CN1822138A - Servo control device, optical disk drive and servo control method - Google Patents

Abstract

A servo control device is connected with an optical read-write head, wherein the optical read-write head outputs a track-seeking error zero-crossing signal, the servo control device comprises a detection module, a signal generation module and a selection module, wherein the detection module detects a bump area on a random read-write type digital video disc to output a bump indication signal, the signal generation module generates a pseudo signal in a calculation or table-looking mode according to the moving speed of the optical read-write head and the track-seeking error zero-crossing signal, and the selection module generates a correction signal according to the bump indication signal, the pseudo signal and the track-seeking error zero-crossing signal. The invention also provides an optical disk drive comprising the servo control device and a servo control method.

Description

Servo control device, optical disk drive and servo control method

technical field

The invention relates to an optical disc drive, in particular to a servo control device and a servo control method for the optical disc drive.

Background technique

With the advent of the information and audio-visual era, optical information storage technology has been widely used by the public. When using this technology to access data, it needs to be applied to storage media, such as optical discs, and optical disc drives for accessing optical discs.

Common optical discs currently on the market include compact discs read-only (CD-ROM), compact discs rewritable (CD-R), re-readable discs (CD-RW), and digital video ROM), re-readable digital video disc (DVD-RW, DVD+RW) and random read-write digital video disc (DVD-RAM).

In existing optical discs, random read-write digital video discs are provided with a plurality of data tracks (tracks) for recording data, as shown in Figure 1, showing the first to third data tracks 11-13, wherein each data The track is to plan the stored data in the form of sectors, and a header (header) Hd is arranged at the front end of each sector. The area formed by these headers Hd is called the emboss area (emboss areas) 20, where the emboss areas The reflectivity of the block area 20 is higher than other areas of the optical disc.

Next, in an existing track seeking process of an optical disc, a tracking error zero crossing signal (TEZC signal) is usually used for tracking. As shown in Figure 2, generally speaking, the tracking error zero-crossing signal has a regular square wave, and the number of square waves represents the number of data tracks that the optical head spans across the optical disc. For example, at time t1 The tracking error zero-crossing signal between t2 and t2 indicates that the optical head straddles the two data tracks of the optical disc at this time. In the prior art, the tracking error zero-crossing signal is used as the tracking signal, and the optical disc drive can use the tracking signal to know the number of data tracks that the optical head spans across the optical disc, and then can control the optical head. Moving speed.

However, when the optical pick-up head corresponds to the bump area 20 of the optical disc, the tracking error signal (tracking error signal, TE signal) will easily have burrs or glitches due to the high reflectivity of the bump area 20. ), so that the corresponding tracking error zero-crossing signal forms a plurality of smaller frequency square waves, as shown between time t3 and t4, at this time, the tracking error zero-crossing signal is used as the tracking signal , will cause tracking errors.

Therefore, how to provide a servo control device and a servo control method for an optical disc drive, which can correct the tracking error zero-crossing signal as a correct tracking signal, is one of the current important issues.

Contents of the invention

In view of the above problems, the object of the present invention is to provide a servo control device and a servo control method for an optical disc drive, in order to correct the tracking error zero-crossing signal as a correct tracking signal.

The reason is that, in order to achieve the above object, the servo control device of the present invention is connected with an optical read-write head, wherein the optical read-write head outputs a tracking error zero-crossing signal, and the servo control device includes a detection module, a signal A generation module and a selection module, wherein the detection module detects a bump area on a random read-write digital video disc to output a bump indication signal (emboss indication signal), and the signal generation module is based on the moving speed of the optical read-write head and tracking error zero crossing signal, generate a false signal (pseudosignal) by calculation or table lookup, and the selection module receives bump indication signal, false signal and tracking error zero crossing signal and generates a correction based on these signals Signal (modified TEZC signal), the modified signal is the modified tracking error zero-crossing signal.

