KR19990038613A - Optical Disc Discrimination Device and Method - Google Patents

Abstract

end. TECHNICAL FIELD OF THE INVENTION The invention described in the claims relates to an apparatus and method for determining the type of a given optical disc mounted on a tray.

I. SUMMARY OF THE INVENTION An object of the present invention is to provide an apparatus and method for determining an optical disk capable of quickly determining the type of optical disk mounted on a tray.

All. Summary of the Invention: An optical pickup for optically picking up information recorded on an optical disk and converting the information into an electrical RF signal, and amplifying and waveform-shaping the electrical RF signal and outputting the focus servo. An optical disk discriminating apparatus having an RF amplifier for detecting and outputting a generated focus error signal and capable of reproducing different types of optical disks, the apparatus comprising: an S curve level of a focus error signal output from the RF amplifier; A focus error signal level comparator for gating the detected signals generated by comparison with each of the preset reference levels and outputting them as an optical disc discrimination signal; and the RF according to the optical disc discrimination signal input from the focus error signal level comparator. And a control unit for changing gain parameters of the amplification unit.

la. Important use of the invention: It can be used in an optical disc player such as a CD-ROM drive.

Description

Optical Disc Discrimination Device and Method

The present invention relates to an optical disc reproducing apparatus for reproducing information recorded on an optical disc recording surface using laser light, and more particularly, to an apparatus and method for determining a predetermined type of optical disc mounted on a tray.

Originally developed by Philips of the Netherlands in 1978, optical recording media and playback devices have been steadily developed with the development of semiconductor technology. Currently, CD (Compact Disc), CD-ROM (Compact Disc-Read Only Memory), CD Various optical recording media such as Compact Disc ReWritable (R / W) and Digital Video (Versatile Disc) are introduced. One of the important research subjects of today is the development of an optical disc reproducing apparatus that can normally reproduce information recorded on the above-described various optical recording media in one drive or player. The problem to be solved first in order to normally reproduce all the various types of optical discs in one optical disc reproducing apparatus is to determine the type of the mounted disc. In general, the optical disk reproducing apparatus first adjusts the position of the objective lens so that the optical disk reflecting surface falls within the depth of focus in order to normally pick up a signal from the optical disk. This is generally referred to as focusing servo control and starts various servo controls for signal reproduction after checking the focusing state to become the focus " on ".

Hereinafter, a brief description will be made of a method of discriminating an optical disk mounted on a tray, for example, a CD-ROM and a CD-R / W-, by using the above-described focusing servo control. First, an optical disk is mounted on a tray of a CD-ROM drive. After the loading is completed, the controller of the drive sets the current drive mode to the CD-ROM play mode, and repeatedly drives the objective lens up and down to check whether the focus is turned on. When the inspection results in the focus "on" state, the optical disc currently loaded in the tray is recognized as a CD-ROM. However, if the objective lens is not turned on even though the objective lens is driven up and down for a preset number of times, the controller sets the current drive mode to the CD-R / W playback mode and then sets the objective lens to Repeatedly drive down to check if the focus is on. When the focus is on, the optical disc currently loaded in the tray is recognized as a CD-R / W.

However, the conventional optical disc discrimination method described above requires a large number of operations of the type of the reproducible optical disc. As a result, it takes much time to determine the type of the mounted optical disc, and the optical disc discrimination algorithm also has a complex disadvantage. .

Accordingly, an object of the present invention is to provide an optical disk discriminating apparatus and method for quickly determining the type of optical disk mounted on a tray.

It is still another object of the present invention to provide an optical disk discriminating apparatus and method for simplifying a conventional optical disk discriminating algorithm for discriminating a type of optical disk mounted on a tray.

The present invention for achieving the above object is an optical pickup that optically picks up the information recorded on the optical disk and converts it into an electrical RF signal, and outputs by amplifying and waveform-shaping the electrical RF signal and at the same time focus servo An optical disc discrimination apparatus of an apparatus having an RF amplifier for detecting and outputting a focus error signal generated during control and capable of playing different types of optical discs,

A focus error signal level comparison unit for comparing the S curve level of the focus error signal output from the RF amplifier with each of the preset reference levels and gating combinations of the detection signals generated as an optical disc determination signal;

And a control unit for changing gain parameters of the RF amplifier according to the optical disk discrimination signal input from the focus error signal level comparison unit.

