JP4618320B2 - Optical disk device - Google Patents

Description

  The present invention relates to an optical disc apparatus, and more particularly to an optical disc apparatus that determines the type of a Blu-ray disc.

  The types of Blu-ray disc include a read-only Blu-ray disc (BD-ROM) and a Blu-ray disc (BD-R, BD-RE) into which data can be written. Conventionally, as a method for discriminating the type of Blu-ray disc, a method for detecting wobble from a Blu-ray disc is known.

  The wobble discriminating method determines the presence / absence of wobble by calculating the number of times the period of the wobble signal detected from the Blu-ray disc is not within a certain range, and based on this determination, determines the type of Blu-ray disc. Judging. Specifically, when it is determined that there is no wobble signal, it is determined that the Blu-ray disc type is BD-ROM, and when it is determined that there is a wobble signal, the Blu-ray disc type writes data. It is determined that the BD-R or BD-RE is possible.

  By the way, as a type of Blu-ray disc, when data is written, the reflectivity of the recording film becomes lower after writing (High to Low disc; hereinafter referred to as HTL disc), and the disc becomes higher after writing (Low). to High Disk; hereinafter referred to as LTH disk). Therefore, when performing various adjustments of HTL disks and LTH disks and reading data, it is necessary to match the filter settings during tracking servo to the characteristics of each disk.

  When discriminating the type of Blu-ray disc with respect to an HTL disc or LTH disc, the conventional discrimination method as described above can accurately measure the period of the wobble signal when the filter setting at the time of tracking is not appropriate. It may not be possible and it may be erroneously determined that there is no wobble. Therefore, there is a problem that the disc type cannot be determined accurately.

  On the other hand, Patent Document 1 discloses an optical disc apparatus that can determine whether the type of the optical disc is a high reflectivity disc or a low reflectivity disc. By combining this optical disc apparatus and a conventional wobble discriminating method, a method for discriminating the type of optical disc with high accuracy even for an HTL disc or an LTH disc can be considered. However, in this determination method, it is necessary to determine the type of the optical disk after determining whether the type of the optical disk is an HTL disk or an LTH disk. is there. Normally, the type determination process of the optical disc is performed during the spin-up, but the optical disc apparatus disclosed in Patent Document 1 has a problem that the type of the optical disc cannot be determined during the spin-up.

  Patent Document 2 discloses an optical disc apparatus that discriminates the type of disc by discriminating the disc ID recorded in the BCA area of the optical disc. However, this apparatus does not prevent erroneous determination due to the presence or absence of wobble.

Patent Document 3 discloses an optical disc apparatus that determines whether or not an optical disc is writable by detecting wobble. Patent Document 4 discloses an optical disc apparatus that determines whether the type of a DVD disc is a + disc or a −disc by calculating the period of a wobble signal and comparing the period with a threshold value. Yes. However, in these optical disk devices, when the type of the Blu-ray disk is an HTL disk or an LTH disk, it does not prevent erroneous determination of the presence / absence of wobble, so the above problem cannot be solved.
JP 2004-171614 A JP 2007-115329 A Japanese Patent No. 3883073 JP 2006-179138 A

  The present invention has been made to solve the above-described problems, and an optical disc capable of accurately determining the type of a Blu-ray disc in a short time even if the type of the Blu-ray disc is an HLT disc or an LTH disc. An object is to provide an apparatus.

