JP2003059057A - Measuring method for characteristic data of multi-level optical recording medium and multi-level optical recording medium where pattern for characteristic data measurement is recorded - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for measuring the dynamic range of a multi-level optical recording medium more accurately. SOLUTION: The measuring method for characteristic data of the multi-level optical recording medium capable of multi-level recording to one virtual recording cell has the steps of measuring the light reflection factor of a virtual recording cell array S0 having a plurality of unrecorded virtual recording cells successively formed and measuring the light reflection factor of a virtual cell array S7 having a plurality of virtual recording cells with an allocated recording mark Mg successively formed. The values of the light reflection factor obtained from the virtual recording cell arrays S0 and S7 are values in a state wherein it is guaranteed that adjacent virtual recording cells have the same contents as the virtual recording cells. Consequently, the influence of other adjacent virtual recording cells can be minimized, so the dynamic range of the multi-level optical recording medium can be measured more accurately.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for measuring characteristic data for a multilevel optical recording medium capable of multilevel recording in one virtual recording cell, and more specifically,
The present invention relates to a dynamic range measuring method for a multilevel optical recording medium. The present invention also relates to a multilevel optical recording medium having a characteristic data measurement pattern recorded thereon,
More specifically, the present invention relates to a multi-level optical recording medium on which a dynamic range measuring pattern is recorded.

[0002]

2. Description of the Related Art Conventionally, an optical recording medium typified by a CD and a DVD has been widely used as a recording medium for recording digital data. The data recording method is to record data to be recorded on a track. The method of modulating to the length of the pit along it is widely used.

When such a recording method is used, when reading data, a reproducing laser beam is irradiated along the track of the optical recording medium, and the presence or absence of pits is determined by detecting the reflected light. Further, at the time of writing data, a recording laser beam is irradiated along the track of the optical recording medium to form a pit having a predetermined length.

However, in recent years, there has been a demand for higher density recording on an optical recording medium, and a so-called "multilevel recording system" has been proposed as a method for realizing this. Unlike the above-mentioned conventional recording method, the multi-level recording method is a method of assigning one of a plurality of recording marks having different meanings to one virtual recording cell, and is used for reproduction when reading data. The type of the recording mark assigned to each virtual recording cell is determined by irradiating the laser beam along the track of the multilevel optical recording medium and detecting the reflected light. When writing data, a recording laser beam is irradiated along the tracks of the multilevel optical recording medium, and recording marks to be assigned are recorded in each virtual recording cell.

Virtual recording cells to which recording marks different from each other are different in light transmittance with respect to the reproducing laser beam. Therefore, at the time of writing data, by controlling the irradiation amount of the recording laser beam at a multi-level for each virtual recording cell,
The light transmittance is controlled in multiple levels for each virtual recording cell.

Here, the "light transmittance" means the ratio of the laser beam that has passed through the virtual recording cell to the reproducing laser beam that has been irradiated onto the virtual recording cell. Therefore, when reading data, the reproducing laser beam irradiated to the virtual recording cell passes through the virtual recording cell,
The intensity of the laser beam that is reflected by the reflective layer and then passes through the same virtual recording cell again and is emitted to the outside of the multi-level optical recording medium is detected, whereby the type of recording mark assigned to each virtual recording cell is detected. Is determined.

As is clear from the above, in order to record data with higher density on a multi-level optical recording medium, it is effective to control the light reflectance of each virtual recording cell in multiple stages. . For example, if the light reflectance of each virtual recording cell is controlled in four steps, the information stored in one virtual recording cell is 2 bits, but the light reflectance of each virtual recording cell is controlled in eight steps. Then, the information stored in one virtual recording cell has 3 bits. In order to control the light reflectance in multiple stages, the light reflectance of the virtual recording cell to which the recording mark with the highest light transmittance and the recording mark with the lowest light transmittance are assigned. Also, it is required that the difference from the light reflectance of the virtual recording cell, that is, the so-called dynamic range is sufficiently wide. Therefore, as the recording layer used for the multilevel optical recording medium, a material that can secure a sufficient dynamic range is selected.

On the other hand, as another method for recording data with higher density on a multilevel optical recording medium, there is a method of further reducing the physical area of each virtual recording cell. If the area of each virtual recording cell is reduced, the number of virtual recording cells included in one multi-level optical recording medium can be increased, which enables higher density recording.

