KR100607940B1 - Method for recording servo signal on optical recording medium and optical pickup apparatus recordable servo signal on optical recording medium - Google Patents

Abstract

Disclosed are a method of recording a servo signal on an optical recording medium such that an optical spot formed on one track of the optical recording medium does not affect a neighboring track during narrow track recording, and an optical pickup apparatus capable of recording a servo signal.

The disclosed servo signal recording method comprises the steps of: recording a servo signal on one track of an optical recording medium; Recording the servo signal on another track while tracking the track on which the servo signal is recorded so that the wobbling pattern of the servo signal recorded between adjacent tracks is similar; In the recording / reproducing process, the distance between adjacent tracks is made approximately constant so that the light spot does not interfere with the adjacent tracks.

In addition, the disclosed optical pickup apparatus includes a light source for recording a servo signal; Is irradiated from the light source tracking irradiating the servo signal when the Rimed track the light spot to as T _{n + 1,} the track T _{n +} prior to the _first light spot for tracking in the track T _n of the servo signal already recorded temperature may cause problems optical Light irradiation means; Optical path changing means; An objective lens for focusing incident light; And a photodetector for detecting the servo signal and the tracking error signal, wherein the wobbling of the track T _{n + 1 has} a type similar to the wobbling type of the track T _n .

Description

Method for recording servo signal on optical recording medium and optical pickup apparatus recordable servo signal on optical recording medium}

1 is a schematic view of a conventional optical disc and tracks of the optical disc;

2 is a schematic view showing an optical arrangement of the optical pickup device according to an embodiment of the present invention.

3 is a schematic view showing an optical arrangement of an optical pickup apparatus according to another embodiment of the present invention.

4 is a schematic view of a track of an optical disc on which servo signals are recorded in accordance with embodiments of the present invention.

5 is a flowchart illustrating a method of recording a servo signal on an optical recording medium according to an embodiment of the present invention.

6 is a schematic view showing an optical arrangement of an optical pickup apparatus according to another embodiment of the present invention.

7 schematically shows a track of an optical disc on which a servo signal is recorded according to an embodiment of the present invention.

8 is a flowchart illustrating a method of recording a servo signal on an optical recording medium according to another embodiment of the present invention.

<Description of the symbols for the main parts of the drawings>

20, 50, optical recording medium 31, light source for recording servo signal

33.Optical conversion means 35 ... Objective lens

37.Photodetector 41.Tracking light source

45 ... light modulator 60 ... first photodetector

61 ... first objective lens 70 ... second photodetector

71.2nd objective lens

The present invention relates to a method for recording a servo signal on an optical recording medium having no lands and grooves, and to an optical pickup apparatus capable of recording a servo signal. In detail, an optical spot formed on one track of the optical recording medium during narrow track recording is neighboring. A method of recording a servo signal on an optical recording medium which does not affect one track, and an optical pickup apparatus capable of recording a servo signal.

In general, optical recording media are becoming more dense and large with the development of DVD, high-density DVD (HD-DVD), near field recording (Near Field Recording) optical discs, and the track pitch is gradually narrowing. . In addition, an optical pickup apparatus has been developed such that the size of an optical spot formed on an optical recording medium is gradually reduced.

In particular, in the case of an optical disc for nearfield recording, the distance between the track and the track of the optical disc has approximately 2 m. On the other hand, the size of the optical spot formed on the optical disc has a size of the track pitch as compared with the interval between the track and the track, that is, the track pitch. Further, the nearfield recording optical disc does not have lands and grooves for distinguishing tracks from tracks.

On the other hand, when the servo signal is to be recorded on the optical disk having such a structure, there is an error with respect to the virtual track which forms a complete concentric circle due to the shaking due to the rotational drive of the optical disk.

1 is a view schematically showing a track of an optical disc formed by a conventional optical pickup apparatus capable of recording servo signals using a conventional narrow track optical disc and one light source.

Referring to the drawings, actual tracks T _n-3 , T _n-2 , T _n-1 , T _n , T _{n + 1} , T _{n + 2} of the optical disc 10 formed by the optical pickup device (not shown) Each is formed while wobbling around an ideal track 11, indicated by a dashed line. Here, the actual tracks are formed by a conventional optical pickup apparatus and are formed independently for each track.

