JPH05109084A - Optical information recording medium, information recording and erasing method, and tracking error signal detecting device - Google Patents

Abstract

PURPOSE:To provide an optical information recording medium which is high in linear recording density as compared with the conventional medium and, at the same time, has a continuous spiral track which is double in track density. CONSTITUTION:Bit recording cells formed of recessing and projecting pits are arranged at a pitch which is equal to or smaller than the diffraction limit and identifiable clock marks 2 are provided at every prescribed number of pits. In addition, wobble marks having the positive and negative polarities are alternately arranged so that an odd number of wobble marks can be arranged at every track period.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical information recording medium and an optical recording method for recording information by the heat of a focused laser beam, and a tracking error signal for obtaining a tracking error signal from the optical information recording medium. The present invention relates to a detection device.

[0002]

2. Description of the Related Art In recent years, an increase in S / N and an increase in recording density of optical information recording media have been studied.

An example of a conventional optical information recording medium will be described below with reference to the drawings. FIG. 14 shows a block diagram of a conventional optical information recording medium. In FIG. 14, 10 is an optical information recording medium substrate, and 20 is a bit recording cell formed in a concave or convex shape with respect to the optical information recording medium substrate. The bit recording cells 20 form tracks, and are arranged at intervals longer than the diffraction limit of the laser head, that is, the minimum reading resolution, so that the bit recording cells 20 can be identified by the laser head. What is the diffraction limit?
When the wavelength of the laser head is λ and the aperture ratio is NA, the length is expressed by λ / 2NA.

The operation of the optical information recording medium having the above structure will be described below.

When information is recorded on the above optical information recording medium, an arbitrary bit recording cell 20 is selectively irradiated with a strong laser beam and the information is recorded by its heat. The advantage of this optical information recording medium is that recording with high S / N and low jitter can be easily realized. That is, the bit recording cells 20 corresponding to 1 bit are formed on the optical information recording medium substrate 10 independently and in a concavo-convex shape of substantially equal size. Therefore, even if a strong laser beam is irradiated, each bit recording cell is thermally shielded, so that the adjacent bit recording cells are not affected and a signal can be recorded only in a desired bit recording cell 20. This is possible, and as a result, variations in the size of recording marks, which cause jitter and noise in photothermal recording, are unlikely to occur.

On the other hand, however, in the case of such a recording system, when the laser power is strongly raised and information is recorded, the laser beam is always positioned substantially in the center of the bit recording cell 20 to be recorded in advance. There must be.
Otherwise, a strong laser beam may be emitted between two adjacent bit recording cells, and two bits may be generated halfway. Therefore, the laser head uses the bit recording cells 2 to be recorded in advance when recording information.
The position of 0 must be recognized accurately. In the conventional example, the bit recording cell 20 is irradiated with a laser beam,
The position is recognized from the change in the reflected light amount during scanning. That is, as shown in FIG. 14, when the vicinity of the center of an arbitrary bit recording cell 20 is scanned, the amount of reflected light takes a minimum value (P in the figure). Therefore, if this minimum value is detected, a clock signal is generated from this, and the laser is strongly emitted at that timing, information can be surely recorded in the bit recording cell 20, and accurate information recording is possible. become. (For example, US Pat. No. 4,811,33
No. 1)

[0007]

However, in the above-described structure, if the intervals between adjacent bit recording cells are reduced, each bit recording cell cannot be identified.
There was a problem that the recording density was limited. That is, as described above, if the wavelength of the laser beam is λ and the aperture ratio is NA, the bit recording cells must be formed at intervals sufficiently wider than λ / 2NA. Below this, since the amount of reflected light when scanning the bit recording cells does not change at all, the positions of the arbitrary bit recording cells 20 cannot be recognized individually, and therefore, the above-mentioned arbitrary bit recording cells 20 cannot be correctly recognized. Information cannot be recorded.

A similar problem occurs when the distance between the bit cell group and the bit cell group on the adjacent track is reduced. When the track pitch is reduced to the minimum resolution of the information reading head, it is impossible in principle to distinguish between the track in which an arbitrary bit recording cell group is formed and its adjacent track, in other words, to detect the tracking error signal. Tracking control, which is essential for recording / reproducing information, cannot be performed.

