KR20010095389A - Method for adjusting skew in an optical disc apparatus - Google Patents

Abstract

PURPOSE: A method for controlling a skew in an optical disc device is provided to perform properly a skew control operation in a combination device using various kinds of discs. CONSTITUTION: A disc is in a state of a play mode(S11). A skew value of a tangential direction is measured(S12). A motor is connected with a tangential skew control portion(S15). The motor is rotated in the first level(S16). The motor is connected with a radial skew control portion(S17). The motor is rotated in the first level(S20). A tangential potentiometer value, a radial potentiometer value, and an error rate are measured and stored in a memory within a control portion. The radial skew control operations of the first to the tenth level are repeatedly performed while the tangential skew control operation of the first level is performed(S21,S19). The tangential skew control operation of the second level is performed and the radial skew control operations of the first to tenth level are repeatedly performed(S13). The potentiometer value of the lowest error rate is determined as an optimum skew value and the optimum skew value is stored in the memory(S23).

Description

{Method for adjusting skew in an optical disc apparatus}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a skew adjusting method in an optical disk device, and more particularly, to a skew adjusting method in a device that uses various types of disks.

As a digital information storage medium, optical discs, such as commercially available CDs (Compact Discs), and DVDs (Digital Versatile Discs) in which a large amount of information is stored are compared to CDs. In particular, in DVD, since the laser wavelength to be read is small and the focal radius is small, the jitter is very sensitive to skew due to skew (tilt of the disc). To lower jitter, precise adjustments are necessary.

There are usually skews in the disc track direction (Tangetial Skew) and in the radial direction of the disc radial (Skew), and the disc device also has two adjustment devices correspondingly. There are many ways to adjust this, including adjusting the inclination of the turntable and the sled (pickup transfer mechanism) shaft on which the disk is seated. The method of adjusting skew so that it may be known is known. The latter case is more efficient.

However, these methods suffer from problems. In the former method, the skew is mechanically correct, but in reality, since the amount of skew per pickup is different, reproduction data cannot be obtained equally for all devices. That is, when mass production is a method that can have a high defect rate.

In addition, the latter method is applied to a device that plays various types of discs, for example, a device that combines CD and DVD is not adjusted by adjusting the skew by playing one of the discs, CD or DVD. Other discs have relatively poor playback performance. The reason for this is that aberrations (errors) for CDs and DVDs are different depending on pickups, and even if skew is adjusted on the DVD, it may adversely affect CD playback in some cases.

Accordingly, it is an object of the present invention to provide a skew adjusting method suitable for an apparatus which uses various kinds of disks.

1 shows an example of a device according to the invention,

2 is a flow chart showing a skew adjusting method according to the present invention.

In order to achieve the above object, the skew adjusting method according to the present invention provides a step of providing a plurality of skew states between a particular type of disk and the device, and detects the skew state value and the error rate by detecting the error rate of the reproduction signal according to each skew state. Correspondingly temporarily storing the memory in a memory, and selecting an optimal skew state value among the plurality of skew state values stored in the memory.

Other objects, features and advantages of the present invention will become apparent from the detailed description of the embodiments with reference to the accompanying drawings.

Hereinafter, an embodiment according to the present invention will be described with reference to FIGS.

First, FIG. 1 illustrates a disk device to which the present invention is applied, and shows a device for playing a playback-only disk such as a CD-ROM, a DVD-ROM, and the like. Although a reproduction-only disc reproducing apparatus is taken as an example, the same applies to the recording / reproducing apparatus corresponding to recordable discs such as CD-RW, DVD-RAM and the like.

An optical pickup 2 for detecting a signal from the disc (CD or DVD) 1, a signal processing unit 3 for signal-processing the signal to restore data, and a control unit 4 for controlling the entire apparatus. have.

