KR100712332B1 - Method for discriminating a type of an optical disc - Google Patents

Abstract

The present invention relates to an optical disc type discriminating method for accurately discriminating the type of optical disc inserted and inserted, and it is an object of the present invention to provide an optical disc type discriminating method for accurately discriminating the type of an inserted optical disc, A first step of confirming; A second step of advancing a time from the detection point when the servo error signal is detected; A third step of confirming whether or not the next servo error signal is detected when the advanced time is a preset predetermined time; And a fourth step of discriminating the type of the optical disc according to the result of the determination. The method includes determining whether the next servo error signal is detected after a predetermined time elapses from the first servo error signal generated during vertical movement of the focus lens in the optical pickup It is possible to accurately discriminate whether the optical disc is a single layer or a multi-layer based on the optical disc. Therefore, it is a very useful invention that enables a servo operation and a signal processing operation suited to the type of the optical disc to be normally performed.

Single layer, dual layer, focus error signal, timer, optical disc type discrimination

Description

[0001] The present invention relates to a method for discriminating an optical disc,

Figure 1 shows a normal focus error signal for a single layer disc,

Figure 2 shows a normal focus error signal for a multi-layer disc,

Figure 3 shows an abnormal focus error signal for a single layer disc,

4 is a block diagram of an optical disc apparatus for implementing a method of determining the type of an optical disc according to an embodiment of the present invention.

5 is a flowchart illustrating a method of determining the type of an optical disc according to an embodiment of the present invention.

FIG. 6 shows a normal focus error signal for a multi-layer disc and an abnormal focus error signal for a single layer disc.

[Description of Drawings]

10: optical disk 11: spindle motor

20: Optical pickup 30: R / F part

40: digital signal processing unit 50: A / D converter

60: servo unit 70: drive unit

80: Microcomputer 90: Timer

The present invention relates to an optical disc type discrimination method for accurately discriminating the type of an inserted optical disc.

In recent years, there are many cases where an optical disc is manufactured in a dual layer. This is to increase the disc capacity as compared with a single layer disc, and in the case of a multi-layer DVD, the capacity can be generally secured to 17 Gbytes.

As an example of the multi-layered disc, the multi-layer DVD has a thickness of 1.2 mm, and the first recording layer and the second recording layer are spaced apart from each other with a distance of about 50 탆 from the center of the disc thickness.

Since the optical disc is manufactured as a multi-layer or single layer, it is necessary to correctly discriminate whether the inserted optical disc is a multi-layer or a single layer in a drive for recording / reproducing the optical disc. Hereinafter, a conventional optical disc type discriminating method will be described .

1 and 2 show a normal focus error signal for each of a single-layer disc and a multi-layer disc. The focus error signal is composed of a minus sign and an inverse signal. In the case of a single-layer disc as shown in FIG. 1, A focus error signal is generated due to reflection of light in one layer at the time of down / up, whereas in the case of a multi-layer disc, light is reflected at two layers when the optical pickup is down / Two occur.

The reference level shown in FIGS. 1 and 2 is a value set to determine a focus error signal. When the detected signal level exceeds the reference level, the reference level is determined as a focus error signal. At this time, Each of the mnemonic signal and the inverse signal constituting one focus error signal exceeds the reference level. Therefore, if two signals exceeding the reference level are detected, it is determined as one focus error signal. If four signals are detected, two focus error signals .

As described above, since one focus error signal is generated for a single-layer disk and two focus error signals are generated for a multi-layer disk in a normal case, it is determined from the number of focus error signals whether the type of the inserted disk is a single- It is possible to determine whether the disc is a disc.

However, in the above-described conventional optical disc type discrimination method, discrimination errors occasionally occur. Examples are as follows.

FIG. 3 shows an abnormal focus error signal for a single-layer disc. Noise may occur as shown in FIG. 3 depending on the variation in gain and sensitivity of the optical pickup and the characteristics of the disc. In this case, The excess signal is detected as four and two focus error signals are determined from the two signals. As a result, there is a problem that the inserted optical disc is erroneously discriminated as a multi-layer disc even though it is a single layer disc.

In addition, when the type of the optical disc is erroneously determined as described above, there is a problem that the servo operation and the signal processing operation suited to the type of the inserted optical disc can not be normally performed.

SUMMARY OF THE INVENTION Accordingly, the present invention has been made to solve the above-mentioned problems, and it is therefore an object of the present invention to provide a focus error correction method and a focus error correction method which are based on whether or not a next focus error signal is detected The present invention has been made in view of the above problems, and it is an object of the present invention to provide an optical disc type discriminating method capable of more accurately discriminating the type of an inserted optical disc.