Therefore, when looking at the interval between neighboring tracks, for example, tracks T _n and T _{n + 1,} there is a wide interval A and a narrow interval B between two tracks. In this case, it is not a problem in the wide section A because there is no light spot (S) interference between adjacent tracks T _n-1 and T _n , but in the narrow section B, a part of the light spot S 'following the track T _n is not included. Interference with neighboring tracks T _{n + 1} . Therefore, there is a problem that recording / reproducing of normal information on the track is impossible since it is affected by the adjacent track.

SUMMARY OF THE INVENTION The present invention has been made in view of the above, and the servo signal wobbling type between adjacent tracks does not affect an optical track that is formed on one track of an optical recording medium during narrow track recording. It is an object of the present invention to provide a method of recording a servo signal on an optical recording medium and an optical pickup apparatus capable of recording a servo signal.

In order to achieve the above object, a method for recording a servo signal on an optical recording medium according to the present invention comprises the steps of: recording the servo signal on one track of the optical recording medium; Recording the servo signal on another track while tracking the track on which the servo signal is recorded so that the wobbling pattern of the servo signal recorded between adjacent tracks is similar; In recording / reproducing a signal, the distance between adjacent tracks is made approximately constant so that the light spot does not interfere with the adjacent track.

Further, in order to achieve the above object, an optical pickup apparatus capable of recording a servo signal according to the present invention comprises: a servo signal recording light source for recording servo signals on a plurality of tracks constituting an optical recording medium; When the investigation is the servo signal light spot is Rimed track in the servo signal recording light source to be referred to as T _{n + 1,} the track T _{n +} prior to the _first servo signal is already group the light spot for tracking in the track T _n temperature may cause problems recorded Tracking light irradiation means for irradiating light; Optical path converting means for converting a traveling path of the incident light; An objective lens for focusing incident light so that each of the light irradiated by the servo signal recording light source and the light irradiated by the tracking light irradiation means is formed on the track Tn + 1 and the track Tn, respectively; A photodetector that receives the light reflected from the optical recording medium and detects a servo signal and a tracking error signal, such that the wobbling of the track T _{n + 1 has} a type similar to the wobbling type of the track T _n . It is characterized by.

Hereinafter, a method of recording a servo signal on an optical recording medium and an optical pickup apparatus capable of recording a servo signal according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

2 and 3, a servo signal recordable optical pickup apparatus according to an embodiment of the present invention includes a servo signal light source 31, tracking light irradiation means for irradiating light to a track preceding the recording track, It is comprised between the light source 31 and the optical recording medium 20, and the optical path converting means 33 which converts the advancing path of incident light, the objective lens 35, and the photodetector 37. As shown in FIG.

The optical recording medium 20 is a medium having no land and groove structure, such as a near field optical disk, and has a narrow track structure having a track pitch of approximately 20 μm. In this optical recording medium 20, a track servo signal must be recorded on a track so as to detect a track error signal through a sample servo.

The servo signal recording light source 31 irradiates light for recording the servo signal to the optical recording medium 20 configured as described above. The light irradiated from the servo signal recording light source 31 has an optical power of approximately 30 to 50 mW.

The tracking light irradiation means tracks the preceding track such that when the servo signal is recorded for one track, the wobbling of the track in which the servo signal is recorded has a type similar to that of the preceding track. To this end, when the track irradiated by the servo signal recording light source 31 and formed with the servo signal light spot S _{n + 1} is called T _{n + 1} , the light irradiated by the tracking light irradiation means becomes the track T _{n. The} tracking optical spot S _n is formed in the track T _n in which the servo signal has already been recorded before ₊₁ .

As shown in FIG. 2, the tracking light irradiation means may include a tracking light source 41 disposed around the servo signal recording light source 31 to independently irradiate light. . In this case, each of the two light sources 31 and 41 has a semiconductor laser array structure, and is preferably mounted in one module.

In addition, another embodiment of the tracking light irradiation means is disposed on an optical path between the servo signal recording light source 31 and the optical path changing means 33, as shown in FIG. And an optical modulator 45 for modulating a part of the light irradiated from the recording light source 31. In this case, the optical modulator 45 causes incident light to form light spots S _{n + 1} and S _n respectively at the track T _{n + 1} and the track T _n . The light modulator 45 is composed of an acoustic light modulator (AOM), an electric light modulator (EOM), and the like.