In view of the above problems, the present invention has a good S / N ratio,
Moreover, the present invention provides an optical information recording medium having a high recording density.

[0010]

In order to solve the above-mentioned problems, the optical information recording medium of the present invention has a λ on an arbitrary track.
A bit recording cell group composed of a plurality of bit recording cells arranged at intervals of / 2NA or less, and provided on the same track as the bit recording cell group and at a position separated by λ / 2NA or more from the bit recording cell group. It is equipped with a clock mark.

Further, in the information recording medium of the present invention, first and second wobble mark pairs for generating tracking error signals having polarities opposite to each other are alternately provided in the area other than the area where the bit cell group is formed, and 1 It is arranged so that the total number per track cycle is an odd number.

[0012]

According to the present invention, with the above-described structure, the laser head can identify the clock mark, and the position of each bit recording cell forming the bit recording cell group can be calculated from the position of the clock mark. Even if the laser head cannot identify each of the bit recording cells, information can be correctly recorded in any bit recording cell, and as a result, the recording density can be improved.

Further, according to the present invention, since the wobble mark pairs having the positive and negative tracking error polarities are arranged in a zigzag pattern by the above-described structure, even if the track density is set to the diffraction limit, the adjacent wobble marks will be adjacent to each other. The spacing becomes about twice the diffraction limit and each can be independently identified, and as a result, the tracking error signal is detected.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An optical information recording medium according to an embodiment of the present invention will be described below with reference to the drawings. 1 is a perspective view of an optical information recording medium in a first embodiment of the present invention, and FIG. 2 is a sectional view thereof. 1 and 2, 1
Is an optical information recording medium substrate, and an optical recording film 1a is formed on its recording surface. Reference numeral 2 denotes a clock mark formed in a convex shape or a concave shape on the recording surface, which is arranged along the recording track. Reference numeral 3 denotes a bit recording cell group arranged in a column, which is formed in a convex shape or a concave shape for each one bit on the same track as the clock mark. The center interval between the arbitrary bit recording cells 3a and the bit recording cells adjacent thereto in the bit recording cell group 3 is set within the minimum reading interval (= λ / 2NA) of the optical head used for reproducing recorded information. However,
The clock mark 2 and the end of the bit recording cell group 3 are separated from each other by an appropriate distance (> λ / 2NA), and no concave-convex mark is formed therebetween.

The operation of the optical information recording medium having the above structure will be described below with reference to FIGS. 1, 2 and 3. Similar to the conventional example, the information signal is sequentially recorded in the bit recording cell group 3 by one channel bit by the pulse laser beam. For example, when recording "0", the laser emits no light or with a sufficiently weak power, and when recording "1", the laser emits light with a strong power.
The physical properties of the optical recording film 1a are changed. Even if the optical recording film 1a is a phase change material based on tellurium oxide,
It may be a magneto-optical recording material.

However, at this time, in order to record information "1" in any bit recording cell 3a of the recording bit cell group 3, the laser beam just scans around the center of the bit recording cell where "1" is to be recorded. Sometimes it is necessary to raise the laser power strongly. For that purpose, the optical head must be able to identify the position of each bit recording cell. In the conventional example, since the interval between adjacent bit recording cells is sufficiently longer than the reading limit of the reading laser head, the center position of each bit cell can be identified from the change in the amount of light reflected on the optical recording surface. However, in this embodiment, since each recording bit cell is arranged at a pitch of λ / 2NA or less, each recording bit cell cannot be identified.
Therefore, in this embodiment, the clock mark 2 is provided at a predetermined position at a distinguishable distance from the bit recording cell group 3.
Is provided. FIG. 3 shows the reflected light amount when the laser beam scans the clock mark 2 and the bit recording cell group 3.

The level of the reflected light amount when the laser beam is shining on the mirror surface portion (where the unevenness is not formed) of the optical information recording medium is set to level 1 (thin solid line in the figure), and the uneven portion is irradiated. Level 2 of the amount of reflected light when there is
(Dashed line in the figure). Since the front and rear of the clock mark 2 are surrounded by a mirror surface, when the laser beam crosses the mirror surface, the clock mark 2, and the mirror surface in order, the reflected light amount is level 1 (A in the figure), level 2 (B in the figure), level 1 (C in the figure). However, when the bit recording cell group 3 is scanned, the bit recording cells are arranged at a pitch equal to or less than the identification limit, so that the bit recording cells are not observed independently of each other. In other words, the amount of light reflected by the bit recording cell group 3 remains constant at level 2 (D in the figure).

