern signal (for example, a tilt detection signal) can be detected from the pattern region 23 with good timing.

  The output signals, which are sample 1 and sample 2 from the sample & hold & smoothing circuit 122, are subtracted, integrated and further held by an operation (subtraction) & integration & hold circuit 123. As a result, for example, a specific parameter detection error signal is generated as a pattern signal forming one pattern across seven tracks or based on the pattern signal thus obtained.

  When the specific parameter detection error signal is input to the correction mechanism 105, the driving operation in the correction mechanism 105 is performed according to the value of the signal or the characteristics such as positive / negative or the degree of modulation. For example, in the case of tilt correction, driving is performed so as to reduce the tilt error by an actuator for tilt correction.

  Hereinafter, with reference to FIGS. 18 to 20 in addition to FIG. 15, the configuration and operation of each component of the recording / reproducing apparatus 101 of this embodiment will be described together with the overall operation of the recording / reproducing apparatus 101. 18 shows a recording / reproducing operation in the information recording / reproducing apparatus 101, FIG. 19 shows details of an example of the recording operation, and FIG. 20 shows details of an example of the reproducing operation.

  In FIG. 18, first, the optical disk 11 having the format according to the above-described embodiment is mounted on the recording / reproducing apparatus 101 by manual or mechanical operation by the user (step S11).

  Then, an operation start command corresponding to an operation on the operation button 203 when the user looks at the display panel 204 is generated by the drive-side operation / display control unit 202 and the CPU 111, the host-side CPU 211, and the like. In response to this operation start command, rotation of the optical disk 11 by the spindle motor 104 is started under the control of the signal recording / reproducing unit 103. Before and after this, light irradiation by the optical pickup 102 is started under the control of the signal recording / reproducing unit 103. Further, the reading servo system for the guide layer 12 is operated. That is, the first beam LB1 is irradiated and condensed on the guide layer 12, and the tracking operation is started (step S12).

  The various commands including the operation start command and various data including user data and control data are transferred by the host side bus 206 and the data input / output control unit 213, and the drive side bus 106 and the data input / output control unit. 113.

  Subsequently, irradiation of the track TR with the first beam LB1 is continued on the guide layer 12, and a wobble signal and a prepit signal (a tracking error signal obtained from the at least one of them by the push-pull method or the DPD method) are generated. , Detected from the mark area 22. Further, disk management information recorded in advance as at least one of these signals is acquired by the CPU 111 on the drive side or the CPU 211 on the host side.

  Note that the disc management information may be recorded and read together in a lead-in area, a TOC (Table Of Content) area, etc., located on the innermost circumference side in the guide layer 12. The content may be compliant with the disc management information of an existing DVD, BR disc or the like. The management information is separately recorded in advance or separately in advance in a lead-in area, a TOC area, or the like specially provided in the recording layer, and may be read at this time or at an arbitrary time.

Next, the CPU 111 on the drive side or the CPU 211 on the host side determines whether the requested operation is data recording (step S14). Here, in the case of data recording (step S14: Yes), a recording process for a new optical disc 11 is executed (step S15). This recording process will be described in detail later (see FIG. 19).
On the other hand, when it is not data recording in the determination of step S14 (step S14: No), or when the recording process for the new optical disk 11 is completed in step S15, the request is made by the CPU 111 on the drive side or the CPU 211 on the host side. It is determined whether the operation being performed is data reproduction (step S16). Here, in the case of data reproduction (step S16: Yes), reproduction processing for the new optical disc 11 is executed (step S17). This reproduction process will be described later in detail (see FIG. 20).

  If it is determined in step S16 that the data is not reproduced (step S16: No), or if the reproduction process for the new optical disc 11 is completed in step S17, the operation button 203 indicates that the eject, that is, the ejection of the tray is performed. It is determined whether or not the request is made through the process (step S18). Here, if the ejection is not requested (step S18: No), the process returns to step S14, and the subsequent steps are executed again.

  On the other hand, when ejection is requested in the determination in step S18 (step S18: No), the ejection operation is executed (step S19), and a series of recording / reproducing processes on the optical disc 11 is completed.

  Next, an example of a recording process (step S15 in FIG. 20) for the new optical disc 11 will be described with reference to FIG.

