KR100319552B1 - Method for discriminating a type of an optical disc - Google Patents

Abstract

The present invention relates to an optical disc type discrimination method capable of accurately determining the type of an optical disc by using a focus error signal detected from an inserted optical disc. A first step of detecting an error signal; A second step of storing a magnitude of the detected focus error signal; A third step of redetecting the magnitude of the focus error signal by changing the optical disk mode from the first step; A fourth step of accumulating the magnitude of the redetected focus error signal and the magnitude of the stored focus error signal and confirming a value thereof; And a fifth step of determining the number of zero crossing signals detected in the focus error signal redetection process according to the result of the check, and determining the type of the optical disk therefrom. The focus error signal detected by the mode and its cumulative value can be used to more accurately determine the types of the various discs, and even if the type of the inserted optical disc is a rewritable optical disc. By making the subdivision more detailed, it is a very useful invention having generality that can be applied anywhere in the current disk apparatus in which various disk media exist.

Description

Method for discriminating a type of an optical disc}

The present invention relates to an optical disc type discrimination method capable of accurately determining the type of an optical disc by using a focus error signal detected from an inserted optical disc.

Generally, optical discs are largely classified into compact discs (CDs) and digital multi-function discs (DVDs). In particular, DVD discs are DVD dual layers. Subdivided into DVD Single Layer, CD and DVD are optical discs of the same shape having a thickness of 1.2 mm and a diameter of 12 cm.

However, the CD is formed where the recording surface is about 1.2 mm away from the coating surface, and the DVD is formed as a single layer or a plurality of layers where the recording surface is about 0.6 mm away from the coating surface.

Therefore, in order to focus the laser beam on recording surfaces formed at different positions as described above, it is necessary to first accurately determine the type (type) of the optical disk.

Fig. 1 shows a configuration of a device related to conventional optical disc type determination, comprising: an optical pickup (P / U) 2 for reading out a signal recorded on the optical disc 1; Focus Zero Crossing (FZC) is output by comparing a focus error signal (FE) output from a photo diode (PD) included in the optical pickup 10 with a reference signal. A zero crossing signal generator 40; A servo unit 3 for controlling a focusing operation of the optical pickup 10 in response to the focus error signal; A sled motor 11 moving the optical pickup 10 horizontally; A spindle motor 12 for rotating the optical disc 1 according to a control signal output from the servo unit 20; A driver (30) for driving the sled motor (11) and the spindle motor (12); An A / D converter 50 for converting the zero crossing signal into a digital signal; A microcomputer 60 for determining the type of optical disc 1 from the converted digital signal; And a memory 70 for storing data necessary for the operation of discriminating the microcomputer.

FIG. 2 is a detailed configuration diagram of the zero crossing signal generator 40, focusing on electrical signals A + C and B + D output from the photodiode PD included in the optical pickup 10. Referring to FIG. A subtractor converts and outputs an error signal FE = ((A + C)-(B + D)), and converts the output into a zero crossing signal by comparing the focus error signal FE with a reference signal Ref. It consists of a comparator.

In the conventional optical disk type discrimination method of the apparatus having the above-described configuration, first, when the optical disk 1 is inserted and seated in a tray (not shown) provided in the optical disk apparatus, the microcomputer 60 By controlling the servo unit 20 so that the driving voltage of the driver 30 is applied to the spindle motor 12 and the sled motor 11, the optical disk 1 is rotated at a constant speed and the optical pickup 10 ) Horizontally to the initial focusing position. Thereafter, while focusing servo control of the servo unit 20, the objective lens provided in the optical pickup is gradually moved vertically in the optical disk direction, while detecting a focus error signal output from the photodiode PD. The zero crossing signal generator 40 generates and outputs a zero crossing signal from the focus error signal FE.

