JP2005135548A - Optical disk device and signal processing method in optical disk device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a signal processing method in an optical disk device, by which a signal in each region of an optical disk can be easily and appropriately reproduced even when the optical disk has two or more regions different in signal. <P>SOLUTION: When an optical pickup 28 moves from a read-in area 14 to a data area 16, when the optical pickup 28 detects the signal of a connection area 18, a change-over switch 44 register is set to an equalizer 48 and a signal read from the data area 16 is processed by the equalizer 48 and a PRML circuit 52 and decoded by an ECC decoder 50. When the optical pickup 28 moves from the data area 16 to the read-in area 14, a change-over switch 44 resister is set to an A/D converter 46 by the signal of the connection area 18 and a signal from the read-in area 14 is converted into a digital signal by the A/D converter 46 and then decoded by the ECC decoder 50. The signals of the read-in area 14 and the data area 16 can be appropriately reproduced respectively by one system of the equalizer 48 and the PRML circuit 52. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an optical disk device and a signal processing method in the optical disk device, and particularly, for example, a first area in which disk information is recorded in advance, a second area, a first area, and a second area in which the signal format is different from the signal format of the first area. The present invention relates to an optical disc apparatus and a signal processing method in the optical disc apparatus, in which an optical pickup records / reproduces an optical disc having a third area (mirror area) in which no signal is recorded.

  When reproducing a signal recorded on a disc in an optical disc apparatus, the optical disc apparatus has a PRML (Partial) so that it can be decoded even if the quality of the read signal is poor as the density of the optical disc increases and the signal reading speed improves. A signal processing technique using a Response Maximum Likelihood circuit is employed.

  If the signal format of the entire surface of the optical disc is the same, the set values of the equalizer and the PRML circuit are matched to the signal format.

  However, if the optical disc is divided into a plurality of areas and the signal formats in these areas are different, the signal quality read from each area also changes. Therefore, the equalizer and PRML circuit having the same set value should be used for each area. I can't. Therefore, a signal processing function such as an equalizer may be mounted for each region. However, when a signal is read from each region, it is necessary to switch the equalizer and the PRML circuit in accordance with those regions. Then, when switching, it is necessary to detect the current position of the optical pickup and then determine in which area. When the address of the optical pickup is used for determining the area, a complicated process for obtaining the address of the optical pickup and determining the current position and area based on the acquired address is required.

  In addition, there is a method of performing signal processing by using one system equalizer or the like in accordance with the signal quality of the better one, but this method is inefficient in that the signal processing is performed after the good signal quality is degraded. Processing must be done.

  SUMMARY OF THE INVENTION Therefore, a main object of the present invention is to provide a signal processing method in an optical disc apparatus that can easily and appropriately reproduce signals in each region even in an optical disc having two or more regions having different signal formats. .

  According to the first aspect of the present invention, a first area in which a signal of disc information is recorded in advance, a second area where a signal can be recorded in a signal format different from the signal format of the first area, and between the first area and the second area Is a signal processing method in an optical disc apparatus that records / reproduces an optical disc including a third region having a mirror-like surface with an optical pickup, and decodes the RF signal read from the first region after A / D conversion In this signal processing method, the RF signal read from the second region is subjected to signal processing by an equalizer and a PRML circuit and then decoded.

  According to the first aspect of the present invention, in order to reproduce the signal recorded in the first area of the optical disc divided into three areas, the optical pickup is moved to the first area and the laser light is irradiated to the first area. . The laser light is reflected on the optical disk, and the reflected light is converted into an RF signal in an analog signal processing circuit. Since the signal quality of this RF signal is better than the signal quality of the second area, the RF signal is decoded after A / D conversion without signal processing, and the signal of the first area is reproduced.

  In order to reproduce the signal recorded in the second area, the optical pickup is moved to the second area, the laser light is irradiated to the second area, and the RF signal obtained from the analog signal processing circuit is supplied to the equalizer and the PRML circuit. The signal in the second area is reproduced by decoding the signal after using it.

  If the signal quality of the second region is subjected to signal processing using an equalizer and a PRML circuit and then decoded, the signal can be reproduced with high accuracy and at high speed.

  If the first region signal is decoded without signal processing and the second region signal is decoded after signal processing, only the second region equalizer and the PRML circuit need be mounted. In addition, the cost of the PRML circuit can be reduced.

