KR100194047B1 - Disc determination device and method - Google Patents

Abstract

A disc reproducing apparatus having reproducing systems of CD and DVD having different synchronizing signals, the CD reproducing system having a CD synchronizing detection unit, and analyzing the presence or absence of detecting a CD synchronizing signal by selecting a CD reproducing system when the disc is detected. When the CD sync signal is detected, the CD playback system is driven to perform the CD playback mode. When the CD sync signal is not detected for the set time, the DVD playback system is driven to perform the DVD playback mode.

Description

Disc determination device and method

The present invention relates to an apparatus and method for reproducing a disc, and more particularly, to an apparatus and a method for automatically determining the type of a disc mounted in an apparatus for reproducing a plurality of discs.

Generally, a representative disc as an optical disc for performing a non-contact reading by using a laser beam is a compact disc (hereinafter referred to as a CD). However, the current disc recording and reproducing apparatus is in need of high speed, overwrite, and high density (large capacity). On the other hand, digital image compression technology is also a trend that the MPEG (Moving Picture Experts Group) compression method is practical. Accordingly, digital disc media represented by Digital Video Discs (hereinafter referred to as DVDs) will emerge as a core medium of multimedia storage.

Fig. 1 shows a block configuration of a DVD player, where the disk 20 is a high density optical disk, which can be a DVD. In addition, it is assumed that the pickup unit 111 is a short wavelength optical head, and the numerical aperture of the objective lens is 0.6 and the red semiconductor laser wavelength is used. The signal amplifier 112 converts the optical signal output from the pickup unit 111 into an electrical signal and amplifies the signal. The demodulator and corrector ECC decoder 113 demodulates the modulated signal output from the signal amplifier 112 and corrects an error generated during the reproduction process. The servo controller 114 controls the pickup unit 11 by inputting the output of the signal amplifier 112 (focusing tracking error signal) and the demodulation and correction unit 113 (Contant Linear Velocity control signal). A system decoder 116 decodes a DVD data stream output from the demodulation and correction unit 113 and separately outputs the DVD data stream into a video elementary stream and an audio elementary stream. The video decoder 117 decodes the video data stream output from the system decoder 117 and converts it into a form of playable image data. The encoder 118 encodes video data output from the video decoder 117 in a corresponding video display method (NTSC or PAL) and outputs the video data to the display unit. An audio decoder 119 converts the encoded audio data stream output from the system decoder 116 into original audio data. The D / A converter 120 converts the data output from the audio decoder 119 into an analog audio signal and outputs the analog audio signal.

In the configuration of FIG. 1, a system controller for controlling the overall operation of the disc reproducing apparatus is not shown.

The DVD player having the above structure uses a modulation, error correction, and video encoding method different from that of a general CD player, and thus the signal processing method of the DVD and CD player is completely different. In the disc 20, the pit size and track pitch of the DVD and the CD are different, and the laser wavelength of the pickup unit 11 and the numerical aperture of the objective lens are also different.

It is important to reduce the size of the focusing spot in order to achieve high density in such a DVD recording / reproducing system. As a method of doing this, the wavelength of the first laser is shortened and the numerical aperture of the second objective lens is reduced. (NA) is increased, and the third method is to use a modulation method with excellent coding efficiency. At this time, the DVD uses a red laser semiconductor laser (650nm-635nm) among the above three methods, the numerical aperture (NA) of the objective lens is 0.6, and EFM-Plus is used as a modulation method. (Eight to Fourteen Modulation plus) is used.

In order to reproduce information on a high density optical disc, the optical pickup unit 111 must be able to form a small optical focus. The diameter of the optical focus is proportional to the wavelength of light λ as shown in FIG. 2 and inversely proportional to the numerical aperture NA of the objective lens. As described above, the present semiconductor laser wavelength has a lower limit of about 635 nm. In general, DVD uses a laser wavelength of 650nm as standard, and CD uses a 780nm laser wavelength. On the other hand, in the numerical aperture NA of the objective lens, since the CD is 0.45 while the DVD is 0.6, the optical focal diameter of the DVD is about 60% or more of the optical focal diameter of the CD. Thus, the DVD can obtain a reproduction signal equivalent to that of a CD on an optical disc of about 2.6 times the recording density of the CD. The DVD can realize the improvement of the reproduction waveform by the actual circuit processing, so that the DVD can have a recording density of about 4.2 times that of the CD as shown in FIG.

