KR100424488B1 - Method for discriminating a type of an optical disc - Google Patents

Abstract

The present invention relates to an optical disc type discrimination method for quickly and accurately discriminating the type of an optical disc inserted and inserted into the optical disc by vertically moving a focus lens in the optical pickup for a predetermined time in the optical disc direction. A first step of checking whether the signal is normally output; A second step of detecting a level of a high frequency reproduction signal RF and a zero crossing signal FZC while vertically moving the focus lens again when the focusing ok signal is not normally output; And a third step of determining the type of the optical disc based on the detected level of the high frequency reproduction signal and the zero crossing signal, wherein the level of the focusing ok (FOK) signal and the RF signal for the optical disc inserted in this manner is included. And, it is a very useful invention that the type of the optical disc can be determined more quickly and accurately from the SENSE signal.

Description

Method for discriminating a type of an optical disc}

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

Generally, optical discs are classified into compact discs (CDs) and digital versatile discs (DVDs). CDs and DVDs are optical discs of the same shape having a thickness of 1.2 mm and a diameter of 12 cm, respectively. The CD is formed where the recording surface is about 1.2 mm away from the disk surface (coating surface), and the DVD is formed as a single layer or a double layer where the recording surface is about 0.6 mm away from the disk surface.

Therefore, in order to accurately focus the laser beam on recording surfaces formed at different positions as described above, the type of the optical disc should be accurately determined first. A conventional method of determining the type of the optical disc is as follows.

First, a reference value for discriminating an optical disc type is stored in a memory in a set, and the reference value is a value determined through experiments on a plurality of sets, and the focus lens in the optical pickup is placed upward, that is, inserted and mounted. When the vertical movement is made in the direction of the optical disk, the FOK signal is output from the surface and the recording surface of the optical disk in the normal case. Therefore, as shown in FIG. 1 and FIG. The reference value (for example, about 0.9 msec) is determined from the time size tCD (for example, about 1.2 msec) between the FOK signals (high signal) of the CD and stored in the memory.

As described above, when a reference value for discriminating the type of optical disc is stored in advance, when the optical disc is inserted and mounted, the time size between the FOK signal generated on the surface and the recording surface of the optical disc is detected by detecting the vertical movement of the focus lens in the optical pickup. If the time size is smaller than the previously stored reference value, the optical disc is determined as a DVD, and if the time size is larger than the reference value, the optical disc is determined as a CD.

However, in the conventional method of determining the type of an optical disc as described above, if the FOK signal is not normally output due to scratches or contamination of the optical disc, the type of the optical disc cannot be determined, and thus, the optical disc cannot be played normally. There was a problem.

In addition, there is a problem that it is impossible to determine whether the type of optical disc is a multi-layer DVD (DVD Dual) or a single-layer DVD (DVD Single) and a CD-R or a CD-RW only by the time size between the FOK signals.

Accordingly, the present invention was created to solve the above problems, and more accurately discriminates the type of optical disc from the level of a focusing ok (FOK) signal and an RF signal and a sense signal of an inserted optical disc. It is an object of the present invention to provide a method for determining the type of optical disc that can be used.

FIG. 1 illustrates an example of a time size tDVD between FOK signals (high signals) of DVDs measured by experiments for a plurality of sets.

FIG. 2 shows an example of a time size tCD between FOK signals (high signals) of CDs measured by experiments for several sets.

3 is a block diagram of an embodiment of an optical disk device (Set) for implementing an optical disk type discrimination method according to the present invention;

4A to 4D show the flow of a preferred embodiment of the optical disc type discrimination method according to the present invention;

5A to 5C show an example of a reference table stored in the memory of FIG. 3 and used for determining an optical disc type;

6 and 7 show examples of the output of the FOK signal, the RF signal, and the SENSE signal.