Therefore, by first reading the clock mark from the amount of reflected light which changes from A to B to C and generating a synchronizing signal, and appropriately multiplying this synchronizing signal, the center position of each bit recording cell group can be obtained. It is possible to obtain the clock generated at the timing. If the clock is obtained, the laser beam will blink in time with the clock,
Information can be recorded in any bit cell.

The recorded information is reproduced as shown in FIG. 4, for example. If the reflected light quantity when the laser beam scans the bit recording cell in which information is recorded becomes level 3 which is lower than level 2 (F in the figure), information "1"
If the threshold value level is set in the middle, the information can be easily read out from the change of the reflected light amount by associating the information with the level 3 and the information “0” with the level 2.

As described above, according to the present embodiment, the bit recording cell group 3 in which an appropriate number of concave and convex recording bit cells are arranged at a pitch below the reading limit of the optical head, and on the same track as this, On the other hand, by providing the clock mark 2 at a fixed position that can be identified, it is possible to realize an optical information recording medium having a higher recording density than the conventional one.

A second embodiment of the present invention will be described below with reference to the drawings. FIG. 5 is a block diagram of an optical information recording medium showing a second embodiment of the present invention. Reference numeral 1 denotes an optical information recording medium substrate formed in a disc shape, and an optical recording film 1a is formed on the recording surface thereof. Reference numeral 2 is a clock mark, and 3 is a bit recording cell group, both of which are formed in an uneven shape on the recording surface. 3a is an arbitrary bit recording cell in the bit recording cell group 3. The feature of this embodiment is that
The clock marks 2 are arranged at equal intervals in all tracks so that they are arranged in a row in the radial direction of the disc, and the number of recording bit cells on the outer periphery of the disc is larger than that on the inner periphery so that the intervals of each recording bit cell are That is, it is set to be almost constant regardless of the inner and outer circumferences.

The function of the optical information recording medium configured as described above will be described below. First, the clock marks 2 are present in the same number on all the tracks and at equal intervals in order to speed up track access and information recording / reproduction. That is, as described in the previous embodiment,
In the present invention, the clock mark 2 serves as a reference for obtaining a synchronization signal for accurately recording information in the vicinity of the center of each bit cell of the recording bit cell group 3, and this must always be identified. Here, if the clock marks are present differently on each track, the pull-in operation for extracting the sync signal must be performed on each track. For example, if you jump from one track to another and there is a phase or frequency difference between the clock mark on the jump destination track and the clock mark on the original track, synchronization will occur on the new track and It may take some time before the synchronization takes place, and the information recording / reproducing cannot be executed immediately after the track jump ends. Therefore, the clock marks need to be arranged so that they can be detected in the same phase over all tracks, and the arrangement shown in FIG. 3 is inevitably required. However, in this case, the intervals of the clock marks become wider toward the outer circumference. Here, if the number of recording bit cells forming the recording bit cell group 3 is the same in the inner and outer circumferences, the interval between the recording bit cells is inevitably widened. If the distance between the recording bit cells is sufficiently wider than the reading limit, each recording bit cell can be identified. Although this seems convenient from the viewpoint of the conventional example, it may cause a malfunction in the present invention. That is, as described in the first embodiment, in the present invention, recording / reproducing of information on / from the optical information recording medium is all performed with reference to the clock mark 2, but here, the intervals of the bit recording cells are sufficiently wide, When a change in the amount of reflected light by each bit recording cell is observed, the clock mark 2 based on the change in the amount of reflected light is detected.
It becomes difficult to distinguish between the bit recording cell 3a and the bit recording cell 3a. On the contrary, if the distance between the bit recording cells on the outer circumference is set to be equal to or less than the reading limit, the distance between the bit recording cells on the inner circumference becomes too close, and it becomes impossible to form cells having irregularities, which are independent bit by bit.

Therefore, in this embodiment, the number of recording bit cells on the outer circumference of the disc is made larger than that on the inner circumference so that the intervals between the respective recording bit cells become substantially constant.