The zero crossing signal generation process will be described in detail with reference to FIGS. 3A to 3C. First, FIG. 3A is an optical disk in which one data surface is formed at a position 0.6 mm away from a coating surface. , Which illustrates the generation / output of a zero crossing signal from a DVD single layer (1), wherein the zero crossing signal generator 40 has an arbitrary position of an optical pickup 10, in particular, an objective lens. While reaching the specific position L1, the focus error signal Sc detected by the coating surface and the focus error signal Sd1 detected by the recording surface are detected, and the detected focus error signals Sc , Sd1 is compared with the reference signal Ref to output a zero crossing signal of the square wave, and the zero crossing signal is sampled by the A / D converter 50 and input to the microcomputer 60. Accordingly, the microcomputer 60 stores the detection times (tc, td1) at which the sampled value becomes a predetermined value or more.

In addition, FIG. 3B shows a zero crossing signal from an optical disk, that is, a DVD Dual Layer 1, in which two data surfaces are formed about 0.6 mm away from a coating surface. As shown, the zero crossing signal generation unit 40 is connected to the coating surface while the optical pickup 10, in particular, the position of the objective lens reaches a certain position L2; L2> L1. The focus error signal Sc detected by the detection signal and the focus error signals Sd1 and Sd2 detected by the multilayer recording surface are detected, and the detected focus error signals Sc, Sd1, and Sd2 are the reference signals Ref. When the zero crossing signal of the square wave is output, the microcomputer 60 stores the detection time (tc, td1, td2) according to the same process as described above.

On the other hand, Fig. 3C generates and outputs a zero crossing signal from an optical disc, that is, a CD Single Layer 1, in which one data surface is formed 1.2 mm away from a coating surface. The zero crossing signal generation unit 40 is configured to perform the microcomputer operation while the optical pickup 10, in particular, the position of the objective lens reaches an arbitrary specific position L3 (L3> L2> L1). 60) confirms and stores each detection time (tc, td3) of the focus error signals Sc and Sd3 detected by the coating surface and the recording surface according to the same process as described above.

Thereafter, the microcomputer 60 calculates a difference between the detection times (tc and td1, tc, td1 and td2 or tc and td3) stored as described above (tc-td1, tc-td2, or tc-td3). From this, the optical disc 1 was discriminated as single layer DVD, double layer DVD, or CD.

However, since the focus error signal Sc detected by the coating surface of the optical disk is quite fine as shown in Figs. 3A to 3C and 4, undetected detection errors frequently occur, and thus, Determining the type of the optical disk has a problem in accuracy, and even if the focus error signal is accurately detected from the coating surface of the optical disk, in such a conventional method, whether the optical disk is a CD or a single-layer DVD, Alternatively, since only the multilayer DVD is determined, if the inserted optical disc is a rewritable CD (CD-RW), the disc cannot be accurately recognized as a rewritable CD, and subsequent optical discs cannot be reproduced correctly. there was.

Therefore, the present invention was created to solve the above problems, and by determining the type of the optical disk using all the size of the focus error signal reproduced and output from the optical disk in different modes, more accurate optical disk It is an object of the present invention to provide an optical disc type discrimination method in which type discrimination is made.

1 and 2 show the configuration of a conventional optical disc type discriminating apparatus,

3A to 3C illustrate a focusing error signal detected by a conventional method,

4 shows an actual waveform of a focus error signal detected by a conventional method,

5 is a block diagram showing the configuration of an optical disc type discrimination apparatus in which an optical disc type discriminating method according to the present invention is implemented;

6a to 6c show a flow of a preferred embodiment of the optical disc type discrimination method according to the present invention,

FIG. 7 shows the contents of memory stored in the device of FIG.

※ Explanation of code for main part of drawing

1: optical disc 10: optical pickup

11: Sled Motor 12: Spindle Motor

20: servo unit 30: driver

40: zero crossing signal (FZC) generator 50: A / D converter

60,61: microcomputer 70,71: memory

80: focus gain unit

According to an aspect of the present invention, there is provided a method of determining an optical disk type, comprising: a first step of detecting a focus error signal while moving an objective lens in a vertical direction of the optical disk; A second step of storing a magnitude of the detected focus error signal; A third step of redetecting the magnitude of the focus error signal by changing the optical disk mode from the first step; A fourth step of accumulating the magnitude of the redetected focus error signal and the magnitude of the stored focus error signal and confirming a value thereof; And a fifth step of confirming the number of zero crossing signals detected in the focus error signal redetection process and determining the type of the optical disk from the focus error signal redetection process.

