JP2007335078A - Optical disc medium and information recording method - Google Patents

Abstract

An optical disk medium capable of recording management information at high density while suppressing crosstalk from adjacent track grooves.
An optical disc medium forms a wobble with a first frequency in a single section, a first wobble shape portion having first information, and a wobble with a second frequency in a single section. And a second wobble shape portion having the second information. Another example of the optical disk medium is an optical disk medium having a wobbled track groove, and in a single section, a first convex shape convex in the outer peripheral direction and a first convex shape convex in the inner peripheral direction. The first wobble shape portion having two convex shapes and the first information is provided, and the convex portion continues in one direction of the inner peripheral side or the outer peripheral side in a single section. A second wobble shape portion having two convex waveforms and having second information.
[Selection] Figure 1

Description

  The present invention relates to an optical disk medium in which information is recorded in the shape of a track groove, an information recording method on the optical disk medium, and an information recording apparatus. In particular, the present invention relates to an information recording method for recording information in a management area on the inner circumference side of an optical disk medium.

  As shown in FIG. 14, the optical disk medium 50 generally has a track groove 52 that spirally extends from the inner peripheral side to the outer peripheral side while increasing the radius of the spiral. Usually, the management area in which information is recorded in advance is provided on the inner circumference side, and the information recording area is provided on the outer circumference side. In recent years, optical disc media are required to have a high density for handling moving images and the like. For this reason, as the density of the entire optical disk medium increases, the management information recorded in the management area on the inner circumference side has become enormous, and there is a demand for higher density in the management area.

  However, the area on the inner peripheral side is small, so in the case of a huge amount of management information, if management information is recorded at high density with pre-pits as in the prior art, crosstalk may occur between adjacent track grooves. .

  Therefore, an object of the present invention is to record management information at a high density while suppressing crosstalk from adjacent track grooves.

  The optical disk medium according to the present invention is characterized in that information is recorded by selecting one of three types of wobble shape portions corresponding to ternary information as wobble shape portions wobbled by track grooves. And

An optical disk medium according to the present invention is the optical disk medium, wherein a first direction out of the directions perpendicular to the longitudinal direction of the track groove is positive, and the second direction is opposite to the first direction. When the direction is negative, the three types of wobble shapes are
A flat wobble-shaped portion having an amplitude of 0 from the longitudinal direction of the track groove;
A positive pulse wobble shape portion having a positive amplitude from the longitudinal direction of the track groove;
The track groove has three types of wobble shape portions including a negative pulse wobble shape portion having a negative amplitude from the longitudinal direction.

  The shape of the positive / negative pulsed wobble shape may be any of a rectangular shape, a trapezoidal shape, an arc shape, a triangular shape, and the like, and is not limited to the listed shapes.

  Furthermore, the optical disc medium according to the present invention is the optical disc medium, wherein the pulse widths of the positive pulse wobble shape portion and the negative pulse wobble shape portion are equal to or greater than the width of the track groove, and the track It is characterized in that it is ¼ period or less of the reference signal recorded in the wobble shape portion of the groove.

  The lower limit of the pulse width is determined by the beam diameter forming the track groove, that is, the width of the track groove is the lower limit. Further, in order to shift the signal portion between the adjacent track grooves, the length of the wobble shape portion of ¼ period or less becomes the upper limit value. The pulse width is preferably in the range of 1/6 cycle to 1/4 cycle of the wobble shape portion.

  Still further, the optical disc medium according to the present invention is the optical disc medium, wherein the phase difference between the wobble shape portions of the adjacent first track groove and second track groove is equal to or greater than the pulse width, and It is characterized by being not more than ¼ period of the reference signal recorded in the wobble shape portion.

  As described above, by setting the phase difference in the wobble shape portion of each adjacent track groove within the above range, the pulse width of the positive / negative pulse shape wobble shape portion where information is recorded is made narrower than the original information signal. Therefore, it is possible to shift a recording portion where information is recorded between adjacent track grooves. As a result, crosstalk from adjacent track grooves can be suppressed. Note that if the phase difference is narrower than the pulse width, the recording portions are adjacent to each other between adjacent track grooves. Therefore, the pulse width is preferably set to the lower limit value.

An optical disk medium according to the present invention includes a first wobble shape portion that forms a wobble at a first frequency in a single section and has first information;
An optical disk medium comprising: a wobble formed at a second frequency in a single section, and a second wobble shape portion having second information.

An optical disk medium according to the present invention is an optical disk medium having a wobbled track groove,
A first wobble shape having a first convex shape having a convex shape in the outer peripheral direction and a second convex shape having a convex shape in the inner peripheral direction in a single section. And
In a single section, there are two convex wavy waveforms that are convex in either the inner peripheral side or the outer peripheral direction, and a second wobble shape portion that has second information. It is characterized by that.