The objective lens 35 focuses incident light so that each of the light irradiated from the servo signal recording light source 31 and the light irradiated from the tracking light irradiation means is formed on the track Tn + 1 and the track Tn, respectively.

The optical path converting means 33 is disposed on an optical path between the servo signal recording light source 31 and the objective lens 35, and converts the advancing path of incident light. That is, the light irradiated from the light sources 31 and 41 is directed toward the objective lens 35, and the light incident from the objective lens 35 is directed to the photodetector 37. To this end, the optical path changing means 33 is composed of a beam splitter having a configuration as shown. The optical path converting means may be composed of a polarizing beam splitter, a hologram element, or the like.

The photodetector 37 receives light reflected from the optical recording medium 20 to detect a servo signal and a tracking error signal. The tracking error signal detected by the photodetector 37 is a result obtained by receiving the light reflected from the track T _n of the optical recording medium 20 after being irradiated by the tracking light irradiation means. Actuating the objective lens 35 on the basis of the signal so that the track T _{n + 1} on which the servo signal is recorded has the same type of wobbling as the track T _n .

When recording the servo signal using the optical pickup device configured as described above, an embodiment of the servo signal recording method will be described with reference to FIGS. 4 and 5.

4, the actual tracks formed by the optical pickup device T _n-3 , T _n-2 , T _n-1 , T _n , T _{n + 1} , T _{n + 2} , ... are each dotted lines. It is formed while wobbling around the ideal track 21 indicated. Here, the wobbling of the track T _{n + 1} is characterized in that it has a type similar to the wobbling type of the track T _n .

To this end, the servo signal is recorded on the first track T _n of the optical recording medium 20 in which the servo signal is not recorded (S100). In this case, the tracking light irradiation means shown in Figs. 2 and 3 is not used.

Then, a servo signal is recorded on the adjacent track T _{n + 1} T _n trailing while tracking a track on which the servo signal is recorded (S110). In this case, since the track T _n in which the servo signal is recorded follows the servo signal in which the light spot S _n irradiated by the tracking light irradiation means is already formed, the optical signal S _{n + 1} for the servo signal follows the track T _{n + 1} . , gatneun similar to the wobbling shape with a wobbling shape of the track T _n tracks is formed in T _{n + 1.}

Subsequently, the servo signal is recorded in the track Tn + 2 that follows, while the track Tn + 1 is newly recorded. By repeating such tracking and servo signal recording, a plurality of tracks of the optical recording medium have a similar wobbling pattern. Therefore, unlike the conventional optical recording medium, the distance between the tracks and the tracks is kept approximately constant without widening or narrowing of the tracks. Therefore, the optical spot SPOT for recording / reproducing the information signal does not interfere with neighboring tracks when following one track, so that the normal information signal can be recorded / reproduced.

A method of recording a servo signal on an optical recording medium according to another embodiment of the present invention will now be described with reference to FIGS. 6 to 8.

This embodiment is for the case where servo signals are recorded on both sides of the optical recording medium 50.

Referring to FIG. 6, the optical pickup apparatus used in the present embodiment is configured to irradiate light to each of the first and second surfaces 51 and 55 of the optical recording medium 50 and to detect a signal therefrom. And first and second optical pickups 60 and 70.

The first optical pickup 60 irradiates light and collects the incident light receiving portion I to receive incident light, and focuses the incident light on the first surface 51 to form an optical spot S _n on the surface. And (61). The second optical pickup includes a transmitter / receiver II and a second objective lens 71 for focusing incident light on a second surface to form an optical spot S _{n + 1} on the surface.

Here, the recording of the servo signal on the first surface 51 of the optical recording medium 50 is recorded by the servo signal recording method according to the embodiment described above.

The optical spot S _n is an optical spot formed on the track T _n of the first surface 51 on which the servo signal has already been recorded, and the optical spot S _{n + 1} is the optical spot on the second surface 55 on which the servo signal is recorded. It is a light spot formed in the track T _n 'facing the spot S _n . Accordingly, the first optical pickup 60 is for tracking, and the second optical pickup 70 is driven in association with a track error signal detected through the optical spot S _n , whereby the track T _n ′ becomes the track. It will have a wobbling type similar to T _n .

