KR100748137B1 - Control method of radial tilt at optical disc, and the device thereused to, and optical disc player equiped with said device - Google Patents

Abstract

A method for controlling a radial tilt of an optical disc, a control device therefor, and an optical disc reproducing apparatus with the same are provided to stably and accurately measure the radial tilt of the disc without using an additional dedicated tilt sensor or device and accurately control the radial tilt during record. A pickup is moved to a desired position in a disc(S501). A tracking servo is turned off, and a tracking error value is measured while changing a radial tilt drive value of the pickup(S502). A tilt drive value in which the tracking error value exists within a certain range is determined as a radial tilt value in a current position of the disc(S503). The entire process is repeated in the other positions, and radial tilt values for respective areas of the disc are determined. The radial tilt values determined in the respective areas are stored, and a radial tilt driving signal corresponding to the current position of the pickup is generated to control a tilt(S504).

Description

Radial tilt control method of optical disc, control device and optical disc reproducing apparatus having same {Control method of radial tilt at optical disc, and the device thereused to, and optical disc player equiped with said device}

1 is a block diagram related to the radial tilt control

2 is an illustration of a radial tilt disk

3 is a graph showing the radial tilt value according to the disc position

4 is a graph showing the change in the tracking error signal size according to the radial tilt change in the disc inner circumference 25m and the outer circumference 50m

5 is a radial tilt measurement flowchart of a disc.

6 is a radial tilt control flowchart

<Code Description of Main Parts of Drawing>

1: spindle motor 2: pickup

3: tilt actuator 4: tilt drive

5: radial tilt control unit 6: disc radial tilt measuring unit

7: disc

The present invention relates to a radial tilt control method, a control device, and an optical disk reproducing apparatus having the same on an optical disc. More specifically, the radial tilt of a disc is stably and accurately measured without using a separate tilt sensor or device. The present invention also relates to a radial tilt control method, a control device, and an optical disc reproducing device having the same, which can accurately control the radial tilt during recording.

In the case of an optical disc for recording, ideally, the surface of the disc is made flat without tilting. However, in the case of an actual disc, the disc tilts as shown in FIG. Discs curved in the circumferential direction according to the tendency of bending are called tangential tilt discs, and discs curved in the radial direction are called radial tilt discs. 2 shows a radial tilt disk.

Strictly speaking, tilt is caused by the object lens side and the disc surface of the optical pickup being out of level and may be caused by the deformation of the disk, but it is not only a mechanical problem when mounting the disk to the spindle motor. It can also be caused by an objective lens mounting process error in the pickup manufacturing process. In other words, the disk tilt can be caused by various factors.

The reason why this tilt component is important is that coma aberration occurs due to the tilt component during recording, resulting in a decrease in recording quality. In particular, when coma aberration is caused by the radial tilt, the recording quality is degraded, such as RF vibration, which is a very important factor in determining the recording quality.

In addition, as the optical disc for recording becomes higher, the track pitch becomes smaller and the margin for the radial tilt component becomes smaller. Therefore, a control method for compensating for the radial tilt component becomes more important.

For this reason, it is very important to control the tilt actuator to minimize the radial tilt present in the disc mounted in the current drive.

In the conventional case, the optical disc system does not perform the tilt control at all or uses a separate tilt sensor for tilt control. The tilt sensor is a method of detecting the amount of light by detecting the amount of light that is reflected on the disk and returning the infrared light to the disk surface to find out the amount of tilt and reflect it on the tilt actuator. However, the use of tilt sensors requires additional configuration of the infrared generator and detector, which can be a load in optical disk system configuration, both in terms of price and space.

If the tilt control is not performed at all, an important problem of deterioration of recording quality occurs.

The present invention has been proposed to solve the problems of the prior art as described above, and an object of the present invention is to stably and accurately measure a radial tilt of a disc without using a separate dedicated tilt sensor or device. Based on this, it provides a way to accurately control the radial tilt during recording.

It is another object of the present invention to provide a control device capable of stably and accurately measuring a radial tilt of a disc without using a separate dedicated tilt sensor or device, and controlling the radial tilt during recording based on this. .

Still another object of the present invention is to provide a control device capable of stably and accurately measuring the radial tilt of a disc without using a separate dedicated tilt sensor or device, and also controlling the radial tilt accurately during recording. An optical disk reproducing apparatus is provided.

In order to achieve the above object, the present invention comprises the steps of moving the pickup to the desired position in the disk; Measuring the tracking error value while turning off the tracking servo and changing the radial tilt drive value of the pickup; Determining a tilt drive value having a tracking error value within a predetermined range as a radial tilt value at a current position in the disc; Repeating the whole process at different positions to determine a radial tilt value for each disc area; And controlling the tilt by storing a radial tilt value determined in each area and generating a radial tilt driving signal corresponding to the current position of the pickup.