  Thus, two types of wobble shape portions can be formed by combining convex shapes having a single frequency. For example, even when a sinusoidal wobble based on a binary FM signal is formed, a long wavelength portion is formed with two continuous convex waveforms without using two different frequency waveforms. Can do.

  Further, the optical disk medium according to the present invention is the optical disk medium, wherein the phase difference between the wobble shape portions of the adjacent first track groove and the second track groove is substantially 90 °. To do.

  Furthermore, an optical disk medium according to the present invention is the optical disk medium, and is characterized by being formatted by a CAV (Constant Angular Velocity) method.

An information recording method for recording information on an optical disk medium according to the present invention includes a wobble signal generation step for generating a wobble signal having at least a first frequency from an information signal,
Displacing the optical axis of the optical head on the optical disc medium in accordance with the wobble signal;
Irradiating light onto the optical disk medium with the optical head to form a wobble shape portion corresponding to the wobble signal in a track groove of the optical disk medium.

The information recording method according to the present invention is the information recording method, wherein the wobble signal generation step includes:
For the rise of the information signal, a positive pulse having a predetermined pulse width and a positive amplitude is generated,
For the falling edge of the information signal, a negative pulse having a predetermined pulse width and a negative amplitude is generated,
When the information signal does not change, a reference signal having an amplitude of 0 is generated.

  Furthermore, the information recording method according to the present invention is the information recording method, wherein the pulse width is equal to or greater than the width of the track groove and is recorded in the wobble shape portion of the track groove. It is characterized by being within the range of 1/4 cycle or less.

  Still further, the information recording method according to the present invention is the information recording method, wherein a phase difference of a wobble signal forming a wobble shape portion in an adjacent track groove is equal to or greater than the pulse width, and the wobble signal It is characterized by being within the range of 1/4 cycle or less of the reference signal recorded in the shape portion.

The information recording method according to the present invention is the information recording method, wherein the wobble signal generation step includes:
Generating a first wobble signal having a first frequency for the first information signal;
A second wobble signal having a second frequency is generated for the second information signal.

Furthermore, the information recording method according to the present invention is the information recording method, wherein the wobble signal generation step includes:
For the first information signal, a first convex pulse that is convex upward or downward from the reference value, and a second convex pulse that is convex downward or upward in the opposite direction to the direction. Generating a first wobble signal having
For the second information signal, a second wobble signal composed of two convex pulses that are convex in either the upper side or the lower side of the reference value is generated.

Furthermore, the information recording method according to the present invention is the information recording method, wherein a reference signal having a single frequency is used in the wobble signal generation step,
Generating the first wobble signal based on a waveform of one cycle of the reference signal;
The second wobble signal is generated based on two waveforms that are consecutive with the same sign by inverting the waveform part of the different sign in one cycle of the reference signal.

  As a result, two types of wobble shape portions can be formed by combining convex pulses corresponding to ½ wavelength in a single frequency reference signal. For example, in the case of forming a sinusoidal wobble based on a binary FM signal, a wobble shape portion having a second frequency is used by using a single frequency reference signal instead of two different frequency pulses. Can be formed. Specifically, the long-wavelength portion of the FM signal can be formed by using two consecutive convex pulses obtained by inverting the waveform portions of different signs in one cycle of the reference signal.

  Still further, the information recording method according to the present invention is the information recording method, wherein the phase difference between the wobble signals forming the wobble shape portions in the adjacent first track groove and the second track groove is substantially equal. It is 90 degrees.

  Thus, by setting the phase difference between the wobble signals formed in the adjacent first track groove and the second track groove to 90 °, the convex shape formed in the track groove can be shifted, so A sufficient interval can be secured. As a result, separation from adjacent track grooves is sufficiently possible, and crosstalk at the time of signal detection can be suppressed.

Further, the information recording method according to the present invention is the information recording method, wherein a rotation synchronization signal generating step for generating a rotation synchronization signal synchronized with the rotation of a spindle motor for rotating the optical disk medium,
A reference signal generating step of generating a reference signal having a predetermined relationship between a frequency and a phase with respect to the rotation synchronization signal;
In the wobble signal generation step, a wobble signal having at least a first frequency is generated from the information signal in synchronization with the reference signal.

Further, the information recording method according to the present invention is the information recording method, wherein the track groove has a circumference R of the optical disc medium, and a reference period length T of the reference signal in the track groove The relation of the following formula is satisfied for the integer n.

Still further, the information recording method according to the present invention is the information recording method, wherein the wobble signal generation step includes:
FM modulating the information signal to generate an FM signal;
Generating a wobble signal having at least a first frequency from the FM signal in synchronization with the reference signal.

An information recording apparatus for recording information on an optical disk medium according to the present invention includes a wobble signal generating means for generating a wobble signal having at least a first frequency from an information signal,
Optical head displacing means for displacing the optical axis of the optical head irradiated on the optical disk medium in accordance with the wobble signal;
An optical head that irradiates light onto the optical disk medium to form a wobble shape portion corresponding to the wobble signal in a track groove;
The wobble signal generation means, the optical head displacement means and a control means for controlling the optical head,
A wobble shape portion corresponding to the wobble signal is formed in a track groove of the optical disc medium, and the recording information is recorded on the optical disc medium.