In addition, to achieve the above purpose, the present invention also discloses an optical disc drive, which includes an optical read/write head, a sled motor and a servo control device. In the present invention, the optical read-write head outputs a tracking error zero-crossing signal; the tracking motor carries the optical read-write head; the servo control device is composed of a detection module, a signal generation module and a selection module, wherein the detection The detection module detects the bump area on a random read-write digital video disc to output a bump indication signal, and the signal generation module is based on the moving speed of the optical read-write head in a tracking program and the tracking error zero-crossing signal , generate a false signal by calculation or table look-up, the selection module receives the bump indication signal, the false signal and the tracking error zero-crossing signal and generates a correction signal according to the above signal, so as to control the tracking according to the correction signal The track motor moves the optical read-write head to perform the track-seeking procedure.

Moreover, in order to achieve the above purpose, the present invention also discloses a servo control method, which is applied to an optical disc drive, and the optical disc drive has an optical pick-up head. The servo control method includes generating a tracking error zero-crossing signal; According to the moving speed of the optical read-write head in a tracking program and the zero-crossing signal of the tracking error, a false signal is generated by calculation or table look-up; the bump area on a random read-write digital video disc is detected to outputting a bump indicating signal; and generating a correction signal according to the bump indicating signal, the false signal and the tracking error zero-crossing signal.

As mentioned above, because the servo control device and the servo control method of the optical disk drive according to the present invention generate correction signals according to the bump indication signal, false signal and tracking error zero-crossing signal, so the correction signal can be used as the correct Tracking signals, thereby avoiding the waste of tracking time caused by existing wrong tracking signals.

Description of drawings

FIG. 1 is a schematic diagram showing a section of data track of an existing random read-write digital video disc;

Figure 2 shows an existing tracking error zero-crossing signal;

3 is a schematic diagram showing a servo control device according to a preferred embodiment of the present invention;

4 is a schematic diagram showing the moving speed of the optical read-write head;

FIG. 5 is a timing diagram showing signals in the servo control device according to a preferred embodiment of the present invention;

FIG. 6 is a schematic diagram showing an optical disc drive according to a preferred embodiment of the present invention; and

FIG. 7 is a flowchart showing a servo control method according to a preferred embodiment of the present invention.

Description of component symbols:

11, 12, 13 data track

20 bump area

3 CD drive

31 Optical read/write head

32 Track-seeking motor

33 Servo control device

331 Detection Module

332 Signal generation module

333 Select module

41 Tracking error zero crossing signal

42 bump indication signal

43 false signal

44 Correction signal

Hd header

S1～S3 Servo control method

Detailed ways

A servo control device and a servo control method for an optical disc drive according to preferred embodiments of the present invention will be described below with reference to related drawings, wherein the same components will be described with the same reference symbols.

Referring to FIG. 3 , a servo control device 33 according to a preferred embodiment of the present invention is connected to an optical pickup 31 , wherein the optical pickup 31 outputs a tracking error zero-crossing signal 41 . The servo control device 33 includes a detection module 331 , a signal generation module 332 and a selection module 333 .

In this embodiment, the detection module 331 detects the bump region 20 to output a bump indication signal 42 to the selection module 333 . The signal generation module 332 receives the tracking error zero crossing signal 41 and generates a dummy signal 43 according to the moving speed of the optical head 31 and the tracking error zero crossing signal 41 and outputs it to the selection module 333 . The selection module 333 generates a correction signal 44 according to the bump indication signal 42 , the false signal 43 and the tracking error zero crossing signal 41 , and the correction signal 44 is the corrected tracking error zero crossing signal. In addition, in this embodiment, the moving speed of the optical pick-up head 31 may be the moving speed of the optical pick-up head 31 in the tracking procedure.

Furthermore, in this embodiment, the signal generating module 332 can generate the false signal 43 by calculating or looking up a table according to the moving speed of the optical head 31 and the tracking error zero-crossing signal 41 . For example, in a track-seeking procedure, the moving speed of the optical read-write head 31 can be represented by a curve (profile) as shown in FIG. Therefore, the curve equation can be used to calculate the period of the optical pick-up head 31 passing through a track, so as to generate the false signal 43 . In addition, a tracking speed reference table (not shown) can also be designed in advance, and then the moving speed of the optical pick-up head 31 is used to look up the tracking speed reference table, so as to obtain the corresponding speed of the optical pick-up head 31 passing through a track. Period, thereby generating false signal 43.

