JP2008234698A - Optical disk player - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately read BCA information (or NBCA information) with a simple construction. <P>SOLUTION: The DSP (Digital Signal Processor) 32 of a DVD player 100 is provided with a first deciding part 323 deciding whether an optical pickup 1 is positioned in a mirror region, a counter-electromotive force detecting part 324 detecting counter-electromotive force of a thread motor 51, a second deciding part 325 deciding whether the optical pickup 1 reaches the innermost peripheral position on the basis of the detected counter-electromotive force, a movement direction setting part 326 setting a movement direction on an inner peripheral side when it is decided for the optical pickup to be positioned in the mirror region and setting the movement direction on an outer peripheral side when it is decided for the optical pickup to reach the innermost peripheral position, a drive controlling part 327 moving the optical pickup 1 in a set movement direction by a preset prescribed distance, and a reading executing part 328 reading BCA information or NBCA information every time the optical pickup 1 is moved. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an optical disc reproducing apparatus that reads out and reproduces BCA (Burst Cutting Area) information or NBCA (Narrow Burst Cutting Area) information stored in an optical disc.

  2. Description of the Related Art Conventionally, CPRM (Content Protection for Recordable Media) is known as a copyright protection technique for an optical disc such as a DVD (Digital Versatile Disk). In CPRM, information recorded in BCA (Burst Cutting Area) or NBCA (Narrow Burst Cutting Area), which is located further inside than the lead-in area of the optical disc, is used.

In order to read out BCA information or NBCA information with a simple configuration, for example, when reproducing NBCA information, the number of revolutions of the spindle motor is controlled by constant voltage control so that the spindle output becomes an average value calculated in advance. Has been proposed (see Patent Document 1).
JP 2006-172594 A

  However, in the optical disc apparatus described above, information can be read from the NBCA without using an FG (Frequency Generator), but the optical pickup is accurately moved to the position of the BCA (or NBCA) in the radial direction of the optical disc (for example, , A mechanism using a stepping motor and a mechanism using a sensor for detecting a position) are necessary, which has been a factor in increasing manufacturing costs.

  In view of the above problems, an object of the present invention is to provide an optical disc reproducing apparatus capable of accurately reading BCA information (or NBCA information) with a simple configuration.

  In order to achieve the above object, an optical disk reproducing apparatus according to claim 1 is an optical disk reproducing apparatus that reads and reproduces BCA (Burst Cutting Area) information or NBCA (Narrow Burst Cutting Area) information stored in an optical disk. First determination means for determining whether or not the optical pickup is located in a mirror area that is an unrecorded area formed on the outer peripheral side of the BCA or NBCA, and a thread motor that drives the optical pickup in the radial direction of the optical disc And a second determination for determining whether or not the optical pickup has reached the innermost circumferential position based on the counter electromotive force detected by the counter electromotive force detection means. Means and the first determination means, the optical pickup is located in the mirror region Is set to the inner circumferential side, and when the second determination means determines that the optical pickup has reached the innermost circumferential position, the moving direction of the optical pickup is set. A moving direction setting means for setting the outer peripheral side, a driving control means for moving the optical pickup by a predetermined distance in the moving direction set by the moving direction setting means, and the optical pickup being moved by the driving control means Reading execution means for reading BCA information or NBCA information each time the first determination means is positioned in the mirror region when the amplitude of the tracking error signal is equal to or less than a predetermined threshold value set in advance. The second determining means determines that the counter electromotive force detected by the counter electromotive force detecting means is less than a predetermined threshold value. If it is, the optical pickup is determined to have reached the innermost position, the predetermined distance, is characterized in that it is set to below 0.07 mm.

  The optical disk reproducing apparatus according to claim 2 is an optical disk reproducing apparatus that reads and reproduces BCA (Burst Cutting Area) information or NBCA (Narrow Burst Cutting Area) information stored in the optical disk, and the optical pickup includes BCA or Detecting the back electromotive force of the first determination means for determining whether or not the mirror area is an unrecorded area formed on the outer peripheral side of the NBCA and the sled motor that drives the optical pickup in the radial direction of the optical disk Back electromotive force detection means, second determination means for determining whether or not the optical pickup has reached the innermost peripheral position based on the back electromotive force detected by the back electromotive force detection means, and the first determination If it is determined by the means that the optical pickup is located in the mirror area, A moving direction for setting the moving direction of the optical pickup to the outer peripheral side when the second determining means determines that the optical pickup has reached the innermost peripheral position while setting the moving direction of the cup to the inner peripheral side BCA information each time the optical pickup is moved by the setting means, the drive control means for moving the optical pickup by a predetermined distance set in the movement direction set by the movement direction setting means, and the drive control means. Or a reading execution means for reading NBCA information.