[0009]

However, when the area of each virtual recording cell becomes smaller than the converging area of the reproducing laser beam, it becomes impossible to irradiate the reproducing laser beam only to a single virtual recording cell. . in this case,
The reproduction laser beam inevitably irradiates not only the virtual recording cell to be read but also other adjacent virtual recording cells. Therefore, the amount of reflected light is the recording mark assigned to the virtual recording cell to be read. Not only that, it is affected by the recording marks assigned to other adjacent virtual recording cells.

Therefore, even when measuring the dynamic range which is one characteristic data of the multi-level optical recording medium, due to the influence of other adjacent virtual recording cells,
There has been a problem that accurate measurement is difficult.

Therefore, it is an object of the present invention to provide a method for more accurately measuring the dynamic range of a multilevel optical recording medium.

Another object of the present invention is to provide a multi-level optical recording medium on which a dynamic range measuring pattern is recorded, which enables more accurate dynamic range measurement.

[0013]

The object of the present invention is to:
A method for measuring characteristic data for a multi-level optical recording medium capable of multi-level recording in one virtual recording cell, wherein a first virtual recording cell in which first information is recorded is continuously formed. A step of measuring the light reflectance of the virtual recording cell array, and a second step different from the first information.
Of the second virtual recording cell row in which a plurality of virtual recording cells in which the information is recorded are continuously formed, and the optical reflectance is measured with respect to the second virtual recording cell row.

According to the present invention, the values of the light reflectances obtained from the first and second virtual recording cell arrays are guaranteed to be the values of the adjacent virtual recording cells that match the contents of the virtual recording cells. It will be the value in the state where it was written. For this reason, the influence of other adjacent virtual recording cells can be minimized, so that the dynamic range of the multilevel optical recording medium can be measured more accurately.

In a preferred aspect of the present invention, the first information is information corresponding to a virtual recording cell having the highest light reflectance.

In a further preferred aspect of the present invention, the second information is information corresponding to a virtual recording cell having the lowest light reflectance.

The object of the present invention is also a multi-level optical recording medium capable of multi-level recording in one virtual recording cell, wherein a plurality of virtual recording cells in which the first information is recorded are continuously formed. Characteristic data including at least a first virtual recording cell sequence and a second virtual recording cell sequence in which a plurality of virtual recording cells in which second information different from the first information is recorded are continuously formed. This is achieved by a multilevel optical recording medium on which a measurement pattern is recorded.

According to the present invention, since the characteristic data measuring pattern is recorded, it is possible to more accurately measure the dynamic range by measuring the light reflectance using the characteristic data measuring pattern. Become.

In a preferred aspect of the present invention, the first information is information corresponding to a virtual recording cell having the highest light reflectance.

In a further preferred aspect of the present invention, the second information is information corresponding to a virtual recording cell having the lowest light reflectance.

In a further preferred aspect of the present invention, the characteristic data measuring pattern is recorded in the lead-in area.

In a further preferred aspect of the present invention, the first virtual recording cell array and the second virtual recording cell array are continuously formed.

[0023]

DETAILED DESCRIPTION OF THE INVENTION Referring to the accompanying drawings,
A preferred embodiment of the present invention will be described in detail.

FIG. 1 is a cutaway perspective view showing the structure of a multilevel optical recording medium 1 (hereinafter, also referred to as "optical recording medium 1").

The optical recording medium 1 is a CD-R type optical recording medium (write-once type optical recording medium), and includes a substrate 11, a recording layer 12, a reflective film 13 and a protective layer 14 as shown in FIG. It is equipped with. The substrate 11 is formed in a disk shape using a transparent resin as a base material. On one surface (upper surface in FIG. 1) of the substrate 11, a groove 11a for guiding a laser beam is provided from the vicinity of the central portion toward the outer edge portion.
The land 11b is formed in a spiral shape. The recording layer 12 is made of an organic dye such as cyanine, merocyanine, a methine dye and its derivative, a benzenethiol metal complex, a phthalocyanine dye, a naphthalocyanine dye, and an azo dye. The organic dye covers the groove 11a and the land 11b. It is applied and formed. The recording layer 12 is decomposed and deteriorated by being irradiated with a recording laser beam by a recording device, and its light transmittance changes according to the irradiation amount of the laser beam. Reflective film 13
Is a thin film layer for reflecting the reproducing laser beam that has passed through the substrate 11 and the recording layer 12 at the time of reproducing the recorded data recorded on the optical recording medium 1, and is recorded by using a metal such as gold or silver as a main raw material. It is formed on the layer 12 by, for example, sputtering. The protective layer 14 is a layer that protects the reflective film 13 and the recording layer 12, and is formed so as to cover the outer surface of the reflective film 13.