  According to the second aspect of the present invention, when the optical pickup receives a signal from the third area when the optical pickup is moved from the first area to the second area, the equalizer and the PRML circuit are used to move from the second area to the first area. The signal processing method according to claim 1, wherein when moving the optical pickup, when the optical pickup receives a signal from the third region, switching is performed so that the equalizer and the PRML circuit are not used.

  In the invention of claim 2, if the surface of the third region is a mirror shape, the reflected light from the third region is strong and the magnitude of the RF signal is larger than the RF signal of the other region. This region can be easily distinguished from other regions. In addition, since the third region is located between the first region and the second region, the third region always passes through the third region when exceeding the region such as the second region from the first region. If the passing direction is known from the access command, the current area of the optical pickup, or the like, the area after movement can be determined from the signal from the third area. Therefore, for example, when moving from the first area to the second area, when the optical pickup passes through the third area, the signal is detected so that the equalizer and the PRML circuit are not used. When the optical pickup detects a signal from the third area when moving from the second area to the first area, the equalizer and the PRML circuit are switched to use.

  Since the region where the optical pickup is located can be easily grasped from the signal from the third region, the determination processing by address acquisition is not required, and the processing time can be shortened. Furthermore, since the determination timing for determining whether or not to adjust the signal in the third area is used, switching suitable for the area can be performed easily and reliably.

  According to a third aspect of the present invention, there is provided a first area in which a disc information signal is recorded in advance, a second area in which a signal can be recorded in a signal format different from the signal format of the first area, and An optical disc apparatus for recording / reproducing an optical disc including a third region having a mirror-like surface with an optical pickup, processing an reproduced signal from the optical pickup and outputting an RF signal, and An optical disc including a digital signal processing circuit that receives an RF signal, the digital signal processing circuit including an equalizer that receives the RF signal, a PRML circuit that receives the output of the equalizer, and a decoder that receives the output of the PRML circuit and reproduces digital data An A / D converter for A / D converting an RF signal applied to a digital signal processing circuit and supplying the signal to a decoder; An optical disc apparatus characterized by further comprising a selector switch for switching whether an RF signal is applied to an equalizer or an A / D converter, and switching the selector switch when the optical pickup passes through the third region. .

  In the invention of claim 3, the reproduction signal read from the optical disk is converted into an RF signal by the analog signal processing circuit, and the digital signal processing circuit is output. Then, the RF signal is given to the A / D converter or the equalizer by the changeover switch. When the RF signal is read from the first region, the changeover switch is switched to the A / D converter. The RF signal from the analog signal processing circuit is input to the A / D converter, converted into digital data, and then reproduced by the decoder. On the other hand, the RF signal read from the second region is input to the equalizer by the changeover switch and then input to the PRML circuit. Therefore, it is converted into digital data and then reproduced by a decoder.

  By simply switching the changeover switch, the signals in the first area and the second area can be appropriately reproduced.

According to the present invention, even in an optical disc having two or more regions having different signal formats, signals from different regions can be easily and appropriately reproduced with only one equalizer and PRML circuit. The objects, features and advantages of the present invention will become more apparent from the following detailed description of embodiments with reference to the drawings.

  An optical disk apparatus 10 according to an embodiment of the present invention shown in FIG. 1 is an optical disk apparatus 10 for recording / reproducing an HD DVD 12 (High Definition Digital Versatile Disc).

  The HD DVD 12 is an optical disc having a thickness of 1.2 mm obtained by bonding two discs having the same thickness of 0.6 mm as the DVD. The HD DVD 12 of the embodiment is a rewritable disc, and the rewritable disc 12 is formed with three regions 14, 16 and 18 concentrically divided as shown in FIG.

  The inner area 14 is called a system lead-in area (lead-in area). In the lead-in area 14, an emboss signal is formed by converting disk information or the like into information using pits 14a during disk formation. Therefore, in the lead-in area 14, a signal is reproduced by a DPD (Differential Phase Detection) method. The track pitch and the shortest pit length of the area 14 are almost the same recording density as the track pitch and the shortest pit of a DVD-ROM using a red laser.

  The outer area 16 is called a data area and is an area where information can be recorded by the user. This data area 16 has a groove structure composed of lands 16a and grooves 16b, and is an area for performing so-called land / groove recording in which signals are recorded on both the lands 16a and the grooves 16b. Therefore, in this data area 16, a signal is reproduced by the PP (Push-Pull) method.