In addition, the present invention is an optical pickup that optically picks up the information recorded on the optical disk surface and converts it into an electrical RF signal, and outputs the amplified and waveform-formed electrical RF signal at the same time the focus servo control The RF amplifier unit detects and outputs a focus error signal, and the S-curve level of the focus error signal output from the RF amplifier unit is compared with each of the preset reference levels to perform a gating combination to generate an optical disk discrimination signal. An optical disc discriminating method of an optical disc recording / reproducing apparatus, comprising a focus error signal level comparing unit for outputting and reproducing information recorded on another type of optical disc or recording predetermined information on an optical disc surface,

Performing focusing servo control by driving the optical pickup unit up and down when loading an optical disc;

And outputting a parameter change signal for changing the parameters of the RF amplifier to correspond to the loaded optical disk in response to the optical disk discrimination signal input from the focus error signal level comparison unit during focusing servo control. do.

1 is a block diagram of a CD-ROM drive as an optical disk reproducing apparatus according to an embodiment of the present invention.

FIG. 2 is a detailed circuit diagram of a focus error signal (FES) level comparing unit 22 in FIG. 1.

3 is a diagram illustrating an S-curve shape of a focus error signal FES having different levels depending on the type of optical disk.

4 is a control flow chart of the disc mounting disc mounting according to an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description and the annexed drawings, numerous specific details, such as CD-ROM drives and specific processing flows, which are examples of optical disc playback devices, are shown to provide a more general understanding of the invention. It will be apparent to those skilled in the art that the present invention may be practiced without these specific details. And detailed descriptions of well-known functions and configurations that may unnecessarily obscure the subject matter of the present invention will be omitted.

Fig. 1 shows a block diagram of a CD-ROM drive as an optical disk player according to an embodiment of the present invention. Referring to FIG. 1, the optical pickup 12 optically picks up the information recorded on the optical disk surface 10, converts the information to an RF signal, which is an electrical signal, and outputs the RF signal to the RF amplifier 18. This optical pickup 12 is driven by a focus actuator for focus servo and a tracking actuator for tracking servo. Tracking servo refers to following the optical pickup 12 to a track on the optical disk 10, and focus servo refers to keeping the optical pickup 102 for the optical disk 10 in a focus " on " state. The spindle motor 14 is driven by the spindle drive signal input from the DSP 20 to rotate the optical disk 10 in the CLV method or the CAV method. The sled feed motor 16 is driven by the sled feed servo control of the servo signal processing unit 26 to transfer the optical pickup 12 in the radial direction on the optical disk 10. The RF amplifier 18 amplifies the signal picked up by the optical pickup 12, removes the noise and distortion of the amplified signal by the waveform equalizing circuit, and removes the waveform-shaped EFM signal from the next DSP ( 20). The RF amplifier 18 generates a focus error detection circuit and a tracking error detection circuit to generate signals for the focus servo and the tracking servo, that is, the focus error signal FES and the tracking error signal. Output to (26). The DSP 20 demodulates data from the EFM signal transmitted from the RF amplifier 18, performs error correction, and outputs the result to the output processor. The output processor processes data output from the DSP 20 to generate a final output signal such as a video signal. The focus error signal (FES) level comparator 22 compares the level of the focus error signal FES output from the RF amplifier 18 with a preset reference level, and generates and outputs an optical disc discrimination signal accordingly. The preset reference level refers to a plurality of preset reference level values for determining the type of optical disc mounted on the tray. The meanings of the plurality are the same as the types of optical discs that can be reproduced. On the other hand, the microcomputer 24 has a ROM in which a control program according to an embodiment of the present invention is stored and a RAM for temporarily storing data generated during a control operation. Controls the overall operation for playback. For example, the microcomputer 24 determines the type of the optical disk 10 mounted in the tray according to the logic level value of the optical disk discrimination signal output from the FES level comparison unit 22 and changes the circuit parameters accordingly. Signals (defined as parameter change signals) are output to the RF amplifier 18. By the parameter change signal, various gains in the RF amplifier 18 are changed according to the type of optical disk. The servo signal processing unit 26 is controlled by the microcomputer 24 and focus servo and tracking servo for the optical pickup 12 according to various servo control related signals (TES, FES, etc.) applied from the RF amplifier 18, A sled feed servo for the sled feed motor 16 is performed.