  The optical disk reproducing apparatus according to claim 3 is the optical disk reproducing apparatus according to claim 2, wherein the first determination means determines whether or not the optical disk reproducing apparatus is located in the mirror area based on the tracking error signal. It is characterized by that.

  The optical disk reproducing device according to claim 4 is the optical disk reproducing device according to claim 3, wherein the first determination means has a tracking error signal whose amplitude is equal to or smaller than a predetermined threshold value. It is characterized in that it is determined that it is located in the mirror area.

  An optical disk reproducing device according to claim 5 is the optical disk reproducing device according to any one of claims 2 to 4, wherein the second determining means detects the back electromotive force detected by the back electromotive force detecting means. It is characterized in that it is determined that the optical pickup has reached the innermost circumferential position when the electric power is equal to or lower than a predetermined threshold value set in advance.

  An optical disk reproducing apparatus according to a sixth aspect is the optical disk reproducing apparatus according to any one of the second to fifth aspects, wherein the predetermined distance is set to 0.07 mm or less.

  According to the optical disk reproducing apparatus of the first aspect, it is determined whether or not the optical pickup is located in a mirror area that is an unrecorded area formed on the outer peripheral side of the BCA or NBCA. Further, the back electromotive force of the sled motor that drives the optical pickup in the radial direction of the optical disk is detected, and it is determined whether or not the optical pickup has reached the innermost circumferential position based on the detected back electromotive force. And when it is determined that the optical pickup is located in the mirror region, the movement direction of the optical pickup is set to the inner peripheral side, and when it is determined that the optical pickup has reached the innermost peripheral position, The moving direction of the optical pickup is set to the outer peripheral side. Further, since the optical pickup is moved by a predetermined distance in the set moving direction, and BCA information or NBCA information is read each time the optical pickup is moved, the BCA information (or NBCA information) can be read with a simple configuration. Information) can be read accurately.

  In other words, since it is determined whether the optical pickup has reached the innermost circumferential position based on the back electromotive force, there is no need to provide a sensor for detecting that the optical pickup has reached the innermost circumferential position. In addition, when it is determined that the optical pickup is located in the mirror area, the movement direction of the optical pickup is set to the inner peripheral side, and when it is determined that the optical pickup has reached the innermost peripheral position. The moving direction of the optical pickup is set to the outer peripheral side, and the BCA information or NBCA information is read each time the optical pickup is moved in the set moving direction by a predetermined distance. Therefore, even when reading of BCA information or NBCA information fails, the BCA information or NBCA information is read while moving the optical pickup in an appropriate direction. Since it is Rukoto, it is possible to accurately read the BCA information (or NBCA information) with a simple configuration.

  In addition, since it is determined whether or not it is located in the mirror region based on the tracking error signal, it can be determined whether or not it is located in the mirror region with a simple configuration, so that the configuration can be further simplified. BCA information (or NBCA information) can be read accurately.

  Further, when the amplitude of the tracking error signal is equal to or smaller than a predetermined threshold value, it is determined that the tracking error signal is positioned in the mirror area, so it is determined whether or not the tracking error signal is positioned in the mirror area with a simpler configuration. Therefore, the BCA information (or NBCA information) can be accurately read with a simpler configuration.

  In addition, since it is determined that the optical pickup has reached the innermost circumferential position when the detected back electromotive force is equal to or less than a predetermined threshold value set in advance, the optical pickup has a simple configuration and the innermost circumferential position. Therefore, it is possible to accurately read BCA information (or NBCA information) with a simpler configuration.

  Further, since the predetermined distance is set to 0.07 mm or less, the BCA information (or NBCA information) can be read more accurately.

  That is, the position where the BCA or NBCA is formed on the optical disc 2 is 21.3 mm to 22.0 mm for a BD (= Blu-ray Disk) as the distance from the center of the center hole, and 22 for a DVD-ROM. .3mm to 23.5mm, and DVD-R / -RW is defined as 22.71mm to 23.51mm, so the optical pickup was set to 0.07mm (= 22.0mm-21.3mm) or less Since the BCA information or NBCA information is read every time it is moved by a predetermined distance (for example, 0.05 mm), the BCA information (or NBCA information) can be read more accurately.