According to another aspect of the present invention, there is provided a method for determining the type of an optical disc, including the steps of: detecting a servo error signal while vertically moving a focus lens of the optical pickup toward the optical disc for a predetermined time, step; A second step of advancing a time from the detection point when the servo error signal is detected; A third step of confirming whether or not the next servo error signal is detected when the advanced time is a preset predetermined time; And a fourth step of discriminating the type of the optical disc according to the check result.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of an optical disc type determining method according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 4 is a block diagram of an optical disc apparatus according to an embodiment of the present invention. The optical disc apparatus 20 includes an optical pickup 20 for detecting a recording signal from the optical disc 10; An R / F unit 30 for shaping a signal detected by the optical pickup 20 and outputting the signal as a binary signal; A digital signal processing unit (40) for restoring the binary signal into original data with its own clock phase-locked to the binary signal; A spindle motor 11 for rotating the optical disc 10 and a drive unit 70 for driving the optical pickup 20; A servo unit 60 for controlling the drive of the drive unit 70 based on the focus error signal FE and the tracking error signal TE output from the optical pickup 20 and the rotational speed of the optical disc 10; An A / D converter 50 for digitally converting an input analog signal and outputting the converted analog signal; A timer 90 for advancing the time; And a microcomputer 80 for discriminating the type of the inserted optical disk 10 from the progress time of the timer 90 and the converted digital value and controlling the servo operation and the signal processing operation according to the discrimination result do.

The focus lens (not shown) included in the optical pickup 20 is moved up and down by a drive voltage applied by the drive unit 70, Thereby performing a focus operation on the recording layer.

When the optical disc 10 is inserted into the apparatus, the microcomputer 80 controls the servo unit 60 to move the focus lens to a predetermined initial position, The focus error signal output from the optical pickup 20 is monitored, and the type of the optical disk is determined. This will be described below in detail.

FIG. 5 is a flowchart illustrating a method of determining the type of an optical disc according to an embodiment of the present invention. Referring to FIG. 4, the method of FIG. 5 according to the present invention will be described in detail.

First, when the optical disc 10 is inserted (S10), the microcomputer 80 determines whether the inserted optical disc 10 is a CD or a DVD (S11), which can be determined by various known methods As an example, it is also possible to discriminate the CD and the DVD through the reflectivity of the optical disc.

The microcomputer 80 drives the actuator within the optical pickup 20 through the servo unit 60 and the drive unit 70 in accordance with the insertion of the optical disc 10 to focus the focus of the optical pickup 20 The lens is vertically moved in the direction of the optical disk 10 for a predetermined time (for example, 20 msec) from the initial position (S12) D converter 50 converts the signal output from the optical pickup 20 into a digital signal and applies the digital signal to the microcomputer 80.

Accordingly, the microcomputer 80 detects the level of the output signal based on the applied digital conversion value, compares the detected level with a predetermined reference level, and determines whether or not the first focus error signal is detected therefrom (S20).

That is, if the detected level is equal to or higher than the reference level, the microcomputer 80 determines that the signal currently output from the optical pickup 20 is the first focus error signal, The timer 90 is operated to start the time (S21), and the signal level detecting operation is temporarily stopped.

The microcomputer 80 continuously checks whether the progress time of the timer 90 is a predetermined time (T, for example, 1.7 ms) (S30). If it is determined that the progress time is the predetermined time, The controller 80 stops the operation of the timer 90 and restarts the signal level detecting operation to check whether or not the next (second) focus error signal is detected (S40).

That is, if the detected level is higher than the reference level as a result of the resumption, the microcomputer 80 determines that the signal currently output from the optical pickup 20 is the second focus error signal, 10) is discriminated as a multi-layer disc (S41).

However, if the detected signal level is not equal to or higher than the reference level, the microcomputer 80 determines that a second focus error signal is not output from the optical pickup 20, The optical disc 10 is discriminated as a single-layer disc (S42).

FIG. 6 illustrates an example of the focus error signal and the predetermined time T for a single layer and a multi-layer disc in order to easily explain the operation of discriminating the single layer and the double layer disc according to the present invention. The focus error signal is not detected after a lapse of time. Therefore, even if noises are generated as in the case of FIG. 6, disc type discrimination can be accurately performed without errors in which a single layer disc is discriminated as a double layer disc, depending on the variation in gain and sensitivity of the optical pickup, .

When the type of the optical disc 10 is determined as described above, the microcomputer 80 determines whether the optical disc 10 inserted in the inserted optical disc 10 is a CD or a DVD, And the signal processing operation to be performed normally (S43).

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention as defined in the appended claims. Addition or the like.

The optical disc type discrimination method according to the present invention as described above is a method for discriminating the type of an optical disc based on whether or not the optical disc is a single layer or a multi layer Therefore, it is a very useful invention that enables the servo operation and the signal processing operation suitable for the type of the optical disk to be performed normally.

Claims (7)

A first step of verifying whether or not a servo error signal is detected while vertically moving a focus lens of an optical pickup in a direction of the optical disc for a predetermined time during insertion of the optical disc; A second step of stopping the operation for confirming whether or not the servo error signal is detected when the servo error signal is detected in the first step and counting the time from the detection time point; A third step of restarting the servo error signal detection operation when the counted time reaches a preset predetermined time; A fourth step of confirming whether or not the servo error signal is detected by the third step; And And a fifth step of discriminating the type of the optical disc according to the result of the fourth step. delete The method according to claim 1, And the servo error signal is a focus error signal. delete The method according to claim 1, Wherein the step of detecting whether or not the servo error signal is detected in the fourth step includes detecting a level of a signal output from the optical pickup in accordance with the vertical movement, comparing the detected level with a preset level, And determining whether or not the optical disc type is determined. The method according to claim 1, The method of claim 5, wherein, when the servo error signal is detected in the fourth step, the optical disc is discriminated as a multi-layer disc. The method according to claim 1, Wherein the fifth step discriminates the optical disc as a single-layer disc when the servo error signal is not detected in the fourth step.

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