FIG. 2 illustrates a detailed circuit diagram of the focus error signal (FES) level comparison unit 22 of FIG. 1, and FIG. 3 illustrates an S curve of a focus error signal FES having different levels according to the type of optical disk. will be. In FIG. 3, (a) illustrates the S curve of the focus error signal FES generated by the focus servo control when the CD-ROM is mounted in the tray, and (b) is the focus servo control when the CD-R / W is mounted in the tray. The S curve of the focus error signal FES generated by the amplification to a predetermined level is illustrated. First, referring to FIG. 2, the focus error signal FES output from the RF amplifier 18 of FIG. 1 is input to the non-inverting input terminal (+) of the first comparator 28 and the inverting input terminal of the first comparator 28. (-) Is connected to a connection point with a resistor R2 connected in series with a resistor R1 of which one side is grounded. Therefore, the voltage level divided by the resistors R1 and R2 connected in series is applied to the inverting input terminal (-) of the first comparator 28. The focus error signal FES generated by the focus servo control when the CD-ROM is mounted as shown in FIG. 3 (a) is a voltage level (hereinafter referred to as reference voltage level 1) applied to the inverting input terminal (-). When the values of the resistors R1 and R2 are set to have a value smaller than the maximum level of, the CD-ROM sensing signal according to the comparison result of the maximum level of the focus error signal FES and the reference voltage level 1 is output from the first comparator 28. Is output. The focus error signal FES is amplified to a predetermined level by the level amplifier 32 and applied to the non-inverting input terminal (+) of the second comparator 34. The voltage level divided by the resistors R3 and R4 connected in series is applied to the inverting input terminal (-) of the second comparator 34. At this time, the voltage level (hereinafter referred to as reference voltage level 2) applied to the inverting input terminal (-) is generated by the focus servo control when CD-R / W is mounted as shown in FIG. When the values of the resistors R3 and R4 are set to have a value smaller than the maximum level of the focus error signal FES amplified by, the maximum level and the reference voltage level 2 (<reference voltage level 1) of the focus error signal FES amplified to a predetermined level are set. The CD-R / W detection signal is output from the second comparator 34 according to the comparison result. On the other hand, the CD-ROM detection signal output from the first comparator 28 is inverted and output from the inverter 30 to the AND gate 36, and the CD-R / W signal output from the second comparator 34 is The other end of the AND gate 36 is input and gated with the inverted output CD-ROM detection signal and output as an optical disc determination signal.

4 is a flowchart illustrating a mounting optical disc determination control according to an embodiment of the present invention. Hereinafter, a method of determining the type of optical disc mounted on a tray will be described in detail with reference to FIGS. 2 to 4.

First, when the computer system user unloads the tray and mounts a predetermined optical disc on the tray, the microcomputer 24 checks whether the tray is completely loaded in step 40 of FIG. If the tray is loaded, the microcomputer 24 proceeds to step 42 to check whether the optical disk is mounted. Whether or not the optical disk is mounted can be inspected by using a sensor installed on the bottom surface of the tray. The microcomputer 24, which detects whether the optical disk is mounted through the monitoring sensor installed on the lower surface of the tray, proceeds to step 44 and performs focus servo control. That is, the microcomputer 24 drives the objective lens in the vertical direction to induce the generation of the focus error signal FES by the focus servo control. At this time, the play mode of the drive is set to the CD-ROM mode. Therefore, due to the driving of the objective lens, the RF amplifier 18 outputs the focus error signal FES having the same level as in FIG. Since the focus error signal FES output from the RF amplifier 18 is compared with the reference voltage level 1 in the first comparator 28, a CD-ROM detection signal having a "high" level is generated. Therefore, the optical disc discrimination signal is input to the microcomputer 24 at the "low" level irrespective of the level of the CD-R / W sensing signal. On the other hand, the microcomputer 24 checks whether the optical disc discrimination signal is input to the "high" level in step 46 of FIG. 4 and recognizes the optical disc currently mounted in the tray as the CD-ROM when the input is at the "low" level. Proceed to Thereafter, the microcomputer 24 switches to the data reproducing mode for CD-ROM reproducing in step 50, and then ends the optical disc discrimination method according to the embodiment of the present invention. On the other hand, if the optical disk mounted in the tray is a CD-R / W, the maximum S curve of the focus error signal FES generated by the up and down driving of the objective lens performed in step 44 is the S curve generated when the CD-ROM is mounted. It is much smaller than the maximum level. The reason is that there is a difference in reflectance of the optical disk surface. Therefore, the focus error signal FES output from the RF amplifier 18 is input to the non-inverting input terminal (+) and the level amplifier 32 of the first comparator 28, respectively. The focus error signal FES input to the level amplifier 32 is amplified by a predetermined level as shown in FIG. 3 (b) and then applied to the non-inverting input terminal (+) of the second comparator 34, thereby providing a CD-ROM detection signal. The CD-R / W sensing signals are output at the "low" level and the "high" level, respectively. The optical disc discrimination signal is input to the microcomputer 24 at the "high" level. On the other hand, if the optical disc discrimination signal input in step 46 of FIG. 4 is at the "high" level, the microcomputer 24 recognizes the optical disc currently mounted in the tray as the CD-R / W and proceeds to step 48. In step 48, the microcomputer 24 sets the drive mode to the CD-R / W mode, and proceeds to step 52, and outputs the parameter change signal according to the setting mode to the RF amplifier 18 to record the CD-R / W. Outputs gain parameters for playback. In step 54, the data recording / reproducing mode is switched to record data on the optical disk surface or to reproduce predetermined data from the optical disk surface.

