KR100194049B1 - Disc determination device and method - Google Patents

Abstract

A disc reproducing apparatus having reproducing systems of CD and DVD having different synchronizing signals, the DVD reproducing system having a DVD synchronous detecting unit, and checking whether a DVD synchronizing signal outputted from the DVD synchronous detecting unit is detected when the disc is mounted. When the DVD sync signal is detected, the DVD player is selected and driven to perform the DVD play mode. When the DVD sync signal is not detected for the set time, the CD play system is selected and driven to perform the CD play 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.

SUMMARY OF THE INVENTION An object of the present invention is to set a digital video disk mode during initial operation in a system for playing digital video disks and compact disks, and then to detect and analyze a sync pattern of the mounted disk to determine the type of the mounted disk. In providing a method.

Disc reproducing apparatus according to an embodiment of the present invention for achieving the above object comprises a playback system of the CD and DVD having a different synchronization signal, the DVD playback system is provided with a DVD synchronization detection unit, when the disc is detected Analyzing the detection of the DVD sync signal output from the DVD sync detector, and performing a DVD play mode by selectively driving a DVD player when the DVD sync signal is detected, and when the DVD sync signal is not detected for a predetermined time. Selectively driving the CD playback system to perform a CD 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 condensing spot diameter in the disc reproducing apparatus;

FIG. 3 is a diagram for explaining the relationship between bits and condensation spots for digital video discs and compact discs. FIG.

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 showing an example of synchronizing patterns of a DVD.

FIG. 7 is a diagram showing a characteristic of detecting a DVD synchronization signal in order to determine the type of disc in the embodiment of FIG.

FIG. 8 is a diagram showing a configuration for detecting a DVD synchronization signal in the embodiment of FIG.

9 is a flowchart showing an operation of determining the type of a loaded disc 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 reproducing system according to an embodiment of the present invention, wherein a CD reproducing system and a DVD reproducing system are provided, and the optical pickup 111 is for both CD and DVD. Assume that an optical pickup unit is used. The RF receiver 512 amplifies and outputs the 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 CD reproduction system, the CD equalizer 513 filters and equalizes an RF signal of a CD band from an RF signal output from the RF receiver 512. The CD 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.

Second, referring to the DVD playback system, the DVD equalizer 516 filters the DVD signal RF signal from the received RF signal and then outputs the equalized signal. At this time, the DVD band is a broadband including a CD band. The DVD signal processor 517 receives the data stream of the DVD band output from the DVD equalizer 516, demodulates the 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.

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 DVD synchronous detection unit 521 is provided inside the DVD signal processor 517. The control unit 511 determines the type of the mounted disc according to whether or not the DVD frame synchronization pattern is output from the DVD synchronous detection unit 521, and then selects a corresponding playback system. Select drive.

The frame synchroinzation pattern of the DVD uses a pattern not generated in the modulated data. This synchronization method can reliably synchronize as long as no bit error occurs. The modulation method used for the DVD uses EFM-plus (Eight to Fourteen Modulation plus). In the DVD playback system using the EFM-plus modulation scheme as described above, the pattern of pure data is 11T (100000000001 _B ) at maximum. Therefore, in the DVD sync pattern, a pattern not used in the pure data is commonly used. In this case, the above pattern should exceed at least 12T. In addition, a plurality of sync patterns are used in the DVD, and these sync patterns are combined and used in an appropriate manner. At this time, these sync patterns have a specific pattern that does not use the data pattern as described above.

In the embodiment of the present invention, it is assumed that the common pattern used for the sync pattern is 14T (hereinafter referred to as a sync pattern), and these common patterns are assumed to be located at the lower 14 bit positions of each sync pattern.

6 shows an example of one sector format as an example in which a sync pattern and data of a DVD are stored. In FIG. 6, SP denotes synchronization patterns, and D1-Dn denotes pure data. In addition, in FIG. 6, a1-a2 indicates the length of a sync pattern, b1-b2 indicates the length of data, and c1-c2 indicates the length of a sync frame. , E denotes two sync frame lengths. The data length b has a length b >> a which is much larger than the length a of the sync pattern. Also, in FIG. 6, F denotes the number of columns of two frame sinks constituting a sector. Accordingly, it can be seen that the size of one sector of the DVD becomes F * E [= 2c * F = 2 (a + b) * F].