Next, regarding the recording principle of the optical recording medium 1,
A description will be given with reference to the drawings.

In this optical recording medium 1, as shown in FIG. 1, the groove 11a is formed along the rotation direction (circumferential direction) thereof.
.. are virtually defined, and virtual recording cells S, S ... Are defined as recording units.

FIG. 2 is a conceptual diagram conceptually showing the recording marks Ma to Mg recorded on the optical recording medium 1. As shown in FIG. 2, the length of the virtual recording cell S in the direction along the groove 11a is defined to be shorter than the focused beam diameter (beam waist diameter) D.

In this case, the irradiation time of the recording laser beam emitted from the pickup of the recording device (ie,
By controlling the irradiation amount of the laser beam) in multiple stages according to the value of the recording data, as shown in FIG.
Recording marks Ma to Mg (hereinafter, also referred to as “recording marks M” when not distinguished) having different degrees of decomposition and alteration of (mainly organic dye) are formed in the virtual recording cell S.
In the same figure, the degree of decomposition and alteration is conceptually shown by the size of the recording mark M. Further, when the recording data is recorded by the recording laser beam, the recording laser beam is irradiated while rotating the optical recording medium 1, so that the recording mark M becomes an ellipse having a length corresponding to the irradiation time. .

Therefore, when performing multi-level recording on the optical recording medium 1, the light reflectance when the virtual recording cell S is irradiated with the reproducing laser beam is, for example, 7 steps (8 steps including the unrecorded portion). Recording marks Ma to
Degradation and alteration degree of each Mg (change amount of light transmittance)
Stipulate. In this case, the light reflectance increases as the degree of decomposition and alteration of the recording layer 12 decreases. Therefore, the virtual recording cell S to which the recording mark M is not assigned has the characteristic of maximum light reflectance, and the virtual recording cell S to which the smallest recording mark Ma is assigned is the largest light reflectance of the recording marks M. Of the recording marks Mb to M
The light reflectance decreases in the order of the virtual recording cells S to which f is assigned, and the virtual recording cell S to which the largest recording mark Mg is assigned has the characteristic of the minimum light reflectance. Therefore, by controlling the irradiation amount of the laser beam and appropriately setting the area ratio of the decomposed and deteriorated portion (that is, the light transmittance of the recording layer 12), the recording marks Ma to which the light reflectance becomes 7 steps can be obtained.
It becomes possible to form Mg.

Next, the characteristics of the organic dye used in the recording layer 12 of the optical recording medium 1 will be described with reference to the drawings.

The organic dye used in the recording layer 12 generally has the characteristic that the degree of decomposition and alteration increases as the irradiation time (irradiation amount) of the recording laser beam increases. On the other hand, the change in the light reflectance at this time is not linear with the irradiation time (irradiation amount) of the recording laser beam. Also, the irradiation time (irradiation amount) of the recording laser beam
Degradation deterioration due to, the degree is gentle for a while from the start of irradiation, the degree becomes steep and linear after the lapse of a predetermined time, then the degree becomes gentle again, after a certain irradiation time Indicates that the degree hardly increases.

Further, the light transmittance of the organic dye which has not been decomposed and modified, and the light transmission of the organic dye which has been decomposed and modified to the greatest extent (the organic dye which has been decomposed and modified until the degree of decomposition and modification hardly increases). The rate and the amount of change in light transmittance depending on the degree of decomposition and alteration also vary depending on the material of the organic dye used. Therefore, for example, when five kinds of optical recording media 1 in which the recording layers 12 are formed of different organic dyes are produced, each recording layer 12 of each optical recording medium 1 is manufactured.
The absolute light reflectances at are different from each other. Here, the “absolute light reflectance” means the optical reflectance of each optical recording medium 1 in the case where the value of the light reflectance of a disk body having a smooth surface coated with a thin film such as gold by sputtering is 100%. It means the light reflectance in the unrecorded portion (unrecorded virtual recording cell S).