※ Explanation of code for main part of drawing

10: optical disc 11: spindle motor

20: Optical pickup 30: R / F part

40: servo part 50: drive part

60: digital signal processor 70: microcomputer

71: memory

In the optical disc type discriminating method according to the present invention for achieving the above object, it is determined whether the FOK signal is normally output while vertically moving the focus lens in the optical pickup for the predetermined time in the optical pickup. Confirming the first step; A second step of detecting a level of a high frequency reproduction signal RF and a zero crossing signal FZC while vertically moving the focus lens again when the focusing ok signal is not normally output; And a third step of determining the type of the optical disc based on the detected level of the high frequency reproduction signal and the zero crossing signal.

In addition, when the optical disk is inserted and mounted, a first step of confirming that a focusing ok signal is normally output while vertically moving a focus lens in the optical pickup toward the optical disk for a predetermined time; If the focusing ok signal is normally output, determining a type of the optical disc from a time size between the focusing ok signal detected on the surface and the recording surface of the optical disc; A third step of detecting a level of a high frequency reproduction signal RF while vertically moving the focus lens according to the optical disc type determination result; And a fourth step of subdividing and discriminating the type of the optical disc based on the detected high frequency reproduction signal level.

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

3 is a block diagram of an embodiment of an optical disk apparatus for implementing an optical disk type discrimination method according to the present invention, and includes: an optical pickup 20 for reading a recording signal from the optical disk 10; An R / F unit 30 for filtering the signal detected by the optical pickup 20 and outputting it as a binary signal; A drive unit (50) for driving the spindle motor (11) for rotating the optical pickup (20) and the optical disc (10); Servo for controlling the drive of the drive unit 50 from the servo error signal (focusing error signal FE and tracking error signal TE) output by the optical pickup 20 and the rotational speed of the optical disc 10. Part 40; A digital signal processor (60) for restoring the binary signal to original data with its clock synchronized with the binary signal; A memory 71 in which control data necessary for discriminating the type of the optical disc 10 and reproducing operation, and a reference value and a reference table for determining the type of the optical disc 10 are stored; And a microcomputer 70 for determining the type of the inserted optical disc 10 using the stored value of the memory 71, the level of the RF signal, the SENSE signal, and the like.

4A to 4D show the flow of a preferred embodiment of the optical disc type discriminating method according to the present invention. Hereinafter, the discriminating method of FIGS. 4A to 4D according to the present invention will be described in detail with reference to FIG. do.

First, the memory 71 stores a reference value and a reference table for discriminating the type of the inserted optical disc 10. The reference value (for example, about 0.9 msec) is stored in the DVD as in the conventional method described above. The time size between the FOK signal (tDVD (for example, about 0.6 msec)) and the time size (tCD (for example, about 1.2 msec) between the FOK signal (high signal) of the CD are determined and stored. 5C, which is stored in the memory 71 in the form shown in FIG. 5C, so that the microcomputer 70 accurately determines the type of the optical disc 10 mounted on the basis of the stored reference value and the reference table. The explanation is as follows.

When the optical disk 10 is inserted into the set (S10), the microcomputer 70 uses the DVD LD (Laser Diode) of the optical pickup 20 to set the focus lens to the optical disk for a predetermined time (for example, 20 msec). While moving vertically in the direction of (10) (Focus Up) (S11), the signal output from the digital signal processing unit 50 is continuously monitored (S12), if normal, the digital during the vertical movement of the focus lens Since the signal processor 50 outputs FOK signals (high signals) on the surface and the recording surface of the optical disc 10, two FOK signals are detected during vertical movement of the focus lens.

While the microcomputer 70 monitors the output signal of the digital signal processor 50, when the FOK signal (high signal) is output from the digital signal processor 50, the microcomputer 70 uses an internal timer. From then on, time advances, which continues until the next FOK signal is output.

As shown in FIG. 6, when two FOK signals are output from the digital signal processing unit 50 during vertical movement of the focus lens (S20), the microcomputer 70 generates a FOK signal based on the elapsed time. The time size t is detected, and the detected time size t is compared with a reference value previously stored in the memory 71 to determine whether the type of the optical disc 10 is a CD or a DVD (S21). I.e., if the detected time size t is larger than the reference value, the type of the optical disc 10 is determined as CD, and if the detected time size t is smaller than the reference value, the optical disc 10 ) Is determined by DVD.

