JP2768466B2 - Information recording method for optical recording medium - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to an information recording method for an optical recording medium, and more particularly, to an irradiation order of recording radiation spots on recording tracks formed on the optical recording medium. About.

[Conventional technology]

Conventionally, as a tracking error detection method for a write-once or rewritable optical recording medium, a push-pull method, also known as a far-field method, has been most used since the detection device is simple. Many are used.

The principle of this method is as shown in FIGS. 7 (a), (b) and (c), wherein a pre-groove 22 formed on an optical recording medium 21 is formed.
When the recording / reproducing radiation spot 23 is irradiated along the line, the diffraction pattern of the pre-groove 22 changes the reflected light field pattern 24 depending on the relative positional relationship between the pre-groove 22 and the recording / reproducing radiation spot 23. It is a thing to use.

That is, when the center of the recording / reproducing radiation spot 23 coincides with the center of the pregroove 22 in the width direction,
As shown in FIG.
24 is symmetrical, and therefore, the intensity distribution of the diffracted light incident on the photodiode 25 provided on the optical path reflected from the optical recording medium 21 is symmetrical. However, if the recording / reproducing radiation spot 23 is deviated to the left or right from the center of the pre-groove 22, the field pattern 24 becomes asymmetrical as shown in FIGS. Becomes in the left-right asymmetry.

Accordingly, a change in the diffracted light intensity distribution due to the pre-groove 22 is detected by the two-divided or four-divided photodiode 25, and the difference signal is taken out by the differential transformer 26, whereby the tracking error signal is detected. Can be obtained.

In the above, the case where the recording / reproducing radiation spot 23 is focused on the pre-groove 22 (in-group recording) has been described, but the recording / reproducing radiation spot 23 is located between two adjacent pre-grooves. In the case where is focused (on-land recording), a tracking error can be similarly detected.

On the other hand, with respect to an address signal management method for specifying the order of recording tracks for irradiating the recording / reproducing radiation spot,
Conventionally, no special consideration has been made, and recording / recording is continuously performed from the innermost recording track to the outermost recording track.
The method used when the radiation spot for reproduction is irradiated is adopted.

If there is a defect in the recording track on which data is to be written, the data to be written in the recording track is written in a spare track set in advance, and new data following this data is recorded in the recording track following the defective track. A recording method of writing data on a track has been conventionally known, but this recording method can be adopted as it is in the present invention and is not a prior art of the present invention.

[Problems to be solved by the invention]

However, when the tracking error detection method and the address signal management method as described above are adopted, when data is recorded on a recording track adjacent to a previously recorded recording track, the pit formed by the previous recording is on the photodiode. In this case, a tracking error signal is output as if the recording radiation spot is accurately on-track, even though the recording radiation spot is accurately tracked.

For example, as shown in FIG.
12 having a pre-groove 22 of 1.6 μm and a width W of 0.46 μm
When an inch optical disk is driven to rotate at a constant linear velocity (1800 rpm), the linear velocity with respect to the recording radiation spot is low in the inner peripheral recording area, and the exposure intensity of the recording layer increases, so that the width S of the pit 27 is 0.8 μm. 0.90.9 μm.

On the other hand, this optical recording medium has a diameter D ₁ (D ₁ = K · λ / N) determined by the wavelength λ of the radiation and the numerical aperture NA of the objective lens.
(A and K are constants). Intensity distribution within the light beam is decreased to the Gaussian distribution, the intensity is defined as the radiation Supotsuto diameter for recording / reproducing with a diameter D ₂ becomes 1 / e ² of the peak intensity. Usually, in the optical recording medium, Supotsuto diameter D ₂ recording / reproducing radiation Supotsuto of 1.6μm is used.

In this case, since the periphery of the light beam 28 is applied to the pit 27 recorded on the adjacent recording track (on the pre-groove 22), the center of the recording radiation spot 23 coincides with the center of the pre-groove 22. Also, as in FIG. 7 (b) or (c), the left and right non-uniformity of the field pattern 24 from the optical recording medium is applied, and a tracking servo is applied in a direction to correct this. As a result, the pit formation position deviates from the center of the pregroove, and crosstalk tends to occur during reproduction.

In recent years, in optical recording media, the track pitch tends to be narrowed more and more due to the demand for larger recording capacity, and the above-mentioned inconvenience is more likely to occur.

An object of the present invention is to solve the above-described problems and to provide an information recording method for an optical recording medium having no crosstalk and having a high CN ratio of a reproduction signal.