Hereinafter, an embodiment of an optical disc type determination method according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 5 shows a configuration related to the type discrimination of the optical disk reproducing apparatus in which the optical disk type discrimination method according to the present invention is implemented. The configuration is the same as the configuration of the apparatus of FIG. 1, but is provided in the optical pickup 10 only. It further includes a focus gain unit 80 for varying / amplifying a focusing error signal (FE) output from a photo diode (PD), and the reference size of each focusing error signal is The function of the microcomputer 61 which performs the type discrimination operation on the memory 71 stored therein and the optical disk 1 inserted using the respective reference size values stored in the memory 71 is different from that shown in FIG. Different.

Fig. 6 shows the flow of a preferred embodiment of the optical disc type discriminating method according to the present invention. Hereinafter, the discriminating method of Fig. 6 according to the present invention will be described in detail with reference to the configuration of Fig. 5. In the memory 71, the size of the focus error signal to be used for the optical disc type discrimination includes a reference value (a first reference size (Level3), a second reference size (Level4), a third reference size (Level2), and a fourth reference size). And the reference number of zero crossing signals to be used for optical disc type discrimination. The contents of the storage are as shown in Fig. 7, and the magnitude relationship of each reference value is the second reference. It is equal to the size (Level4)> the first reference size (Level3)> the third reference size (Level2)> the fourth reference size (Level1).

The reference value and the number of reference values are values previously detected by experiments for use in optical disc type discrimination. When the reference values are each expressed in hexacode, the first reference size (Level3) is 0x4500, and the second The reference size Level4 is 0x6400, the third reference size Level2 is 0x2200, and the fourth reference size Level1 is 0x1500.

In the state in which the reference value for the type discrimination of the optical disk is previously stored in the memory 71 as described above, the microcomputer 61 sets the optical disk type determination mode S1 and controls the servo unit 20. The driving voltage of the driver 30 is applied to the spindle motor 12 to rotate the optical disk 1 at a constant speed according to the driving of the motor. At this time, the microcomputer 61 first determines whether or not the optical disk 1 is inserted and seated (S2), which means that the time until the constant speed after the spindle motor 12 is driven is a no disk (No Disk). In other words, it is the fastest when the optical disk 1 is not inserted and seated, thereby determining whether the optical disk 1 is inserted or not.

In addition, the microcomputer 61 moves the optical pickup 10 to an initial focusing position, and increases and sets a gain value of the focus gain unit 80. After setting, the objective lens of the optical pickup 10 is gradually moved in the vertical direction of the optical disk 1 to perform the type discriminating operation of the optical disk 10.

The optical pickup 10 photoelectrically converts the signal S3 reflected and detected by the optical disk 1 according to the movement of the objective lens and outputs the electrical signal, and the output signal is the focus gain unit 80. Amplified output at a predetermined level, the gain value of the focus gain unit 80 is set to a very large value in the CD mode, and the shape of the focus error signal amplified and output at the predetermined level is almost as shown in FIG. It will be saturated.

The focus error signal amplified and output at the predetermined level is sampled by the A / D converter 50 and its value is applied to the microcomputer 61, and the microcomputer 61 receives the optical signal from the sampled digital data. The type of the disc 1 is determined. To this end, the microcomputer 61 detects the magnitude (level) of the focus error signal which is the maximum value of the applied digital data (S4) and stores it in itself.

The microcomputer 61 compares the magnitude of the detected focus error signal with Level 3, which is a first reference size value among the reference values stored in the memory 71 (S10), and the size of the detected focus error signal is determined by the comparison result. If the first reference size value is greater than Level 3, the microcomputer 61 determines the type of the optical disc 1 as a general CD (S11), and adjusts the servo and RF gain characteristics according to the determination result. Ensure proper playback.