The characteristics between the DVD and the CD having the above characteristics are shown in Table 1 below.

CD DVD Remarks Disc diameter 120 mm 120 mm DVD is double sided multi layer Disc thickness 1.2 mm 0.6mm Recording capacity 640Mbyte 4.7Gbyte For single-sided tomography Laser wavelength 780 nm 650 nm Numerical aperture of the objective lens 0.45 0.6 Minimum fitting size 0.9 μm 0.4 μm Track pitch 1.6 μm 0.74μm Modulation method EFM EFM-plus Error correction method CIRC RS-PC

In Table 1, it can be seen that the CD and DVD having the same disc diameter have many differences. However, since the accumulation of the vast soft resources of the CD cannot be ignored, compatibility with the CD and the DVD is very important. One of the major reasons that the compatibility between the DVD and the CD is hindered is that a separate optical pickup must be used. In other words, in order to reproduce the information on the disk, a part of the optical system is configured according to the thickness of the disk. Therefore, the object lens is designed according to the thickness of the disk. Therefore, when the thickness of the disk deviates from the design value, spherical aberration occurs and convergence of the optical focus is lowered. In other words, this means that the DVD has a thickness of 0.6 mm while the CD has a thickness of 1.2 mm, so that two discs cannot be played by one pickup unit. Therefore, a problem arises in that a separate optical pickup unit must be used for the compatibility of the CD player and the DVD player.

In order to solve the above problems, a two-focal two-way optical pickup unit of CD and DVD has been proposed. The optical pickup unit as shown in FIG. 4 solves the problem caused by the disc thickness difference by forming both the optical focus for the DVD and the optical focus for the CD at an optical axis direction. The principle of the two-way optical pickup as shown in FIG. 4 is to overlap two types of lens operations using a hologram. The objective lens numerical aperture of the pick-up apparatus is 0.6 in accordance with the DVD standard. However, a hologram is arranged in which a part of the light in the center portion thereof is refracted like a lens by diffraction. Therefore, the light that is not diffracted in the hologram is converged by an objective lens having a numerical aperture of 0.6 to form an optical focus of the DVD, and the diffracted light has a composite lens numerical aperture of 0.4 with the hologram and the object and a CD having a thickness of about 1.2 mm. The hologram is formed to suit.

Therefore, when using the optical pickup as shown in FIG. 4, the optical focus for the CD is formed at a position farther than the optical focus for the DVD. In this case, the photodetector is disposed on the photodetector so that a reflection image of the optical focus converged on the disk can be formed. Therefore, when the DVD is reproduced, the optical focus for DVD is converged on the disc, and the optical focus for CD is shifted, resulting in a blurry image in which the focus is not matched. Thus, although the image of the optical focus for the DVD is formed on the photodetector, the reflected light at the optical focus for the CD is diffused to a wide range so as not to give external impact to the reproduction of the DVD. In addition, at the time of CD playback, the DVD is reversed.

However, in the case of a system having a pickup device capable of simultaneously playing a DVD and a CD in an optical disc player or a pickup device capable of independently playing a DVD and a CD, the type of disc to be inserted can be determined. Must be able to operate in Discrimination of the DVD and the CD can be implemented in various ways. That is, there may be a method of determining whether the inserted disc is a DVD or a CD by comparing the magnitude of the focus error detection signal of the optical focus reproduced by the optical pickup or by comparing the magnitude of the RF signal according to the pit size.

In addition to the above method, there may be a method of determining the type of the mounted disc using the synchronization pattern. Since the CD and the DVD use different sync codes, the CD and DVD can automatically determine the type of the inserted disc by analyzing the sync codes detected in the specific mode.

Accordingly, an object of the present invention is to provide an apparatus and a method for automatically determining the type of a mounted disc in a system for reproducing a plurality of disc types.

Another object of the present invention is to set a compact disc mode at the time of initial driving in a system for playing digital video discs and compact discs, and to detect and analyze a sync pattern of the mounted disc, and to determine the type of the mounted disc; In providing a method.

Disc reproducing apparatus according to an embodiment of the present invention for achieving the above object comprises a reproduction system of the CD and DVD having a different synchronization signal, the CD reproduction system is provided with a CD synchronization detection unit, when the disc mounting detection When the CD sync signal is detected, the CD sync signal is detected and the CD sync signal is detected. When the CD sync signal is detected, the CD play system is selected and driven to perform the CD play mode and when the CD sync signal is not detected for a predetermined time. Selectively driving the DVD playback system to perform a DVD playback mode.

