JP2013229076A - Optical disk device and optical disk read method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent an optical disk from colliding and so on while maintaining fast actuation.SOLUTION: When it is determined in steps 24, 26 that the medium type of an optical disk which is temporarily positioned first through temporary positioning processing is wrong, the processing does not proceed to a step 28 to inhibit a focus-on operation and after the type of a laser light source for reading is changed in a step 32 in retry processing, a focus search is made in a step 36 utilizing a laser light source to count the number of S shapes. The count result is stored and the processing returns to the focus-ono operation processing again to initiate the focus-on operation including error determination.

Description

  The present invention relates to an optical disc apparatus and an optical disc reading method for reading an optical disc using a plurality of types of laser light sources.

There are a plurality of types of optical disk media. When an optical disk is read, the setting must be set according to the type. One that uses the number of so-called S-characters when determining the medium type of an optical disc is known.
Japanese Patent Application Laid-Open No. 2004-228561 discloses a technique for determining whether or not an optical disc is mounted correctly by detecting an S-shaped curve of an FE signal.
Patent Document 2 discloses a technique for discriminating the type of an optical disk by counting the number and the time of S-curves of the FE signal.

Patent Document 3 discloses a technique for determining the type of an optical disc by performing a focus search.
Patent Document 4 discloses a technique for identifying an optical disc from a drive value when an S-shaped signal appears.
Patent Document 5 discloses a technique for detecting the number of recording layers of an optical disc using a focus S-shaped signal.
These publications disclose techniques for using the S-shaped signal of the FE signal to identify an optical disc.

  Patent Document 6 is known as a disclosure of collision prevention. Patent Document 6 discloses a technique for preventing a collision between an objective lens and an optical disc apparatus caused by discriminating a disc type.

JP 2007-026580 A JP 2007-095144 A JP 2009-059401 A JP 2011-076684 A JP 2009-070486 A JP 2006-1114086 A

  When playing back (reading) an optical disc, it takes a very long time to try to read with the settings according to the media type of all optical discs as an initial setting and to discriminate the same type. Therefore, discriminating an optical disk by taking this step every time reading is forced to make the user wait for each time, and lacks usability as a product. That is, for a high-speed start-up, the complete optical disc medium type is not determined at the start-up.

  The present invention provides an optical disc apparatus and an optical disc reading method for preventing collision of optical discs while maintaining high-speed startup.

  The present invention is capable of using a plurality of types of laser light sources, and first performs a focus search and provisionally determines the medium type of the optical disk, and then executes focus-on on the premise of the medium type of the optical disk determined in the same manner. If the media type of the optical disc that was initially determined is incorrect, the focus-on operation is prohibited, the type of the laser light source is changed, a focus search is performed using the laser light source, and an S-shape is obtained. The configuration is such that the number is counted, the result of the count is stored, and the focus on operation is performed again.

  In the above configuration, the focus search is first performed and the medium type of the optical disk is provisionally determined, and then the focus-on is executed on the premise of the medium type of the optical disk that is provisionally determined. However, since the provisional decision is not always correct, the focus-on operation is prohibited when the medium type of the optical disc that is initially decided is incorrect. After that, the type of the laser light source is changed, a focus search is performed using the laser light source, the number of S-characters is counted, the result of the count is stored, and the focus on operation is performed again.

  According to the present invention, the focus-on operation is not performed with an incorrect setting, and a complete medium type determination is not performed, so that a request for high-speed activation can be met.

1 is a schematic block diagram of an optical disc device. It is a flowchart of the starting program which this optical disk apparatus performs. It is a wave form diagram of the FE signal at the time of a focus search.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing an optical disc apparatus according to an embodiment of the present invention.
In the figure, the disc device 10 can read each optical disc of Blu-ray disc, DVD and CD. Depending on the medium type of each optical disc, the type and amount of light of the laser light source are different, and it is necessary to pass a predetermined setting. In this embodiment, the type and amount of light of the laser light source can be changed. In this sense, it can be said that a plurality of types of laser light sources can be used.
The disk device 10 includes an optical pickup 12 provided with an optical lens 14. The optical lens 14 is supported by the tracking actuator 16 and the focus actuator 18, and laser light having a desired type and a desired amount of light emitted from the laser light source 20 is converged by the optical lens 14 and recorded on the optical disk 38. The surface is irradiated. The optical pickup 12 is moved in the radial direction of the optical disk 38 by the thread motor 36.

  Reflected light from the optical disk surface passes through the same optical lens and enters the photodetector 22. The output of the photodetector 22 is input to a TE signal detection circuit 24 and an FE signal detection circuit 26, and a TE signal (tracking error signal) and an FE signal (focus error signal) are detected respectively. The detected TE signal and FE signal are respectively input to A / D converters 30a and 30b provided in a DSP (Digital Signal Processor).