An information recording apparatus according to the present invention is the information recording apparatus, wherein a spindle motor that rotates the optical disk medium;
A rotation synchronization signal generating means for generating a rotation synchronization signal synchronized with the rotation of the spindle motor;
A signal synchronization means for generating a reference signal having a predetermined relationship in frequency and phase with respect to the rotation synchronization signal;
The wobble signal generating means generates a wobble signal having a binary value or more from an information signal in synchronization with the reference signal.

Furthermore, the information recording apparatus according to the present invention is the information recording apparatus, further comprising FM modulation means for generating an FM signal by performing FM modulation on the information signal,
The wobble signal generation means generates a wobble signal having at least a first frequency from the FM signal.

  The optical disk medium according to the present invention records information by selecting one of three types of wobble shape portions corresponding to each of the three values as the wobble shape portion of the track groove. Further, a predetermined phase difference is provided in the wobble shape portion of the adjacent track groove, and the information recording portions are shifted from each other between the adjacent track grooves. As a result, the width of the information recording portion is narrower than that of the original information signal and is shifted between adjacent tracks, so that crosstalk during reproduction can be suppressed.

  An optical disc medium according to the present invention has a wobbled track groove, forms a wobble at a first frequency in a single section, and has a first wobble shape section having first information, and a first section in a single section. The wobble is formed at a frequency of 2, and has a second wobble shape portion having second information. Specifically, the two types of wobble-shaped portions include, in a single section, a first convex shape that is convex in the outer peripheral direction and a second convex shape that is convex in the inner peripheral direction. A first wobble shape portion having a second wobble shape portion having two convex waveforms that are convex in either the inner peripheral side direction or the outer peripheral side direction in a single section. . Further, a predetermined phase difference is provided in the wobble shape portion of the adjacent track groove, and the information recording portions are shifted from each other between the adjacent track grooves. As a result, when a peak portion having a convex shape is used as a reading point, a phase difference is provided between adjacent tracks and the peak portions are shifted from each other, so that crosstalk during reproduction can be suppressed.

  An information recording method for recording information on an optical disk medium according to the present invention generates a wobble signal having at least a first frequency from an information signal, displaces the optical axis of the optical head in accordance with the wobble signal, and creates a track groove. A wobble shape portion corresponding to the wobble signal is formed. In addition, a predetermined phase difference is provided when information is recorded in adjacent track grooves. As a result, the width of the information recording portion of the wobble shape portion formed in the track groove is narrower than the original information signal, and the information recording portions are shifted from each other by providing a predetermined phase difference between adjacent tracks. Therefore, crosstalk during playback can be suppressed.

  An information recording apparatus for recording information on an optical disk medium according to the present invention includes a reference signal generating means for generating a reference signal having a predetermined relationship in frequency and phase with respect to a rotation synchronization signal of the optical disk medium, and synchronizing with the reference signal. And wobble signal generating means for generating a wobble signal having at least a first frequency from the information signal. As a result, the width of the information recording portion of the wobble shape portion formed in the track groove is made narrower than the original information signal, and the information recording portions are shifted from each other by providing a predetermined phase difference between adjacent tracks. Therefore, crosstalk during playback can be suppressed.

  An optical disk medium according to an embodiment of the present invention will be described below with reference to the accompanying drawings.

(Embodiment 1)
An optical disc medium according to Embodiment 1 of the present invention will be described with reference to FIGS. 1 to 4 and FIG. As shown in FIG. 1, the optical disk medium 10 has a track groove (guide groove) 12 that extends by gradually increasing the radius of the helix from the inner circumference side toward the outer circumference side. ing. In this optical disc medium 10, information is recorded by selecting any one of three types of wobble shape portions corresponding to ternary information as wobble shape portions in which the track grooves meander (wobble). Specifically, FIG. 1 shows an enlarged view of the wobble shape portion of three adjacent track grooves. The wobble shape portion records information by selecting one of three types of wobble shape portions each corresponding to ternary information. Of the directions perpendicular to the longitudinal direction of the track groove, when the first direction is positive and the second direction opposite to the first direction is negative, the wobble shape portion is selected from the following three types Is done.
(1) A flat wobble shape portion having an amplitude 0 from the longitudinal direction of the track groove.
(2) A positive pulse wobble shape portion having a positive amplitude from the longitudinal direction of the track groove.
(3) A negative pulse wobble shape portion having a negative amplitude from the longitudinal direction of the track groove.
Of the above three types of wobble shape portions, the information recording portion where information is recorded is a positive pulse wobble shape and a negative pulse wobble shape portion, and the information recording portion is narrower than in the case of an information signal. . This suppresses crosstalk caused by information recording portions between adjacent tracks.