1 is a diagram showing the configuration of a digital video disc reproducing apparatus;

2 is a view for explaining the relationship between the wavelength of light, the numerical aperture of the objective lens, and the optical focal diameter in the disc reproducing apparatus;

3 is a diagram for explaining the relationship between bits and optical focus for digital video discs and compact discs;

4 is a diagram for explaining the principle of a bifocal two-way optical pickup.

5 is a diagram showing a configuration for determining the type of a disc loaded in the disc reproducing apparatus according to the embodiment of the present invention;

FIG. 6 is a diagram illustrating a characteristic of detecting a CD frame synchronization signal in order to determine the type of disc in the embodiment of FIG.

FIG. 7 is a diagram showing a configuration for detecting a CD frame synchronization signal in the embodiment of FIG.

8 is a flowchart showing an operation of determining the type of a disc loaded in the disc reproducing apparatus according to the embodiment of the present invention.

FIG. 5 is a diagram showing a configuration for automatically determining the type of a disc mounted in a disc recording / reproducing system according to an embodiment of the present invention, comprising a CD player and a DVD player, wherein the optical pick-up up) 111 assumes that an optical pickup unit for both a CD and a DVD is used. An RF receiver 512 amplifies and outputs a weak optical signal reproduced by the optical pickup 111. At this time, the RF signal output from the RF receiver 512 is a signal reproduced from a CD or DVD.

First, referring to the DVD player, the DVD equalizer 516 filters the equalized DVD signal from the received RF signal and outputs the equalized signal. At this time, the DVD band is a broadband including a CD band. The DVD signal processor (which can be implemented as a digital signal processor) 517 receives a data stream of a DVD band output from the DVD equalizer 516 and demodulates modulated data, and corrects an error generated in this process. . The DVD signal processor 517 corresponds to the demodulation and correction unit 113 of FIG. The A / D decoder 518 separates the video data and the audio data from the data output from the DVD signal processor 517 and performs signal processing to output the same. The A / V decoder 518 corresponds to the system decoder 116, the video decoder 117 and the audio decoder 119 of FIG.

Secondly, referring to the CD reproduction system, the CD equalizer 513 filters and equalizes the RF signal of the CD band from the RF signal output from the RF receiver 512. The CD signal processor (which can be implemented as a digital signal processor) 514 demodulates the modulated data stream output from the CD equalizer 513 and corrects and outputs an error generated in this process. The audio processor 515 signals and outputs the data output from the CD signal processor 514.

As described above, the disc reproducing apparatus according to the embodiment of the present invention has a CD player and a DVD player, and the optical pickup 111 uses a two-way optical pickup unit capable of playing CDs and DVDs. Therefore, when a disc is mounted in the disc reproducing apparatus, it is necessary to determine whether the mounted disc is a CD or a DVD and selectively drive the corresponding reproducing system. To this end, a CD sync detector 521 is provided inside the CD signal processor 514. The controller 511 determines a type of a disc mounted according to whether a CD frame sync pattern is output from the CD sync detector 521, and then selects a corresponding playback system. Select drive.

The frame synchroinzation pattern of the CD uses a pattern not generated in the modulated data. This synchronization method can reliably synchronize as long as no bit error occurs. Data recorded on the CD uses EFM modulation (Eight to Fourteen Modulation). The EFM method converts 8-bit data into 14-bit data and enables pattern combinations of the shortest 3-bit (3T) and the longest 11-bit (11T) lengths. Thus, the CD frame sync pattern uses 1000000000010000000000100 _B (11T + 11T + 2T) as in FIG. 6A, which is not used as data. The CD synchronization pattern as shown in FIG. 6A is recorded on the CD in the form as shown in FIG. 6B or 6C.

The format of data recorded on the CD is configured as shown in 6d of FIG. The CD synchronous detection unit 521 is configured as shown in FIG. Referring to FIG. 7, the input data stream is applied to the input register 71 and shifted out. Also, the reference register 72 stores the CD frame synchronization pattern as shown in FIG. 6A. The comparator 73 comparing the parallel output bit data of the input register 71 and the parallel output bit data of the reference register 72 outputs a result of the comparison in the unit of bits. Then, the synchronization signal detection unit 74 generates a signal for determining whether or not to detect the CD synchronization signal by logical combination of the bit data output from the comparator 73. In this case, the synchronization signal detection unit 74 may use a gate circuit. When all of the comparators 73 output high logic signals during synchronization detection, the synchronization signal detection unit 74 may use an AND gate.