The present invention preferably provides a method of controlling a radial tilt on an optical disc comprising determining a tilt drive value that maximizes a tracking error value as a radial tilt value at a current position in the disc.

The present invention preferably provides a radial tilt control method on an optical disc, characterized in that the radial tilt value for the entire disc area is determined by interpolation with respect to the radial tilt value measured in each disc area.

The present invention also includes a pickup including a tilt actuator and a tilt drive unit, a radial tilt control unit and a disk radial tilt measuring unit, wherein the radial tilt control unit changes the radial tilt drive value of the pickup through the tilt drive unit in the tracking servo off state, The disc radial tilt measuring unit receives a tracking error signal output from a pickup according to the tilt drive value, and sets a tilt drive value at which a tracking error value satisfies a predetermined condition as a radial tilt value at a current position in the disc. The radial tilt value at is determined by using the interpolation method to determine the radial tilt value for the entire disc area, and records the measured result value in the memory together with the position information, and the radial tilt control unit uses the disc obtained by the disc radial measurement device. By location of A driving signal of the tilt actuator to be equivalent by the radial tilt values and provides an optical disk radial tilt control device, characterized in that for transmitting the tilt driving unit.

The present invention preferably provides an optical disc radial tilt control apparatus for determining a tilt drive value that maximizes a tracking error value as a radial tilt value at a current position in the disc.

The present invention also includes a pickup including a tilt actuator and a tilt drive unit, a radial tilt control unit and a disk radial tilt measuring unit, wherein the radial tilt control unit changes the radial tilt drive value of the pickup through the tilt drive unit in the tracking servo off state, The disc radial tilt measuring unit receives a tracking error signal output from a pickup according to the tilt drive value, and sets a tilt drive value at which a tracking error value satisfies a predetermined condition as a radial tilt value at a current position in the disc. The radial tilt value at is determined by using the interpolation method to determine the radial tilt value for the entire disc area, and records the measured result value in the memory together with the position information, and the radial tilt control unit uses the disc obtained by the disc radial measurement device. By location of It provides an optical disk reproducing apparatus comprising an optical disk radial tilt control device, characterized in that sending the driving signal to the tilt actuator to be equivalent by the radial tilt value to the tilt driving unit.

The present invention preferably provides an optical disc reproducing apparatus for determining a tilt drive value that maximizes a tracking error value as a radial tilt value at a current position in the disc.

Hereinafter, the content of the present invention will be described in detail with reference to the drawings showing preferred embodiments.

1 shows a control apparatus for implementing the method of controlling the radial tilt of the optical recording medium of the present invention.

The control device according to the invention shown in FIG. 1 comprises a pickup 2 comprising a tilt actuator 3 and a tilt drive 4, a radial tilt control 5 and a disc radial tilt measurement 6.

The radial tilt control unit 5 stores the radial tilt value for each position of the disc obtained by the disc radial measurement unit 6 in the memory, and then, based on the position information of the disc input during recording, the corresponding tilt actuator 3 The driving signal is sent to the tilt driver 4.

The radial tilt control unit 5 changes the radial tilt drive value of the pickup through the tilt drive unit 4 in the tracking servo off state. A tracking error signal is output from the pickup in accordance with the tilt drive value, and this signal is input to the disc radial tilt measuring device 6. The tilt measuring section 6 sets the tilt drive value at which the tracking error value becomes the maximum value as the radial tilt value at the current position in the disc, and this value can be obtained for each disc area, and the radial in each obtained area is obtained. The tilt value is determined for the entire disc area using the interpolation method, and the measured result value is recorded in the memory together with the position information.

As described above, although preferred embodiments of the present invention are described as performing one or more functions in a single device configuration, these functions may be physically implemented in one device or may be performed separately in two or more different devices. It may be. In addition, each of the above functions may be implemented in hardware or / and of course.

The optical disc reproducing apparatus according to the present invention is the same as a conventional optical disc reproducing apparatus, but the present invention is characterized in that the optical disc radial tilt control apparatus as shown in FIG. Do it.

2 illustrates a disk in which radial tilt exists. Taking the case of this disc as an example, the radial tilt control method according to the present invention will be described. Disks having a radial tilt as shown in FIG. 3 have different radial tilts according to their positions. Referring to FIG. 3, a radial tilt value of approximately -0.13 deg exists at a disc radius of about 25 mm. At this point, the tracking servo is turned off, and the tracking error signal is changed while changing the radial tilt value of the pickup actuator. Investigate.

Fig. 4 is a tracking error signal obtained by changing the radial tilt value of the pickup actuator at the inner 25m and outer 50m positions. In the present invention, the disc tilt is measured by using the correlation between the tracking error signal and the radial tilt of the disc in the tracking servo-off state. This is because the tracking error signal is maximized in the tracking servo-off state when the amount of radial tilt of the disk is accurately compensated.