  According to the optical disk reproducing apparatus of the second aspect, it is determined whether or not the optical pickup is located in a mirror area which is an unrecorded area formed on the outer peripheral side of the BCA or NBCA. Further, the back electromotive force of the sled motor that drives the optical pickup in the radial direction of the optical disk is detected, and it is determined whether or not the optical pickup has reached the innermost circumferential position based on the detected back electromotive force. And when it is determined that the optical pickup is located in the mirror region, the movement direction of the optical pickup is set to the inner peripheral side, and when it is determined that the optical pickup has reached the innermost peripheral position, The moving direction of the optical pickup is set to the outer peripheral side. Further, since the optical pickup is moved by a predetermined distance in the set moving direction, and BCA information or NBCA information is read each time the optical pickup is moved, the BCA information (or NBCA information) can be read with a simple configuration. Information) can be read accurately.

  In other words, since it is determined whether the optical pickup has reached the innermost circumferential position based on the back electromotive force, there is no need to provide a sensor for detecting that the optical pickup has reached the innermost circumferential position. In addition, when it is determined that the optical pickup is located in the mirror area, the movement direction of the optical pickup is set to the inner peripheral side, and when it is determined that the optical pickup has reached the innermost peripheral position. The moving direction of the optical pickup is set to the outer peripheral side, and the BCA information or NBCA information is read each time the optical pickup is moved in the set moving direction by a predetermined distance. Therefore, even when reading of BCA information or NBCA information fails, the BCA information or NBCA information is read while moving the optical pickup in an appropriate direction. Since it is Rukoto, it is possible to accurately read the BCA information (or NBCA information) with a simple configuration.

  According to the optical disk reproducing apparatus of the third aspect, since it is determined whether or not it is located in the mirror area based on the tracking error signal, it is determined whether or not it is located in the mirror area with a simple configuration. Therefore, the BCA information (or NBCA information) can be accurately read with a simpler configuration.

  According to the optical disk reproducing apparatus of the fourth aspect, since it is determined that the tracking error signal is located in the mirror region when the amplitude of the tracking error signal is equal to or smaller than a predetermined threshold value, the configuration is further simplified. Since it can be determined whether or not it is located in the mirror area, the BCA information (or NBCA information) can be accurately read with a simpler configuration.

  According to the optical disk reproducing apparatus of the fifth aspect, since it is determined that the optical pickup has reached the innermost peripheral position when the detected back electromotive force is equal to or less than a predetermined threshold value set in advance, it is simple. Since it can be determined whether or not the optical pickup has reached the innermost peripheral position with a simple configuration, the BCA information (or NBCA information) can be accurately read with a simpler configuration.

  According to the optical disk reproducing apparatus of the sixth aspect, since the predetermined distance is set to 0.07 mm or less, the BCA information (or NBCA information) can be read more accurately.

  That is, the position where the BCA or NBCA is formed on the disc is a distance from the center of the center hole, for example, 21.3 mm to 22.0 mm in BD (= Blu-ray Disk), and in DVD-ROM, Since 22.3 mm to 23.5 mm and DVD-R / -RW are defined as 22.71 mm to 23.51 mm, the optical pickup is set to 0.07 mm (= 22.0 mm-21.3 mm) or less. Since the BCA information or NBCA information is read every time it is moved by a predetermined distance (for example, 0.05 mm), the BCA information (or NBCA information) can be read more accurately.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an example of a DVD player according to the present invention. A DVD player 100 (corresponding to an optical disk playback device) includes an optical pickup 1, an output device 3, a control device 4, a drive device 5, a display unit 6, and an operation unit 7 according to the present invention.

  The optical pickup 1 includes a CD LD (Laser Diode) and a DVD LD, converts reflected light from an optical disc 2 (CD or DVD) to be reproduced into an electric signal, and the optical disc 2 (CD or DVD). Various kinds of information such as audio information and image information stored in is read. The LD for CD irradiates a laser beam that reads information stored on the CD. The LD for DVD irradiates a laser beam that reads information stored on the DVD.

  The optical pickup 1 (corresponding to a part of the first determination unit and a part of the reading execution unit) can be moved in the radial direction and the vertical direction (proximity and separation direction) of the optical disc 2 by the thread motor 51. It is configured. Further, the optical pickup 1 is moved in the vertical direction of the optical disc 2 via the sled motor 51 in accordance with an instruction from the DSP 32, and a focusing error signal and a tracking error signal to the DSP 32 via an RF amplifier 31 described later. Etc. are output.

  The output device 3 converts information such as sound information and image information from the optical pickup 1 into sound and image, and outputs them to a speaker and a monitor (not shown). A digital signal processor (32), a reproduction processing circuit (33), and an output circuit (34).