In this case, when the CD frame format is configured as shown in 6d of FIG. 6, the CD sync detector 521 detects and outputs a CD sync signal in a sync pattern period as shown in 6e of FIG. 6, and the sync signal generation period is generated at a 13.3 ms period. . The signal output from the CD synchronous detection unit 521 having the configuration as shown in FIG. 7 is applied to the control unit 511.

The controller 511 sets the initial driving mode to the CD mode when the initial disk is mounted. Then, when the CLV servo (Continous Linear Velocity servo) in the CD mode is turned on, the frame synchronization signal of the reproduction system is generated at a 13.3ms period. That is, when data and synchronization patterns are recorded on the CD in the form as shown in 6d of FIG. 6, the frame synchronization signal during reproduction is detected at 13.3 ms period as described above. The frame synchronizing signal is generated in all CD-based discs such as CD and VCD. At this time, the CLV servo is based on 11T of the RF signal.

As described above, when the control unit 511 sets the CD mode to the initial operation mode, the CD synchronization pattern can be detected normally when the mounted disc is a CD. However, if the DVD is loaded while the CD mode is set, the CLV servo is applied but the frame synchronizing signal cannot be detected. In the embodiment of the present invention, as described above, the CD or DVD is determined by detecting the detection of the synchronous signal reproduced after the CLV servo is applied when the disc is loaded with the initial drive mode set to the CD mode. Select CD Play Mode or DVD Play Mode.

8 is a flowchart illustrating a process in which the controller 511 determines the type of a disc and selects and plays a corresponding play mode according to an embodiment of the present invention. As shown in FIG. 8, in the embodiment of the present invention, when the disc is loaded, the initial play mode is set to the CD mode, and then the CD frame sync signal is detected. The drive is judged to selectively drive the CD player, and if the synchronous signal is not detected for the set time, the drive is judged to be a DVD disc and the drive is driven.

Referring to FIG. 8, the controller 511 checks whether a disk is mounted. First, the controller 511 checks the state of the input unit 510 to check the on / off state of the tray. That is, when the tray is turned on / off, the controller 511 detects this in steps 811 and 813 and determines that the disk is mounted. The controller 511 controls the servo controller (not shown) in step 815 to perform the focusing operation of the optical pickup 111. In this case, since the optical pickup 111 is a two-way pickup unit that can be used for both CD and DVD, the servo control unit drives the optical pickup 111 as a CD pickup unit. In step 817, the controller 511 turns the focus of the optical pickup 111 up and down, and checks whether it is a focus lock in step 817. In this case, if the focus lock is not performed, the controller 511 detects this in step 817 and determines that the disc is not loaded in step 819 and processes the process. In this case, the tray is turned on / off without the user loading the disc.

However, when the focus lock is performed in step 817, since the disk is mounted on the tray, the controller 511 rotates the mounted disk by controlling the servo control unit in steps 821 to 825 and tracking servo. ) And turn on the CLV servo. At this time, the servo control unit rotates the disk by driving a spindle motor under the control of the control unit 511, and performs the tracking servo so that the optical pickup 111 can accurately follow the track of the data. At this time, when the tracking servo is completed, the rotation speed of the disk is controlled by controlling the spindle motor to the CLV mode of the CD playback mode. In the above state, when the disc is loaded, the CLV mode of the CD playback mode is set, and the CD frame synchronization signal detection operation is prepared.

When the CD CLV servo is turned on, the controller 511 receives the output of the CD sync detector 514 in step 827 and checks whether a CD frame sync signal is detected. In this case, the CD synchronous detection unit 521 inputs the filtered and equalized data streams into the CD band, and compares the input data stream with a previously stored CD frame synchronization pattern. At this time, the CD frame synchronization pattern stored in the reference register 72 is a unique pattern (11T + 11T + 2T) having a different form from the data in the data area recorded on the CD. Accordingly, the CD sync detecting unit 521 compares the sync pattern with the received data stream and outputs the CD sync signal when the pattern having the same value is detected.

