KR20050049439A - Multilayered recording media and writing and/or replaying method therdof - Google Patents

Abstract

SUMMARY OF THE INVENTION An object of the present invention is to provide a multilayer recording medium and a recording and / or reproducing method thereof capable of improving recording / reproducing performance, such as facilitating power control of a laser diode or gain control of a photodetector.

A multi-layer recording medium according to the present invention includes at least two or more recording layers, the first recording layer and the second recording layer having different recording densities, and recognition information defining the recording layer, and the corresponding recording layer. Its feature is that it contains characteristic information about.

In addition, the data recording and / or reproducing method for a multi-layer recording medium according to the present invention includes at least two or more recording layers, wherein the first recording layer and the second recording layer have different recording densities, This feature is characterized in that the recognition information to be defined and the characteristic information of the recording layer are read out from a specific area to control data recording and / or reproduction of the recording layer.

Description

Multilayered recording media and writing and / or replaying method therdof}

The present invention relates to a multilayer optical disc and a driving method thereof.

As a digital information storage medium, optical discs, such as commercially available CDs (Compact Discs), and DVDs (Digital Versatile Discs) in which a large amount of information is stored are compared to CDs. Recently, a disk having a larger capacity is required to store high-definition data such as digital TV, and research and development on this is being actively conducted.

In order to achieve high capacity while maintaining the same size as CD, DVD, etc., a high-density disc with higher track density or the like is required, and for this purpose, the spot diameter of the reproduction light beam must be reduced. Accordingly, the use of a short wavelength laser in the blue band and an objective lens having a large numerical aperture (NA) should be accompanied. On the other hand, there is a method of increasing the recording capacity by using a plurality of recording layers.

As described above, there is a problem in driving a disk having a plurality of recording layers (hereinafter referred to as a multilayer disk).

When there are more layers and multiple specifications are embedded in one disc, the reflectance of each layer may be lower than the standard suggested by the specification. In the case of DVD, the sector information only indicates whether the reflectance is 40% or more. In the case of a dual layer in a DVD, a layer farther from the head has a lower reflectance so that the power of the laser diode (LD) of the optical pickup is increased or the gain of the photodetector (PD) is increased. Access the floor.

However, in the case of three or more layers, it is not easy to determine how much the LD power up or how much the PD gain should be. In particular, when using the method of changing the PD gain, the gain selection of the current / voltage conversion amplifier (I / V amp) connected to the PD cannot be changed to an arbitrary magnification because only a few steps are predetermined.

A method of changing the LD power or the PD gain may be used by using the magnitude of the focus error signal generated in the corresponding layer or the magnitude of the RF signal read after the focus servo is turned on. However, in case of adjusting LD power or PD gain by using focus error, it is difficult to check the magnitude of the focus error in the low reflectance layer generated in each layer when there are multiple layers.

In addition, it is more difficult to adjust the LD power or the PD gain by using the high frequency (RF) signal size by turning on the focus servo on each layer.

However, these methods suffer from problems. In the former method, the skew is mechanically correct, but in reality, since the amount of skew per pickup is different, reproduction data cannot be obtained equally for all devices. That is, when mass production is a method that can have a high defect rate.

In addition, the latter method is applied to a device that plays various types of discs, for example, a device that combines CD and DVD is not adjusted by adjusting the skew by playing one of the discs, CD or DVD. Other discs have relatively poor playback performance. The reason for this is that aberrations (errors) for CDs and DVDs are different depending on pickups, and even if skew is adjusted on the DVD, it may adversely affect CD playback in some cases.

Accordingly, an object of the present invention is a multilayer recording medium and its recording and / or reproducing method capable of improving recording / reproducing performance, such as facilitating power control of a laser diode or gain adjustment of a photodetector, for driving a multilayer disk. To provide.

In order to achieve the above object, the multilayer recording medium according to the present invention comprises at least two or more recording layers, wherein the first recording layer and the second recording layer have different recording densities, and define the recording layer. This feature is characterized in that it includes recognition information and characteristic information on the recording layer.

Further, in order to achieve the above object, the data recording and / or reproducing method of the multi-layer recording medium according to the present invention comprises at least two or more recording layers, wherein the first recording layer and the second recording layer have different recording densities. And the recognition information defining the recording layer and the characteristic information of the recording layer from the specific region to control data recording and / or reproduction of the recording layer.

Other objects, features and advantages of the present invention will become apparent from the detailed description of the embodiments with reference to the accompanying drawings.

Hereinafter, an embodiment according to the present invention will be described with reference to FIGS. 1 to 6. In addition, the embodiments will be described below for convenience.

(First embodiment: a disk in which a plurality of recording layers of one format are formed)

This is the case with at least two recording layers and the recording layers having the same physical format. In this case, the relative reflectances of the following recording layers are recorded in the lead-in area of the first recording layer (layer 0) closest to the light source. For example, the relative reflectance when the reflectance of the first recording layer (layer 0) is 1 can be recorded. Details of the related data structure recorded in the lead-in area will be described later.

The reflectance recorded as described above is first read from the corresponding region (lead-in region) during data recording or reproduction, and stored in the memory of the recording / reproducing apparatus, and when reflecting between recording layers, the reflectance of the layer being reproduced It is easy to calculate the power of LD and gain of PD by easily calculating the reflectance of the target layer.

(Second embodiment: Disk in which recording layers of various formats are formed)

In the case where the plurality of recording layers are in different formats, for example, the recording layer of the CD format, the recording layer of the DVD format, and the recording layer of the next-generation disc (hereinafter referred to as HD-DVD) format are each separated from the light source. The disk is composed of three recording layers in total (see FIG. 1).