However, when the size of the detected focus error signal is not greater than Level 3, which is the first reference size value, the micom 61 switches from CD mode to DVD mode. In operation S20, the gain value of the focus gain unit 80 is reset to a focus gain value suitable for the DVD mode.

Subsequently, the objective lens provided in the optical pickup 10 is moved in the vertical direction, whereby incident light is reflected from the optical disk 1, and the reflected electrical signal is detected as described above using the focus gain unit ( 80 amplifies and outputs a signal of a predetermined level.

The zero crossing signal generator 40 generates and outputs a zero crossing signal that is a pulse signal having a high level when the amplified output focus error signal is greater than or equal to a predetermined level, and the microcomputer 61 generates and outputs the zero crossing signal. Each time the cross signal is input, the focus error signal count value, which is initialized by itself, is increased by one, and the value is stored (S21).

The focus error signal amplified and output by the focus gain unit 80 is sampled by the A / D converter 50 and applied to the microcomputer 61, and the microcomputer 61 receives the applied digital data. Detecting the magnitude of the focus error signal, which is the maximum value of, and summing the value and the magnitude value previously detected and stored in the previous CD mode (S22), and storing the summed magnitude value in the memory 71 Among the reference size values, the second reference size value is compared with Level 4 (S30).

As a result of the comparison, when the summed size value is larger than Level 4 which is the second reference size value, the microcomputer 61 determines the type of the optical disc 1 as a single-layer DVD (S31), The characteristics of the regeneration system are adjusted accordingly so that subsequent regeneration operations are appropriately performed.

However, if the summed size value is not greater than the second reference size value Level4, the microcomputer 61 detects the magnitude value of the focus error signal detected immediately before, that is, detected in the current DVD mode. Among the size values stored in the memory 71, a comparison is made with Level 2 which is a third reference size value (S40).

As a result of the comparison, when the magnitude value of the focus error signal detected in the DVD mode is larger than Level2, which is the third reference size value, the microcomputer 61 counts and stores the zero crossing signal itself and the memory. The reference number (= 2) of the zero crossing signal FZC previously stored at 71 is compared (S50). As a result of the comparison, the number of the zero crossing signal counted is greater than or equal to 2, the reference number. In this case, the microcomputer 61 determines the type of the optical disc 1 as a multilayer DVD (S51). When the number of the zero crossing signals counted is less than 2, the reference number, the microcomputer ( 61 determines the type of the optical disc 1 as a single-layer DVD (S31), and sets the focus accordingly so that subsequent playback operations can be performed properly. Even if the magnitude value of the detected focus error signal is not larger than Level2 which is the third reference size value, the microcomputer 61 counts and stores the number of zero crossing signals which are counted and stored as described above and the memory 71. The reference number of the zero crossing signal (= 2) previously stored is compared with (S60). As a result of the comparison, the number of the zero crossing signal counted is greater than or equal to 2, which is the reference number, and is previously summed. When the magnitude value of the focus error signal is greater than or equal to Level1 which is the fourth reference size value among the stored values of the memory 71 (S70), the microcomputer 61 can rewrite the type of the optical disk 1 to the CD. (CD-RW) (S71), and the characteristics of the reproduction system are adjusted accordingly so that subsequent reproduction operations are appropriately performed.

However, when the number of the zero crossing signal counted is less than 2 as a result of the comparison and the summed magnitude value is greater than or equal to Level 1 which is the fourth reference size value (S80), the microcomputer 61 The type of the optical disc 1 is determined as a multilayer DVD (S81).