  A connection area 18 is formed between the lead-in area 14 and the data area 16. Nothing is recorded in the connection area 18, and therefore the surface is a flat mirror with no irregularities.

  In the case of an HD DVD 12 playback-only disc, the lead-in area 14 and the connection area 18 are the same as the rewritable disc 12 described above, but the data area 16 is different. In the read-only disc, the data area 16 is formed by embossed pits 14 a like the lead-in area 14. However, the track pitch is as narrow as about 60% of the track pitch of the lead-in area 14, and the shortest pit length is as small as 50%. Therefore, in the read-only disc, the optimum value of the servo coefficient differs between the lead-in area 14 and the data area 16 even with the same emboss signal.

  Returning to FIG. 1, the optical disc apparatus 10 includes an MPU 20, and the MPU 20 has a memory 22. The MPU 20 controls the entire operation of the optical disk apparatus 10, issues a command to the servo DSP 24 to rotate the disk 12, and controls the laser driver 26. In the memory 22, initial information of each of the servo coefficient and the optical pickup 28 laser power is registered in advance. This initial information is used for servo control and laser power control when the optical disc 12 is loaded or when the optical disc apparatus 10 is activated, that is, in the initial processing.

  More specifically, the servo DSP 24 executes various servos such as focus, tracking, sled, spindle, and tilt in accordance with commands from the MPU 20. The motor / coil driver 30 supplies drive power to the spindle motor 32 and drives the focus coil 34 of the optical pickup 28. The spindle motor 32 rotates the optical disc 12.

  The optical pickup 28 includes, for example, a blue-violet laser diode 36, and the blue-violet laser light from the laser diode 36 is applied to the optical disk 12 through an objective lens (not shown) that is transmission-controlled by the focus coil 34. . The laser beam reflected by the optical disk 12 is incident on the photodetector 38 through the objective lens. As is well known, the photodetector 38 has four detection areas, and inputs four optical detection signals to the analog signal processing circuit 40.

  The analog signal processing circuit 40 generates a focus error signal and a tracking error signal based on the four light detection signals, and inputs an RF signal to the digital signal processing circuit 42. The focus error signal and tracking signal are transmitted to the servo DSP 24 for focus servo and tracking servo.

  The RF signal transmitted to the digital signal processing circuit 42 is output to the A / D converter 46 or the equalizer 48 by the changeover switch 44 in the digital signal processing circuit 42. As will be described later, when the RF signal is read from the lead-in area 14, the MPU 20 switches the selector switch 44 so that the RF signal is supplied to the A / D converter 46. Therefore, the RF signal is digitally converted by the A / D converter 46 and sent to the ECC decoder 50 where it is decoded. On the other hand, if the RF signal is read from the data area 16, the MPU 20 switches the changeover switch 44 so that the RF signal is supplied to the equalizer 48, as will be described later. Therefore, the RF signal is waveform-shaped by the equalizer 48, then replaced with a digital signal by the PRML circuit 52, and then sent to the ECC decoder 50. The data is decoded from the optical disk 12 by the ECC decoder 50.

  The digital data reproduced by the digital signal processing circuit 42 is temporarily stored in the RAM 54, and the reproduced data is sent to a host (not shown) such as a personal computer via the interface 56 as necessary.

  Specifically, in an initial process such as when the optical disk device 10 is started up, the optical pickup 28 is sent to the lead-in area 14 and reads the disk information. The disc information is input to the analog signal processing circuit 40 and converted into an RF signal. At this time, the changeover switch 44 is switched to the A / D converter 46 side. The RF signal is A / D converted by the A / D converter 46 and then decoded by the ECC decoder 50. Then, after the optical pickup 28 reads the disc information, the optical pickup 28 is sent to the data area 16. When the optical pickup 28 moves from the lead-in area 14 to the data area 16, if the optical pickup 28 passes through the connection area 18, the servo DSP 14 obtains the RF signal of the connection area 18 from the analog signal processing circuit 40, and the changeover switch 44. In order to switch between them, an interrupt signal is transmitted to the MPU 20.

  Upon receiving the interrupt signal, the MPU 20 executes interrupt processing according to the flowchart shown in FIG. In step S1, the interrupt information is confirmed. In step S3, it is determined whether or not the information is due to the optical pickup 28 passing through the connection area 18. If the optical pickup 28 has not passed through the connection area 18, the interrupt process is another process, so that the process is performed in step S5 and the process ends.