  The pulse width of the positive pulse wobble shape portion and the negative pulse wobble shape portion is not less than the width of the track groove and not more than ¼ period of the reference signal recorded in the wobble shape portion of the track groove. preferable. The width of the positive / negative pulsed wobble shape portion depends on the beam diameter for recording, and the lower limit is determined by the width of the track groove formed by the beam diameter. In this case, since the width of the track groove is about 160 nm, the lower limit value of the pulse width is about 160 nm. Further, the upper limit of the pulse width is preferably ¼ period or less of the reference signal so that the positive and negative pulse wobble shape portions do not overlap between adjacent track grooves.

  Further, in this optical disk medium, the phase difference between the wobble shape portions of adjacent track grooves is ¼ period of the wobble shape portion, that is, 90 °. In this way, by setting the phase difference in the wobble shape portion of each adjacent track groove to 90 °, the information recording portions where information is recorded between the adjacent track grooves can be shifted from each other. As a result, crosstalk from adjacent track grooves can be suppressed. Note that the phase difference provided between adjacent track grooves is not limited to 90 °, and is equal to or greater than the pulse width of the positive and negative pulsed wobbles and is ¼ of the reference signal recorded in the wobble shape portion. What is necessary is just to be below a period.

  Further, the track groove and the wobble shape portion formed in the track groove in this optical disk medium will be described with specific examples. In this optical disk medium, the width of the track groove is 160 nm, and the track pitch is about 0.32 μm (320 nm). Of the three types of wobble-shaped portions, the amplitude of the positive pulse wobble and the negative pulse wobble can be 30 to 50 nm from the end of the track groove, and preferably about 40 nm. The amplitude difference between the positive and negative pulsed wobbles can be 60 to 100 nm. In this case, the interval between adjacent track grooves is 160 nm in a place where there is no positive / negative pulse wobble. Even when positive and negative pulsed wobbles exist in adjacent track grooves, the positions of the positive and negative pulsed wobbles in the information recording portion are shifted from each other, so that 110 to 160 nm can be secured as the adjacent track interval. As a result, separation from adjacent track grooves is sufficiently possible, and crosstalk can be suppressed.

  In this optical disk medium, the case where the track groove in the management area on the inner circumference side is wobbled and information is recorded in the three types of wobble shape portions has been described, but the present invention is not limited to this. Further, in the information recording area on the outer peripheral side, information may be recorded in three types of wobble shape portions in the track groove in the same manner as described above. Further, in the information recording area on the outer peripheral side, information may be recorded in another wobble shape portion.

  Next, an information recording apparatus for recording information on the optical disk medium will be described with reference to FIG. The information recording device 20 converts the information signal 22 into a ternary wobble signal, displaces the optical head 30 according to the wobble signal, and forms a wobble shape portion corresponding to the wobble signal on the track groove of the optical disk medium. Form. Specifically, the information recording apparatus 20 includes a signal conversion system that converts the information signal 22 into a ternary wobble signal, and a rotation drive system that generates rotation signals of the optical disk medium and a synchronization signal thereof. As the former signal conversion system, there are a buffer 24 for capturing an information signal 22, an FM modulation circuit 26 for generating an FM signal by FM modulation of the captured information signal 22, and a wobble for converting the FM signal into a ternary wobble signal. A ternary conversion circuit 28 that is a signal generation circuit, an optical head displacement device 29 that displaces the optical axis of the optical head 30 in response to the ternary wobble signal, and the optical disc medium 40 are irradiated with light corresponding to the wobble signal. And an optical head 30 for forming a wobble-shaped portion corresponding to the wobble signal in the track groove. The latter rotational drive system includes a spindle motor 38 that rotates the optical disk medium 40, a rotation synchronization signal generator 36 for the spindle motor 38, a counter 34 that counts the rotation synchronization signal, and a PLL 32. Yes. Both systems are synchronized by sending synchronization signals from the PLL 32 to the buffer 24, the FM modulation circuit 26, and the wobble signal generation circuit 28, respectively. Further, the rotation angular velocity of the optical disc medium 40 and the time interval of the reference signal for recording information by the optical head 30 are selected so as to satisfy a predetermined relational expression as described in detail in the information recording method described later. The control device 31 controls the buffer 24, the FM modulation circuit 26, the wobble signal generation circuit 28, the optical head displacement device 29, the optical head 30, the PLL 32, the counter 34, the rotation synchronization signal generation device 36, and the spindle motor 38. Can do.

  Thus, a wobble shape portion corresponding to the wobble signal can be formed in the track groove of the optical disc medium 40, and a predetermined phase difference can be provided in the period of the wobble shape portion of the adjacent track groove. Therefore, since the portions where signals are recorded on the track grooves can be shifted from each other, crosstalk from adjacent track grooves in the information recording portion can be suppressed as shown in the reproduction waveform diagram of FIG. 9A shows a reproduction waveform, and FIG. 9B shows a waveform of the reference signal. In FIG. 9A, the apex portion of the triangle is the information recording portion 42, and the node portion is the flat wobble portion where no information is recorded. The apex portion is clear because almost no crosstalk occurs. On the other hand, the section portion is affected by crosstalk from the adjacent track groove, but no information is recorded in the crosstalk portion 44, so there is no problem.