  In FIG. 19, when the recording process is started, first, irradiation of the track TR with the first beam LB1 is continued on the guide layer 12 under the control of the CPU 111 and the signal recording / reproducing unit 103 (that is, The wobble signal and the pre-pit signal are detected from the mark area 22 while the tracking operation is being performed. Thereby, the address information on the track TR is acquired by the CPU 111 or the like. By referring to this address information, the CPU 211 or the like searches for a desired recording address designated as an address to start data recording. That is, the first beam LB1 is moved to the address position. As a result of this search operation, the second beam LB2 having the optical system such as the objective lens 102L in the optical pickup 102 in common with the first beam LB1 (see FIGS. 1 and 2) is also recorded on the recording layer 13. It is moved to a planar position in the recording surface corresponding to the address (step S21).

  Subsequently, under the control of the CPU 111 and the signal recording / reproducing unit 103, the optical pickup 102 applies the focus servo of the second beam LB2 to the desired recording layer 13 on which data is to be recorded (step S22).

  Subsequently, in the state where the focus servo of the second beam LB2 is closed by the optical pickup 102, the tracking servo for the track TR by the first beam LB1 is continued. That is, the tracking servo for the desired recording layer 13 is indirectly performed by the tracking servo for the guide layer 12 (step S23a).

  Subsequently, the correction mechanism 105 performs correction based on the specific parameter detection result (see FIGS. 16 and 17). This correction is performed intermittently or periodically or irregularly according to detection of a pattern signal such as a tilt detection signal. For example, in the case of tilt correction, tilt correction is performed according to the tilt error signal, and after correction, the tilt servo is locked and the next opportunity for correction is waited (step S23b).

  The correction in step S23b may be performed at least partially during the data recording process in the next step S23c.

  Subsequently, data recording on the desired recording layer 13 is started by irradiating the second beam LB2 while modulating it in accordance with the data value to be recorded (step S23c).

  Subsequently, it is monitored by the CPU 111 and the like whether or not a predetermined amount of recording has been completed (step S24). Here, as long as the recording is not completed, the data recording to the recording layer 13 is continued (step S24: No).

  Here, when the recording ends (step S24: Yes), the management information is updated according to the recorded data (step S25). The management information may be recorded together in a lead-in area, a TOC area, or the like provided in at least one of the plurality of recording layers 13. The position may be on the inner peripheral side, but may be on the outer peripheral side or in the middle, or may be recorded in a somewhat dispersed form. In addition to or instead of this, the management information provided in the memory 112, the memory 212, and the like and associated with the optical disc 11 may be updated.

  Thus, a series of recording processes for the new optical disc 11 (step S15 in FIG. 18) is completed.

  Next, with reference to FIG. 20, an example of the reproduction process (step S17 in FIG. 18) for the new optical disk 11 will be described. In this example, the first beam LB is not used for tracking or the like during the reproduction process. That is, in this example, unlike the recording process, the second beam LB2 is also used for tracking.

  In FIG. 16, under the control of the CPU 111 and the signal recording / reproducing unit 103, the focus servo of the second beam LB2 is applied to the desired recording layer 13 from which data is to be reproduced by the optical pickup 102. In parallel or in parallel, tracking servo is applied to the recorded information track by the second beam LB2 (step S31).

  Subsequently, recorded address information on the recorded information track is acquired by the CPU 111 or the like. By referring to this address information, a desired reproduction address designated as an address at which reproduction of desired data is to be started is searched by the CPU 211 or the like. That is, the second beam LB2 is moved to the address position (step S32).

  Subsequently, the correction mechanism 105 performs correction based on the specific parameter detection result (see FIGS. 16 and 17). This correction is performed intermittently or periodically or irregularly according to detection of a pattern signal such as a tilt detection signal. For example, in the case of tilt correction, tilt correction is performed in accordance with the tilt error signal, and after correction, the tilt servo is locked and the next opportunity for correction is waited (step S33a).

  The correction in step S33a may be executed at least partially during the data reproduction step in the next step S33b.

  Subsequently, in a state where the tracking servo and the focus servo are closed by the optical pickup 102, the reflected light caused by the second beam LB2 is received through the objective lens 102L, whereby data from the desired recording layer 13 is received. Is started (step S33b).

  Subsequently, it is monitored by the CPU 111 or the like whether or not the predetermined amount of reproduction has been completed (step S34). Here, the reproduction of data from the recording layer 13 is continued unless the reproduction ends (step 34: No).

  Here, when the reproduction is finished (step S34: Yes), a series of recording processes for the new optical disc 11 (step S17 in FIG. 18) is completed.

  As described in detail with reference to FIGS. 15 to 20 above, since the pattern area is arranged with a plurality of tracks as one group GR, it is possible to freely arrange the tracks within the grouped track, and recording / reproduction is performed. The degree of freedom of arrangement of specific parameter detection points such as tilt error detection points that can be detected by the apparatus 101 can be ensured. Since one pattern area 23 and another adjacent pattern area 23 are independent, it is possible to arrange a specific parameter detection pattern such as a tilt detection pattern independently of each other. However, a flexible arrangement is possible.