Next, as shown in FIG. 1 , FIG. 3 and FIG. 5 , when the optical read/write head 31 corresponds to the bump region 20 , such as between time t7 and t8, the detection module 331 detects the bump region 20 at this time. To output a first level (high level) bump indication signal 42 . On the contrary, when the optical read-write head 31 is not corresponding to the bump area 20 , such as between time t5 and t6 , the detection module 331 outputs a bump indication signal 42 of a second level (low level).

In addition, when the selection module 333 receives the bump indication signal 42 of the first level, the selection module 333 generates the correction signal 44 according to the false signal 43 . When the selection module 333 receives the bump indication signal 42 of the second level, the selection module 333 generates the correction signal 44 according to the tracking error zero-crossing signal 41 . For example, as shown in FIG. 5, between time t5 and t7, the bump indication signal 42 is at the second level, so the selection module 333 generates the correction signal 44 according to the tracking error zero-crossing signal 41, because the tracking The error zero-crossing signal 41 has a regular square wave and the number of square waves of the tracking error zero-crossing signal 41 can represent the number of data tracks across the optical disc, so that the correction signal 44 is between time t5 and There is also a regular square wave between t7 and the number of square waves of the correction signal 44 can also represent the number of data tracks across the optical disc by the optical pick-up head. And between time t7 and t8, the bump indication signal 42 is at the first level, so the selection module 333 generates the correction signal 44 according to the false signal 43, because the false signal 43 has a regular square wave and the number of square waves of the false signal 43 It can represent the number of data tracks across the optical disc by the optical pickup, so the correction signal 44 also has a regular square wave between time t7 and t8 and the number of square waves of the correction signal 44 can also represent the optical pickup The number of data tracks across the optical disc, thus using the correction signal 44 as a correct tracking signal.

In this embodiment, the detection module 331, the signal generation module 332, and the selection module 333 can all be digitally designed integrated circuits to realize their functions. For example, the detection module 331 can be a comparator, and the signal generation module 332 can be It is a clock generation circuit, and the selection module 333 can be a multiplexer. The above descriptions are illustrative only, not restrictive. Any equivalent modifications or changes made without departing from the spirit and scope of the present invention shall be included in the scope of the appended claims.

Based on the above, the servo control device 33 can be applied to the optical disc drive, so that the optical disc drive can avoid the waste of tracking time caused by the existing wrong tracking signal. An example will be given below to illustrate the preferred implementation of the present invention. CD-ROM for example.

Referring to FIG. 6 , an optical disc drive 3 according to a preferred embodiment of the present invention includes an optical head 31 , a tracking motor 32 and a servo control device 33 .

In this embodiment, the optical read-write head 31 outputs a tracking error zero-crossing signal 41 to the servo control device 33, the tracking motor 32 carries the optical read-write head 31 to move, and the servo control device 33 includes a detection module 331, A signal generation module 332 and a selection module 333. The main structure of the servo control device 33 is as described above, so it will not be repeated here.

Furthermore, in this embodiment, the servo control device 33 outputs a correction signal 44 to the tracking motor 32 so as to control the tracking motor 32 to move the optical head 31 according to the correction signal 44 to perform the tracking process.

In order to make the present invention more clear, an embodiment will be given below to explain how to apply the servo control method to an optical disk drive, so that the optical disk drive can avoid the waste of tracking time caused by the existing wrong tracking signal.

Referring to FIG. 7 , a servo control method according to a preferred embodiment of the present invention is applied to an optical disk drive, and the optical disk drive has an optical pick-up head. The method includes steps S1 to S3.

In step S1, a tracking error zero-crossing signal is generated.

In step S2, a false signal is generated according to the moving speed of the optical read-write head and the zero-crossing signal of the tracking error, wherein when the optical read-write head corresponds to a bump area, a bump indication of a first level is output Signal. In addition, when the optical pick-up head does not correspond to the bump area, a second-level bump indication signal is output, and the moving speed of the optical pick-up head can be the moving speed of the optical pick-up head in the tracking process.