The sector format recorded on the DVD has the form as shown in FIG. 6, and in this case, the sync pattern is configured as shown in FIG. 7A. Here, the length of the sync pattern is composed of a bit, and the lower bits of the sync pattern have 14T in common as described above. Therefore, the plurality of synchronization patterns used for the DVD have the lower 14 bits having the same value, and the upper bits except for this have different values. As shown in FIGS. 7B and 7C of FIG. 7, the data transfer time between the DVD frame sync pattern and the DVD frame sync pattern is 1.2 ms.

The DVD synchronous detection unit 521 for detecting the DVD frame synchronization patterns as shown in FIGS. 6 and 7 is configured as shown in FIG. Referring to FIG. 8, the input data stream is input to the input register 81 and shifted out. In addition, the reference register 82 stores lower 14-bit data having a common value as shown in 7a of FIG. 7 in the DVD frame synchronization patterns. The comparator 83 comparing the parallel output bit data of the input register 81 and the parallel output bit data of the reference register 82 outputs a result of the comparison in bit units. Then, the synchronization signal detection unit 84 generates a signal for determining whether or not the CD synchronization signal is detected by logically combining the bit data output from the comparator 83. In this case, the synchronization signal detection unit 84 may use a gate circuit, and when the comparator 83 outputs a high logic signal during synchronization detection, the synchronization signal detection unit 84 may use an AND gate.

In this case, when the DVD sector format is configured as shown in FIG. 6, the DVD synchronous detection unit 521 detects and outputs a DVD frame sync signal in a sync pattern period as shown in 7c of FIG. 7, and the sync signal generation period is generated in a 1.2 ms period. The signal output from the DVD synchronous detection unit 521 having the configuration as shown in FIG. 8 is applied to the control unit 511.

The controller 511 sets the initial driving mode to the DVD mode when the initial disk is mounted. Then, when the CLV servo (Continous Linear Velocity servo) in the DVD mode is turned on and the mounted disk is a DVD in which data and synchronization patterns are recorded in the form as shown in Fig. 6, the DVD frame synchronization signal is 1.2 ms as described above. It is detected at intervals. The CLV servo is based on 14T of the RF signal.

As described above, when the control unit 511 sets the DVD mode to the initial operation mode, the DVD sync pattern can be detected normally when the mounted disc is a DVD. However, if the CD is loaded while the DVD mode is set, CLV servo is applied but the DVD frame synchronizing signal cannot be detected. In the exemplary embodiment of the present invention, it is determined whether the synchronization signal to be reproduced after the CLV servo is applied when the disc is loaded with the initial driving mode set to the DVD mode as described above is determined as DVD or CD, and according to the determination result. Select and play the DVD play mode or CD play mode.

9 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. 9, in the embodiment of the present invention, when the disc is loaded, the initial play mode is set to the DVD mode, and then the detection of the DVD frame sync signal is detected. The DVD player is selected and driven when judged to be mounted. If the DVD frame synchronizing signal is not detected for a predetermined time, the CD player is judged and driven by the CD disc.

Referring to FIG. 9, 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 control unit 511 detects this in steps 911 and 913 and determines that the disk is mounted. The controller 511 controls the focusing of the optical pickup 111 by controlling a servo controller (not shown) at step 915. 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 915, the controller 511 turns the focus of the optical pickup 111 up and down, and checks whether it is a focus lock in step 917. In this case, when the focus lock is not performed, the controller 511 detects this in step 917 and determines that the disc is not mounted in step 919 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 917, since the disk is mounted on the tray, the controller 511 controls the servo controller to rotate the mounted disk in steps 921 to 925, and tracks the 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 spindle motor is controlled in the DVD CLV mode to control the rotation speed of the disk. In the above state, when the disc is loaded, the DVD CLV mode is set, and the DVD frame synchronization signal detection operation is prepared.

When the DVD CLV servo is turned on, the controller 511 receives the output of the DVD sync detector 514 in step 927 to check whether a DVD frame sync signal is detected. In this case, the DVD synchronous detection unit 521 inputs the filtered and equalized data streams into the DVD band, and compares the input data stream with a previously stored DVD frame synchronization pattern. In this case, the reference data stored in the reference register 82 is a unique pattern 14T having the DVD frame synchronization patterns in common and having a different form from the data in the data area recorded on the DVD. Accordingly, the DVD synchronous detection unit 521 compares the sync pattern with the received data stream and outputs it as a DVD frame sync signal when a pattern having the same value is detected.