  For the recording / reproducing apparatus 101 that simultaneously reads a plurality of high-density tracks TR as the guide layer 12, the pattern region 3 is arranged with the plurality of tracks TR that are simultaneously read as one group GR. The arrangement of is easy to read and can realize an extremely convenient arrangement.

Further, since the groove is wobbled in the guide layer 12 to form the mark area 22, the recording / reproducing apparatus 101 can grasp the exact position of the pattern area 23 from the wobble signal detected in the mark area 22 (FIG. 16). And the detected error signal sample timing can be easily generated. In particular, since the wobble period of the mark area 22 and the section of the pattern area 23 have a predetermined integer ratio (see FIG. 8), sample timing can be easily generated. In the mark area 22, a wobble is formed, and the pattern area 23 is arranged behind the wobble. If the PLL circuit is pulled in by the detected wobble signal, the exact position of the pattern area 23 can be grasped, and the sample timing for sampling the detected error signal can be generated.

As shown in FIG. 21, for example, if presence information indicating that the slot 300B (ie, “B Slot”) exists in the slot 300A (ie, “A Slot”) is included or overlapped, After the slot 500 of the group (corresponding to 3 bits), information indicating that “the pattern area 23 is arranged later and the track currently being read by the first beam LB1 is a center track” Acquired when 500 is read. Accordingly, the position of the tilt error detection pattern in the pattern area 23 can be grasped. Next, referring to FIGS. 22 to 25, the tracking servo can operate in a predetermined frequency band along the track direction. A method of determining the arrangement interval or the longest arrangement interval (that is, an example of the “predetermined distance” according to the present invention) of the mark areas 22 arranged discretely will be described together with the tracking servo system.

  As shown in FIG. 22, the tracking servo system includes an error detector 301 including a subtractor, a sampler 302 including a sampling switch, a capacitor, and a buffer, and an amplifier and equalizer (Amplifier & Equalizer) 303. And an actuator 304.

  A disturbance for tracking servo is input to the error detector 301, and a feedback signal from the actuator 304 is subtracted (minus addition) and output as a subtraction signal. The subtraction signal from the error detector 301 is input to the sampler 302.

  The sampler 302 is configured as a so-called “zero-order hold circuit” that holds sample values. Specifically, a sampling switch that closes at a sampling timing, a capacitor that holds the sampling switch, and a buffer are provided. The subtracter signal is sampled by the sampler 302 at the sampling timing corresponding to the frequency band for operating the tracking servo by the sampling switch, further held by the capacitor, and buffered by the buffer. The sampling timing is generated by a mark signal such as a wobble signal and a prepit signal detected by a light receiving element that receives the first beam LB1. However, the method of generating the sampling timing is not limited to this, and may be generated according to the medium configuration such as a modified example described later. Further, the configuration of the sampler 302 is not limited to this, and needless to say, a “primary hold circuit” or the like may be used.

  The buffer output from the sampler 302 sampled in this way is amplified and equalized by an amplifier and equalizer 303 and further input to the actuator 304.

  In accordance with the input amplified signal, the irradiation position of the first beam LB1 on the guide layer 12 provided in the optical pickup 102 by the actuator 304 (accordingly, the irradiation position of the second beam LB2 on the recording layer 13). ) Is moved in the radial direction. A feedback signal corresponding to the fluctuation is fed back from the actuator 304 to the error detector 301.

  Here, in particular, the sampling timing in the sampler 302 will be examined with reference to FIGS.

  FIG. 23 schematically shows the operation output of the sampler 302 when the eccentric component which is the maximum disturbance element input to the error detector 301 changes. From FIG. 23, it can be seen that the tracking error undulates from the plus side to the minus side with a substantially constant period with respect to time.

  FIG. 24 shows a Bode plot (Bode Plot of zero-order hold) of the transfer function when “zero-order hold” is performed by the sampler 302. In other words, here, the frequency characteristic of the zero hold is shown, and in particular, the gain characteristic (upper characteristic curve) and phase (lower characteristic curve) are shown superimposed in the Bode diagram. Has been. In this example, a case where sampling is performed at 1 ms is shown, but actually, the sampling is performed at a shorter time interval.