In this case, when the loaded disc is a CD, the form of the synchronization signal output from the CD sync detection unit 521 is generated at a 13.3 ms period as shown in 6e of FIG. 6. Then, the control unit 511 detects that the CD frame synchronization signal has been detected in step 827 and detects the synchronization signal until the set number of times through steps 829 and 831. The number of times of detecting the CD frame synchronizing signal is set to the number of times to determine that the loaded disc is a CD. When the set number of CD frame synchronization signals is detected, the control unit 511 sets the optical pickup 111 as a CD pickup unit in step 833 and resets the CLV servo for CD playback. In step 835, the DVD signal processing unit 517 And the A / V decoder 518 to deactivate the DVD playback system, and to control the CD signal processing section 514 and the audio processing section 515 to activate the CD playback system and perform the CD playback mode.

However, if the CD frame synchronization signal is not detected in step 827, the controller 511 checks whether the set time has elapsed in step 837. This means that even if the loaded disc is a DVD, the CD frame synchronization signal is detected for a predetermined time. After the CD CLV servo is turned on, the control unit 511 waits for the CD frame synchronization signal to be detected for a predetermined time. If the synchronization signal is not detected during this time, the control unit 511 determines that the loaded disc is a DVD. At this time, the setting time may be a time for detecting several CD frame synchronization signals. If the CD frame synchronization signal is not received during the set time, the control unit 511 detects this in step 837 and determines the loaded disc as a DVD in step 839. In step 841, the optical pickup 111 is set as a pickup device for a DVD. Turn on the DVD CLV servo. When the CLV is locked, the control unit 511 detects this in step 843, and in step 845, the CD signal processing unit 514 and the audio processing unit 515 are turned off to stop the operation of the CD playback system, and the DVD signal processing unit 517 and the A / V decoder. 518 is activated to drive the DVD playback system to perform the DVD playback mode.

As described above, in the embodiment of the present invention, when a disc is mounted in a disc reproducing system capable of simultaneously reproducing a CD and a DVD, a CD reproducing mode is first performed to check whether a disc has a CD frame synchronization signal. At this time, if the CD frame synchronizing signal is detected, the mounted disc is judged to be a CD and CD reproducing system is activated to perform the CD play mode. Activates the DVD player to enter the DVD play mode.

In addition, in the embodiment of the present invention, a single pickup device capable of playing both CD and DVD by the optical pickup unit is described as an example, but a disc playback system including a CD-only pickup device and a DVD-only pickup device is provided separately. The same can be applied. In this case, when the disc is loaded, it first analyzes the received data stream generated from the CD-only pickup device and checks whether the CD frame sync signal is detected. In this case, if the CD frame sync signal is detected, the CD play mode is performed. If the synchronization signal is not detected during the set time, the DVD playback mode may be performed by activating the DVD dedicated pickup device and selecting the DVD playback system.

As described above, the type of the disc to be inserted can be automatically determined by the apparatus for reproducing the plurality of discs. In particular, it is possible to accurately determine the type of the disc by detecting the presence or absence of a synchronization signal of the mounted disc, and there is an advantage in that the disc play mode can be automatically performed according to the determination progress.

Claims (3)

A disc reproducing apparatus having CD and DVD reproducing systems having different synchronization signals, wherein the CD reproducing system includes a CD synchronizing detection unit, and detects whether or not a CD synchronizing signal output from the CD synchronizing detection unit is detected when the disc is mounted. Analyzing and performing a CD play mode by selectively driving a CD player when the CD sync signal is detected, and performing a DVD play mode by selectively driving the DVD player when the CD sync signal is not detected for a set time. An optical disc reproducing apparatus, characterized in that. An optical pickup capable of reproducing CDs and DVDs having different synchronization signals, and a disc reproducing apparatus having a CD reproducing system and a DVD reproducing system, wherein the CD reproducing system includes a CD synchronous detecting unit and the optical pickup when the disc is loaded. Control the CD exclusively and analyze the presence or absence of the detection of the CD synchronization signal output from the CD synchronization detection unit, and when the CD synchronization signal is detected, select and drive a CD playback system to perform the CD playback mode and the CD synchronization for a set time And reproducing the DVD playback mode by controlling the optical pickup to DVD only when no signal is detected and selectively driving the DVD playback system. An optical pickup capable of playing CDs and DVDs having different synchronization signals, and a CD playback system and a DVD playback system, wherein the CD playback system includes a CD synchronous detection unit. Control the optical pickup to CD only, analyze the presence or absence of the detection of the CD synchronization signal output from the CD synchronization detection unit, and perform the CD playback mode by selectively driving the CD playback system when the CD synchronization signal is detected, for a set time And controlling the optical pickup to DVD only when the CD synchronization signal is not detected, and selectively driving the DVD playback system to perform a DVD playback mode.