In this case, when the mounted disc is a DVD, the type of the synchronization signal output from the DVD synchronous detection unit 521 is generated at a 1.2 ms period as shown in 7c of FIG. 7. Then, the controller 511 detects that the DVD frame sync signal is detected in step 927 and detects the sync signal until the number of times set in steps 929 and 931 is reached. The number of times of detecting the DVD frame synchronizing signal is set to the number of times to determine that the loaded disc is a DVD. When the set number of DVD frame synchronization signals is detected, the control unit 511 sets the optical pickup 111 to the DVD pickup unit in step 933 and resets the CLV servo for DVD playback. In step 935, the DVD signal processor 517. And the A / V decoder 518 to activate the DVD playback system to perform the DVD playback mode, and to control the CD signal processor 514 and the audio processor 515 to deactivate the CD playback system.

However, if the DVD frame synchronization signal is not detected in step 927, the controller 511 checks whether the set time has elapsed in step 937. This means that even if the loaded disc is a CD, the DVD frame synchronization signal is detected for a predetermined time. After turning on the DVD CLV servo, the controller 511 waits for the detection of the DVD frame synchronizing signal for a predetermined time. If the DVD frame synchronizing signal is not detected during this time, the control unit 511 determines that the loaded disc is a CD. At this time, the setting time may be a time for detecting several DVD frame synchronizing signals. If the DVD frame synchronizing signal is not received during the set time, the control unit 511 determines that the loaded disc is a CD in step 939, and sets the optical pickup 111 as a CD pickup device in step 941 and turns on the CD CLV servo. Let's do it. When the CLV is locked, the control unit 511 detects this in step 943 and in step 945 turns on the CD signal processing unit 514 and the audio processing unit 515 to activate the operation of the CD playback system and the DVD signal processing unit 517 and the A / V decoder. The 518 is turned off to deactivate the operation of the DVD player, which causes the disc player to enter the CD play 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 DVD reproducing mode is first performed to check whether a disc has a DVD frame synchronization signal. At this time, if the DVD frame synchronizing signal is detected, the mounted disc is judged to be a DVD and the DVD playback system is activated to perform the DVD play mode.If the DVD frame synchronizing signal is not detected for a predetermined time, the mounted disc is determined as CD. Activate the CD player to enter CD 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 DVD-only pickup device and checks for the detection of the DVD frame sync signal. When the DVD frame sync signal is detected, the DVD play mode is performed. If the synchronization signal is not detected during the set time, the CD playback mode is selected by activating the CD-only pickup device and selecting the CD 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 reproducing systems of CD and DVD having different synchronizing signals, wherein the DVD reproducing system includes a DVD synchronizing detection unit and detects whether or not a DVD synchronizing signal outputted from the DVD synchronizing detection unit is detected when the disc is mounted. When the DVD sync signal is detected, the DVD player is selected and driven to perform a DVD playback mode. When the DVD sync signal is not detected for a predetermined time, the CD player is selected to drive the CD playback mode. An optical disc reproducing apparatus, characterized in that. In a disc reproducing apparatus having a two-way optical pickup capable of reproducing CDs and DVDs having different synchronization signals, and a CD reproducing system and a DVD reproducing system, the DVD reproducing system includes a DVD synchronous detecting unit, and when the disc is detected, The optical pickup is controlled by the DVD pickup unit, the presence or absence of the detection of the DVD synchronization signal output from the DVD synchronization detection unit is detected, and when the DVD synchronization signal is detected, the DVD playback system is selectively driven to perform the DVD playback mode for a set time. And controlling the optical pickup to a CD pickup unit when the DVD synchronization signal is not detected, and selectively driving the CD reproduction system to perform a CD playback mode. In the playback method of a disc reproducing apparatus comprising a two-focal two-way optical pickup capable of reproducing CDs and DVDs having different synchronization signals, a CD player system and a DVD player system, wherein the DVD player system comprises a DVD synchronous detection unit. When the disc is detected, the optical pickup is controlled exclusively for the DVD, the DVD sync signal is detected from the DVD sync detector, and the DVD playback system is selectively driven when the DVD sync signal is detected. And if the DVD synchronization signal is not detected for a predetermined time, controlling the optical pickup as a CD pickup unit, and selectively driving the CD player to perform a CD playback mode.