  FIG. 24 shows that when the phase characteristic is sampled at 1 KHz, the signal at 100 Hz rotates about several degrees as shown by the characteristic curve portion 1001 in the phase. On the other hand, if the bandwidth around the phase is negligible, 100 Hz, a sample interval of about 10 times (1 KHz) or more is necessary (that is, sampling at a frequency higher than 1 KHz is necessary).

FIG. 25 shows an example of the disk disturbance characteristic and the tracking servo open loop characteristic for the tracking servo. In this example, the “disturbance characteristics of the disc (that is, the optical disc 11)” has an eccentric component of 35 μm on one side up to a frequency of 23.1 Hz, and 1.1 m / S ² in the acceleration region. That is, the disturbance of the disk is approximately flat at 64 db corresponding to 35 μm in the characteristic diagram up to a frequency of 23.1 Hz, and 1.1 m from 0 dB corresponding to 0.022 μm on the higher frequency side. / S ² slope down. The open loop characteristic of the tracking servo is shown as an example of a characteristic capable of suppressing such a disk disturbance. That is, in the characteristic diagram, the open loop characteristic is set to be on the higher gain side at any frequency, and thus disturbance can be suppressed in any frequency band. In this example, f0 (cut-off band) = 2.4 KHz.

  In the case of this example described with reference to FIGS. 23 to 25, the “predetermined distance” is determined as follows.

That is, if the tracking servo band is 2.4 KHz, for example, the influence of the sampler 302 realized as the hold circuit described above can be ignored, so that the time interval T = 10 times corresponds to about 24 kHz. 1 / (24 × 10 ³ ) = 46.7 [μsec]. From the relationship between this time interval T and the rotational linear velocity of the optical disc 11 by the spindle motor 104, as the arrangement interval or arrangement pitch (see FIG. 9) of the two mark areas 22 arranged discretely in the track direction. An example of the longest necessary distance, that is, a “predetermined distance” according to the present invention is determined.

  For example, when the linear velocity v is 4.917 m / sec, the predetermined distance L is obtained as L = v × T≈230 [μm]. That is, when the mark region 22 is inserted at a ratio of 5 slots along the track TR, the slot configuration is determined so that the length of the 5 slots is shorter than 230 [μm], or It is determined how many slots one mark area 22 is to be inserted.

  Note that the method for determining the arrangement interval (that is, arrangement pitch) of the mark area 22 is not limited to this example, and the required servo band as shown in FIGS. May be determined in consideration of the linear velocity or the like.

  As described above in detail with reference to FIGS. 1 to 25, according to the present embodiment, the mirror surface region 21 (or groove region) and the mark region continuously spiral from the inner periphery to the outer periphery. 2 (or a guide area or servo area) is formed with a track TR at a predetermined interval. Then, when recording data on the other recording layer 13 while following the track TR of the guide layer 12, a continuous tracking signal can be stably generated by sampling the push-pull signal.

  In the pattern area 23, a plurality of tracks are grouped as one group, and a predetermined tilt detection pattern is formed in the center track 23TR so that a desired tilt error can be detected. The pattern area 23 has a predetermined position or interval. It is arranged on the medium. Therefore, when the center track 23TR is followed, a predetermined tilt error at that position can be detected.

  Since the mark area 22 and the pattern area 23 are configured in units of one wobble period, a timing signal of the slot 300A and the slot 300B is obtained by configuring a PLL with the wobble signal obtained in the mark area 22. be able to. This makes it possible to generate preformat address acquisition timing and tilt error acquisition timing.

  For the recording / reproducing apparatus 101 that simultaneously reads a plurality of high-density tracks TR as the guide layer 12, the pattern region 23 is arranged with the plurality of tracks TR that are simultaneously read as one group GR. The arrangement of is easy to read and can realize an extremely convenient arrangement.

  In particular, the region where the wobble is not arranged is configured as a mirror surface region 21 as a mirror surface region, so that the first beam LB1 is not affected or hardly affected by other tracks TR. A continuous tracking signal can be obtained by a signal from the mark area 22 that is on-track.

  In the above-described embodiment, based on the wobble period, an integer multiple (or a fraction of an integer) is used as a unit. Therefore, a highly robust timing reference signal can be generated via the PLL using the detected wobble signal. It can also be used for various gates, sample timing signals, and timing signals at the start of recording.

  In particular, according to the slot format mainly related to the slot 300A shown in FIG. 12, a plurality of types of slots can be secured. The mark region 22 is provided with at least five adaptively arranged slots in order to avoid overlapping arrangement between a plurality of tracks. Further, in order to eliminate the influence of the beam diameter, a buffer slot having a length in consideration of the beam diameter (that is, , A buffering slot disposed in the mirror surface region 21 is provided in front of and behind the mark region 22, and the mark region 22 is not disposed in the buffer slot, and at least one of the five consecutive slots is a mark. An area 22 is arranged and predetermined information such as pre-address information is embedded.