  The RF amplifier 31 (corresponding to a part of the first determination means and a part of the reading execution means) amplifies a signal corresponding to audio information, image information, etc. from the optical pickup 1, and is a CD LD. Alternatively, a focusing error signal (= FE signal) indicating the amount of deviation of the focal position of the irradiation light from the LD for DVD with respect to the position of the recording surface of the reproduction target optical disc 2 (CD or DVD), and the reproduction target optical disc 2 ( A tracking error signal (= TE signal) indicating the amount of deviation from a track of CD or DVD) is output to the DSP 32.

  The DSP 32 and the reproduction processing circuit 33 perform various information processing (for example, image processing) for reproduction on the signal from the RF amplifier 31. The output circuit 34 performs DA conversion processing or the like to output information from the reproduction processing circuit 33 to a speaker and a monitor (not shown).

  The control device 4 controls the operation of the optical pickup 1 and the drive device 5 based on an instruction operation received via the operation unit 7, and includes a system controller 41 and a driver 42. The system controller 41 receives information from the operation unit 7 and transmits it to the DSP 32, and transmits information from the DSP 32 to the display unit 6. The driver 42 (corresponding to a part of the drive control means) controls the operations of the optical pickup 1 and the drive device 5 based on an instruction from the DSP 32.

  The driving device 5 includes a thread motor 51 and a spindle motor 52. The sled motor 51 is formed of a DC motor or the like, and moves the optical pickup 1 in the radial direction and the vertical direction of the optical disc 2 based on an instruction from the driver 42. The spindle motor 52 is composed of a DC motor or the like, and rotationally drives the optical disc 2 based on an instruction from the driver 42.

  The display unit 6 includes an LCD (Liquid Crystal Display) or the like, and displays information from the DSP 32 so as to be visible from the outside. The operation unit 7 includes various operation buttons and the like, and receives an operation from the user and outputs an operation signal corresponding to the DSP 32.

  FIG. 2 is a functional configuration diagram showing an example of the configuration of the main part of the DVD player 100 according to the present invention. The DSP 32 includes an MPU (Micro Processing Unit), a RAM (Random Access Memory), and an unillustrated ROM (Read Only Memory). The MPU functionally includes a preliminary processing unit 321, a TE detection unit 322, a first determination unit 323, a back electromotive force detection unit 324, a second determination unit 325, a movement direction setting unit 326, a drive control unit 327, and a reading unit. The RAM includes an execution unit 328 and functionally includes a direction storage unit 329.

  Here, the MPU reads and executes a control program stored in advance in a ROM (not shown) or the like, so that the preliminary processing unit 321, the TE detection unit 322, the first determination unit 323, the back electromotive force detection unit 324, 2 functions as a function unit such as a determination unit 325, a movement direction setting unit 326, a drive control unit 327, and a reading execution unit 328, and also functions as a function unit such as a direction storage unit 329.

  Among various data stored in RAM or ROM (not shown), data that can be stored in a removable recording medium is, for example, hard disk drive, optical disk drive, flexible disk drive, silicon disk drive, cassette medium reader, etc. In this case, the recording medium is a hard disk, an optical disk, a flexible disk, a CD, a DVD, a semiconductor memory, or the like.

  The direction storage unit 329 stores the movement direction set by the movement direction setting unit 326. Specifically, the direction storage unit 329 stores a movement direction flag indicating whether the movement direction is a direction moving toward the inner circumference side or a direction moving toward the outer circumference side. For example, when the movement direction flag is “1”, it indicates that the movement direction is the inner circumference side. When the movement direction flag is “0”, the movement direction flag is the movement direction. Is.

  The preliminary processing unit 321 switches the spindle motor 52 to constant voltage drive (or CAV (Constant Angular Velocity) control) via the driver 42 and turns off the tracking servo to move the moving direction of the optical pickup 1 toward the inner circumference side. Initially set in the direction of movement.

  The TE detection unit 322 (corresponding to a part of the first determination means) is a tracking error signal indicating the amount of deviation from the track of the optical disc 2 (CD or DVD) to be reproduced via the optical pickup 1 and the RF amplifier 31. Is detected.

  The first determination unit 323 (corresponding to a part of the first determination unit) determines whether or not the optical pickup is located in a mirror area that is an unrecorded area formed on the outer peripheral side of the BCA or NBCA. Is. Specifically, the first determination unit 323 determines that the position is in the mirror region when the amplitude A of the tracking error signal detected by the TE detection unit 322 is equal to or less than a predetermined threshold ASH set in advance. (See FIG. 3).