FIG. 3 is a characteristic diagram showing the relative light reflectance characteristics of the optical recording medium 1 using various organic dyes.

The characteristics of the relative light reflectance in each recording layer 12 of each optical recording medium 1 also differ from each other, as shown by the characteristics C1 to C5 in FIG. As shown in the figure, the above-mentioned degree of decomposition and alteration contributes to the slope of the curves of the characteristics C1 to C5. Here, the "relative light reflectance" means the corresponding optical recording when the value of the absolute light reflectance of the unrecorded portion of each optical recording medium 1 (that is, the unrecorded virtual recording cell S) is 100%. It means the light reflectance of each recording portion of the medium 1 (that is, the recorded virtual recording cell S).

Further, due to the fact that the absolute light reflectance and the relative light reflectance differ for each organic dye, the modulation degree and relative dynamic range (D0
7), jitter characteristics, and B.I. E. Various characteristics such as R (bit error rate) are also different. Further, these various characteristics differ not only according to the material of the organic dye but also according to various parameters such as the coating thickness of the organic dye, the structure of the groove 11a (depth or width or shape of the groove) and the material of the reflective film 13. To do. Here, “relative dynamic range (D07)” means the value of the absolute light reflectance of the unrecorded portion of each optical recording medium 1 (that is, the unrecorded virtual recording cell S) is I0.
When the absolute light reflectance value of the virtual recording cell S to which the largest recording mark Mg is assigned is I7, it is defined by (I0-I7) × 100 / I0 (1).

In this case, since the multi-level recording is possible only when the light reflectance of the optical recording medium 1 is accurately controlled in multiple stages, the absolute light of the unrecorded virtual recording cell S having the highest light reflectance is obtained. High reflectance to some extent (for example, 40% ~
80%) and the virtual recording cell S (the virtual recording cell S to which the recording mark Ma is assigned) having the largest absolute light reflectance and the smallest virtual recording cell S (the virtual recording cell S to which the recording mark Mg is assigned). If the difference in the light reflectance with the above is not large to some extent, it becomes difficult to reproduce the recorded data recorded in multi-level. From this viewpoint, the relative dynamic range (D07) is preferably 50% or more.

Such a relative dynamic range (D0
In the case of measuring 7), a recording laser beam is applied to a certain virtual recording cell S to assign a recording mark Mg, and then a reproducing laser beam is applied to determine the absolute light of the unrecorded virtual recording cell S. Reflectance and
The absolute light reflectance of the virtual recording cell S to which the recording mark Mg is assigned may be measured. However, as described above, since the length of the virtual recording cell S in the direction along the groove 11a is defined to be shorter than the focused beam diameter (beam waist diameter) D, a single reproduction laser beam is used. It is not possible to irradiate only the virtual recording cell S, and the reproducing laser beam is irradiated not only to the virtual recording cell S that is the measurement target but also to another adjacent virtual recording cell S. Therefore, the absolute light reflectance of the reproducing laser beam is affected by the recording mark assigned to another virtual recording cell S adjacent to the virtual recording cell S that is the measurement target.

In order to eliminate such an influence, in the present embodiment, the dynamic range measuring pattern 20 is recorded on the optical recording medium 1, and the relative dynamic range (D07) is measured by reading out the dynamic range measuring pattern 20. It

FIG. 4 is a conceptual diagram conceptually showing the virtual recording cell array in which the dynamic range measuring pattern 20 is formed.

As shown in FIG. 4, the dynamic range measuring pattern 20 has ten consecutive unrecorded virtual recording cell rows S0 and ten consecutive recording marks Mg.
Of the virtual recording cell column S7 to which is assigned. Although not particularly limited, the lead-in area is preferable as a position where such a dynamic range measurement pattern 20 is formed. The lead-in area is an area that is first read when the optical recording medium 1 is loaded in the recording / reproducing apparatus. In the optical recording medium 1, in addition to the maximum light reflectance information and the minimum light reflectance information, the optical recording medium is recorded. Information indicating that the medium 1 is a multi-level optical recording medium (hereinafter, also referred to as “medium specifying information”) and an unrecorded portion of the recording mark M are recorded or recorded by, for example, 7-step multi-level recording. Various information such as information (hereinafter, also referred to as “recorded data stage information”) indicating that the information is recorded is recorded.