In the above case, when the magnitude value of the summed focus error signal is smaller than Level1, which is the fourth reference size value, the microcomputer 61 checks the possibility of the non-disk mounting state (S90). 61) determines whether the disk is not mounted on the basis of whether or not the optical disk is previously seated and the reflection amount of the light beam by the optical pickup 10. In other words, it is confirmed that the optical disc has not been inserted and settled by the microcomputer 61, and when the amount of reflection of the light beam by the optical pickup 10, that is, the size of the focus error signal is low, it is reflected by the disc. The microcomputer 61 determines that the optical disk is not inserted into the tray (not shown) currently provided in the apparatus (S91), and takes appropriate measures such as outputting a guide message. Done.

When the type discrimination of the optical disc 1 is completed as described above, the microcomputer 61 adjusts the gain of the focus gain unit 80 so as to adjust the gain of the optical disc 1. It is set so that the focusing of the optical disc 1 and the reproduction thereof are normally performed.

In the optical disc type determination method according to the present invention made as described above, it is possible to more accurately determine the type of the various discs by using the focus error signal detected by the dual mode and its accumulated value from the inserted optical disc, and It is possible to determine whether the type of the inserted optical disc is a rewritable optical disc, and the disc type discrimination is made more finely. Therefore, it is a very useful invention that has a versatility that can be applied anywhere in the current disc device in which various disc media exist. will be.

Claims (9)

A first step of detecting a focus error signal while moving the objective lens in the vertical direction of the optical disk; A second step of storing a magnitude of the detected focus error signal; A third step of redetecting the magnitude of the focus error signal by changing the optical disk mode from the first step; A fourth step of accumulating the magnitude of the redetected focus error signal and the magnitude of the stored focus error signal and confirming a value thereof; And And a fifth step of determining the number of zero crossing signals detected in the focus error signal redetection process, and determining the type of the optical disk from the focus error signal redetection process. The method of claim 1, The second step, And when the size of the stored focus error signal is larger than the size of the first reference signal stored in advance for use in optical disc type discrimination, discriminating the optical disc as a compact disc (CD). How to determine the type of optical disc. The method of claim 1, The fifth step, As a result of the checking, when the accumulated value is larger than the second reference signal size (> first reference signal size) previously stored so as to be used for optical disc type discrimination, the optical disc is identified as a single-layer digital video disc (DVD). Optical disc type determination method characterized in that. The method of claim 1, The fifth step, As a result of the checking, when the accumulated value is not larger than the second reference signal size (> first reference signal size) previously stored so as to be used for the optical disc type discrimination, the size of the redetected focus error signal is the optical disc. Confirming whether the size of the third reference signal (<first reference signal magnitude) is greater than the pre-stored third reference signal magnitude for use in type discrimination; Checking the number of zero crossing signals detected in the focus error signal redetection process; And And determining the type of the optical disc according to the comparison result with the third reference signal magnitude and the identified number. The method of claim 4, wherein The determining of the optical disc type may include: As a result of the checking, if the size of the redetected focus error signal is larger than the third reference signal and the number of zero crossing signals is greater than or equal to a preset number for use in optical disc type discrimination, An optical disc type discrimination method characterized in that it is discriminated by a digital video disk (DVD). The method of claim 4, wherein The determining of the optical disc type may include: As a result of the checking, if the size of the redetected focus error signal is not larger than the size of the third reference signal, and the number of zero crossing signals is greater than or equal to a preset number for use in optical disc type discrimination, the optical disc is rewritten. Discrete optical disc type discrimination method characterized in that it is determined as a compact disc (CD-RW) possible. The method of claim 4, wherein The determining of the optical disc type may include: As a result of the checking, when the redetected focus error signal is not larger than the third reference signal, and the number of zero crossing signals is smaller than a preset number for use in optical disc type discrimination, An optical disc type discrimination method characterized in that it is discriminated by a digital video disk (DVD). The method according to claim 6 or 7, The accumulated value is compared with the fourth reference signal magnitude (<third reference signal magnitude) previously stored for use in optical disc type discrimination, and the optical disc is converted into a single layer digital video disc (DVD) according to the comparison result. Discrimination method, characterized in that the disc type. The method of claim 1, The optical disc mode of the first step is a CD mode, and the optical disc mode of the third step is a DVD mode.