In order to achieve the above object, the invention of claim 1 is directed to an optical pickup for receiving reflected light from an optical disk after irradiating the optical disk with laser light, and a wobble of the optical disk from reflected light received by the optical pickup. Wobble detection means for detecting, storage means for storing various information, and disk discriminating means for discriminating the type of the optical disc based on the wobble detected by the wobble detection means, wherein the wobble detection means comprises data Filter mode for detecting wobble from an optical disc whose reflectance after writing is lower than the reflectance before writing (hereinafter referred to as HTL filter mode), and the reflectance after writing rather than the reflectance before writing data Optical filter having a filter mode (hereinafter referred to as LTH filter mode) for detecting wobble from an optical disc having a high In a disk device, when the wobble cannot be detected by the wobble detection means, a wobble NG period calculation means for calculating a period in which wobble cannot be detected (hereinafter referred to as a wobble NG period), and the wobble detection means function as the HTL filter mode. Then, while detecting the wobble of the optical disc, the wobble NG period (hereinafter referred to as HTL wobble NG period) is calculated using the wobble NG period calculation means, and the wobble detection means functions as the LTH filter mode. The wobble NG cycle mode calculating means for calculating the wobble NG cycle (hereinafter referred to as LTH wobble NG cycle) using the wobble NG cycle calculating means while detecting the wobble of the optical disc, and the HTL wobble NG cycle. and the LTH wobble NG week The wobble NG period setting means for setting the smaller one as the minimum wobble NG period and the larger one as the maximum wobble NG period, the optical disc is a Blu-ray disc, and the storage means When the optical disc has a wobble NG cycle smaller than this, the optical disc has a minimum threshold cycle that is determined to have wobble, and when the optical disc has a wobble NG cycle larger than this, the optical disc has no wobble. The maximum threshold period to be determined is stored, and when determining the type of the optical disc, the wobble NG period mode calculation means calculates the LTH wobble NG period and the HTL wobble NG period, and the wobble NG period Setting means includes the minimum wobble NG period and the maximum wobble period. After each of the wobble NG periods is set, the disk discriminating unit determines whether or not the minimum wobble NG period is less than the minimum threshold period. And determining that the optical disc has wobble. If the result of the determination is not less than the minimum threshold period, it is determined whether or not the maximum wobble NG period exceeds the maximum threshold period. When the threshold period is exceeded, it is determined that the optical disc has no wobble. As a result of the determination, when the maximum threshold period is not exceeded, a value obtained by subtracting the maximum wobble NG period from the maximum threshold period is It is determined whether or not a value obtained by subtracting the minimum threshold period from the minimum wobble NG period, and as a result, the minimum threshold period is subtracted from the minimum wobble NG period. The optical disc is determined to have wobble, and if the result of the determination is not equal to or greater than the value obtained by subtracting the minimum threshold period from the minimum wobble NG period, the optical disk is determined to have no wobble; Thereafter, the type of the optical disc determined to have wobble is determined to be an optical disc on which data can be written, and the type of optical disc determined to have no wobble is determined to be a read-only optical disc. is there.

  According to a second aspect of the present invention, in the optical disc apparatus according to the first aspect, when determining the type of the optical disc, the wobble NG cycle mode calculation means calculates the LTH wobble NG cycle and the HTL wobble NG cycle. After the calculation and the wobble NG cycle setting unit sets the minimum wobble NG cycle and the maximum wobble NG cycle, respectively, the disc determination unit determines whether the minimum wobble NG cycle is less than the minimum threshold cycle. If the result is less than the minimum threshold period, it is determined that the optical disc has wobble. If the result of the determination is not less than the minimum threshold period, the maximum wobble NG period is the maximum wobble period. It is determined whether or not a threshold period has been exceeded. As a result, if the maximum threshold period is exceeded, the optical disc is If the result of the above determination does not exceed the value, the value obtained by subtracting the maximum wobble NG period from the maximum threshold period is equal to or greater than the value obtained by subtracting the minimum threshold period from the minimum wobble NG period. As a result, if it is equal to or larger than the value obtained by subtracting the minimum threshold period from the minimum wobble NG period, the calculation means for each wobble NG period mode uses the LTH wobble NG period and the HTL wobble NG period. After the wobble NG cycle setting means resets the minimum wobble NG cycle and the maximum wobble NG cycle, a value obtained by subtracting the reset maximum wobble NG cycle from the maximum threshold cycle is calculated as follows: The determination as to whether or not the minimum wobble NG period is less than or equal to a value obtained by subtracting the minimum threshold period is repeated a predetermined number of times. If it is determined a predetermined number of times that the value obtained by subtracting the maximum wobble NG period from the maximum threshold period is equal to or greater than the value obtained by subtracting the minimum threshold period from the minimum wobble NG period, it is determined that wobble exists. If the value obtained by subtracting the maximum wobble NG period from the maximum threshold period is not less than a predetermined number of times as being equal to or greater than the value obtained by subtracting the minimum threshold period from the minimum wobble NG period, it is determined that there is no wobble, and then The type of the optical disc determined to have wobble is determined to be an optical disc on which data can be written, and the type of optical disc determined to have no wobble is determined to be a read-only optical disc.

