JP6480799B2 - Optical disk device - Google Patents

Description

  Embodiments described herein relate generally to an optical disc apparatus that avoids repeated search errors when performing a search operation for tracking on and jumping to a desired track.

  In the optical disc apparatus, when reading the target recording data, it is necessary to execute a search operation to move the pickup to the target data area.

  Since this search operation needs to cross tracks in the disk, the recording data is read by turning off the tracking servo once, reaching the target track, and then turning on the tracking servo again.

  However, when the tracking servo is turned on again in the search operation, the tracking servo signal (abbreviated as TE signal), which is a control signal, may not be turned on.

  In such a case, the tracking servo can be easily turned on by monitoring the frequency of the TE signal used for the tracking servo and performing an on process at a point where the frequency becomes slow. Thereafter, a retry process for restarting the search operation and moving to the target track is executed.

  However, (1) the tracking-on position after failure of tracking-on is likely to be the same position every time because the frequency of the TE signal is monitored and turned on. (2) Software processing up to search processing after tracking-on The time from tracking on to the start of search is almost the same every time. (3) In the retry operation, the number of jumps is usually the same and the search time is fixed. The operation is performed at the same position and at the same timing.

  For this reason, even if the retry process is executed up to a predetermined number of times, there is a problem that the tracking servo cannot be turned on and an error occurs and a search error occurs continuously. Such inconvenience is remarkable when, for example, the diameter of the center hole of the disk is due to a disk having a standard tolerance.

JP 2005-276257 A JP 2009-129499 A

  The problem to be solved by the present invention is to provide an optical disc apparatus capable of reliably tracking on a desired track in a search operation.

The optical disc apparatus according to the embodiment includes a moving unit that moves the optical pickup along a direction perpendicular to the recording surface of the storage medium with respect to a disc-shaped storage medium having a plurality of tracks concentrically or spirally, An optical disc apparatus that performs focus search by the moving means and reads information by emitting laser light from an optical pickup, and after a search process to the desired track position of the storage medium fails, when retrying the search process, It provided a predetermined waiting time before starting the jump of the optical pickup for the search process, a control unit to start the jumping operation of the optical pickup after the waiting time, the waiting time, the storage medium When set to the length of time that a quarter turn.

It is a figure which shows the structural example of the optical disk apparatus which concerns on embodiment of this invention. It is a figure explaining the search process which concerns on this embodiment. 5 is a flowchart showing a flow of search processing in the optical disc apparatus according to the present embodiment.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a configuration example of an optical disc apparatus according to an embodiment of the present invention. As shown in FIG. 1, in the optical disc apparatus 100, the optical disc 1 is rotated by a spindle motor 2 and a driver circuit 3. The light emitted from the laser diode 5 mounted on the optical pickup unit 4 passes through the beam splitter 6 and the spherical aberration correction mechanism 7 and is condensed on the data recording surface on the optical disc 1 by the objective lens 8.

  Then, the light condensed on the optical disk 1 is reflected by the data recording surface, and the reflected light passes through the objective lens 8, the spherical aberration correction mechanism 7, and the beam splitter 6 again, enters the light receiving element 9, and is converted into an electric signal. Is done. An electrical signal output from the light receiving element 9 is input to the control unit 10. The control unit 10 processes the input signal, communicates with an externally connected device through the interface 11, and feeds back to the driver circuit 3 to control the spindle motor 2, the optical pickup unit 4, and the stepping motor 12. . Further, as will be described later, the control unit 10 also controls search processing for jumping to a desired track.

  In this embodiment, when tracking-on cannot be performed in the search process, search errors are prevented from occurring continuously. The optical disk device according to the present embodiment is suitable for, for example, a so-called low voltage drive with a power supply voltage of 7V and a drive voltage of 5V or less.

<Search processing>
Next, search processing in the optical disc apparatus configured as described above will be described. FIG. 2 is a diagram for explaining search processing according to the present embodiment. 2A shows the relationship between the amplitude level of the control signal (TE signal) and the rotational position of the disk, and FIG. 2B shows the jump start position and jump end position on the disk in the search. It is a figure explaining.

  The control signal (TE signal) is a signal in which an error generated between the pits on the disk and the laser beam is detected, and is generated by adding and amplifying the signal output from the pickup. In order to stably follow (track) the laser light to the pit, the tracking servo is stabilized by adjusting the amplification amount so as to obtain the target control signal (TE signal) amplitude. The frequency of the control signal (TE signal) can be obtained from the track crossing period.

  An example will be described in which the rotation period of the disk is 20 msec (50 Hz), that is, 90 ° rotation at 5 msec. If it takes 5 msec to jump 10 tracks in the search process, the jump starts from the starting point A, and the jump end position is a position B of 90 ° in terms of the rotation angle of the disc.