In the dynamic range measuring pattern 20 shown in FIG. 4, the unrecorded virtual recording cell array S
Although 0 is arranged on the upstream side and the virtual recording cell row S7 to which the recording mark Mg is allocated is arranged on the downstream side, they may be arranged in reverse.

In the measurement of the relative dynamic range (D07), such a dynamic range measuring pattern 20 is irradiated with a reproducing laser beam, and the absolute light reflectance of the unrecorded virtual recording cell row S0 and the recording are recorded. It is calculated by measuring the absolute light reflectance of the virtual recording cell array S7 to which the mark Mg is assigned and substituting these into the above equation (1). Furthermore, as the absolute light reflectance used for measuring the relative dynamic range (D07),
For the unrecorded virtual recording cell sequence S0, the first virtual recording cell S0-start and the last virtual recording cell S0-
Absolute light reflectance other than end is used, and the recording mark Mg
For the virtual recording cell row S7 to which is assigned, absolute light reflectances other than those of the first virtual recording cell S7-start and the last virtual recording cell S7-end are used. As a result, the value of the absolute light reflectance used for measuring the relative dynamic range (D07) is the same as that of the adjacent virtual recording cell S.
Is a value in a state in which it is guaranteed that the value coincides with the content of the virtual recording cell S.

As described above, the relative dynamic range (D07) using the dynamic range measurement pattern 20 is used.
According to the above measurement, the absolute light reflectance of the unrecorded virtual recording cell S can be obtained under the condition that the decrease in the value due to the influence of another adjacent virtual recording cell S is minimal, and the recording mark Mg As the absolute light reflectance of the virtual recording cell S to which is assigned, a value can be obtained in a situation where the increase in the value due to the influence of another adjacent virtual recording cell S is the smallest. This makes it possible to measure the relative dynamic range (D07) more accurately.

Next, an optical recording / reproducing apparatus 40 for recording recording data on the optical recording medium 1 and reproducing the recording data will be described.

FIG. 5 is a block diagram schematically showing the structure of the optical recording / reproducing apparatus 40.

As shown in FIG. 5, the optical recording / reproducing apparatus 4 is used.
Reference numeral 0 is a so-called CD-R recorder, which includes a spindle servo 41, a spindle motor 42, a pickup 43,
A focus tracking servo 44, a feed servo 45 and a controller 46 are provided. Spindle motor 42
Is controlled by the spindle servo 41 to rotate the optical recording medium 1 under the condition of constant linear velocity. Under the control of the control device 46, the pickup 43 drives a laser light source (both not shown) by a laser driver to irradiate the optical recording medium 1 with a recording laser beam or a reproducing laser beam. As a result, the virtual recording cell S
The recording mark M is recorded with respect to, and the electric signal is output from the virtual recording cell S according to the level of the reflected laser. In this case, at the time of recording the recording data, the laser driver of the pickup 43 follows the control of the control device 46 and, according to the content of the recording data to be recorded, the irradiation amount of the laser beam with which one virtual recording cell S is irradiated. (The number of laser pulses and / or irradiation power, pulse height, etc.) is adjusted. As a method of adjusting the irradiation amount of the laser beam, in addition to the adjusting method by the laser driver, an optical modulator is arranged on the optical path of the laser beam, and the control device 46 drives and controls the optical modulator. It can also be adjusted.

The pickup 43 is provided with an objective lens and a half mirror (neither is shown), and a recording or reproducing laser beam is recorded on the recording layer 12 of the optical recording medium 1.
Focus on. Specifically, the objective lens is subjected to focus tracking control by the focus tracking servo 44, whereby the recording or reproducing laser beam is focused on the recording layer 12 of the optical recording medium 1.
The pickup 43 is reciprocated by a feed servo 45 between the inner peripheral side and the outer peripheral side along the diameter direction of the optical recording medium 1. The control device 46 controls the drive of the spindle servo 41, the pickup 43, the focus tracking servo 44, and the feed servo 45, and at the same time, records the recording data recorded on the recording layer 12 based on the electrical signal output from the pickup 43. Decipher.

As described above, according to this embodiment, since the relative dynamic range (D07) is measured using the dynamic range measuring pattern 20, the absolute light reflectance of the unrecorded virtual recording cell S is calculated. , A value under the condition that the value is less reduced by the influence of another adjacent virtual recording cell S can be obtained, and the absolute light reflectance of the virtual recording cell S to which the recording mark Mg is assigned can be obtained as the other adjacent It is possible to obtain the value under the condition that the increase in the value due to the influence of the virtual recording cell S is the smallest. This makes it possible to measure the relative dynamic range (D07) more accurately.