  Here, the configuration of the optical disc 2 will be described with reference to FIG. FIG. 6A is an explanatory diagram showing an example of the configuration of the optical disc 2. The optical disc 2 includes a center hole 21, a BCA (or NBCA) 22, a mirror area 23, and a data storage area 24 in order from the inner circumference side. The BCA (or NBCA) 22 is formed between the center hole 21 and the mirror region 23, and barcode information is formed by etching. The mirror area 23 is an unrecorded area formed between the BCA (or NBCA) 22 and the data storage area 24. Since the mirror area 23 is an unrecorded area, the amplitude of the tracking error signal is substantially zero. Therefore, the first determination unit 323 determines that the amplitude A of the tracking error signal is equal to or less than a predetermined threshold ASH set in advance. In addition, it is determined that it is located in the mirror region (see FIG. 3).

  The radial position where the BCA (or NBCA) 22 is formed on the optical disc 2 is a distance from the center of the center hole 21, for example, 21.3 mm to 22 in BD (= Blu-ray Disk). 0.02 mm, 22.3 mm to 23.5 mm for DVD-ROM, and 22.71 mm to 23.51 mm for DVD-R / -RW. Accordingly, as will be described later, every time the drive control unit 327 moves the optical pickup 1 by 0.05 mm in the radial direction and the reading execution unit 328 moves the optical pickup 1 by the drive control unit 327, the BCA information Alternatively, BCA information (or NBCA information) can be accurately read by reading NBCA information.

  Again, the functional configuration of the DSP 32 will be described with reference to FIG. The counter electromotive force detection unit 324 (corresponding to a counter electromotive force detection means) detects the counter electromotive force of the sled motor 51 that drives the optical pickup 1 in the radial direction of the optical disc 2. Specifically, when the optical pickup 1 is moved by a predetermined distance (here, 0.05 mm) by the drive control unit 327, the back electromotive force detection unit 324 is set to a predetermined distance (here, 0.05 mm). The average back electromotive force during the movement is detected.

  A second determination unit 325 (corresponding to a second determination unit) determines whether or not the optical pickup 1 has reached the innermost peripheral position based on the counter electromotive force detected by the counter electromotive force detection unit 324. Is. Specifically, the second determination unit 325 sets the optical pickup 1 to the innermost circumferential position when the back electromotive force V detected by the back electromotive force detection unit 324 is equal to or less than a predetermined threshold value VSH set in advance. It is determined that it has arrived (see FIG. 5).

  That is, even when the optical drive 1 is driven by the drive control unit 327 to move to the inner peripheral side, when the optical pickup 1 reaches the innermost peripheral position, the optical pickup 1 does not move and thus no back electromotive force V is generated. . Therefore, when the back electromotive force V is equal to or less than a predetermined threshold value VSH set in advance, it can be determined that the optical pickup 1 has reached the innermost circumferential position.

  The movement direction setting unit 326 (corresponding to the movement direction setting means) receives light when the first determination unit 323 determines that the optical pickup 1 is located in the mirror region 23 (see FIG. 5A). The moving direction of the pickup 1 is set to the inner peripheral side, and when the second determination unit 325 determines that the optical pickup 1 has reached the innermost peripheral position, the moving direction of the optical pickup 1 is set to the outer peripheral side. To do. Further, when the movement direction is set to the inner circumference side, the movement direction setting unit 326 stores the movement direction flag as “1” in the direction storage unit 329, and when the movement direction is set to the outer circumference side, The flag is stored in the direction storage unit 329 as “0”.

  Further, each time the moving direction is changed, the moving direction setting unit 326 counts up the counter RTN that counts the number of retries, and the value of the counter RTN is equal to or greater than a preset number (for example, 10 times). Then, it is determined that the BCA information (or NBCA information) cannot be read (= an error has occurred), and the drive control unit 327 moves the optical pickup 1 and the reading execution unit 328 reads the BCA information (or NBCA information). Is to end.

  The drive control unit 327 (corresponding to a part of the drive control means) sets the optical pickup 1 in a predetermined distance in the movement direction set by the movement direction setting unit 326 via the driver 42 and the sled motor 51. It is moved by L (here, L = 0.05 mm).

  A reading execution unit 328 (corresponding to a part of the reading execution unit) reads BCA information or NBCA information each time the optical pickup 1 is moved by the drive control unit 327. Specifically, the reading execution unit 328 detects an RF missing signal (hereinafter referred to as a defect signal) and reads BCA (or NBCA) information. Here, the defect signal is usually a Lo level, and is a signal that outputs a High level at a point where reflection from the optical disc 2 is lost due to dirt or the like.

  FIG. 5B is a diagram illustrating an example of the defect signal. As shown in the figure, the defect signal is output as a high level at a location corresponding to a barcode in BCA (or NBCA).