If the type of the optical disc 10 is determined to be a CD (S30), the microcomputer 70 must determine whether the type of the optical disc 10 is a CD-R or a CD-RW. 70 is used to move the focus lens down from the current position again using the CD LD (Laser Diode) of the optical pickup 20 (Focus Down), 1), to the R / F unit 30 The level of the output RF signal is detected from (S31).

When the level of the RF signal is detected as described above, the microcomputer 70 determines the type of the optical disc 10 from the level of the detected RF signal based on the reference table of FIG. 5A stored in the memory 71. That is, when the level of the detected RF signal is greater than 2400 as in the reference table of FIG. 5A, the optical disk 10 is referred to as CD-R, and when the level of the detected RF signal is smaller than 2400, The optical disc 10 is determined as a CD-RW (S31).

However, if the type of the optical disc 10 is determined to be DVD in the above embodiment (S40), the microcomputer 70 must determine whether the type of the optical disc 10 is a single layer DVD or a multi-layer DVD. To this end, the microcomputer 70 uses the DVD LD of the optical pickup 20 to vertically move the focus lens downward from the current position again (Focus Down), from the R / F unit 30. The level of the output RF signal is detected, and the microcomputer 70 detects the number of SENSE signals output from the digital signal processor 50 (S41), wherein the sense signal is the digital signal. The signal processor 50 is a signal output through the sense terminal, that is, a zero crossing signal (FZC: Focus Zero Crossing).

As described above, when the focus lens is vertically moved downward and the number of the level of the RF signal and the number of the sense signals are detected, the microcomputer 70 detects the detected based on the reference table of FIG. 5B stored in the memory 71. The type of the optical disc 10 is determined from the level of the RF signal and the number of sense signals. That is, when the level of the detected RF signal is smaller than a predetermined value, the optical disc 10 is a multi-layer DVD. When the level of the detected RF signal is greater than a predetermined value, the optical disc 10 is determined as a single-layer DVD. When the level of the detected RF signal is at a critical point, the microcomputer 70 determines The type of the optical disc 10 is determined in consideration of the level of the detected RF signal as well as the number of sense signals (S42). For example, when the level of the detected RF signal is less than 3000, as in the reference table of FIG. 5B, the optical disc 10 is a multilayer DVD. If the level of the detected RF signal is greater than 3000 and less than 3800, If the number of the detected sense signals is 2, the optical disc 10 is a multilayer DVD. If the level of the detected RF signal is greater than 3800 and the number of the detected sense signals is 1, the optical disc 10 ) Can be discriminated more accurately on the basis of the reference table of FIG.

However, in the above embodiment, when one FOK signal is output from the digital signal processing unit 50 while the focus lens is vertically moved toward the optical disc 10 as shown in FIG. 7 (S50). Since the microcomputer 70 cannot determine whether the type of the optical disc 10 is a CD or a DVD from the time size between the FOK signals, first, the focus lens is moved to the current position by using the DVD LD of the optical pickup 20. In the vertical movement, the microcomputer 70 detects the level and the sense signal of the RF signal as described above (S51). When the vertical movement of the focus lens is completed, the microcomputer 70 moves the focus lens vertically back to the optical disc 10 using the CD LD of the optical pickup 20 (Focus Up), as described above. The level of the RF signal is detected (S52).

As described above, if the level of the RF signal and the number of the sense signals are detected while the focus lens is vertically moved downward, and the level of the RF signal is detected while the focus lens is vertically moved toward the optical disc 10, the microcomputer ( 70) shows whether the type of the optical disc 10 is a single-layer DVD or a multi-layer DVD based on the detected RF signal level and the number of sense signals based on the reference table of FIG. 5C type stored in the memory 71; It is correctly determined whether the CD-R or CD-RW (S53).