  In particular, according to the slot format mainly relating to the slot 300B shown in FIG. 13, the mark regions 22 are arranged at almost predetermined intervals over the entire circumference. At the time of recording on a certain recording layer 13, a continuous tracking signal can be stably acquired by the sampled push-pull signal. Further, in the pattern region 23, a stable tracking signal can be obtained by holding the tracking signal. In addition, since the pattern area 23 is arranged with a plurality of tracks as one group, it is possible to freely arrange the tracks within the grouped track, and to secure the degree of freedom in arranging the tilt error detection points. Moreover, since one pattern area 23 having a plurality of tracks as one unit and another pattern area 23 having a plurality of different tracks as one unit are independent, the arrangement of the tilt detection patterns is irrelevant. It is possible, and as a whole, a flexible arrangement is possible. At this time, as a guide layer 12, for the recording / reproducing apparatus that simultaneously reads a plurality of high-density tracks, the pattern region 23 is arranged with one group GR having the same number of tracks as the number of tracks simultaneously read. This type of arrangement is easy to read and can provide a very convenient arrangement.

By adopting the slot format as shown in FIGS. 12 and 13, the ease of adaptive placement of the slot 300A can be obtained. That is, based on the wobble period, the integral multiple (or a fraction of an integer) is made to correspond as one slot, and a plurality of slots can be configured and adaptively arranged for the slot 300A. The adaptive arrangement with respect to the slot 300A becomes extremely easy. At the same time, the ease of arrangement of the slot 300B is obtained. That is, similarly, by arranging the integral multiple (or a fraction of an integer) as one slot based on the wobble period, the slot 300B can be easily arranged in relation to the slot 300A. When the slot 300B is arranged as a group of a plurality of tracks, free arrangement in the group becomes easy. It becomes easy to arrange the slot 300B for other purposes (for example, arrangement of a track deviation detection pattern). Furthermore, the ease of mixed arrangement of these two types of slots can be obtained. That is, since it is an integer multiple, it becomes easy to set the appearance probability of these two types of slots to a desired ratio. Slots 300B where a plurality of tracks should be arranged as one unit and slots 300B which should be arranged under completely different conditions can be easily and independently arranged, and as a whole, a flexible arrangement is possible. .
<Various modifications>
Hereinafter, various modifications of the embodiment will be described with reference to FIGS.

  FIG. 26 shows a physical track configuration formed in the mark area 22 in the above-described embodiment, and FIGS. 27 to 29 show modifications thereof.

In the present embodiment of FIG. 26, the track TR of the mark area 22 is composed of the wobble WB and the land prepit LPP1. Here, the period between the wobble WB and the land prepit LPP1 is set to an integral multiple, and a land prepit LLP1 is formed at each vertex of the wobble WB. For this reason, detection of the prepit signal and the wobble signal can be facilitated. In the modification of FIG. 27, a sharp curve portion where the wobble amplitude (amount of shake) is locally increased at each vertex of the wobble WB1 of the groove track. 501 is provided. That is, the track TR of the mark area 22 is configured from the special wobble WB1 without the pre-pit. In this case as well, the detection of the wobble signal can be facilitated. In the modification of FIG. 28, the continuous arrangement itself along the track TR of the plurality of grooves 502 dug into pieces is wobbled. Thus, the wobble WB2 is formed. For example, if the wobble WB2 is formed by pre-embossing, the track TRw having such a structure can be constructed in each mark region 22.

  In the modified example of FIG. 29, a plurality of grooves 502 dug into pieces that have a constant radial width and an appropriately modulated length in the track direction are continuously and along the track TR. A linear arrangement (in other words, a “mark pattern”) is a track TR. In this modification, the track TR is not wobbled. For example, if the mark pattern is formed by pre-embossing, the track TRw having such a structure can be constructed in each mark region 22.

  Next, FIG. 30 shows a modification of the basic layer configuration (see FIGS. 1 and 2) of the optical disc 11 in the above-described embodiment. FIG. 30 is a schematic perspective view having the same concept as that of FIG. 1 of the optical disc of the present modification.