  According to the first aspect of the present invention, when the minimum wobble NG cycle is less than the minimum threshold cycle, the disc determination means determines that the Blu-ray disc has wobble, and when it is not less than the minimum threshold cycle, the maximum wobble NG cycle is When the maximum threshold period is exceeded, the Blu-ray disc determines that there is no wobble. Then, when the maximum wobble NG cycle does not exceed the maximum threshold cycle, the disc determination means has a value obtained by subtracting the maximum wobble NG cycle from the maximum threshold cycle equal to or greater than a value obtained by subtracting the minimum threshold cycle from the minimum wobble NG cycle. If there is, the Blu-ray disc is determined to have wobble, and if it is not equal to or less than the value obtained by subtracting the minimum threshold period from the minimum wobble NG period, the Blu-ray disk is determined to have no wobble. The disc discriminating means discriminates that the type of Blu-ray disc determined to have wobble is a Blu-ray disc to which data can be written, and the type of Blu-ray disc determined to have no wobble is a read-only Blu-ray disc. It is determined that

  Therefore, regardless of whether the type of Blu-ray disc is an HLT disc or an LTH disc, the type of disc can be determined with high accuracy. Further, since it is not necessary to discriminate the type of the disc after determining the type of the Blu-ray disc, the type of the Blu-ray disc can be discriminated in a short time.

  According to the second aspect of the present invention, the disc discriminating unit determines that the Blu-ray disc has wobble if the minimum wobble NG cycle is less than the minimum threshold cycle, and if it is not less than the minimum threshold cycle, the maximum wobble NG cycle is When the maximum threshold period is exceeded, the Blu-ray disc determines that there is no wobble. Then, when the maximum wobble NG cycle does not exceed the maximum threshold cycle, the disc determination means has a value obtained by subtracting the maximum wobble NG cycle from the maximum threshold cycle equal to or greater than a value obtained by subtracting the minimum threshold cycle from the minimum wobble NG cycle. At a certain time, after calculating the LTH wobble NG cycle and the HTL wobble NG cycle, the minimum wobble NG cycle and the maximum wobble NG cycle are set again. Then, the determination as to whether or not the value obtained by subtracting the maximum wobble NG cycle set again from the maximum threshold cycle is equal to or greater than the value obtained by subtracting the minimum threshold cycle from the reset minimum wobble NG cycle is repeated a predetermined number of times.

  When the disc discriminating unit determines that the value obtained by subtracting the maximum wobble NG cycle from the maximum threshold cycle is equal to or greater than a value obtained by subtracting the minimum threshold cycle from the minimum wobble NG cycle, the Blu-ray disc is wobbled. On the other hand, if it is determined that there is no predetermined number of times, the Blu-ray disc is determined to have no wobble. The disc discriminating means discriminates that the type of Blu-ray disc determined to have wobble is a Blu-ray disc to which data can be written, and the type of Blu-ray disc determined to have no wobble is a read-only Blu-ray disc. It is determined that

  For this reason, the determination as to whether or not the value is equal to or greater than a value obtained by subtracting the minimum threshold period from the reset minimum wobble NG period is repeated a predetermined number of times, so that the type of Blu-ray disc can be accurately determined.

  A Blu-ray disc recorder (optical disc apparatus) according to an embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a block diagram showing an internal configuration of the Blu-ray disc recorder 1, and FIG. 2 is a block diagram showing an internal configuration of the optical disc drive 14.

  The Blu-ray disc recorder 1 is operated by a user and provides an operation unit 11 for giving instructions to each part of the apparatus, a terminal unit 12 including an HDMI terminal provided so as to be exposed outside the casing, and a Blu-ray disc 2. And an optical disk drive 14 for reading data from and writing data to the Blu-ray disc 2 mounted inside, and a control unit (microcomputer; disk discriminating means, wobble NG cycle) for controlling each part of the apparatus (Calculation means, wobble NG cycle mode calculation means, wobble NG cycle setting means) 10 and a storage unit (memory; storage unit) 13 in which a program for operating the control unit 10 is stored.