Referring to FIG. 4, when the tracking error signal at the disk radius of 25 mm is found, the radial tilt value is approximately -0.13 deg, and the tracking error signal at the disk radius of 50 m is obtained. It can be seen that the maximum radial tilt value is about 0.16 deg. In the disk radial tilt measurement method using this principle, the radial tilt value for each position of the disk is measured through an algorithm described below.

Fig. 5 shows a radial tilt measurement flow chart of a disc presented as a preferred embodiment according to the present invention.

First, the pickup is moved to a desired position in the disc (S501).

The tracking error value is measured while turning off the tracking servo and changing the radial tilt drive value of the pickup (S502). The above process is a process of acquiring data for finding a point at which the tracking error signal is maximized by using a correlation between the tracking error signal and the radial tilt of the disc in the tracking servo-off state during the disc radial tilt measurement.

Then, the tilt drive value having a tracking error predetermined value is determined as the radial tilt value at the current position in the disc using the measured data (S503). At this time, preferably, a radial tilt value for maximizing the tracking error signal is obtained, but any radial tilt value of a lower value including a maximum margin including a maximum value without substantially affecting the radial tilt control. You can use one.

The radial tilt values measured by repeating the entire process N times are interpolated (interpolated) to obtain a radial tilt value for each disk area (S504).

6 shows a radial tilt control flow diagram presented as a preferred embodiment according to the present invention.

The radial tilt data of each area of the disk obtained by the procedure of FIG. 5 is stored in the memory of the radial tilt controller (S601).

If the pickup is located at any point on the disc, the position information of the disc is input to the radial tilt control unit (S602).

Then, the radial tilt driving signal corresponding to the input disk position is sent to the tilt driving unit to control the radial tilt (S603).

The method of controlling the radial tilt according to the present invention does not require a separate dedicated tilt sensor or device. That is, the present invention can reliably and accurately measure the radial tilt of a disc even if such a separate dedicated device is not provided, and can also accurately control the radial tilt during recording.

According to the present invention, it is possible to stably and accurately measure the radial tilt of a disc without using a separate dedicated tilt sensor or device, and also to accurately control the radial tilt during recording.

As described above, although described with reference to a preferred embodiment of the present invention, those skilled in the art will be variously modified and modified within the scope of the present invention without departing from the spirit and scope of the present invention described in the claims below. It will be appreciated that it can be changed.

Claims (7)

Moving the pickup to a desired location on the disc; Measuring the tracking error value while turning off the tracking servo and changing the radial tilt drive value of the pickup; Determining a tilt drive value having a tracking error value within a predetermined range as a radial tilt value at a current position in the disc; Repeating the whole process at different positions to determine a radial tilt value for each disc area; And controlling the tilt by storing a radial tilt value determined in each area and generating a radial tilt driving signal corresponding to the current position of the pickup. 2. The method of claim 1, comprising determining a tilt drive value that maximizes a tracking error value as a radial tilt value at a current position in the disc. The method of claim 1, wherein the radial tilt value of the entire disc area is determined by interpolation with respect to the radial tilt value measured in each disc area. A pickup including a tilt actuator and a tilt driver, a radial tilt controller, and a disk radial tilt measurement unit, wherein the radial tilt controller changes the radial tilt drive value of the pickup through the tilt driver in the tracking servo off state, and the disc radial tilt. The measuring device receives a tracking error signal output from the pickup according to the tilt drive value, sets the tilt drive value at which the tracking error value satisfies a predetermined condition as a radial tilt value at the current position in the disc, and the radial in each area obtained. The tilt value is used to determine the radial tilt value for the entire disc area using interpolation, and record the measured result value along with the position information in the memory, and the radial tilt control unit for each position of the disc obtained by the disc radial measurement device. Radial Tilt To the optical disk radial tilt control device, comprising a step of transmitting a driving signal of the tilt actuator to tilt the driver is a result. 5. The optical disc radial tilt control apparatus according to claim 4, wherein the tilt drive value that maximizes the tracking error value is determined as a radial tilt value at a current position in the disc. A pickup including a tilt actuator and a tilt driver, a radial tilt controller, and a disk radial tilt measurement unit, wherein the radial tilt controller changes the radial tilt drive value of the pickup through the tilt driver in the tracking servo off state, and the disc radial tilt. The measuring device receives a tracking error signal output from the pickup according to the tilt drive value, sets the tilt drive value at which the tracking error value satisfies a predetermined condition as a radial tilt value at the current position in the disc, and the radial in each area obtained. The tilt value is used to determine the radial tilt value for the entire disc area using interpolation, and record the measured result value along with the position information in the memory, and the radial tilt control unit for each position of the disc obtained by the disc radial measurement device. Radial Tilt The optical disk reproducing apparatus comprising an optical disk radial tilt control device, characterized in that sending the driving signal to the tilt actuator to tilt the driver is a result. 7. The optical disc reproducing apparatus according to claim 6, wherein the tilt drive value that maximizes the tracking error value is determined as a radial tilt value at the current position in the disc.

Images