  3 and 4 are flowcharts showing an example of the operation of the DVD player 100 (mainly DSP 32) according to the present invention. First, the preliminary processing unit 321 switches the spindle motor 52 to constant voltage driving (S101). Then, the tracking servo is turned off by the preliminary processing unit 321 (S103). Next, the preliminary processing unit 321 initializes the movement direction of the optical pickup 1 in the direction in which it moves toward the inner circumference (= the movement direction flag stored in the direction storage unit 329 is set to “1”) (S105).

  Next, the optical pickup 1 is moved to the inner peripheral side by the drive control unit 327, and the tracking error signal is detected by the TE detection unit 322 (S107). Then, the first determination unit 323 determines whether or not the amplitude A of the tracking error signal detected in step S107 is equal to or smaller than a predetermined threshold value ASH (S109). If it is determined that it is not equal to or lower than the threshold ASH (NO in S109), the process returns to step S107, and the processes after step S107 are repeatedly executed.

  When it is determined that the value is equal to or less than the threshold ASH (YES in S109), the movement direction setting unit 326 initializes the value of the counter RTN for counting the number of retries to 0 (S111). Then, the defect signal is detected by the reading execution unit 328 (S113). Next, the reading execution unit 328 determines whether or not the BCA (or NBCA) has been reached based on the defect signal detected in step S113 (S115). If it is determined that BCA (or NBCA) has not been reached (NO in S115), the process proceeds to step S125 shown in FIG.

  If it is determined that the BCA (or NBCA) has been reached (YES in S115), the reading execution unit 328 reads the BCA information (or NBCA information) (S117). Then, the reading execution unit 328 determines whether or not the reading in step S117 is successful (S119). If it is determined that the reading is successful (YES in S119), the movement direction setting unit 326 determines whether the value of the counter RTN is 10 or more (= whether the number of retries is 10 or more). Is determined (S121). When it is determined that the value of the counter RTN is 10 or more (YES in S121), the movement direction setting unit 326 determines that an error has occurred (S123), and the process ends. If it is determined that the value of the counter RTN is not 10 or more (= 9 or less) (NO in S121), the process proceeds to step S125 shown in FIG.

  If NO in step S115 or NO in step S121, as shown in FIG. 4, the optical pickup 1 is moved in the direction indicated by the movement direction flag stored in the direction storage unit 329 by the drive control unit 327. , 0.05 mm is moved (S125). Then, the second determination unit 325 determines whether or not the direction indicated by the movement direction flag stored in the direction storage unit 329 is the inner peripheral side (S127).

  If it is determined that the direction is on the inner peripheral side (YES in S127), the counter electromotive force of the sled motor 51 is detected by the counter electromotive force detection unit 324 (S129). Then, the second determination unit 325 determines whether or not the back electromotive force V is equal to or less than a predetermined threshold value VSH (S131). If it is determined that it is not less than or equal to the predetermined threshold VSH (= exceeds the predetermined threshold VSH) (NO in S131), the process returns to step S113 shown in FIG. 3, and the processes after step S113 are repeatedly executed. Is done. When it is determined that it is equal to or less than the predetermined threshold value VSH (NO in S131), the movement direction setting unit 326 sets the movement direction of the optical pickup 1 to the outer peripheral side, and the movement direction stored in the direction storage unit 329 is stored. The flag is set to “0” (S133). Then, the movement direction setting unit 326 increments the value of the counter RTN by 1 (S135), the process returns to step S113 shown in FIG. 3, and the processes after step S113 are repeatedly executed.

  If NO in step S127, the TE detection unit 322 detects a tracking error signal (S137). Then, the first determination unit 323 determines whether or not the amplitude A of the tracking error signal detected in step S137 is equal to or smaller than a predetermined threshold value ASH (S139). If it is determined that the amplitude A is not equal to or smaller than the predetermined threshold ASH (= greater than the predetermined threshold ASH) (NO in S139), the process returns to step S113 shown in FIG. Is repeatedly executed. When it is determined that the amplitude A is equal to or smaller than the predetermined threshold ASH (YES in S139), the movement direction setting unit 326 sets the movement direction of the optical pickup 1 to the inner peripheral side and stores it in the direction storage unit 329. The moved direction flag is set to “1” (S141). Then, the movement direction setting unit 326 increments the value of the counter RTN by 1 (S143), the process is returned to step S113 shown in FIG. 3, and the processes after step S113 are repeatedly executed.