On the other hand, the optical disk 38 is mounted on the spindle 40 and is rotated by the spindle motor 42. The spindle motor 42 generates an FG signal related to the rotational speed, and this FG signal is input to the A / D converter 30c of the DSP 28.
The TE signal, the FE signal, and the FG signal input to the A / D converters 30a to 30c in this way are converted into digital signals and then input to the DSP core 32. The DSP core 32 executes tracking servo processing based on the TE signal, performs focus servo processing based on the FE signal, and executes spindle servo processing based on the FG signal.

  A tracking actuator control signal and a thread control signal are generated by the tracking servo process, and corresponding PWM signals are output to the tracking actuator 16 and the thread motor 36 from the PWM drivers 34a and 34c. Further, a focus actuator control signal is generated by the focus servo process, and a corresponding PWM signal is output from the PWM driver 34 b to the focus actuator 18. Further, a spindle motor control signal is generated by the spindle servo process, and a corresponding PWM signal is output from the PWM driver 34d to the spindle motor 42.

  Thus, the TE servo detection circuit 24, the DSP 28, the tracking actuator 16, and the sled motor 36 form a tracking servo system, and the tracking of the optical lens 14 is appropriately controlled based on the TE signal. Further, a focus servo system is formed by the FE signal detection circuit 26, the DSP 28, and the focus actuator 18, and the focus of the optical lens 14 is appropriately controlled based on the FE signal. Further, a spindle servo system is formed by the spindle motor 42 and the DSP 28, and the rotation speed of the spindle 40, that is, the optical disk 38 is appropriately controlled based on the FG signal. As a result, a desired type of laser light output from the laser light source 20 is irradiated to a desired track with a desired light amount, irradiated to the disk surface, reflected, and recorded data can be read from the reflected signal.

The DSP 28 executes software processing shown in FIG. 2 in addition to the servo processing described above.
FIG. 2 is a flowchart of a startup program executed by the optical disc apparatus.
This program is roughly divided into a Blu-ray Disc (BD), DVD or CD provisional decision process (temporary decision means, provisional decision step), and focus on operation process (focus on function, focus on step and focus on operation step). ) And retry processing (retry function, retry step). Then, after executing the first provisional determination process, the focus-on operation process is performed. However, if the tentative decision is determined to be an erroneous determination in the focus-on operation process, the retry process is executed, and the focus-on operation process is executed again.

In the first provisional decision process, laser light is emitted in step 10 (denoted as S10; hereinafter the same), focus search is executed (focus search function) in step 12, and S-shaped characters are counted during that time.
FIG. 3 shows a waveform diagram of the FE signal during focus search.
The focus search is performed based on the change in the FE signal while changing the focus position in a state where the laser light is emitted. When the focus position is changed by the focus actuator 18, the reflected light of the laser beam is input to the photodetector 22, and the FE signal detection circuit 26 outputs the FE signal based on the output signal. This FE signal changes so as to cross a predetermined threshold before and after the focal point of the laser beam coincides with a desired recording surface.

This change point is the focal position, and is called an S-shape because of the change shape of the FE signal before and after that. As described above, the S-shaped waveform has a maximum value and a minimum value sandwiching a predetermined threshold value from the change of the FE signal based on the reflected light from the optical disc while changing the focus position in a state where the laser beam is irradiated. A waveform having a value. The detection of the number of waveforms corresponds to the process of counting S-characters.
In the case of a single disc, S-shaped characters may appear at three points: the surface, the recording layer, and the label surface. Since the signal change may be weak on the surface or label surface, it is 3 points or less and 1 point or more. In the case of two-layer recording, since there are two recording layers, the number of points is 4 or less and 2 or more even if the surface and the label surface are taken into account. In the case of a Blu-ray disc of the BD-XL standard, since there are three or four recording layers, the S-shape is 6 points or less and 3 points or more.

In step 14, it is determined whether or not a disk is to be determined. This determination of the disk is basically only a process for determining the medium type of the disk determined in advance, and there is no process for determining the medium type of the disk. Of course, a very simple determination process is performed, and only when the determination process clearly reveals that the medium type of the default disk is not clear, return to step 10 to emit laser light based on the medium type of another disk. Focus search may be performed.
Through the above processing, the medium type of the default optical disc is usually temporarily determined, and the number of S-characters is stored as the result of executing the focus search.