  As an information reproducing apparatus for reproducing the information of the wobble shape portion formed on the track groove of the optical disk medium, for example, as a detector for receiving reflected light, the first detector on the inner peripheral side of the optical disk medium and the first detector on the outer peripheral side are used. Two detectors of two detectors and a differential circuit for obtaining a difference between the intensity of the reflected light received by the second detector and the intensity of the reflected light received by the first detector are used. When the reproduction laser beam spot 18 is irradiated onto the track groove 12 of the optical disk medium, the difference between the reflected light intensities received by the first and second detectors is obtained by a differential circuit, and three types are obtained. Each wobble shape portion can be discriminated. That is, when the reflected light intensity received by the second detector is stronger than the reflected light intensity received by the first detector, it is a positive pulse wobble, and vice versa. . Further, when the difference is substantially zero, it is understood that the wobble is flat. The information reproducing apparatus is not limited to the above configuration.

Further, an information recording method for recording information on the optical disk medium will be described with reference to FIGS. First, a method for converting an information signal into a ternary wobble signal in the track groove of the optical disk medium and forming a wobble shape portion corresponding to the wobble signal in the track groove will be described with reference to the flowchart of FIG. This information recording method may be operated using, for example, a computer as the control device 31 that controls each component of the information recording device.
(1) From the information signal 22, a ternary conversion circuit 28, which is a wobble signal generation circuit, generates a positive pulse that lasts for a predetermined time from the rising time of the signal, a negative pulse that lasts for a predetermined time from the falling time, and a signal A ternary wobble signal (Signal of Tri-State: STS) consisting of either a flat portion between each pulse indicating a portion that does not change is generated (101). Here, it is assumed that the information signal has a binary value of “1” and “0”. Further, for example, as shown in the FM signal in FIG. 2B, “1” has a rising portion and a falling portion, and “0” is only one of the rising portion and the falling portion. It is supposed to have.
(2) The optical axis of the optical head 30 relative to the optical disk medium is displaced by the optical head displacement device 29 by the generated ternary wobble signal (102).
(3) The optical head 30 irradiates the optical disk medium 40 with light corresponding to the wobble signal to form a wobble shape portion of the track groove corresponding to the ternary wobble signal (103). Here, a material capable of forming a wobble shape by light irradiation is used for the track groove portion of the optical disk medium.

The wobble signal generation step for generating the wobble signal will be described in more detail. In this wobble signal generation step, a ternary wobble signal is generated in the following manner as shown in FIG. 2C according to the state of the information signal.
(A) For the rising edge of the information signal, a positive pulse having a predetermined pulse width and a positive amplitude is generated.
(B) For the falling edge of the information signal, a negative pulse having a predetermined pulse width and a negative amplitude is generated.
(C) When the information signal does not change, a reference signal having an amplitude of 0 is generated.

  The pulse width of the positive / negative pulse is preferably not less than the width of the track groove and not more than ¼ period of the reference signal recorded in the wobble shape portion of the track groove. In the original FM signal, for example, as shown in FIG. 2, almost the whole of one cycle is used as the information recording part. As described above, focusing on the rising part and the falling part, the positive and negative of the short pulse width is used. The information recording portion can be narrowed by generating the pulse. Since this pulse width cannot be made smaller than the diameter of the beam to be recorded, that is, the width of the track groove, the width of the track groove becomes the lower limit value. More specifically, for example, since the width of the track groove is about 160 nm, 160 nm or more is more preferable. In addition, in the case of a pulse width exceeding a quarter period of the reference signal, the information recording portion is adjacent to the adjacent track, so that the quarter period or less of the reference signal is preferable.

  Further, the phase difference of the wobble signal that forms the wobble shape portion in each adjacent track groove is equal to or greater than the pulse width of the positive and negative pulses, and is a quarter cycle of the reference signal recorded in the wobble shape portion. It is preferable to be within the following range. In this way, by setting the phase difference of the wobble signal for each adjacent track groove within a predetermined range, the information recording portion can be shifted between adjacent tracks, and crosstalk can be suppressed.

A method for setting the phase difference of the wobble signal within a predetermined range in forming the wobble shape portion of the adjacent track groove will be described with reference to the flowchart of FIG.
(1) A rotation synchronization signal 36 synchronized with the rotation of the spindle motor 38 that rotates the optical disk medium is generated (201).
(2) A reference signal having a predetermined relationship in frequency and phase with respect to the rotation synchronization signal 36 is generated (202).
(3) In synchronization with the reference signal, the ternary conversion circuit 28 generates a ternary wobble signal from the information signal (203).