In the lead-in area of the CD recording layer, which is the recording layer closest to the light source, the relative reflectances for the next recording layers, the DVD recording layer and the HD-DVD recording layer, are recorded. In other words. This is the relative reflectance of the wavelength of the laser diode corresponding to the CD.

Similarly, in the DVD recording layer as the next recording layer, the relative reflectance (based on LD wavelength corresponding to DVD) for the HD-DVD recording layer as the next recording layer is recorded in the lead-in area as described above.

Therefore, as in the first embodiment, the recording / reproducing performance can be improved by effectively adjusting the power of the LD and the gain of the PD by using the reflectances of the current layer and the target layer when moving between recording layers.

Also, as shown in the disk of the composite structure of FIG. 1, even when several formats each form a plurality of layers (layer 0, layer 1, --- layer n as in the DVD recording layer in FIG. 1), the present embodiment The example and the first embodiment can be applied in combination.

(Third embodiment)

In the disk of the complex structure as shown in Fig. 1, in the lead-in area of the recording layer, which is the recording layer closest to the light source, the relative reflectances of the next recording layers, the DVD recording layer and the HD-DVD recording layer, are recorded. The relative reflectance with respect to the wavelength of the laser diode (for example, blue LD) corresponding to DVD is recorded. In other words, reflectance reflecting backward compatibility is recorded.

Similarly, in the lead-in area of the DVD recording layer, the relative reflectance of the HD-DVD recording layer on the basis of LD corresponding to the HD-DVD is recorded.

This makes it possible to use a blue LD corresponding to a high-density disc (HD-DVD) as one light source, and to effectively reproduce DVD and CD, which are the lower disc formats, by using a method such as adjusting the numerical aperture. This allows adjustment of LD power, PD gain, and the like.

(Example of lead-in data structure according to the present invention)

An example of the data structure such as the relative reflectance described above will be described with reference to Figs.

FIG. 2 shows a data structure recorded in the lead-in area of the disc, and has been described above in the Disc Structure item of Physical Format Information of Control Data in the lead-in area. The same information is recorded. An example described in the disc structure section according to the present invention is shown in FIG. 3. On the other hand, such information may exist in each lead_in area of each recording layer.

First, assuming that various types of discs according to the present invention are known, the format type (Spec type) information is included as 1 byte as information for disc format included in the disc. This is specifically illustrated in FIG. 4. As shown in FIG. 4, information indicating whether a CD, a DVD, or an HD-DVD is embedded (bit 2, bit 3, bit 4) corresponding to the case of including a recording layer of a complex format as in the second embodiment described above. And information (bit 1, bit 0) indicating the type of the recording layer in progress, that is, the current recording layer. Furthermore, it may include the total number of layers of the same format as the current recording layer, that is, the number of layers of a format including the lead-in area currently being read.

Secondly, the characteristic information of each layer is included as 3 bytes for each recording layer of a specific format, and the relative reflectance information as described above is included here. As shown in detail in FIG. 5, "Layer Number" indicating the number of recording layers of the same format, "Track Path" indicating whether or not the track progress direction coincides with the first same format layer (match or reverse), and furthermore, the recording layer is read only. A "Layer Type" indicating whether the (ROM) type or the Rewritable type is recorded in one byte.

In addition, "Line Density" information (unit: µm) indicating the density in the track progress direction, that is, the linear density, and "Track Density" information indicating the density between tracks, that is, the track density, are included as 1 byte.

In addition, the relative reflectance or the inverse of the relative reflectance as described above is displayed. In addition, it may also include information (Reflectivity Index) indicating the inverse of the reflectance in case of mixing the two.

Third, in the case of including the recording layer of the complex format as described above, the information on the recording layer of the lower format than the format is included as "low Spec" information. 6 shows one example thereof. First, there is "Spec Indentity" information as format identification information, which indicates which of the other formats included in the disc is information. In addition, reflectance information (Reflectivity) records the relative reflectance of another specific format (layer 0 reference) relative to the LD used by the format currently being accessed (in progress). That is, it corresponds to Embodiment 3 mentioned above. The rest is as described with reference to FIG. 5.

As mentioned above, although one Embodiment of this invention was described, this invention is not limited only to the said Example, It can implement by a sufficient correction or modification within the range which does not deviate from the summary of this invention.

As described above, according to the present invention, since the relative reflectance of each recording layer is recorded in the lead-in area of each recording layer of the disc, when it is read and stored during the initial driving, it is reproduced during the interlayer movement (jump). It is possible to reliably calculate the reflectance of the layer and the reflectance of the target recording layer to adjust the LD power or the PD gain, thereby reliably guaranteeing the recording / reproducing performance.

Furthermore, even in a disc in which recording layers of various formats are combined, relative low reflectances based on wavelengths corresponding to other formats are provided, so that lower long-wavelength discs are compatible with, for example, LDs for short wavelengths. , Backwards compatibility).

1 is a view showing an example of a multilayer optical disk to which the present invention is applied;

2 is a data structure diagram of a lead_in area of a disc;

3 to 6 are data structure diagrams of disc structure items according to the present invention;

Claims (2)

At least two or more recording layers, the first recording layer and the second recording layer having different recording densities, And recognition information defining the recording layer and characteristic information of the recording layer. At least two or more recording layers, the first recording layer and the second recording layer having different recording densities, Recognizing information defining the recording layer and characteristic information of the recording layer are read from a specific area to control data recording and / or reproduction of the recording layer. Way.