In the focus-on operation process, an operation of focusing on the recording layer is performed in order to read the recording data of the optical disk 38 loaded with the spindle 40. First, the disk is rotated at step 20, the FE signal is adjusted at step 22, and preparation for execution of focus-on at step 28 is completed. However, before executing Step 28, before executing Step 28, Step 24 and Step 26 perform error determination based on the number of S-characters.
The disk device may record the number of S-characters corresponding to the medium type of the optical disk in advance in the lookup table. This makes it possible to determine at a high speed whether or not the media type of the optical disc that has been provisionally determined is correct. Further, when the media type of the optical disc is expanded, the lookup table may be updated. Will improve.

In step 24, it is determined whether the number of S-characters is zero. As described above, as long as there is a recording layer, at least the number of S-characters should be one or more. Therefore, if the number of S-characters is 0, it is considered that the setting of the laser light source when the focus search is executed is incorrect. That means that the medium type of the temporarily determined optical disk is incorrect (determined that the medium type of the temporarily determined optical disk is NO).
That is, based on the number of waveforms (S-characters) detected in this way, it can be said that the correctness of the medium type of the optical disk provisionally determined previously can be determined, and a determination means is realized.
Of course, since the medium type of the optical disk is tentatively determined according to a predetermined order for high-speed startup, it is assumed that such an erroneous determination occurs, and a retry process is prepared as a manifestation thereof.
In step 26, if the media type of the optical disc that is provisionally determined is a Blu-ray disc of the BD-XL standard, the number of S-characters should be 3 or more as described above, and the number of S-characters stored is 2. If the number is less than or equal to the number, the medium type of the temporarily determined optical disk is incorrect.
In other words, in this case, the determination that the medium type of the optical disk is the BD-XL standard Blu-ray disk is determined to be NO based on the detection result that the number of S-characters is two or less. Thus, the determination means is realized. Although it is limited, it can be said that the correctness of the media type of the temporarily determined optical disc is determined based on the number of detected waveforms and the media type of the temporarily determined optical disc.
Further, when the provisionally decided is the BD-XL standard, if the number of S-characters is 5 or more, it can be determined that the provisional decision is correct. That is, it can be said that the determination means determines that the medium type of the temporarily determined optical disk is positive when the number of detected waveforms is the number corresponding to the medium type of the temporarily determined optical disk.
As described above, by arranging the combinations that can be determined as a lookup table, there may be a case where the determination of provisional determination can be made based on the number of waveforms and the medium type that has been provisionally determined. is there.

  As described above, if it is found that the medium type of the optical disk provisionally determined in any of the determinations is incorrect, the retry process is executed without executing the focus-on execution in step 28. Note that executing the retry process without executing the focus-on execution means that the focus-on execution in step 28 is not performed. In this sense, it can be said that “the focus-on operation is prohibited”. Of course, it is also possible to provide a flag when the processes are parallel, and to give this flag a function indicating permission and prohibition of the focus-on operation, and to set a value indicating prohibition to the flag.

  In the retry process, in steps 30 to 36, after the focus-on operation is prohibited, the spin-down is performed, and the focus search is performed after changing the setting of the laser light source. In step 30, the rotation of the optical disk is stopped (spun down), and the rotation of the optical disk 38 on the spindle 40 is stopped. In step 32, the disk type (medium type of the optical disk) is switched. This is one of the processes of changing the medium type of the optical disc in accordance with a predetermined order. For example, it is assumed that the order of normal Blu-ray disc, BD-XL standard Blu-ray disc, DVD, CD is set. Since both of the first two are Blu-ray discs, there may be differences in the desired light quantity while keeping the same laser light source. The third and fourth are DVD and CD, and the light source is common, but the amount of light is different. Since the amount of light differs from the laser light source corresponding to the medium type of the optical disk in this way, the process of setting the one that matches the medium type of the optical disk in this order is the process of switching the disk type (medium type of the optical disk) in step 32. Equivalent to. In other words, the number of provisional changes may be counted, and the combination of the laser light source type and the light amount corresponding to the medium type of the optical disk stored separately may be read and set using the number of changes as an argument.

In step 34, laser light is emitted corresponding to the medium type of the optical disk temporarily determined in this way, and in step 36, the focus search is performed as described above. Then, the counted number of S-characters is stored as a count result.
In this retry process, the medium type of the optical disk is provisionally determined according to a preset order, a focus search is performed with settings corresponding to the medium type, and the number of S-characters is counted. Therefore, the type of the optical disc is not strictly discriminated. However, it can be said that it meets the purpose of fast startup. Further, the counted number of S-characters is used in the focus-on operation process, and when it is determined to be an erroneous determination in steps 24 and 26 as the determination of the optical disk, the focus-on operation is performed with the focus-on prohibited. Therefore, the collision between the objective lens and the optical disk due to misclassification can be prevented.
In the retry process, the medium type of the optical disk is provisionally determined according to a preset order, but the order may be changed. For example, the disk device may record the medium type for which the focus-on operation has been executed as a history, and may order the medium type having the highest number of executions, or may be the first medium type executed first. Further, the medium type of the optical disk that is provisionally determined first may be provisionally determined based on the history. Thereby, the number of retries can be reduced.