  Since the disk position and the amplitude level of the control signal (TE signal) are fixed, if the jump start position is the same position on the disk every time the search process is performed, the jump end position is also the same position, and the control signal (TE If the jump ends when the signal level is small (for example, at position B), the search error is repeated.

  Therefore, in this embodiment, in order to prevent the jump start position in the search process from being repeated at the same position with respect to the position of the disk, tracking is turned on at the time of retry and a jump for the search operation is started. A predetermined waiting time is provided before starting the jump operation, and the jump operation is started after the waiting time has elapsed. For example, if the period of one rotation of the disk is 20 msec, the standby time is preferably 5 msec for ¼ rotation (90 ° rotation) of the disk.

  During the jump, the tracking signal is turned off, and after the jump, the pickup is located at a position where the frequency is low and the amplitude level of the control signal (TE signal) is large and tracking is easily performed (for example, position C).

  It is preferable to change the value of the standby time for each retry when tracking-on cannot be performed. For example, the waiting time for the second retry is 10 msec for the disk being halved (180 ° rotation), and the waiting time for the third retry is the ¾ rotation (270 ° rotation) for the disc. Change to 15 msec. As a result, the jump start position, that is, the tracking on position is changed by changing the timing at each retry, and the probability of encountering a position where the control signal (TE signal) has a large amplitude level and a low frequency is easily detected. Therefore, it is possible to prevent search errors from occurring continuously.

  FIG. 3 is a flowchart showing the flow of search processing in the optical disc apparatus according to the present embodiment.

  First, when the search process is started, the number of jumps is set (step S31). Here, the number of jumps is the number of tracks crossing from the starting point on the disk to the desired track position. Here, the starting point is, for example, the position of the origin of the pickup. The desired track position is a location where data reading is set by the user.

  Next, a jump process is executed to turn on the desired track position (step S32).

  Subsequently, it is determined whether or not tracking-on is OK (step S33).

  If tracking on fails (No in step S33), the retry counter is incremented by one (step S34).

  Next, it is determined whether or not the number of retries is greater than a predetermined number N (step S35). Here, N can be arbitrarily set. For example, N = 3.

  If the number of retries is greater than the predetermined number N (Yes in step S35), the search process is stopped as an error (step S38).

  On the other hand, when the number of retries is not greater than the predetermined number N (No in step S35), a standby time timer is set (step S36). For example, it is set to 5 msec.

  Next, it is determined whether or not the standby time timer has become zero (step S37).

  If the standby time timer is not zero (No in step S37), the process returns to step S37, and if the standby time timer becomes zero (Yes in step S37), the process proceeds to step S32.

  On the other hand, if the tracking-on is successful (Yes in step S33), the process proceeds to a data reading process after the search process.

  According to the present embodiment, it is possible to prevent a search error from being repeated, to reliably perform tracking-on to a desired track, and to avoid a stop due to a search error. In particular, in a drive mechanism driven at a low voltage, it is difficult to set a large control gain, and an error is likely to occur if the control signal is small, which is effective in avoiding repeated search errors.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 1 ... Optical disk 2 ... Spindle motor 3 ... Driver circuit 4 ... Optical pick-up unit 5 ... Laser diode 6 ... Beam splitter 7 ... Spherical aberration correction mechanism 8 ... Objective lens DESCRIPTION OF SYMBOLS 9 ... Light receiving element 10 ... Control part 11 ... Interface 12 ... Stepping motor 100 ... Optical disk apparatus

Claims (6)

For a disk-shaped storage medium having a plurality of concentric or spiral tracks, the optical pickup is moved along a direction perpendicular to the recording surface of the storage medium, and a focus search is performed by the moving means. An optical disk device for reading information by emitting laser light from an optical pickup,
After the search process to the desired track position of the storage medium fails, when retrying the search process, a predetermined standby time is provided before the jump of the optical pickup for the search process is started, and after the standby time has elapsed A control unit for starting a jump operation of the optical pickup ;
The waiting time is, the optical disk apparatus to set the length of time during which the storage medium is 1/4 turn. The controller is
A tracking error signal, which is a control signal, is monitored during rotation of the storage medium, and the standby time is set so that the jump operation of the optical pickup ends at a location where the frequency is low and the amplitude level of the tracking error signal is large. Item 4. The optical disk device according to Item 1. At the time of the second retry, the waiting time is set to the length of time for which the storage medium rotates 1/2, and at the time of the third retry, the waiting time is set to the length of time for which the storage medium rotates by 3/4. The optical disc apparatus according to claim 1 or 2 . The optical disc apparatus according to claim 2 , wherein the tracking error signal is turned off during the jump operation of the optical pickup. The optical disk apparatus according to any one of claims 1 to 4 , wherein the diameter of the center hole of the storage medium is substantially equal to a standard tolerance of the storage medium. Driving voltage, an optical disk apparatus according to any one of claims 1 to 5 is of the following low voltage 5V.

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