The third embodiment of the present invention will be described below. This embodiment relates to a method of recording information on the optical information recording medium shown in the first or second embodiment.
As already described in the first embodiment, the optical recording film 1a is formed on any bit recording cell 3a. Therefore, it is possible to record information by changing the physical properties of the optical recording film 1a by the heat of the laser beam. Particularly when the optical recording film 1a is a phase change type material containing tellurium oxide as a main component, not only information recording / reproducing but also erasing and rewriting are possible. That is, if the material is photothermally melted and then rapidly cooled, it solidifies in an amorphous state, and if gradually cooled from an appropriate high temperature, it solidifies in a crystalline state. If the crystal is erased and the amorphous is recorded, there are three levels of laser power, weak power for reproduction, and strong power for recording (writing "1").
Information can be overwritten on the same material by appropriately using the medium power for erasing (writing "0").

In FIG. 6, "00101" is formed on the optical recording film 1a.
The intensity modulation waveform of the laser beam light when the information "00" is overwritten is illustrated. The laser power at the time of reproduction is P1, the power at the time of erasing (writing "0") is P2, and the recording power (writing "1"). Is set to P3, that is, the laser is constantly emitted at the power P1 when reading the clock mark 2, and the laser power is set to P when recording or erasing information on any bit recording cell 3a.
1, P2, P1 or P1, P3, P1 in pulse form. This is for the following reason. That is, since the optical recording film 1a formed in the bit recording cell 3a is thermally isolated from that formed in the adjacent bit recording cell, the bit recording cell 3a does not affect the surroundings.
It has already been described that it is possible to record and erase only the information in a. However, when a laser beam is irradiated to a part of the adjacent bit recording cells due to a laser start timing error, etc., It is possible that some of the information in will be destroyed. Therefore, in this embodiment, in order to secure such a margin of timing error, when the laser beam is emitted in a pulsed manner at the time of recording and at the time of erasing, the laser beam passes near the boundary of the bit recording cell. Laser power has dropped to a level below P1.

The bit recording cell is useful not only for heat isolation but also for material leakage prevention. As described above, when information is recorded on the phase change recording material, it is necessary to once bring it into a molten state. Since the bit recording cell functions to confine this molten material, it also extends the life of the recording material.

The fourth embodiment of the present invention will be described below. FIG. 7 is a timing chart of the fourth embodiment.
In this embodiment as well, as in the third embodiment, recording and reproduction of information "00101000" is executed by using a pulsed laser beam. This embodiment is different from the third embodiment in that
Recording and erasing are not performed by switching the laser power, but the power is kept constant (P4) and switched by the pulse width of the laser. This is for the following reason. That is, although a semiconductor laser is used as the light source of the laser beam, the emission wavelength of the semiconductor laser generally has the property of varying depending on the emission power. At this time, if the optical system of the laser head, especially the objective lens has chromatic dispersion, the image forming point moves when the power of the laser beam is changed, and as a result, information is correctly recorded in the desired bit recording cell 3a.・ Sometimes it cannot be erased.
Therefore, in this embodiment, the laser pulse width is switched in order to switch the thermal energy input to the optical information recording medium while keeping the laser power constant during recording and erasing. This makes it possible to suppress fluctuations in the laser emission wavelength and realize more reliable recording / erasing.

An optical information recording medium according to the fifth embodiment of the present invention will be described below with reference to the drawings.

FIG. 8 is a top view of an optical information recording medium according to an embodiment of the present invention, and FIG. 9 is a main part configuration diagram thereof. In FIG. 8, reference numeral 100 denotes a spiral track-shaped center line along which the clock mark 2 and the bit recording cell group 3 are formed. Track pitch is about diffraction limit, that is, laser wavelength 0.8μ
If m and NA are 0.5, it is about 0.8 μm. Reference numerals 11 and 12 are first wobble marks formed along the track center line 100, and 13 and 14 are second wobble marks formed along the same track center line 100. The distance of the wobble mark from the track center line is 1/2 track pitch. First wobble marks 11, 12 and second wobble marks 13, 1
The difference from No. 4 is that, as clearly shown in FIGS. 8 and 9, the arrangement of wobble marks in each is reversed. That is, the first wobble mark 1
For tracking error signals obtained from 1 and 12,
The tracking error signals obtained from the second wobble marks 13 and 14 have opposite polarities.