In step S3, a correction signal is generated according to a bump indicator signal, a dummy signal and a tracking error zero-crossing signal, wherein when the first level bump indicator signal is received, the correction signal is generated according to the dummy signal. In addition, when the bump indication signal of the second level is received, the correction signal is generated according to the tracking error zero-crossing signal, and according to the moving speed of the optical read-write head and the tracking error zero-crossing signal, the calculation method can be Or look-up table way to generate false signal.

As mentioned above, because the servo control device and the servo control method of the optical disk drive according to the present invention generate correction signals according to the bump indication signal, false signal and tracking error zero-crossing signal, so the correction signal can be used as the correct Tracking signals, thereby avoiding the waste of tracking time caused by existing wrong tracking signals.

The above descriptions are illustrative only, not restrictive. Any equivalent modifications or changes made without departing from the spirit and scope of the present invention shall be included in the scope of the appended claims.

Claims (10)

1. A servo control device, which is connected with an optical read-write head, wherein the optical read-write head outputs a tracking error zero-crossing signal, and the servo control device includes: A detection module, which detects a bump area on a random read-write digital video disc to output a bump indication signal; A signal generation module, which generates a false signal by calculating or looking up a table according to the moving speed of the optical read-write head and the zero-crossing signal of the tracking error; and A selection module, which receives the bump indicator signal, the false signal and the tracking error zero-crossing signal and generates a correction signal according to the bump indicator signal, the false signal and the tracking error zero-crossing signal. 2. The servo control device according to claim 1, wherein: When the detection module detects the bump area, it outputs the bump indication signal of a first level, otherwise the detection module outputs the bump indication signal of a second level. 3. The servo control device according to claim 2, wherein: When the selection module receives the bump indication signal at the first level, generate the correction signal according to the dummy signal; and When the selection module receives the bump indication signal of the second level, the correction signal is generated according to the tracking error zero-crossing signal. 4. The servo control device according to claim 1, wherein The moving speed of the optical pick-up head refers to the moving speed of the optical pick-up head in a tracking procedure. 5. A CD player, comprising: An optical read-write head, which outputs a tracking error zero-crossing signal; a tracking motor, which carries the optical read-write head; and A servo control device, comprising: A detection module, which detects a bump area on a random read-write digital video disc to output a bump indication signal; A signal generation module, which generates a false signal by calculating or looking up a table according to the moving speed of the optical read-write head in a tracking program and the tracking error zero-crossing signal; and A selection module, which receives the bump indication signal, the false signal and the tracking error zero-crossing signal and generates a correction signal according to the bump indication signal, the false signal and the tracking error zero-crossing signal, so that The track-seeking motor is controlled to move the optical read-write head according to the correction signal to perform the track-seeking procedure. 6. The optical disc drive of claim 5, wherein: When the detection module detects the bump area, it outputs the bump indication signal of a first level, otherwise the detection module outputs the bump indication signal of a second level. 7. The optical disc player of claim 6, wherein: When the selection module receives the bump indication signal at the first level, generate the correction signal according to the dummy signal; and When the selection module receives the bump indication signal of the second level, the correction signal is generated according to the tracking error zero-crossing signal. 8. A servo control method, which is applied to an optical disc drive, and the optical disc drive has an optical pick-up head, the servo control method comprising: generating a tracking error zero-crossing signal; According to the moving speed of the optical read-write head in a tracking program and the tracking error zero-crossing signal, a false signal is generated by calculation or table look-up; detecting a bump area on a random access digital video disc to output a bump indication signal; and A correction signal is generated according to the bump indicator signal, the false signal and the tracking error zero-crossing signal. 9. The servo control method according to claim 8, wherein: When a bump area is detected, output a first level of the bump indication signal, otherwise output a second level of the bump indication signal. 10. The servo control method according to claim 9, wherein: when receiving the bump indication signal of the first level, generating the correction signal according to the dummy signal; and When receiving the bump indication signal of the second level, the correction signal is generated according to the tracking error zero-crossing signal.

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