  In this way, it is determined whether or not the optical pickup 1 is located in the mirror area 23 (see FIG. 5A) that is an unrecorded area formed on the outer peripheral side of the BCA (or NBCA) 22. . Further, the back electromotive force V of the sled motor 51 that drives the optical pickup 1 in the radial direction of the optical disc is detected, and whether or not the optical pickup 1 has reached the innermost peripheral position based on the detected back electromotive force V. Is determined. When it is determined that the optical pickup 1 is located in the mirror region 23, the movement direction of the optical pickup 1 is set to the inner peripheral side, and it is determined that the optical pickup 1 has reached the innermost peripheral position. In this case, the moving direction of the optical pickup 1 is set to the outer peripheral side. Further, since the optical pickup 1 is moved in the set moving direction by a predetermined distance (here, 0.05 mm), BCA information or NBCA information is read each time the optical pickup 1 is moved. The BCA information (or NBCA information) can be accurately read with a simple configuration.

  That is, since it is determined whether or not the optical pickup 1 has reached the innermost circumferential position based on the back electromotive force V, a sensor that detects that the optical pickup 1 has reached the innermost circumferential position is provided. When it is determined that the optical pickup 1 is located in the mirror region 23, the moving direction of the optical pickup 1 is set to the inner peripheral side, and the optical pickup 1 reaches the innermost peripheral position. When it is determined that the optical pickup 1 is moved to the outer peripheral side, the optical pickup 1 is moved in the set movement direction by a predetermined distance (here, 0.05 mm), Since BCA information or NBCA information is read each time the optical pickup 1 is moved, the optical pickup 1 can be used in an appropriate manner even when reading of the BCA information or NBCA information fails. It is possible to read the BCA information or NBCA information while moving in, it is possible to accurately read the BCA information (or NBCA information) with a simple configuration.

  Further, since it is determined based on the tracking error signal whether or not it is located in the mirror region 23, it is possible to determine whether or not it is located in the mirror region 23 with a simple configuration. With the configuration, BCA information (or NBCA information) can be read accurately.

  Furthermore, since it is determined that the tracking error signal is located in the mirror region 23 when the amplitude A of the tracking error signal is equal to or smaller than a predetermined threshold value ASH set in advance, is it positioned in the mirror region 23 with a simpler configuration? Therefore, it is possible to accurately read the BCA information (or NBCA information) with a simpler configuration.

  In addition, when the detected back electromotive force V is equal to or less than a predetermined threshold value VSH set in advance, it is determined that the optical pickup has reached the innermost circumferential position. Since it can be determined whether or not the inner circumferential position has been reached, BCA information (or NBCA information) can be accurately read with a simpler configuration.

  Further, since the predetermined distance L is set to 0.07 mm or less, the BCA information (or NBCA information) can be read more accurately.

  That is, the position where the BCA (or NBCA) 22 is formed on the optical disc 2 is a distance from the center of the center hole 21 in the BD (= Blu-ray Disk), 21.3 mm to 22.0 mm, DVD- In ROM, it is specified as 22.3 mm to 23.5 mm, and in DVD-R / -RW, it is specified as 22.71 mm to 23.51 mm (see FIG. 5A), so that the optical pickup is 0.07 mm (= 22). .0mm-21.3mm) BCA information or NBCA information is read each time it is moved by a predetermined distance (0.05mm in this case), so that BCA information (or NBCA information) is read more accurately. Can do it.

The present invention can also be applied to the following forms.
(A) In the present embodiment, the case where the optical pickup 1 has two light sources (= CD LD and DVD LD) has been described. However, the optical pickup 1 may have one light source, The form in which the pickup 1 has three or more light sources may be used. For example, the optical pickup 1 may include a BD (Blu-ray Disk) LD in addition to the CD LD and the DVD LD.

  (B) In the present embodiment, the DSP 32 includes a preliminary processing unit 321, a TE detection unit 322, a first determination unit 323, a back electromotive force detection unit 324, a second determination unit 325, a movement direction setting unit 326, a drive control unit 327, Although the case where a functional unit such as the reading execution unit 328 is provided has been described, the TE detection unit 322, the first determination unit 323, the back electromotive force detection unit 324, the second determination unit 325, the movement direction setting unit 326, and the drive control unit 327 Further, at least one functional unit of the reading execution unit 328 may be realized by hardware such as a circuit.

  (C) In the present embodiment, a case has been described in which it is determined whether or not the first determination unit 323 is located in the mirror region 23 (see FIG. 5A) based on the tracking error signal. It may be configured to determine whether the unit 323 is located in the mirror region 23 based on other signals (for example, a focusing error signal or the like).

  (D) In this embodiment, the case where the drive control unit 327 moves the optical pickup 1 by 0.05 mm has been described. However, the drive control unit 327 sets the optical pickup 1 in advance, and the predetermined distance L is 0.07 mm or less. It is only necessary to have a form that only moves. For example, the drive control unit 327 may move the optical pickup 1 by 0.03 mm. As the predetermined distance L is smaller, the BCA information (or NBCA information) can be read more accurately.