In summary, the present invention can determine the type of the optical disk mounted on the tray by only comparing the S curve maximum level of the focus error signal generated during the focus servo control with the reference level.

Meanwhile, in the embodiment of the present invention, only the FES level comparison unit for determining only the CD-ROM and CD-R / W and the algorithm thereof are described. However, the S-curve generated during focus servo control shows different levels depending on the type of optical disk. In such a case, such optical disks may be discriminated without any deformation.

As described above, the present invention has the advantage that the type of the optical disk mounted on the tray can be quickly determined by comparing the S curve maximum level of the focus error signal generated during the focus servo control with the reference level. There is an advantage that can provide a simplified optical disc determination algorithm than the disc determination algorithm.

Claims (5)

Optical pickup which optically picks up the information recorded on the optical disk and converts it into an electrical RF signal, and outputs the amplified and waveform-formed electrical RF signal and detects a focus error signal generated during focus servo control. In the optical disk discrimination apparatus of the apparatus having an RF amplifier for outputting and outputting different types of optical disk, A focus error signal level comparison unit for gating combinations of detection signals generated by comparing the S curve level of the focus error signal output from the RF amplifier with each of the preset reference levels and outputting the result as an optical disc determination signal; And a control unit for changing gain parameters of the RF amplifier according to the optical disk discrimination signal input from the focus error signal level comparison unit. The apparatus of claim 1, wherein the focus error signal level comparison unit comprises: a focus error signal level comparison unit; A first comparator configured to output a first optical disk detection signal by comparing a preset first reference voltage level with an S curve maximum level of a focus error signal output from the RF amplifier; An amplifier for amplifying and outputting a focus error signal output from the RF amplifier; A second comparator configured to output a second optical disc detection signal by comparing a preset second reference voltage level with a maximum S curve of a focus error signal output from the amplifier; And a gate element for outputting an optical disk discrimination signal by performing an AND operation on the inverted first optical disk sensing signal and the second optical disk sensing signal. The apparatus of claim 2, wherein the first optical disc detection signal is a CD-ROM detection signal. The optical disc discrimination apparatus according to claim 2, wherein the second optical disc detection signal is a CD-R / W detection signal. Optical pickup that optically picks up the information recorded on the optical disk and converts it into an electrical RF signal, and outputs by amplifying and waveform-shaping the electrical RF signal and focus error signal generated during focus servo control. A focus error that detects and outputs an RF amplification unit and a detection signal generated by comparing the S-curve level of the focus error signal output from the RF amplification unit with each of the preset reference levels, and outputs the result as an optical disc discrimination signal. In the optical disk discriminating method of the optical disk recording / reproducing apparatus, provided with a signal level comparator, for reproducing information recorded on another type of optical disk or recording predetermined information on the optical disk surface, Performing focusing servo control by driving the optical pickup unit up and down when loading an optical disc; And outputting a parameter change signal for changing the parameters of the RF amplifier to correspond to the loaded optical disk in response to the optical disk discrimination signal input from the focus error signal level comparison unit during focusing servo control. Optical disc discrimination method.