[Means for solving the problem]

In order to achieve the above object, the present invention irradiates a recording radiation spot along a required recording track on the optical recording medium while driving the optical recording medium, and records the recording radiation spot on the recording track. In an information recording method for an optical recording medium for recording information according to an irradiation pattern, when recording information, the recording radiation spot is positioned at the center of a recording track on which both adjacent recording tracks are unrecorded. After the recording, the irradiation order of the recording radiation spots is changed so that the recording radiation spot is positioned at the center of another recording track on which both adjacent recording tracks are both already recorded and the information is recorded. It was configured to be controlled.

[Action]

If two recording tracks adjacent to the recording track to be irradiated with the recording / reproducing radiation spot are both unrecorded or both recorded, the optical effect of the reflecting surface when the recording / reproducing radiation spot is irradiated is reduced. Because they are equal
The field pattern and thus the intensity distribution of the diffracted light on the photodiode become symmetrical, and the center of the recording / reproducing radiation spot can completely match the center of the recording track. Therefore, recording / reproducing characteristics such as a CN ratio can be improved without crosstalk.

If the recording tracks on both sides of the recording track to be irradiated with the recording / reproducing radiation spot are already recorded, and if the recorded contents are not the same, the light intensity distribution of the photodiode is different from the conventional one. Similarly, there is a case where the left and right are non-uniform. However, after the photodiode detects the diffracted light from the optical information recording medium,
It takes some time before the servo mechanism operates. Therefore, if data is recorded in the recording track such that the light intensity distribution of the photodiode becomes symmetrical or vice versa during that time, the deviation of the recording / reproducing radiation spot can be reduced. / The recorded contents recorded on both sides of the recording track to be irradiated with the reproducing radiation spot need not be completely the same.

〔Example〕

FIG. 1 is a block diagram of an optical information recording medium driving device according to the present invention.

As shown in FIG. 1, the optical information recording medium driving device according to the present invention mainly includes a spindle motor 2 for rotationally driving the optical information recording medium 1, a motor control unit 3 for controlling the rotation of the spindle motor 2, and an optical system. A pickup 4, a laser device 5 for emitting a recording radiation beam or a reproducing radiation beam, a preamplifier 6 for amplifying a signal read out by the optical pickup 4, and a recording / reproducing radiation spot should be irradiated. An address signal management unit 7 as an irradiation order management unit for instructing a recording track, a signal recording / reproducing system 8, a servo system 9 of the motor control unit 3 and the optical pickup 4, a number signal management unit 7, and a recording system. / Reproduction system 8 and a system controller 10 for controlling the servo system 9.

The essential part of the optical recording medium driving device according to the present invention resides in the program contents of the address signal management unit 7, and the overall configuration is the same as that of the conventional driving device. The same parts as those of the conventional driving device are well-known matters, and thus description thereof is omitted.

The address signal management unit 7 irradiates the recording / reproducing radiation spots in an order such that two recording tracks adjacent to the recording track to be irradiated with the recording / reproducing radiation spot are both unrecorded or both recorded. Programs that do

The gist of the present invention includes all programs for irradiating the recording / reproducing radiation spot in this order.

<First Embodiment> As shown in FIG. 2, an optical recording medium mounted on a drive device is an optical disk, and a single spiral pregroove 11 is formed on the optical disk. When one round of the pre-group 11 constitutes one recording track A, B, C..., The recording is performed in such a manner that signals are written in the order of A → C → B → D →. The address signal management unit 7 is programmed.

When data is written in such an order, when writing data to the recording tracks A, C,..., As shown in FIG. Since only the pregroove 11 having the same optical effect on the spot 23 is arranged, the intensity distribution of the diffracted light on the light receiving surface of the photodiode that receives the diffracted light from the optical disk 1 becomes symmetrical,
The center of the recording / reproducing radiation spot 23 can completely coincide with the center of the recording track A or C (pre-groove 11).

Similarly, when writing data to the recording tracks B, D,..., As shown in FIG.
In adjacent tracks A, C, and E, there are formed pits 12 having almost the same optical influence on the recording radiation spot, so that the light receiving surface of the photodiode for receiving the diffracted light from the optical disc 1 is formed. The diffracted light intensity distribution is also left-right symmetric, and the center of the recording / reproducing radiation spot 23 can completely coincide with the center of the recording track B or D (pre-groove 11). Therefore, at the time of reproduction, there is no occurrence of data crosstalk, and the recording / reproducing characteristics such as the CN ratio can be improved.