Referring to Fig. 7, each of the actual tracks T _n-1 , T _n , T _{n + 1} ,... Formed by the first surface 51 by the optical pickup device is warped around the ideal track 52 indicated by the dotted lines. It is formed while bling. Here, the wobbling of the track T _{n + 1} has a type similar to the wobbling of the track T _n .

Meanwhile, the actual tracks T _n-1 ′, T _n ′, T _{n + 1} ′, ... formed on the second surface 55 are each wobbled around the ideal track 56 indicated by dotted lines. , Each of these tracks is wobbled to have a type similar to each of the tracks T _n-1 , T _n , T _{n + 1} ,. As shown in FIG. 8, the first track number of the second surface 56 of the optical recording medium on which the servo signal is not recorded is counted (S200). Subsequently, the track T _n of the first surface 51 is tracked (S210). At the same time as tracking, the servo signal is recorded on the track T _n ′ of the second surface (S220).

Then, the recording a servo signal on the basis of the servo signal and the tracking the recording track T _{n + 1} tracks T _n 'a trailing track T _{n + 1} adjacent to'. In this case, since the optical spot S _n follows the track T _{n + 1} on which the servo signal is recorded, when the optical spot S _{n + 1} for the servo signal follows the track T _{n + 1, it} is similar to the wobbling pattern of the track T _n . A track T _{n + 1} having the same wobble shape is formed. By repeating such tracking and servo signal recording, the plurality of tracks of the optical recording medium have a similar wobbling pattern.

A method of recording a servo signal on an optical recording medium and a servo signal recordable optical pickup apparatus according to the present invention configured as described above are provided such that the servo signal wobbling of one track is similar in the type of servo signal wobbling between neighboring tracks. do. Therefore, unlike the conventional optical recording medium, the distance between the tracks and the tracks is kept approximately constant without widening or narrowing of the tracks.

Therefore, there is an effect that the optical spot for recording / reproducing the information signal does not interfere with neighboring tracks when following one track, so that the normal information signal can be recorded / reproduced.

Claims (6)

Recording a servo signal on one track of the optical recording medium; Recording the servo signal on another track while tracking the track on which the servo signal is recorded so that the wobbling pattern of the servo signal recorded between adjacent tracks is similar; In the recording / reproducing of the information signal by forming an optical spot on one track, the interval between adjacent tracks is constant so that the optical spot does not interfere with the adjacent track. Way. The method of claim 1, One track constituting the optical recording medium is a preceding track T _n , That the servo signals are recorded while tracking the other track adjacent to the trailing track, the track T _n to T _{n + 1,} And the trailing track T _{n + 1} has a wobbling type similar to the preceding track T _n . The optical recording medium of claim 1, wherein the optical recording medium is a medium having information signals recorded on both surfaces thereof. One track constituting the optical recording medium is a track T _n formed on one surface of the optical recording medium, The other track on which the servo signal is recorded while tracking is track T ' _n arranged to face the track T _n formed on the other side of the optical recording medium, And the track T ' _n has a wobbling type similar to the track T _n . A servo signal recording light source for recording servo signals on a plurality of tracks forming an optical recording medium; When the track irradiated by the servo signal recording light source to form the optical signal for servo signal is T _{n + 1} , the tracking optical spot is formed on the track T _n in which the servo signal has already been recorded before the track T _{n + 1} . Tracking light irradiation means for irradiating light; Optical path converting means for converting a traveling path of the incident light; An objective lens for focusing incident light so that each of the light irradiated by the servo signal recording light source and the light irradiated by the tracking light irradiation means is formed on the track Tn + 1 and the track Tn, respectively; And a photodetector configured to receive the light reflected from the optical recording medium to detect a servo signal and a tracking error signal. And the wobbling of the track T _{n + 1 has} a type similar to the wobbling type of the track T _n . The method of claim 4, wherein the tracking light irradiation means, And a tracking light source disposed around the servo signal recording light source and irradiating light independently. The method of claim 4, wherein the tracking light irradiation means, Disposed on an optical path between the servo signal recording light source and the optical path converting means, and modulates a part of the light irradiated from the servo signal recording light source so that incident light is directed to the track Tn + 1 and the track Tn, respectively; An optical pickup apparatus capable of recording a servo signal, comprising: an optical modulator.

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