On the other hand, it is assumed that there is a mechanism (not shown) for adjusting the skew in the track direction and the skew in the radial direction of the disc, for example, a mechanism for adjusting two skews (tilts) between the disk mounted on the turntable and the optical pickup by the rotation of the motor. Then, a potentiometer capable of measuring two skew adjustment amounts, that is, rotational displacement, is provided in the skew adjusting unit. That is, the track potentiometer T and the radial potentiometer R are shown in FIG.

These two skew adjusting units are driven by the motor M in response to the command of the control unit 4, but the drive switching unit SW2 is provided for selective operation. This switching part is a means which can switch power transmission / disconnection between a motor and two skew adjustment parts, for example, can comprise a normal gear converter. In addition, an A / D converter 8 for detecting an adjustment amount (rotational displacement) of the two skew adjustment units, and a memory (EEPROM) for storing an optimum skew value as described later, are provided.

First, a method of setting an optimal skew value will be described with reference to FIG. 2.

FIG. 2 is an example in which an optimal skew value is set by measuring 100 skew values for every 10 steps of radial skew in step 1 of adjusting the track skew.

First, the disc is placed in the playback mode (S11), and the track direction skew value measuring step is entered (S12). The motor M is connected to the track skew adjusting unit (S15), the motor is rotated one step (S16), and the motor M is connected to the radial skew adjusting unit (S17). ), The motor is rotated by one step (S20). At this time, the value of the track potentiometer T_Potentiometer and the value of the radial potentiometer R_Potentiometer are measured and converted by the A / D converter 8. At the same time, the error rate of the signal processing section 3 is measured by the control section 4. The three values in the same skew state, that is, the potentiometer value in the track direction, the potentiometer value in the radial direction, and the corresponding error rate are temporarily stored in a memory (RAM) (not shown) in the controller 4.

This operation is repeated with respect to the radial skew until the 10 steps are performed for each step of adjusting the track direction skew (S21 and S19).

After the measurement of the ten radial skews is finished, the measurement as described above is repeated by increasing the first stage with respect to the track skew. As a result, measurements are made for each of the 100 modes of skew and are temporarily stored in the controller memory. The potentiometer value (track direction and radial direction) having the lowest error rate among the values stored in the memory as the optimum skew value for the CD is stored in the memory (EEPROM) 6 (S23). Then, the same applies to the DVD, and the optimal skew value is obtained and stored in the memory (EEPROM) 6.

The method of using the optimal skew value thus obtained will be described below. When the disc is loaded, the type of the disc is determined by a known method, for example, whether it is a CD or a DVD, and a skew value (track direction, radial direction) corresponding to the disc is read from the memory 6. According to these values, track direction and radial skew adjustment are performed while looking at the value of the potentiometer as described above.

As mentioned above, although one Embodiment of this invention was described, this invention is not limited only to the said Example, It can implement by a sufficient correction or modification within the range which does not deviate from the summary of this invention.

As described above, the present invention obtains an optimal skew value while directly playing a plurality of types of discs (CDs, DVDs, etc.) while the apparatus is assembled, thereby improving playback / recording performance. By applying a skew value, the failure rate due to pickup and deck deviation can be greatly reduced.

Claims (3)

In the skew adjustment method of an optical disk device, Providing a plurality of skew states between the disk and the device; Detecting an error rate of a reproduction signal corresponding to each skew state and storing the skew state value and the error rate in a memory temporarily; Selecting an optimal skew state value among the plurality of skew state values stored in the memory; Skew adjustment method characterized in that consisting of. In the skew adjustment method of the apparatus which drives several types of optical discs, Providing a plurality of skew states between a particular disk and a device; Detecting an error rate of a reproduction signal corresponding to each skew state and storing the skew state value and the error rate in a memory temporarily; Selecting an optimal skew state value among the plurality of skew state values stored in the memory; Skew adjustment method characterized in that consisting of. The method of claim 2, And determining the type of disk to be mounted, and performing skew adjustment using the corresponding optimal skew state value.