  On the other hand, if the interrupt information is due to having passed through the connection area 18 in step S3, then in step S7, the MPU 20 checks the current area or access direction of the optical pickup 28 based on the status returned from the servo DSP 14. Based on this, it is determined in step S9 whether the optical pickup 28 is in the lead-in area 14 or the data area 16 after moving.

  If the optical pickup 28 is moved from the data area 16 to the lead-in area 14 and is currently in the lead-in area 14, the equalizer 48 and the PRML circuit 52 are not used in the lead-in area 14 in step S11. A changeover switch register or flag is set in the / D converter 46. On the other hand, if the optical pickup 28 moves from the lead-in area 14 to the data area 16 and the optical pickup 28 is in the data area 16, the equalizer 48 and the PRML circuit 52 are used for the RF signal from the data area 16 in step S15. In step S13, the changeover switch register or flag is set in the equalizer 48.

  Thus, if the current area of the optical pickup 28 is the lead-in area 14, the equalizer 48 and the PRML circuit 52 are not used, and the RF signal is directly supplied from the A / D converter 46 to the decoder 50. On the other hand, in the case of the data area 16, the data is processed by the equalizer 48 and the PRML circuit 52 and then given to the decoder 50.

  That is, the signals in the lead-in area 14 and the data area 16 can be decoded and reproduced by simple control by simply switching the changeover switch 44 from the region where the optical pickup 28 exists. Therefore, only one equalizer 48 and one PRML circuit 52 for the data area 16 need be mounted on the optical disc apparatus 10, and the component cost can be reduced.

  Further, in this embodiment, since the region where the optical pickup 28 is present is determined by the signal of the connection area 18, no determination process is required when determining from the address, and the processing time can be shortened.

1 is a cross-sectional view showing an optical disc apparatus according to an embodiment of the present invention. (A) is an illustration figure which shows schematic structure of a rewritable disc, (B) is the elements on larger scale of (A). FIG. 8 is a flowchart showing MPU interrupt processing in the optical disc apparatus in FIG. 1 embodiment;

Explanation of symbols

10 ... Optical disc device 12 ... Rewritable disc (HD DVD)
DESCRIPTION OF SYMBOLS 14 ... Lead-in area 16 ... Data area 18 ... Connection area 40 ... Analog signal processing circuit 42 ... Digital signal processing circuit 44 ... Changeover switch 46 ... A / D converter 48 ... Equalizer 52 ... PRML circuit 50 ... ECC decoder

Claims (3)

A first area in which a signal of disc information is recorded in advance, a second area in which a signal can be recorded in a signal format different from the signal format of the first area, and the first area and the second area, A signal processing method in an optical disc apparatus for recording / reproducing an optical disc including the third region having a mirror-like surface with an optical pickup,
A signal processing method, wherein an RF signal read from the first region is decoded after being A / D converted, and the RF signal read from the second region is subjected to signal processing by an equalizer and a PRML circuit and then decoded.   When moving the optical pickup from the first region to the second region, when the optical pickup receives a signal from the third region, the equalizer and the PRML circuit are used. From the second region to the first region, 2. The signal processing method according to claim 1, wherein when the optical pickup is moved to a position, when the optical pickup receives a signal from the third region, switching is performed so that the equalizer and the PRML circuit are not used. A first area in which a signal of disc information is recorded in advance, a second area in which a signal can be recorded in a signal format different from the signal format of the first area, and the first area and the second area, An optical disk device for recording / reproducing an optical disk including the third region having a mirror-like surface with an optical pickup,
An analog signal processing circuit that processes a reproduction signal from the optical pickup and outputs an RF signal; and a digital signal processing circuit that receives the RF signal,
In the optical disk apparatus, the digital signal processing circuit includes an equalizer that receives the RF signal, a PRML circuit that receives an output of the equalizer, and a decoder that receives the output of the PRML circuit and reproduces digital data.
The A / D converter that A / D converts the RF signal applied to the digital signal processing circuit and supplies the A / D converter to the decoder, and switches between supplying the RF signal to the equalizer or the A / D converter An optical disc apparatus, further comprising a changeover switch, wherein the changeover switch is changed over when the optical pickup passes through the third region.

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