  As described above, in this embodiment, if it is determined in steps 24 and 26 that the medium type of the optical disk temporarily determined in the temporary determination process is incorrect, the process does not proceed to step 28. The focus-on operation is prohibited, the type of the laser light source for reading is changed at step 32 in the retry process, and a focus search is performed using the laser light source at step 36 to count the number of S-characters. Then, the count result is stored, and by returning to the focus-on operation process again, the focus-on operation including the error determination is shifted to.

Needless to say, the present invention is not limited to the above embodiments. It goes without saying for those skilled in the art,
・ Applying mutually interchangeable members and configurations disclosed in the above embodiments by appropriately changing the combination thereof.− Although not disclosed in the above embodiments, it is a publicly known technique and the above embodiments. The members and configurations that can be mutually replaced with the members and configurations disclosed in the above are appropriately replaced, and the combination is changed and applied. It is an embodiment of the present invention that a person skilled in the art can appropriately replace the members and configurations that can be assumed as substitutes for the members and configurations disclosed in the above-described embodiments, and change the combinations and apply them. It is disclosed as.

DESCRIPTION OF SYMBOLS 10 ... Disk apparatus, 12 ... Optical pick-up, 14 ... Optical lens, 16 ... Tracking actuator, 18 ... Focus actuator, 20 ... Laser light source, 22 ... Photo detector, 24 ... TE signal detection circuit, 26 ... FE signal detection circuit, 28 ... DSP, 30a-30c ... A / D converter, 32 ... DSP core, 34a-34d ... PWM driver, 36 ... Thread motor, 38 ... Optical disc, 40 ... Spindle, 42 ... Spindle motor.

Claims (6)

An optical disc apparatus capable of reproducing a plurality of types of optical discs,
Focus search function,
Focus on function,
A retry function for retrying the focus search function;
The focus search function
Means for irradiating laser light according to the medium type of each optical disc;
Detection that detects the number of waveforms having one maximum value and minimum value across a predetermined threshold from the change in the FE signal based on the reflected light from the optical disk while changing the focus position in a state where the laser beam is irradiated. Means,
Provisional determination means for provisionally determining the medium type of the optical disc,
The focus on function
Determination means for determining whether or not the medium type of the temporarily determined optical disc is correct based on at least the number of the detected waveforms;
A focus-on operation means for executing a focus-on operation when the medium type of the optical disk temporarily determined by the determination means is determined to be positive,
The retry function changes the medium type of the tentatively determined optical disk when the determination unit determines that the medium type of the tentatively determined optical disk is not, and laser light corresponding to the changed medium type An optical disc apparatus that irradiates and retries the focus search function.   2. The optical disc apparatus according to claim 1, wherein the determination unit determines that the medium type of the optical disc that has been provisionally determined is negative when the number of detected waveforms is zero.   The determination means determines whether the medium type of the temporarily determined optical disk is correct or not based on the number of detected waveforms and the medium type of the temporarily determined optical disk. The optical disk apparatus according to claim 1.   The determining means determines that the medium type of the temporarily determined optical disk is positive when the number of detected waveforms is a number corresponding to the medium type of the temporarily determined optical disk. The optical disk device according to claim 3.   5. The optical disc apparatus according to claim 1, wherein the means for irradiating the laser beam is capable of irradiating a plurality of different types of laser beams in accordance with a medium type of each optical disc. . An optical disk reading method executed by an optical disk device capable of reproducing a plurality of types of optical disks,
Including focus search step and focus on step,
The focus search step includes
Irradiating laser light according to the medium type of each optical disc;
Detection that detects the number of waveforms having one maximum value and minimum value across a predetermined threshold from the change in the FE signal based on the reflected light from the optical disk while changing the focus position in a state where the laser beam is irradiated. Steps,
A provisional determination step for provisionally determining a medium type of the optical disc,
The focus on step includes
A determination step of determining whether the medium type of the temporarily determined optical disc is correct based on at least the number of detected waveforms;
A focus-on operation step of performing a focus-on operation when the medium type of the optical disk temporarily determined in the determination step is determined to be positive,
When it is determined that the medium type of the optical disc that has been provisionally determined in the determination step is changed, the medium type of the optical disc that has been provisionally determined is changed, and laser light is applied according to the changed medium type, An optical disc reading method for retrying the focus search step.

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