The first wobble marks 11, 1 are also used.
The second and second wobble marks 13 and 14 are alternately formed, and further, the first and second wobble marks are formed.
It is assumed that the total number of wobble marks is an odd number per track period (track for one round).

The operation of the optical information recording medium having the above structure will be described below with reference to FIGS. 8, 9 and 10.

FIG. 10 shows the functions of the first and second wobble marks which have polarities opposite to each other and which are alternately arranged. In FIG. 10, black circles represent wobble mark pairs that generate a tracking error signal of one polarity (for example, positive polarity). Now, it is assumed that the laser head is at the position A on the track 100a. At this time, the head obtains a positive tracking error signal from the wobble mark pair 11 and 12. The head then scans over the wobble mark pair 13, 14, but since they provide tracking error signals of opposite polarity (negative polarity), they are ignored and the next wobble mark pair (B position)
Hold the previous tracking error signal. Otherwise, the positive and negative tracking error signals will cancel each other out. Then, if the tracking error signals are sampled every other one in this way, the same polarity can be obtained.

Further, if the head scans one track period, the head comes on the adjacent track 100b, but as described above, the total number of positive and negative wobble mark pairs per track period is an odd number. Therefore, the position of the positive wobble mark pair on the adjacent track comes to the position (C) next to the negative wobble mark pair on the preceding track 100a. The wobble mark 13 that constitutes the negative wobble mark pair in the preceding track forms one corner of the positive wobble mark pair in the adjacent track. The same applies to the adjacent tracks, and eventually all the tracks are continuously formed in a spiral shape. At this time, the positive wobble marks and the negative wobble marks are arranged in a zigzag pattern.

As described above, according to this embodiment, the first and second tracking error signals having opposite polarities are generated.
The wobble mark pairs are alternately arranged, and the total number per track period is an odd number, so that a tracking error signal is generated from an optical information recording medium in which all tracks are continuously connected in a spiral shape at a track pitch of a diffraction limit. Can be detected.

Next, a tracking error detecting device for generating a tracking error signal from the optical information recording medium will be described with reference to the drawings. FIG. 11 is a block diagram of the tracking error detecting device in the sixth embodiment. In FIG. 11, an optical head 40 is assumed to scan an arbitrary track formed on the optical information recording medium. Reference numeral 41 is a clock mark detection circuit for detecting the clock mark 2 (which is periodically scanned) from the reproduction signal of the optical head 40, and 42, 43 and 44 are a phase comparison circuit, a VCO (voltage controlled ocsilator), and a counter / decoder, respectively. This is what constitutes a PLL (phase locked loop). Reference numerals 45 and 46 denote sample and hold circuits which sample and hold the output of the optical head 40 by the output pulse signal of the counter / decoder 44. 47 is a sample hold circuit 45, 4
6 is a differential circuit that takes the difference of the outputs. 55 and 57 are non-inverting and inverting amplifiers, respectively. Reference numeral 53 is a toggle flip-flop, which alternately inverts the logic of the positive logic / non-logic output every time the output pulse of the counter / decoder 44 enters. Reference numerals 56 and 58 denote switching circuits, which open and close the gates according to the positive logic / non-logic output of the toggle flip-flop 53.

The tracking error detecting device configured as described above will be described below. Clock mark detection circuit 41, phase comparison circuit 42, VCO (voltage control circuit)
lledoscilator) 43, counter / decoder 44, and sample and hold circuits 45 and 46 detect the tracking error signal from the wobble marks 11, 12 or 13, 14 shown in FIG. Hereinafter, these operations will be described. First, the clock mark detection circuit 41 is shown in FIG.
Only the clock mark 2 is detected from the optical information recording medium shown in (1) and the clock mark detection signal CM is output. The phase comparison circuit 42 detects the phase difference between the clock mark detection signal CM and the synchronization signal P0, and outputs the VCO in accordance with the output signal.
43 generates a clock signal CLK. The counter / decoder 44 divides this clock signal CLK to generate the synchronizing signal P0. During the operation of the above circuit, the clock mark detection signal CM and the synchronization signal P0 are completely in phase.