These are the block diagrams which show an example of the DVD player based on this invention. These are functional block diagrams showing an example of the configuration of the main part of the DVD player according to the present invention. These are flowcharts (first half) which show an example of operation | movement of the DVD player (mainly DSP) based on this invention. These are the flowcharts (latter half part) which show an example of operation | movement of the DVD player (mainly DSP) based on this invention. These are explanatory drawings which show an example of a structure of an optical disk.

Explanation of symbols

100 DVD player (optical disk playback device)
1 Optical pickup (part of first determination means, part of reading execution means)
2 Optical disc 21 Center hall 22 BCA (NBCA)
23 Mirror area 24 Data storage area 3 Output device 31 RF amplifier (part of the first determination means, part of the reading execution means)
32 DSP
321 Preliminary processing unit 322 TE detection unit (part of first determination means)
323 1st determination part (a part of 1st determination means)
324 Back electromotive force detection unit (back electromotive force detection means)
325 Second determination unit (second determination means)
326 Movement direction setting section (movement direction setting means)
327 Drive control unit (part of drive control means)
328 Reading execution unit (part of reading execution means)
329 Direction storage unit 4 Control device 42 Driver (part of drive control means)
5 Drive device 51 Thread motor 52 Spindle motor

Claims (6)

An optical disc playback apparatus that reads and plays back BCA (Burst Cutting Area) information or NBCA (Narrow Burst Cutting Area) information stored on an optical disc,
First determination means for determining whether or not the optical pickup is located in a mirror area which is an unrecorded area formed on the outer peripheral side of BCA or NBCA;
Back electromotive force detection means for detecting a back electromotive force of a sled motor that drives the optical pickup in the radial direction of the optical disc;
Based on the counter electromotive force detected by the counter electromotive force detection means, second determination means for determining whether or not the optical pickup has reached the innermost circumferential position;
When the first determination means determines that the optical pickup is located in the mirror region, the movement direction of the optical pickup is set to the inner peripheral side, and the optical pickup is moved to the innermost periphery by the second determination means. A moving direction setting means for setting the moving direction of the optical pickup to the outer peripheral side when it is determined that the position has been reached;
Drive control means for moving the optical pickup by a predetermined distance in the movement direction set by the movement direction setting means;
Read execution means for reading BCA information or NBCA information each time the optical pickup is moved by the drive control means;
With
The first determination unit determines that the tracking error signal is located in the mirror region when the amplitude of the tracking error signal is equal to or less than a predetermined threshold value set in advance.
The second determining means determines that the optical pickup has reached the innermost circumferential position when the counter electromotive force detected by the counter electromotive force detecting means is not more than a predetermined threshold value set in advance.
The optical disc reproducing apparatus, wherein the predetermined distance is set to 0.07 mm or less. An optical disc playback apparatus that reads and plays back BCA (Burst Cutting Area) information or NBCA (Narrow Burst Cutting Area) information stored on an optical disc,
First determination means for determining whether or not the optical pickup is located in a mirror area which is an unrecorded area formed on the outer peripheral side of BCA or NBCA;
Back electromotive force detection means for detecting a back electromotive force of a sled motor that drives the optical pickup in the radial direction of the optical disc;
Based on the counter electromotive force detected by the counter electromotive force detection means, second determination means for determining whether or not the optical pickup has reached the innermost circumferential position;
When the first determination means determines that the optical pickup is located in the mirror region, the movement direction of the optical pickup is set to the inner peripheral side, and the optical pickup is moved to the innermost periphery by the second determination means. A moving direction setting means for setting the moving direction of the optical pickup to the outer peripheral side when it is determined that the position has been reached;
Drive control means for moving the optical pickup by a predetermined distance in the movement direction set by the movement direction setting means;
Read execution means for reading BCA information or NBCA information each time the optical pickup is moved by the drive control means;
An optical disc reproducing apparatus comprising:   3. The optical disc reproducing apparatus according to claim 2, wherein the first determination unit determines whether or not the first determination unit is located in a mirror area based on a tracking error signal.   4. The optical disc reproducing apparatus according to claim 3, wherein the first determination unit determines that the tracking error signal is located in the mirror area when the amplitude of the tracking error signal is equal to or less than a predetermined threshold value set in advance. .   The second determination unit determines that the optical pickup has reached the innermost circumferential position when the counter electromotive force detected by the counter electromotive force detection unit is equal to or less than a predetermined threshold value set in advance. An optical disk reproducing apparatus according to any one of claims 2 to 4.   6. The optical disk reproducing apparatus according to claim 2, wherein the predetermined distance is set to 0.07 mm or less.

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