このような基準クロック信号の一周期の長さＴを選択することによって、光ディスク媒体を１回転させた場合に、隣接するトラックグルーブに形成されるウォブル形状部の位相を１／４周期、すなわち９０°だけずらせることができる。 Furthermore, conditions for generating a wobble signal in synchronization with the reference signal will be described. Here, assuming that the length of one cycle of the reference clock signal is T (mm) and the track length of one circumference of the optical disk medium is R (mm), the following relational expression (1) is satisfied between them. Thus, it is preferable to select the length T of one cycle of the reference clock signal.

By selecting the length T of one cycle of the reference clock signal, the phase of the wobble shape portion formed in the adjacent track groove when the optical disk medium is rotated once is set to 1/4 cycle, that is, 90. It can be shifted by only °.

More specific conditions will be described in the case of an optical disk medium formatted by a CAV (Constant Angular Velocity) method with a constant angular velocity ω. Further, in the case where information is recorded on a circumference having an angular velocity ω and a radius r, a condition is considered in which a spiral is made a round and the phase difference between adjacent locations on the inner and outer peripheral sides is within a predetermined range. First, since the time required for one round is 2π / ω (seconds), if one reference time for recording information is t ₀ (seconds), the number of cycles that can be recorded in one round is 2π / (ωt ₀ ). Therefore, one reference length T for recording information satisfies the following relational expression (2).

Then, the relational expression (1) is transformed using the relational expression (2) and R = 2πr, and is a relational expression between the rotational angular velocity ω of the optical disk medium and the one reference time t ₀ for recording information. The following relational expression (3) is obtained.

Here, since n is an integer, the rotation angular velocity ω of the optical disk medium and one reference time t ₀ (or its inverse frequency ν ₀ ) for recording information are selected so that the right side of the relational expression (3) is an integer. There is a need to. By selecting an angular velocity ω satisfying this relational expression (3) and one reference time t ₀ for recording information, a quarter period, that is, a phase difference of 90 ° is provided in the wobble shape portion of the adjacent track groove. Can do. As a result, crosstalk from adjacent tracks can be suppressed.

この関係式（４）を満たす回転角速度ωと情報を記録する一基準時間ｔ_０とを選択することによって隣接するトラックグルーブ間に位相差δを設けることができる。これによって、トラックグルーブに形成したウォブル形状部のパルス幅に応じて、隣接トラックグルーブ間に適当な位相差を設けることができる。 Note that the following relational expression (4) is obtained by rewriting the relational expression (3) with the phase difference δ provided between adjacent track grooves as a unit of the period of formation of the wobble shape portion.

Can be provided a phase difference δ between adjacent track groove that by selecting and this relation (4) first reference time t ₀ for recording the rotational angular speed ω information satisfying. Thus, an appropriate phase difference can be provided between adjacent track grooves in accordance with the pulse width of the wobble shape portion formed in the track groove.

Further, a method of converting the information signal 22 into an FM signal by FM modulation in advance and converting the FM signal into a ternary wobble signal will be described with reference to the flowchart of FIG.
(1) The information signal 22 is FM modulated by the FM modulation circuit 24 to generate an FM signal (301).
(2) From the generated FM signal, the wobble signal generation circuit 28 uses a positive pulse that lasts for ¼ period from the rising time of the FM signal, a negative pulse that lasts for ¼ period from the falling time, and FM A ternary wobble signal (STS) composed of either a flat portion between each pulse indicating a portion where the signal does not change is generated (302).
It should be noted that the conversion from the information signal to the ternary wobble signal is not limited to the FM signal in advance as described above, and the information signal may be converted into various intermediate signals.

  FIG. 4A is a schematic diagram showing the shape of a track groove obtained by an information recording method for forming three types of wobble shape portions using the ternary wobble signal, and FIG. ) Shows a schematic diagram showing a wobble shape portion formed in a track groove using an FM signal subjected to FM modulation as a wobble signal as it is. In the information recording method of the present embodiment shown in FIG. 4 (a), the pulse width of the information recording portion is narrowed between adjacent track grooves, and the predetermined phase difference between them is shifted so that crosstalk occurs. While suppressing, the amplitude of the positive or negative pulse wobble can be 30 to 50 nm, and the amplitude difference between the positive and negative pulse wobble can be 60 to 100 nm. In the example shown in FIG. 4C, the amplitude difference can be set to 80 nm. On the other hand, as shown in FIG. 4B, when the FM signal is used as a wobble signal, the information recording portion overlaps between adjacent track grooves, so that the amplitude difference is as shown in FIG. As shown in (c), it is about 40 nm at most. As described above, in this information recording method, three types of wobble shape portions are provided in the track groove, and a predetermined phase difference is provided in the wobble shape portion between adjacent track grooves, thereby suppressing positive and negative pulses while suppressing crosstalk. The signal-to-noise ratio can be increased by increasing the amplitude difference of the wobbles.