  In FIG. 30, in the modified example of the optical disk 11, two guide layers 12a and 12b are provided. For example, the first address information indicating the address position from the inner circumference to the outer circumference is carried on the track TR-a of the guide layer 12a. The track TR-b of the guide layer 12b carries second address information indicating an address position from the outer periphery toward the inner periphery. In this case, the recording layer 13 is also divided into a first recording layer that is recorded in accordance with the first address information and a second recording layer that is recorded in accordance with the second address information. The layer 12a is used to guide the second recording layer using the guide layer 12b. With this configuration, information is recorded from the inner periphery to the outer periphery in one or more first recording layers, and information is recorded from the outer periphery to the inner periphery in one or more second recording layers. The recording operation becomes efficient or easy. In addition, the reliability and stability of the recording operation can be remarkably improved by using two types of address information properly. Therefore, it is possible to realize the optical disc 11 capable of continuous bi-directional recording or bidirectional recording arbitrarily or independently.

  For example, if the first recording layer is recorded / reproduced from the inner circumference to the outer circumference and the second recording layer is recorded / reproduced from the outer circumference to the inner circumference, the recording / reproduction is performed between these two layers. Since the time required for switching is substantially the time required for performing the interlayer jump, it is extremely advantageous when recording / reproducing is performed continuously over a plurality of recording layers. In other words, the same effect as the so-called “Opposite recording” or “Opposite reproduction” in the dual-layer disc can be obtained. That is, as data to be recorded, continuous data such as video data in real time is recorded using the optical disc 11 of the present modified example, and at the time of reproduction, particularly from the end of the first recording layer to the second recording layer. To the beginning, it can be reached almost only by the time of the interlayer jump. This is very advantageous in the case of the embodiment shown in FIG. 1 considering that the interlayer jump and the time for returning the position of the optical pickup 102 from the outer periphery to the inner periphery are further added. In the case of the embodiment shown in FIG. 1, a large amount of memory may be provided in the recording / reproducing apparatus 101 in order to reproduce data without interruption.

  In this way, by using the modification of FIG. 30 together, continuous reproduction can be easily performed in the reproduction apparatus at low cost.

  As described above in detail, according to the present embodiment and the modification, the arrangement interval (arrangement pitch) of the mark areas 22 along the track TR is set to a predetermined distance or less, and the mark area 22 is formed on the entire surface of the optical disc 11. Since they are arranged (discretely), a continuous tracking signal can be obtained by sampling at any position from the inner circumference to the outer circumference of the optical disc 11 of the guide layer 12.

  Further, in particular, the unit of the data format in the recording layer 13 and one cycle of the wobble WB are in an integer multiple relationship, the slot is configured as an integer multiple of one cycle of the wobble WB, and the mark area 22 is associated with this section. Therefore, the adaptive arrangement is facilitated so that the mark regions 22 in the adjacent tracks TR do not overlap (that is, no crosstalk occurs in the wobble signal or the prepit signal). The wobble signal obtained in this way can be used as a timing reference signal generation excellent in robustness or a timing signal generation at the start of recording via a PLL (Phase Locked Loop) circuit.

  In addition, the present invention can be appropriately changed without departing from the gist or concept of the invention that can be read from the claims and the entire specification, and an information recording medium, an information recording apparatus and a method, and the like accompanying such a change, and An information reproducing apparatus and method are also included in the technical idea of the present invention.

11 Optical disc 12 Guide layer 13 Recording layer 21 Mirror surface area 22 Marking area (servo area)
23 pattern area TR track WB wobble LLP1 land prepit LB1 first beam LB2 second beam 102 optical pickup 102L objective lens 101 recording / reproducing apparatus
201 Host computer

Claims (16)