When data is written to the recording tracks B and D, if the contents of the data written to the recording tracks A, C and E are not the same, the positions of the pits 12 are different. May be left and right non-uniform as in the prior art. However, since it takes some time from when the photodiode detects the diffracted light from the optical disc 1 to when the servo mechanism operates, the diffracted light intensity distribution of the photodiode becomes bilaterally symmetric or inversely asymmetric during that time. If such data is recorded in the recording track, the deviation of the recording / reproducing radiation spot can be reduced. Therefore, recording tracks A, C, and E
Are not necessarily the same.

<Second Embodiment> On the same optical disk as in the first embodiment, first, recording is performed on every other recording track from the inner circumference to A → C → E → G →. After that, the program returns to the innermost peripheral portion and programs the address signal management section 7 so as to record in every other recording track such as B → D → F → H →.

Also in the case of the second embodiment, the same effects as in the case of the first embodiment can be obtained.

<Third Embodiment> As shown in FIG. 5, an optical recording medium mounted on a drive device is an optical disk, and two spiral pregrooves 13 and 14 are parallel and fixed to the optical disk. In the case of being arranged in a pitch and one round of each of the pre-grooves 13 and 14 forms one recording track, first, data is written sequentially from the inner circumference to the outer circumference along one pre-groove 13. After reaching the outermost recording track, the data is returned to the innermost peripheral portion again to write data along the other pregroove 14.

In the case of the third embodiment, the same effects as those of the first and second embodiments are obtained, and the recording / recording is performed for each recording track.
There is no need to jump the radiation spot for reproduction to another recording track, so that the control system can be simplified and the signal transfer speed can be increased.

The number of pregrooves arranged in parallel and at a fixed pitch is not limited to two, but may be an arbitrary number of three or more.

In each of the above embodiments, the case has been described in which the center of the recording radiation spot is focused on the center of the pre-groove to perform in-groove recording.
As shown in the figure, the center of the recording / reproducing radiation spot 23 can be focused on the center of two adjacent pregrooves 11 and 11 to perform on-land recording.

In each of the above embodiments, the optical disk drive is described as an example. However, the present invention can also be applied to a drive for an optical recording medium having a linear pre-groove such as an optical card. .

〔The invention's effect〕

As described above, according to the present invention, when recording information, after recording information by positioning the center of the recording radiation spot at the center of the recording track on which both adjacent recording tracks are unrecorded, Since the recording radiation spot is positioned at the center of another recording track on which both adjacent recording tracks have already been recorded, information is recorded, so that the center of the recording radiation spot is always positioned at the center of the recording track. Accuracy can be matched. Therefore, when information is reproduced, crosstalk from an adjacent track is unlikely to occur, and recording / reproducing characteristics such as a CN ratio can be improved.

[Brief description of the drawings]

FIG. 1 is a block diagram of a main part of an optical recording medium driving apparatus according to the present invention, FIG. 2 is a plan view of a main part of an optical disk showing an irradiation order of recording / reproducing radiation spots, and FIGS. Sectional view of an essential part of an optical disc for explaining effects of the present invention, FIG.
FIG. 6 is a plan view of a main part of another optical disc showing the irradiation order of the recording / reproducing radiation spot, FIG. 6 is a plan view of a main part of an optical recording medium showing an on-land recording system, and FIGS. )
(C) is an explanatory view showing the principle of a conventionally known tracking error detection method, and FIG. 8 is a plan view of a main part of another optical recording medium showing a problem of the prior art. 1: optical recording medium, 2: spindle motor, 3: motor control unit,
4: Optical pickup, 5: Laser device, 6: Preamplifier, 7:
Address signal management unit, 8: signal recording / playback system, 9: servo system,
10: system controller, 11: pre-groove, 12: pit, 23: radiation spot for recording / reproduction.

Claims (2)

(57) [Claims] A recording radiation spot is irradiated along a required recording track on the optical recording medium while driving the optical recording medium, and information corresponding to an irradiation pattern of the recording radiation spot is applied to the recording track. In the information recording method of an optical recording medium to be recorded, in recording information, the recording radiation spot is positioned at the center of a recording track in which both adjacent recording tracks are unrecorded, and the information is recorded. The irradiation order of the recording radiation spots is controlled such that the recording radiation spot is positioned at the center of another recording track on which both recording tracks are already recorded and the information is recorded. An information recording method for an optical recording medium. 2. The information recording method for an optical recording medium according to claim 1, wherein the recording radiation spots are radiated every other track from the inner peripheral side to the outer peripheral side of the recording track to record information. And thereafter recording information by irradiating the recording radiation spot every other track from the inner circumference to the outer circumference of the unrecorded track between the recorded tracks, thereby recording information. Information recording method.