  As an example of the ternary wobble signal generated from the FM signal, as shown in FIG. 2C, the case where positive and negative pulses are assigned only to the rising edge and falling edge of the FM signal has been shown. The ternary wobble signal is not limited to this. For example, as shown in FIG. 10, a pulse having the same polarity as that of the immediately preceding pulse may be generated in a portion where the sign of the FM signal does not change.

  Furthermore, the information recording method can be an information recording program that can be executed using a computer as a control device. The information recording program can be stored in a computer-readable recording medium. By storing the information in the computer-readable recording medium in this way, the information recording program can be easily operated in the information recording apparatus. The computer-readable recording medium includes a magnetic recording medium such as a flexible disk and a hard disk, an optical recording medium such as a CD-ROM, CD-R, CD-RW, and DVD, and a magneto-optical recording such as MO and MD. A semiconductor recording medium such as a medium, EEPROM, DRAM, or flash memory can be used.

  Note that an optical disk medium in which information is recorded on a track groove by the above information recording method may be used as it is. Alternatively, a master, a mother, and a stamper may be created using this optical disk medium as a master, and a plurality of optical disk media may be manufactured using this stamper.

(Embodiment 2)
An optical disk medium according to Embodiment 2 of the present invention will be described with reference to FIGS. As shown in FIG. 11C, the wobble shape portion of the track groove in this optical disc medium is a sine wave having a single frequency as compared with the wobble shape portion of the track groove in the optical disc medium according to the first embodiment. It differs in that it consists of two types of wobble shape portions formed based on the above. Specifically, the first wobble shape portion has, in a single section, a first convex shape that is convex in the outer peripheral direction and a second convex shape that is convex in the inner peripheral direction. 1 information. The second wobble shape portion has two convex waveforms that are convex in one direction of the inner peripheral side or the outer peripheral side in a single section, and has second information. Thus, two types of wobble shape portions can be formed by combining convex shapes having a single frequency.

  In addition, as shown in FIGS. 11C and 11D and FIG. 12, the phase difference between the wobble shape portions of the adjacent first track groove and second track groove is ¼ period, that is, 90 °. It is. As a result, the peak positions of the convex shapes of the adjacent track grooves can be shifted. Therefore, as shown in FIG. 11, when the peak positions (A), (B), (C), and (D) are used as reading points, the corresponding portions on the adjacent track grooves are always reference values. Therefore, the influence from the adjacent track is constant and the crosstalk can be suppressed. For example, FIG. 13A shows a conceptual diagram of a reproduction waveform, and FIG. 13B shows a waveform of a reproduction reference signal. The antinode portion of the reproduced waveform is the peak portion of the wobble shape portion, and the node portion corresponds to the node of the wobble shape portion. The hatched portion of the reproduced waveform is a noise portion, and the white portion is a portion with less noise. Thus, crosstalk can be suppressed by providing a phase difference in the wobble shape portion of the adjacent track.

  Next, an information recording method for recording information on the optical disk medium will be described. Compared with the information recording method according to the first embodiment, this information recording method has two types of wobble shape portions corresponding to binary information signals, for example, “0” and “1” in the wobble signal generation step. It differs in that it forms. The information recording method also includes a first convex pulse that is convex upward or downward from the reference value with respect to the first information signal, and a downward or upward direction from the reference value opposite to the reference value. A first wobble signal consisting of a second convex convex pulse is generated. For the second information signal, a second wobble signal composed of two convex pulses that are convex in either the upper side or the lower side of the reference value is generated. Specifically, in the wobble signal generation step, a first wobble signal is generated based on a waveform of one cycle of the reference signal using a reference signal having a single frequency. The second wobble signal is generated based on two consecutive waveforms with the same sign by inverting the waveform portion of the sign. Accordingly, for example, even for a signal having a plurality of frequencies such as an FM signal, two types of wobble signals can be formed using a reference signal having a single frequency, so that the configuration of the information recording apparatus can be simplified. .

  When a wobble signal having the first and second frequencies is used, a wobble is formed at a first frequency in a single section and the first information is provided, and a single wobble shape portion is provided. It is possible to produce an optical disc medium having a wobble formed in a section at a second frequency and a second wobble shape portion having second information. In this case, the first information can be detected from the first wobble shape portion, and the second information can be detected from the second wobble shape portion.

  Although the case where the CAV method is used in the recording / reproducing of the management area on the inner peripheral side has been described here, the recording / reproducing method of the information recording area on the outer peripheral side is not limited to the CAV method. For example, on the outer peripheral side, recording / reproduction may be performed by a CLV (Constant Linear Velocity) method.