The counter / decoder 44 further divides the clock signal CLK to sample and hold signals P1 and P which rise at the timing when the wobble marks 11, 12 or 13, 14 are read by the optical head 40.
2 is output. The sample-hold circuit 45 has the amplitude of the preceding wobble mark 12 or 14 at the timing of the sample-hold signal P1, and the sample-hold circuit 46 has the amplitude (caused by the tracking error) of the subsequent wobble mark 11 or 13 at the timing of the sample-hold signal P2. The change is sampled and held, and the difference between these outputs is taken as the tracking error signal.

However, as shown in FIG. 9, in the present invention, the polarities of the preceding and succeeding wobble marks, that is, the positions with respect to the track center line 100, are alternately inverted, and as a result, they are detected by the above circuit. The polarity of the tracking error signal is also inverted and output.

In the previous embodiment, it was shown that tracking error signals of the same polarity can be detected by collecting every other wobble mark of the same polarity. However, in other words, this means that the information amount of the tracking error is halved, which is not preferable from the viewpoint of the tracking control system. This embodiment describes an apparatus for detecting tracking error signals of the same polarity without reducing the tracking error information amount. That is, the positive and negative logic outputs of the toggle flip-flop 53 are switching signals issued from the counter / decoder 44. Each time P3 rises, it is sequentially inverted, and the outputs of the non-inverting amplifier 55 and the inverting amplifier 57 are switched accordingly. As a result, the non-inverting amplifier 55 becomes valid for the positive wobble mark pair, and the inverting amplifier 57 becomes valid for the negative wobble mark pair, so that the tracking detection signals of the same polarity are eventually obtained. Will be obtained. The switching signal P3 is a periodic pulse signal obtained by counting / decoding the clock signal CLK so that it is generated at an appropriate timing immediately after the wobble mark pair is detected.

As described above, according to this embodiment, it is possible to detect tracking error signals of the same polarity without reducing the tracking error information amount.

The seventh embodiment of the present invention will be described below with reference to the drawings. FIG. 12 is a schematic view of the essential parts of an optical information recording medium showing a seventh embodiment of the present invention. In the figure, the track center line 100 and the bit recording cell group 3 are the fifth
The embodiment is similar to that of FIG.

The difference from FIG. 9 is that, instead of the first and second wobble mark pairs 11, 12, and 13, 14, there are every other tracking groove 61 on the track center line, and an odd number of tracks is provided in one track cycle. This is a point provided in the existing servo area. As in the first embodiment, positive and negative tracking error signals are obtained alternately in this embodiment. Therefore, also in this case, it is possible to continuously form double-density tracks. It can be said that the feature of this embodiment is that the structure of the optical information recording medium becomes simpler. In the first embodiment, the wobble mark had to be formed at a distance of 1/2 track pitch from the track center line, but in this embodiment, it is almost the same whether or not a groove is formed on the track center line. Function is obtained. The method of obtaining the tracking error signal from the tracking groove is already known in US Pat. No. 4,704,711.

As described above, by providing every other tracking groove on the track center line instead of the first and second wobble mark pairs, an optical information recording medium of high track density with a simpler structure can be obtained. Can be realized.

The eighth embodiment of the present invention will be described below. FIG. 13 is a main part configuration diagram of an eighth embodiment of the present invention. 13, the clock mark 2, the bit recording cell group 3, and the track center line 100 are the same as those shown in FIG. The difference from FIG. 9 is that the tracking groove 62 is provided instead of the wobble mark pair, and the tracking groove 62 is formed by extending the bit recording cell group 3.

As described above, the bit recording cell group 3 viewed from the laser head looks like a continuous groove because the individual cells constituting it are not identified. Therefore, the tracking groove 62 is formed in the bit recording cell group 3
Even if it has the same structure as the tracking groove 6 shown in FIG.
It can be treated as equivalent to 1. As described above, the advantage of providing the tracking groove as an extension of the bit recording cell group 3 is that all the pre-format information (including the tracking groove) in the optical information recording medium can be formed by the uneven pit marks having the same shape. It can be expected to improve the sex.

Similar to the previous embodiment, also in this embodiment, the tracking grooves 62 are formed in every other servo area in which an odd number exists in one track period.