  The storage unit 13 has a wobble in the Blu-ray disc 2 when the period (hereinafter referred to as the wobble NG period) in which the wobble cannot be detected is smaller than the Blu-ray disc 2 used in the wobble detection process (see FIG. 5) described later. When the wobble NG period of the Blu-ray Disc 2 is larger than this, the period (hereinafter referred to as the minimum threshold period) determined that the Blu-ray Disc 2 has no wobble is stored. Has been. The storage unit 13 further stores a threshold light amount used when reading data from the Blu-ray disc 2.

  As shown in FIG. 2, the optical disk drive 14 includes a spindle motor 51 for rotating the Blu-ray disc 2, a spindle motor control unit 52 for controlling the rotation speed of the spindle motor 51, and reading / writing data from / to the Blu-ray disc 2. And an optical pickup (a part of the wobble detection means) 53 for detecting wobble, a sled motor 54 for moving the optical pickup 53 in the radial direction of the Blu-ray disc 2, and a sled motor controller for controlling the operation of the sled motor 54 55. Information such as wobble detected by the optical pickup 53 is transmitted to the control unit 10. The control unit 10 determines the type of the Blu-ray disc 2 based on the received wobble information.

  By the way, there are Blu-ray discs (BD-R, BD-RE) in which data can be written and Blu-ray discs (BD-ROM) for reading only as types of Blu-ray discs 2. A wobble wobbled in a predetermined cycle is formed on a writable Blu-ray disc, and a wobble is usually not formed on a read-only Blu-ray disc.

  In addition, the Blu-ray disc model includes a disc in which the reflectivity of the recording film decreases after writing (High to Low disc; hereinafter referred to as HTL disc) when data is written, and a disc ( Low to High disc; hereinafter referred to as LTH disc).

  As shown in FIG. 3, the optical pickup 53 includes a laser diode 53 a that irradiates the Blu-ray disc 2 with blue-violet laser light, and a photodiode 53 b that receives reflected light from the Blu-ray disc 2. The photodiode 53b includes a light receiving surface divided into a plurality of parts.

  When writing data to the Blu-ray disc 2, the optical pickup 53 writes data by irradiating the Blu-ray disc 2 with laser light. Further, when reading data from the Blu-ray disc 2 or detecting wobble, the optical pickup 53 irradiates the Blu-ray disc 2 with laser light and then receives the reflected light using each light receiving surface of the photodiode 53b. The control unit 10 reads out data and detects wobble by detecting the difference or sum of the amounts of reflected light received by the respective light receiving surfaces of the optical pickup 53.

  The wobble detection means composed of the control unit 10 and the optical pickup 53 includes a filter mode (hereinafter referred to as HTL filter mode) for reading data from the HTL disc and detecting wobble, and reading data from the LTH disc. A filter mode (hereinafter referred to as an LTH filter mode) for detecting wobble.

  Specifically, for example, when the optical pickup 53 reads data from the HTL disk, after the laser beam is irradiated onto the HTL disk, the reflected light from the HTL disk is received, the amount of reflected light of the reflected light, and the storage The threshold light quantity stored in advance in the unit 13 is compared, and the data written in the HTL disc is read by detecting the light quantity with the reflected light quantity lower than the threshold light quantity.

  Further, when the optical pickup 53 reads data from the LTH disk, after irradiating the LTH disk with laser light, the reflected light from the LTH disk is received, and the reflected light quantity of the reflected light and the storage unit 13 are stored in advance. The data written in the LTH disk is read out by comparing the threshold light amount and detecting the light having a reflected light amount higher than the threshold light amount.

  Next, the process of determining the type of the Blu-ray disc 2 will be described with reference to the flowchart shown in FIG. First, the control unit 10 performs a process of detecting the presence or absence of wobble (wobble detection process) using the optical pickup 53 for the Blu-ray disc 2 mounted in the optical disc drive 14 (S1). Details of the wobble detection process will be described later.