A CLV information recording medium,
A guide layer in which tracks are formed in advance;
A plurality of recording layers laminated on the guide layer,
In the track, (i) a plurality of guide regions each having a physical structure for carrying guide information for guide are discretely arranged at an arrangement interval equal to or less than a predetermined distance set in advance in the track direction along the track. And a plurality of tracks arranged adjacent to each other in the radial direction intersecting with the tracks, and being shifted between the plurality of tracks, and (ii) adjacent to the tracks in the radial direction. For detecting a plurality of signals each having a set of predetermined patterns straddling the plurality of track portions so that a specific type of pattern signal can be detected at a center track portion located at least near the center in the radial direction among the portions. An information recording medium characterized in that an area is arranged.   The guide information related to at least one guide area disposed in front of the center track portion in the track direction among the plurality of guide areas is that the corresponding one of the plurality of signal detection areas follows. The information recording medium according to claim 1, wherein the information recording medium is also configured to function as mark information to be displayed. The track is formed in a spiral shape from the inner periphery to the outer periphery or from the outer periphery to the inner periphery in the information recording medium,
The mark area is disposed immediately before the center track portion in the track direction, and indicates that a corresponding one of the plurality of signal detection areas immediately follows. Information recording media. In the physical structure, the length in the track direction of the guide information and the length in the track direction of the minimum structural unit of data recorded in each of the plurality of recording layers have a predetermined integer ratio. Carry guide information,
The predetermined pattern is defined such that a length in the track direction of the minimum structural unit of the pattern signal and a length in the track direction of the minimum structural unit have a predetermined integer ratio. The information recording medium according to claim 1. The plurality of guide regions are each configured as slots of equal length in the track direction,
The information recording medium according to claim 1, wherein the guide information is arranged in each of the slots so as not to be adjacent to each other between the plurality of tracks in the radial direction. The plurality of signal detection areas are each configured as another slot having the same length as the slot,
The predetermined pattern is arranged in each of the slots so as not to be adjacent to each other between the plurality of tracks in the radial direction and so as not to overlap with the plurality of guide regions. Item 6. The information recording medium according to Item 5. In the physical structure, the length in the track direction of the slot and the length in the track direction of the structural unit of the data format to be recorded on each of the plurality of recording layers have a predetermined integer ratio. And carrying the guide information,
In the predetermined pattern, the length in the track direction of the other slot and the length in the track direction of the structural unit of the data format to be recorded in each of the plurality of recording layers is a predetermined integer ratio. The information recording medium according to claim 6, wherein the information recording medium is configured as follows.   The information recording medium according to claim 1, wherein the plurality of guide areas and the plurality of signal detection areas are mixedly arranged according to different arrangement rules.   The plurality of guide regions and the plurality of signal detection regions are spaced apart from each other with a buffer region interposed therebetween so as not to be adjacent to each other in the radial direction. Information recording medium.   The information recording medium according to claim 1, wherein the physical structure includes at least one of a wobble and a pre-pit structure, and a wobble and a partially notched structure. The track is a guide track for tracking servo,
The physical structure can generate the tracking servo signal that constitutes at least a part of the guide information;
Each of the plurality of guide regions is a servo region for generating the tracking servo signal,
The predetermined distance is preset to a distance at which the tracking servo can operate in a predetermined band,
The plurality of servo regions are arranged so as to be shifted between the plurality of tracks based on the diameter of the tracking servo light beam so that the light beam is not irradiated simultaneously. Item 4. The information recording medium according to Item 1.   The information recording medium according to claim 1, wherein the predetermined pattern is configured to detect a tilt detection signal for tilt detection as the pattern signal. An information recording medium of the CLV system, comprising a guide layer in which a track is formed in advance, and a plurality of recording layers laminated on the guide layer, and (i) guide information for guide is provided on the track. A plurality of guide regions each having a physical structure to be supported are discretely arranged at an arrangement interval equal to or less than a predetermined distance set in advance in the track direction along the track, and a plurality of adjacent regions in the radial direction intersecting the track. (Ii) a center located at least near the center in the radial direction among a plurality of track portions adjacent to each other in the radial direction intersecting the track. A plurality of signal detection areas each having a set of predetermined patterns straddling the plurality of track portions are arranged so that a specific type of pattern signal can be detected in the track portions. An information recording device for recording data on an information recording medium placed thereon,
The guide layer can be irradiated with a first tracking light beam and condensed, and one of the plurality of recording layers can be irradiated with a second light beam for data recording and condensed. Light irradiating means capable of
First light based on the irradiated and condensed first light beam from the guide layer is received, and the carried guide information is acquired based on the received first light, and the received light is received. Based on the first light, the plurality of signal detection regions indicated by the acquired guide information functioning as mark information indicating that a corresponding one of the plurality of signal detection regions follows Each of the acquisition and detection means for detecting the pattern signal,
Tracking servo means for controlling the light irradiation means so as to apply tracking servo in a predetermined band to the track based on the acquired guide information;
Processing means for performing a specific type of processing on the light irradiation means based on the detected pattern signal;