The present invention is not limited to the above embodiments, and various modifications can be made within the scope of the invention described in the claims, and these are also included in the scope of the present invention. It goes without saying that it is a thing.

For example, in the above-described embodiment, the dynamic range measuring pattern 20 is composed of a series of 10 unrecorded virtual recording cell rows S0 and a series of virtual recording cell rows to which 10 continuous recording marks Mg are assigned. Although it is configured by S7, the number of virtual recording cells S configuring the unrecorded virtual recording cell sequence S0 and the number of virtual recording cells S configuring the virtual recording cell sequence S7 to which the recording mark Mg is assigned are 10 However, the number is not limited to this, and other numbers may be used.

However, as described above, the first virtual recording cell S
Since 0-start and S7-start and the last virtual recording cells S0-end and S7-end are not suitable for measuring the absolute light reflectance, the number of virtual recording cells S that make up the virtual recording cell sequence S0. Also, the number of virtual recording cells S forming the virtual recording cell column S7 must be at least three. On the other hand, if the number of virtual recording cells S that make up the virtual recording cell row S0 and the virtual recording cell row S7 is too large, the number of available virtual recording cells decreases, so these virtual recording cell rows S0 and Recording cell row S7
It is preferable to set the number of virtual recording cells S constituting the above to 30 or less. Furthermore, the virtual recording cell sequence S0
Of the virtual recording cells S that make up the
It is not necessary that the number of the virtual recording cells S that configure the above-mentioned S be the same, and these may be different from each other.

Further, in the above-mentioned embodiment, the dynamic range measuring pattern 20 is composed of the unrecorded virtual recording cell sequence S0 and the virtual recording cell sequence S7 to which the recording mark Mg is assigned. The pattern is not limited to this, and the dynamic range measurement pattern may be configured by a plurality of virtual recording cell rows made of other combinations. For example, the unrecorded virtual recording cell sequence S0 and the virtual recording cell sequence S4 to which the recording mark Md is assigned may form a dynamic range measurement pattern.
Virtual recording cell sequence S1 and recording mark M to which a is assigned
The dynamic recording pattern may be configured by the virtual recording cell array S6 to which f is assigned. When the former dynamic range measurement pattern is used, the absolute light reflectance of the unrecorded virtual recording cell S and the recording mark Md
It is possible to accurately measure the relative dynamic range (D04) with respect to the absolute light reflectance of the virtual recording cell S to which is assigned, and when the latter dynamic range measurement pattern is used, the recording mark Ma is assigned. The relative dynamic range (D16) between the virtual recording cell S and the absolute light reflectance of the virtual recording cell S to which the recording mark Mf is assigned can be accurately measured.

In the above embodiment, the dynamic range measuring pattern 20 is composed of the two virtual recording cell arrays S0 and S7. However, the number of virtual recording cell arrays forming the dynamic range measuring pattern is as follows. The present invention is not limited to this, and the dynamic range measurement pattern may be composed of three or more virtual recording cell rows. For example, the unrecorded virtual recording cell sequence S0, the virtual recording cell sequence S3 to which the recording mark Mc is assigned, and the virtual recording cell sequence S7 to which the recording mark Mg is assigned may form a dynamic range measurement pattern. Absent. When such a dynamic range measurement pattern is used, a plurality of relative dynamic ranges (D0
7, D03 and D37) can be measured.

Further, in the above embodiment, the two virtual recording cell arrays S0 and S7 forming the dynamic range measuring pattern 20 are continuously formed.
Other virtual recording cells may exist between these virtual recording cell rows S0 and S7.

In the above embodiment, the recording layer 1
Although the example in which the organic dye is adopted as 2 is described, the multilevel optical recording medium in the present invention is not limited to this, and an organic dye or an inorganic material other than the above is used for the recording layer 1.
It can be applied to the multilevel optical recording medium used in
It can also be applied to a multilevel optical recording medium for multilevel recording by phase change or magneto-optical.

Further, in the above embodiment, an example in which the optical recording medium 1 is configured as a CD-R type optical recording medium has been shown, but the present invention is not limited to this, and other optical recording is possible. It is generally applied to a medium, and is not limited to a disk-shaped rotating body.