  If it is determined that there is a wobble as a result of the process of S1 (YES in S2), the type of the Blu-ray disc 2 to be installed in the optical disc drive 14 is a writable Blu-ray disc such as BD-R or BD-RE. 2 is determined (S3), and the process is terminated. On the other hand, if it is determined that there is no wobble (NO in S2), it is determined that the type of the Blu-ray disc 2 installed in the optical disc drive 14 is a read-only Blu-ray disc such as a BD-ROM (S4). The process is terminated.

  Next, the details of the wobble detection process will be described with reference to the flowchart shown in FIG. First, after causing the wobble detection means to function as the HTL filter mode (S11), the control unit 10 tracks the Blu-ray disc 2 using the optical pickup 53 (S12), and when the wobble cannot be detected by the optical pickup 53 The period in which the wobble cannot be detected, that is, the period after the previous wobble is detected until the next wobble is detected (hereinafter referred to as the wobble NG period) is calculated (S13). The wobble NG cycle calculated by the process of S13 is referred to as an “HTL wobble NG cycle” for convenience of explanation.

  Then, after causing the wobble detection means to function as the LTH filter mode (S14), the control unit 10 tracks the Blu-ray disc 4 using the optical pickup 53 (S15), and when the wobble cannot be detected by the optical pickup 53 Then, a wobble NG cycle is calculated (S16). Note that the wobble NG cycle calculated by the process of S16 is referred to as an “LTH wobble NG cycle” for convenience of explanation.

Then, the control unit 10 sets the smaller one of the HTL wobble NG cycle and the LTH wobble NG cycle as MinNGCnt (minimum wobble NG cycle) (S17), and then the larger of the HTL wobble NG cycle and the LTH wobble NG cycle. Is set as MaxNGCnt (maximum wobble NG cycle) (S18). Then, the control unit 10 uses the calculated MixNGCnt and MaxNGCnt and the minimum threshold period and the maximum threshold period stored in the storage unit 13 to determine whether or not wobbles exist (wobble presence determination process). (S19). Details of the wobble presence / absence determination process will be described later.

Next, details of the wobble presence / absence determination process will be described with reference to the flowchart shown in FIG. Here, for convenience of explanation, the minimum threshold period stored in the storage unit 13 is denoted as “A” for convenience of explanation, and the maximum threshold period is denoted as “B” for convenience of explanation.

  First, the control unit 10 determines whether MinNGCnt is less than A. If the result of determination is less than A (YES in S21), the Blu-ray disc 2 mounted in the optical disc drive 14 is determined. Determines that there is wobble (S41), and ends the wobble presence / absence determination processing.

  On the other hand, if MinNGCnt is not less than A in S21 (NO in S21), the control unit 10 determines whether MaxNGCnt exceeds B and, as a result, exceeds B (YES in S22). ), It is determined that there is no wobble in the Blu-ray disc 4 mounted in the optical disc drive 14 (S31), and the wobble presence / absence determination processing ends.

  On the other hand, if MaxNGCnt does not exceed B in S22 (NO in S22), the control unit 10 determines that the value obtained by subtracting MaxNGCnt from B (B-MaxNGCnt) is the value obtained by subtracting A from MinNGCnt (MinNGCnt-A). ) Or not, and if the value of (B-MaxNGCnt) is equal to or greater than the value of (MinNGCnt-A) ((B-MaxNGCnt) ≧ (MinNGCnt-A)) (YES in S23), Is temporarily determined (S32).

  Then, the control unit 10 determines whether or not the tentative determination has been repeated an arbitrary number of times (n times), and when it has not been repeated (NO in S25), the processes of S11 to S19 shown in FIG. 5 are performed again. Specifically, MinNGCnt and MaxNGCnt are set again, and using these values, the presence of wobble is determined by performing the processing subsequent to S21 again.

  On the other hand, when the tentative determination is repeated n times (YES in S25), the control unit 10 determines that there is wobble when it is tentatively determined to be wobbled any number of times (k times) (YES in S26). (S28), the wobble presence / absence determination process is terminated.

  On the other hand, when it is not tentatively determined that wobble exists for an arbitrary number (k times) or more (NO in S26), the control unit 10 determines that there is no wobble (S27), and ends the wobble presence / absence determination process.