In addition, in the above embodiment, if the FOK signal is not output from the digital signal processing unit 50 at all while the focus lens is vertically moved toward the optical disc 10 (S60), the microcomputer 70 is set. It is judged that the optical disc is not inserted into (S61), and outputs " NO Disc " on the LCD (not shown).

When the type of the optical disc 10 inserted and mounted is accurately determined through the above-described embodiment, the microcomputer 70 performs the requested operation (for example, a reproducing operation) with respect to the optical disc 10. To this end, the microcomputer 70 accurately focuses the ray point beam on the recording surface of the optical disc 10 using the DVD LD or CD LD of the optical pickup 20 based on the determination result, and then performs the requested operation. Will be performed.

The above-described preferred embodiments of the present invention are disclosed for purposes of illustration, and those skilled in the art can improve, change, and substitute various other embodiments within the technical spirit and scope of the present invention disclosed in the appended claims below. Or addition may be possible.

In the optical disc type determination method according to the present invention as described above, the type of the optical disc can be determined more quickly and accurately from the FOK signal, the RF signal level, and the SENSE signal of the inserted optical disc. This is a very useful invention in which an optical disc is normally played back.

Claims (10)

A first step of confirming that a focusing ok signal is normally output while vertically moving a focus lens in the optical pickup for a predetermined time when the optical disk is inserted and mounted; A second step of detecting a level of a high frequency reproduction signal RF and a zero crossing signal FZC while vertically moving the focus lens again when the focusing ok signal is not normally output; And And a third step of determining the type of the optical disc based on the detected high frequency reproduction signal level and the zero crossing signal. The method of claim 1, The first step is to determine whether a focusing ok signal is normally output while moving the focus lens vertically for a predetermined time using the DVD LD (Laser Diode) of the optical pickup. Way. The method of claim 1, The second step may include detecting a level and a zero crossing signal of a high frequency reproduction signal by vertically moving the focus lens down using the DVD LD of the optical pickup when the focusing ok signal is not normally output; And And detecting the level of the high frequency reproduction signal by vertically moving the focus lens back to the optical disc by using the CD LD of the optical pickup when the vertical movement is completed. The method of claim 1, And the second and third steps are performed when one of the focusing ok signals is output during vertical movement of the focus lens. The method of claim 1, In the third step, the type of the optical disc is determined by referring to a previously stored reference table to determine the type of the optical disc. A first step of confirming that a focusing ok signal is normally output while vertically moving a focus lens in the optical pickup for a predetermined time when the optical disk is inserted and mounted; If the focusing ok signal is normally output, determining a type of the optical disc from a time size between the focusing ok signal detected on the surface and the recording surface of the optical disc; A third step of detecting a level of a high frequency reproduction signal RF while vertically moving the focus lens according to the optical disc type determination result; And And a fourth step of subdividing and discriminating the type of the optical disc based on the detected level of the high frequency reproduction signal. The method of claim 6, The first step is to determine whether a focusing ok signal is normally output while moving the focus lens vertically for a predetermined time using the DVD LD (Laser Diode) of the optical pickup. Way. The method of claim 6, In the third step, when the optical disc is determined to be a compact disc (CD) by the second step, a high frequency reproduction signal is generated by vertically moving the focus lens down using a CD LD (Laser Diode) of the optical pickup. Detect the level of And the fourth step determines whether the type of the optical disc is a CD-R or a CD-RW based on the detected level of the high frequency reproduction signal. The method of claim 6, In the third step, when the optical disc is determined to be a digital multi-function disc (DVD) by the second step, the focus lens is moved vertically downward by using the DVD LD of the optical pickup, Detect zero crossing signal, And the fourth step determines whether the type of the optical disc is a single-layer DVD or a multi-layer DVD based on the detected high frequency reproduction signal level and the zero crossing signal. The method of claim 6, In the second and fourth steps, the type of the optical disc is determined by referring to a previously stored reference table to determine the type of the optical disc.