FIG. 4 is an enlarged view showing the arrangement of the wobble shape portion of the track groove adjacent to the wobble shape portion of the track groove in the optical disc medium according to Embodiment 1 of the present invention. (A) is a figure which shows the data of an information signal, (b) is a figure which shows the FM signal obtained by FM-modulating an information signal, (c) is obtained by converting from an FM signal. FIG. 4 is a diagram showing a ternary wobble signal and a diagram showing a wobble shape portion of a track groove of the optical disc medium according to Embodiment 1 of the present invention, and (d) is a diagram showing a wobble shape portion of an adjacent track. It is. It is an enlarged view which shows the wobble shape part of three adjacent track grooves. (A) is an enlarged view of the adjacent track groove of the optical disk medium according to Embodiment 1 of the present invention, and (b) is a wobble on the track groove using the FM signal shown in (b) of FIG. It is a reference enlarged view at the time of forming a shape part, (c) is a contrast figure of the amplitude of the positive / negative pulse which can be taken when a ternary wobble signal is used, and the amplitude at the time of using FM signal. . It is a block diagram which shows the structure of the information recording device which records information on the optical disk medium based on Embodiment 1 of this invention. 3 is a flowchart of a method for recording an information signal on an optical disc medium. It is a flowchart which has a predetermined phase difference in the adjacent track groove at the time of conversion to a ternary wobble signal. It is a flowchart which shows the method of FM-modulating an information signal beforehand and setting it as FM signal. (A) is a figure which shows the reproduction | regeneration waveform obtained from the wobble shape part of the track groove of the optical disk medium based on Embodiment 1 of this invention, (b) is a figure which shows the waveform of a reference | standard clock signal. (A) is a figure which shows the data of an information signal, (b) is a figure which shows the FM signal obtained by FM-modulating an information signal, (c) is obtained by converting from an FM signal. It is a figure which shows a ternary wobble signal, and is a figure which shows the wobble shape part of the track groove of the optical disk medium based on another aspect of Embodiment 1 of this invention, (d) is the wobble shape of an adjacent track | truck FIG. (A) is a figure which shows the data of an information signal, (b) is a figure which shows the FM signal obtained by FM-modulating an information signal, (c) is obtained by converting from an FM signal. It is a figure which shows a binary wobble signal, and is a figure which shows the wobble shape part of the track groove of the optical disk medium based on Embodiment 2 of this invention, (d) is a figure which shows the wobble shape part of an adjacent track | truck It is. FIG. 12 is an enlarged view showing a wobble shape portion of three track grooves adjacent to each other in the track groove of FIG. (A) is the schematic of the reproduction | regeneration waveform obtained from the wobble shape part of the track groove of the optical disk medium based on Embodiment 2 of this invention, (b) is a waveform of a reference | standard clock signal. It is the schematic which shows the management area | region and information recording area | region of an optical disk medium.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Optical disk medium 12 Track groove 14 Enlarged area 16 Recording laser beam spot 18 Playback laser beam spot 20 Information recording device 22 Recording information 24 Buffer 26 FM modulation circuit 28 Three-value conversion circuit (wobble signal generation circuit)
29 optical head displacement device 30 optical head 31 control device 32 PLL
34 Counter 36 Motor rotation synchronization signal 38 Spindle motor 40 Optical disc medium 42 Information recording portion 44 Crosstalk portion 50 Optical disc medium 52 Track groove

Claims (6)

Forming a wobble with a first frequency in a single section and having a first information, and a first wobble shape portion,
An optical disk medium comprising: a wobble formed at a second frequency in a single section, and a second wobble shape portion having second information. An optical disc medium having a wobbled track groove,
A first wobble shape having a first convex shape having a convex shape in the outer peripheral direction and a second convex shape having a convex shape in the inner peripheral direction in a single section. And
In a single section, there are two convex wavy waveforms that are convex in either the inner peripheral side or the outer peripheral direction, and a second wobble shape portion that has second information. An optical disc medium characterized by the above. Generating a wobble signal having at least a first frequency from the information signal;
Displacing the optical axis of the optical head on the optical disc medium in accordance with the wobble signal;
Irradiating light onto the optical disk medium with the optical head to form a wobble shape portion corresponding to the wobble signal in a track groove of the optical disk medium, and recording information on the optical disk medium Recording method. The wobble signal generation step includes
Generating a first wobble signal having a first frequency for the first information signal;
4. The information recording method according to claim 3, wherein a second wobble signal having a second frequency is generated for the second information signal. The wobble signal generation step includes
For the first information signal, a first convex pulse that is convex upward or downward from the reference value, and a second convex pulse that is convex downward or upward in the opposite direction to the direction. Generating a first wobble signal having
4. The second information signal is generated by generating a second wobble signal composed of two convex pulses that are convex in either the upper side or the lower side of the reference value. Information recording method described in 1. In the wobble signal generation step, a single frequency reference signal is used,
For the first information signal, a first wobble signal is generated based on the waveform of one cycle of the reference signal,
The second wobble signal is generated based on two waveforms that are consecutive with the same sign by inverting the sign of the waveform part of the different sign in one period of the reference signal for the second information signal. Item 4. The information recording method according to Item 3.

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