In the above embodiment, the optical recording medium 1 has a structure in which the recording and reproducing laser beams are irradiated from the substrate 11 side, but the reflective layer, the recording layer, and the protective layer are sequentially formed on the substrate. It can also be applied to an optical recording medium that is laminated and has a structure in which a recording and reproducing laser beam is irradiated from the protective layer side.

Further, in the above-described embodiment, the recording marks Ma to Mg of seven stages having different degrees of decomposition and alteration from each other are recorded in the virtual recording cell, so that one virtual recording cell stores 3-bit information. However, the number of recording steps is not limited to this, and any number of steps may be used as long as one virtual recording cell can store information exceeding 1 bit.

[0060]

As described above, according to the present invention, a method for more accurately measuring the dynamic range of a multilevel optical recording medium is provided. Further, according to the present invention, there is provided a multi-level optical recording medium in which a dynamic range measuring pattern capable of more accurately measuring a dynamic range is recorded.

[Brief description of drawings]

FIG. 1 is a cutaway perspective view showing a configuration of a multilevel optical recording medium 1.

FIG. 2 is recording marks Ma to M recorded on an optical recording medium 1.
It is a conceptual diagram which shows g conceptually.

FIG. 3 is a characteristic diagram showing relative light reflectance characteristics of the optical recording medium 1 using various organic dyes.

FIG. 4 is a conceptual diagram conceptually showing a virtual recording cell array in which a dynamic range measuring pattern 20 is formed.

5 is a block diagram schematically showing a configuration of an optical recording / reproducing device 40. FIG.

[Explanation of symbols]

1 Multi-level optical recording medium 11 board 11a groove 11b land 12 recording layers 13 Reflective film 14 Protective layer 20 Dynamic range measurement pattern 40 Optical recording / reproducing apparatus 41 Spindle servo 42 spindle motor 43 pickup 44 Focus tracking servo 45 feed servo 46 Control device

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Shuji Tsukamoto             1-13-1, Nihonbashi, Chuo-ku, Tokyo             -In DC Inc. (72) Inventor Takashi Dorai             1-13-1, Nihonbashi, Chuo-ku, Tokyo             -In DC Inc. (72) Inventor Yutaka Taya             1-13-1, Nihonbashi, Chuo-ku, Tokyo             -In DC Inc. (72) Inventor Motohiro Inoue             1-13-1, Nihonbashi, Chuo-ku, Tokyo             -In DC Inc. F term (reference) 5D029 JA04 JB11 JB21 JC02                 5D090 AA01 BB03 CC04 DD03 EE11                       EE13 GG21 HH01

Claims (8)

[Claims] 1. A method of measuring characteristic data for a multilevel optical recording medium capable of multilevel recording in one virtual recording cell, wherein a plurality of virtual recording cells in which first information is recorded are continuously formed. Measuring a light reflectance of the first virtual recording cell array, and a plurality of virtual recording cells continuously recording second information different from the first information. Measuring the light reflectance with respect to the second virtual recording cell array. 2. The characteristic data measuring method according to claim 1, wherein the first information is information corresponding to a virtual recording cell having the highest light reflectance. 3. The characteristic data measuring method according to claim 1, wherein the second information is information corresponding to a virtual recording cell having the lowest light reflectance. 4. A multi-level optical recording medium capable of multi-level recording in one virtual recording cell, wherein a first virtual recording cell in which a plurality of virtual recording cells in which first information is recorded is continuously formed. The recording cell row and the second information different from the first information
The multi-level optical recording medium on which the characteristic data measuring pattern is recorded, which has at least a second virtual recording cell row in which a plurality of virtual recording cells on which the information is recorded are continuously formed. 5. The multilevel optical recording medium according to claim 4, wherein the first information is information corresponding to a virtual recording cell having the highest light reflectance. 6. The multilevel optical recording medium according to claim 4 or 5, wherein the second information is information corresponding to a virtual recording cell having the lowest light reflectance. 7. The pattern for measuring characteristic data is recorded in a lead-in area.
7. The multilevel optical recording medium according to any one of items 1 to 6. 8. The multi according to claim 4, wherein the first virtual recording cell array and the second virtual recording cell array are continuously formed. Level optical recording medium.