[0047]

As described above, according to the present invention, a bit recording cell group composed of a plurality of bit recording cells arranged on an arbitrary track at intervals less than the minimum reading interval of the laser head, and the above bit recording cell group. By providing a clock mark provided on the same track as that at which the laser head can be identified, the position of each bit recording cell forming the bit recording cell group is calculated from the clock mark identified by the laser head. Therefore, information can be correctly recorded in any bit recording cell, and as a result, the recording density can be improved.

Providing the bit recording cell on the recording medium is useful not only for isolating heat but also for preventing the material from flowing out. For example, when recording information on a phase change recording material, it is necessary to once bring it into a molten state. Since the bit recording cell functions to confine this molten material, it also extends the life of the recording material.

Further, the tracking error identifying means for generating the tracking error signals having mutually opposite polarities are alternately arranged, and the total number per one track period is an odd number, so that all tracks are continuous at a track pitch of a diffraction limit. The tracking error signal can be detected from the optical information recording medium that is spirally connected.

[Brief description of drawings]

FIG. 1 is a perspective view of an embodiment of the present invention.

FIG. 2 is a sectional view of an embodiment of the present invention.

FIG. 3 is a timing diagram showing the operation of one embodiment of the present invention.

FIG. 4 is a timing diagram showing the operation of one embodiment of the present invention.

FIG. 5 is a top view of the second embodiment of the present invention.

FIG. 6 is a timing chart showing the operation of the third embodiment of the present invention.

FIG. 7 is a timing chart showing the operation of the fourth embodiment of the present invention.

FIG. 8 is a front view of the fifth embodiment of the present invention.

FIG. 9 is a configuration diagram of main parts of a fifth embodiment of the present invention.

FIG. 10 is a configuration diagram for explaining an operation in the embodiment.

FIG. 11 is a block diagram of a sixth embodiment of the present invention.

FIG. 12 is a configuration diagram of a main part of a seventh embodiment of the present invention

FIG. 13 is a configuration diagram of main parts of an eighth embodiment of the present invention.

FIG. 14 is a perspective view of a conventional example.

FIG. 15 is a sectional view of a conventional example.

[Explanation of symbols]

 1 Optical Information Recording Medium Substrate 2 Clock Mark 3 Bit Recording Cell Group 3a Bit Recording Cell 100 Track Center Line 11, 12 First Wobble Mark 13, 14 Second Wobble Mark 41 Clock Mark Detection Circuit 42 Phase Comparison Circuit 43 VCO 44 Counter / decoder 45,46 Sample and hold circuit 53 Toggle flip-flop 55 Non-inverting amplifier 57 Inversion amplifier 56,58 Switching circuit 61,62 Tracking groove

Claims (16)