The light irradiation so as to record the data by irradiating and condensing the second light beam to the one recording layer in a state where the processing is performed while the tracking servo is applied. An information recording apparatus comprising: data recording control means for controlling the means. An information recording medium of the CLV system, comprising a guide layer in which a track is formed in advance, and a plurality of recording layers laminated on the guide layer, and (i) guide information for guide is provided on the track. A plurality of guide regions each having a physical structure to be supported are discretely arranged at an arrangement interval equal to or less than a predetermined distance set in advance in the track direction along the track, and a plurality of adjacent regions in the radial direction intersecting the track. (Ii) a center located at least near the center in the radial direction among a plurality of track portions adjacent to each other in the radial direction intersecting the track. A plurality of signal detection areas each having a set of predetermined patterns straddling the plurality of track portions are arranged so that a specific type of pattern signal can be detected in the track portions. It is possible to irradiate and collect the tracking layer with the first light beam for tracking on the information recording medium placed on the recording medium, and to record data on one recording layer of the plurality of recording layers. An information recording method for recording data using a light irradiation means capable of irradiating and condensing two light beams,
First light based on the irradiated and condensed first light beam from the guide layer is received, and the carried guide information is acquired based on the received first light, and the received light is received. Based on the first light, the plurality of signal detection regions indicated by the acquired guide information functioning as mark information indicating that a corresponding one of the plurality of signal detection regions follows An acquisition / detection step of detecting the pattern signal in each of
A tracking servo step for controlling the light irradiation means so as to apply a tracking servo in a predetermined band to the track based on the acquired guide information;
A processing step of performing a specific type of processing on the light irradiation means based on the detected pattern signal;
The light irradiation so as to record the data by irradiating and condensing the second light beam to the one recording layer in a state where the processing is performed while the tracking servo is applied. And a data recording control step for controlling the means. An information recording medium of the CLV system, comprising a guide layer in which a track is formed in advance, and a plurality of recording layers laminated on the guide layer, and (i) guide information for guide is provided on the track. A plurality of guide regions each having a physical structure to be supported are discretely arranged at an arrangement interval equal to or less than a predetermined distance set in advance in the track direction along the track, and a plurality of adjacent regions in the radial direction intersecting the track. (Ii) a center located at least near the center in the radial direction among a plurality of track portions adjacent to each other in the radial direction intersecting the track. A plurality of signal detection areas each having a set of predetermined patterns straddling the plurality of track portions are arranged so that a specific type of pattern signal can be detected in the track portions. An information reproducing apparatus for reproducing data from an information recording medium placed thereon,
The guide layer can be irradiated with a first tracking light beam and condensed, and one of the plurality of recording layers can be irradiated with a second light beam for data reproduction and condensed. Light irradiating means capable of
First light based on the irradiated and condensed first light beam from the guide layer is received, and the carried guide information is acquired based on the received first light, and the received light is received. Based on the first light, the plurality of signal detection regions indicated by the acquired guide information functioning as mark information indicating that a corresponding one of the plurality of signal detection regions follows Each of the acquisition and detection means for detecting the pattern signal,
Tracking servo means for controlling the light irradiation means so as to apply tracking servo in a predetermined band to the track based on the acquired guide information;
Processing means for performing a specific type of processing on the light irradiation means based on the detected pattern signal;
In a state where the processing is performed while the tracking servo is applied, the second light based on the irradiated and condensed second light beam from the one recording layer is received and received. And a data acquisition means for acquiring the data based on the second light. An information recording medium of the CLV system, comprising a guide layer in which a track is formed in advance, and a plurality of recording layers laminated on the guide layer, and (i) guide information for guide is provided on the track. A plurality of guide regions each having a physical structure to be supported are discretely arranged at an arrangement interval equal to or less than a predetermined distance set in advance in the track direction along the track, and a plurality of adjacent regions in the radial direction intersecting the track. (Ii) a center located at least near the center in the radial direction among a plurality of track portions adjacent to each other in the radial direction intersecting the track. A plurality of signal detection areas each having a set of predetermined patterns straddling the plurality of track portions are arranged so that a specific type of pattern signal can be detected in the track portions. It is possible to irradiate and condense the first light beam for tracking onto the guide layer from the placed information recording medium, and at the same time, the first recording layer for reproducing data can be recorded on one of the plurality of recording layers. An information reproduction method for reproducing data using a light irradiation means capable of irradiating and condensing two light beams,
First light based on the irradiated and condensed first light beam from the guide layer is received, and the carried guide information is acquired based on the received first light, and the received light is received. Based on the first light, the plurality of signal detection regions indicated by the acquired guide information functioning as mark information indicating that a corresponding one of the plurality of signal detection regions follows An acquisition / detection step of detecting the pattern signal in each of
A tracking servo step for controlling the light irradiation means so as to apply a tracking servo in a predetermined band to the track based on the acquired guide information;
A processing step of performing a specific type of processing on the light irradiation means based on the detected pattern signal;
In a state where the processing is performed while the tracking servo is applied, the second light based on the irradiated and condensed second light beam from the one recording layer is received and received. And a data acquisition step of acquiring the data based on the second light.

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