[Claims] 1. A bit information recording area formed in a concave or convex shape with respect to a substrate, and recording and reproduction of 1-bit information to and from the bit information recording area by an optical head by photothermal means. In an optical information recording medium to be executed, a bit information recording area group formed by arranging a plurality of the bit information recording areas per track, and a clock mark formed on the same track as the bit information recording area group And a plurality of bit information recording areas constituting the bit information recording area group are arranged at an interval equal to or less than a minimum reading interval of the optical head, and the clock mark is provided by the optical head. In order to be distinguishable from each other, the bit information recording area group is provided at an interval equal to or more than the minimum reading interval of the optical head. The aforementioned bit information recording region group,
An optical information recording medium provided with an optical recording film which is brought into a molten state by the photothermal means. 2. The optical recording film has two solid phases, amorphous and crystalline, or crystalline in different states, depending on whether the process of changing from a high temperature molten state to a low temperature solid state is rapid cooling or slow cooling. 2. The optical information recording medium according to claim 1, wherein the optical information recording medium is divided and binary information is recorded by the two phases. 3. An optical head which emits laser light, wherein each of a plurality of bit information recording areas forming a bit information recording area group, where λ is a wavelength of the laser light and NA is an aperture ratio. The optical information recording medium according to claim 1, wherein the distance is shorter than λ / 2NA, and the distance between the bit information recording area group and the clock mark is longer than λ / 2NA. 4. A clock-shaped mark and bit information recording area group are formed on a circular or spiral track provided on a disk-shaped substrate, and the same number of clock marks are provided on each track. 2. The light according to claim 1, wherein the bit information recording areas forming the bit information recording area group are formed such that the number of bits is different depending on the track so that the bit interval is constant. Information recording medium. 5. The optical information recording medium according to claim 2, wherein information is recorded on the optical recording film by light having a first intensity and information is erased by light having a second intensity. .. 6. A method of recording and erasing information on the optical information recording medium according to claim 5, wherein when recording information, light having a first intensity is pulsed to each bit information recording area. When the information is erased by melting the optical recording film by rapidly irradiating it in a circular pattern and then erasing information, by irradiating each bit information recording area with light having a second intensity in a pulse shape, An information recording and erasing method, characterized in that a recording film is gradually cooled from a high temperature state. 7. The information recording and erasing method according to claim 6, wherein the first and second intensities are substantially obtained by changing the pulse width of the light with which each bit information recording area is irradiated. 8. An optical information recording medium in which servo areas and data areas are alternately arranged, and clock marks and track identification marks are formed in the servo areas, wherein the servo areas are odd numbers per track unit. An optical information recording medium characterized by the presence of individual pieces. 9. The servo area is classified into first and second servo areas provided with first and second track identification marks having mutually opposite detection polarities, and further,
9. The optical information recording medium according to claim 8, wherein the first and second servo areas are arranged alternately. 10. The optical information recording medium according to claim 8, wherein each of the first and second track identification marks comprises a pair of wobble marks. 11. The optical information according to claim 8, wherein the first track identification mark and the second track identification mark in the adjacent track share a part of a wobble mark pair. recoding media. 12. The first track identification mark is a groove having a finite length, and the second track identification mark is a groove having a finite length provided on an adjacent track.
9. The optical information recording medium described in 9. 13. A tracking error detecting device for detecting a tracking error signal from the optical information recording medium according to claim 8, comprising clock generating means for detecting a clock mark to generate a synchronizing signal. Means for detecting the track identification mark, tracking error calculation means for obtaining tracking error signals having opposite polarities from the first and second track identification marks, and the polarity of the output signal of the tracking error calculation means is synchronized with each other. A tracking error detection device comprising: a polarity reversing unit that switches alternately according to a signal. 14. A clock generation means identifies a clock mark from an optical head reproduction signal and outputs a detection result as a binary pulse, and a phase difference between the binary pulse signal and the reference pulse signal. And a voltage controlled oscillator that generates a clock signal whose oscillation frequency is controlled by the output of the phase comparison circuit, and a counter / decoder that produces the synchronization signal from the clock signal. The tracking error calculation means samples and holds signals when the first and second track identification marks are reproduced from the optical head reproduction signal with the timing pulse signal output from the counter / decoder. First and second sample and hold circuits, and the first and second sample and hold circuits It is characterized in that it is configured with a differential circuit that takes the difference in output, and the polarity reversing means alternately outputs positive logic and non-logic outputs every time a switching control pulse signal issued from the counter / decoder is input. A tracking error detecting device comprising: a toggle flip-flop for inverting the logic; and a polarity switching circuit for inverting or non-inverting amplifying the differential circuit output according to a positive logic / non-logic output of the toggle flip-flop. .. 15. A data area having a bit information recording area formed in a concave or convex shape on a substrate and a servo area having a clock mark and a track identification mark are alternately arranged, and the bit is formed by an optical head. An optical information recording medium for recording and reproducing 1-bit information in an information recording area, comprising a bit information recording area group formed by arranging a plurality of the bit information recording areas per data area. However, the plurality of bit information recording areas forming the group of bit information recording areas are arranged at intervals less than or equal to the minimum reading interval of the optical head, and the clock mark can be identified by the optical head. As described above, the bit information recording area group is provided at an interval not less than the minimum reading interval of the optical head, In, the servo area is classified into the first and second servo regions track identification mark is formed having an opposite detection polarities, the first and second
The optical information recording medium is characterized in that the servo areas are alternately arranged and the total number per track is an odd number. 16. The second servo area is characterized in that the track identification mark in the first servo area is formed by arranging a plurality of concave or convex pits having the same shape as the bit information recording area. 16. The optical information recording medium according to claim 15, wherein the track identification mark in is a mirror surface sandwiched by the track identification marks in the first servo areas formed on both adjacent tracks.