  As described above, according to the Blu-ray disc recorder 1 according to the present embodiment, as shown in FIG. 5, the wobble NG cycle calculated by causing the optical pickup 53 to function as the HTL mode and the optical pickup 53 as the LTH mode are used. Using the wobble NG cycle calculated by functioning, the presence / absence of wobble is determined as shown in FIG. Therefore, regardless of the type of the Blu-ray disc 2 installed in the optical disc drive 14, the type of the Blu-ray disc 2 can be determined with high accuracy. Further, unlike the conventional patent document 1, it is not necessary to determine the type of the disc after determining the type of the Blu-ray disc 2, so that the type of the Blu-ray disc 2 can be determined in a short time.

  Further, since it is not necessary to determine the type of the Blu-ray disc 2 after determining the type of the Blu-ray disc 2, the type of the Blu-ray disc 2 can be determined during the spin-up. Moreover, since it is not necessary to add a member to the Blu-ray disc recorder 1, the manufacturing cost of the Blu-ray disc recorder 1 can be suppressed.

  In addition, as shown in S25 and S26 of FIG. 6, since the presence / absence of wobble is determined after an arbitrary number of temporary determination processes, the type of the Blu-ray disc 2 can be accurately determined.

  In addition, this invention is not restricted to the structure of the said embodiment, A various deformation | transformation is possible in the range which does not change the meaning of invention.

The block diagram which shows the internal structure of the Blu-ray disc recorder which concerns on one Embodiment of this invention. The block diagram which shows the internal structure of the optical disk drive of the said Blu-ray Disc recorder. The figure which shows schematic structure of the optical pick-up of the said optical disk drive. The flowchart which shows the procedure of the disc type discrimination | determination process in the said Blu-ray disc recorder. 7 is a flowchart showing a procedure of wobble detection processing in the disc type determination processing. The flowchart which shows the procedure of the wobble presence determination process in the said wobble detection process.

Explanation of symbols

1 Blu-ray disc recorder (optical disc device)
2 Blu-ray disc (optical disc)
10 Control unit (disc discriminating means, wobble NG period calculating means, wobble NG period mode calculating means, wobble NG period setting means, wobble detecting means)
13 Storage unit (storage means)
53 Optical pickup (wobble detection means)

Claims (2)

An optical pickup for receiving reflected light from the optical disc after irradiating the optical disc with laser light;
Wobble detection means for detecting wobble of the optical disc from reflected light received by the optical pickup;
Storage means for storing various information;
Disc discriminating means for discriminating the type of the optical disc based on the wobble detected by the wobble detection means,
The wobble detection means includes a filter mode (hereinafter referred to as an HTL filter mode) for detecting wobble from an optical disk whose reflectance after writing is lower than the reflectance before writing data, and the reflectance before writing data. In an optical disc apparatus having a filter mode (hereinafter referred to as LTH filter mode) for detecting wobble from an optical disc having a higher reflectance after writing,
A wobble NG period calculating means for calculating a period (hereinafter referred to as a wobble NG period) in which wobble cannot be detected when the wobble cannot be detected by the wobble detection means;
While the wobble detection unit functions as the HTL filter mode to detect the wobble of the optical disc, the wobble NG cycle calculation unit is used to calculate a wobble NG cycle (hereinafter referred to as an HTL wobble NG cycle), A wobble NG for calculating a wobble NG period (hereinafter referred to as an LTH wobble NG period) using the wobble NG period calculating means while detecting the wobble of the optical disc by causing the wobble detection means to function as the LTH filter mode. Calculation means for each periodic mode;
Wobble NG period setting means for setting the smaller one of the HTL wobble NG period and the LTH wobble NG period as the minimum wobble NG period and setting the larger one as the maximum wobble NG period,
The optical disc is a Blu-ray disc;
The storage means includes a minimum threshold period for determining that the optical disk has wobble when the wobble NG period of the optical disk is smaller than this, and the optical disk when the wobble NG period of the optical disk is larger than this. Each stores a maximum threshold period determined to have no wobble,
When determining the type of the optical disc,
The wobble NG cycle mode calculation unit calculates the LTH wobble NG cycle and the HTL wobble NG cycle, and the wobble NG cycle setting unit sets the minimum wobble NG cycle and the maximum wobble NG cycle, respectively. rear,
The disc discriminating means is
It is determined whether or not the minimum wobble NG period is less than the minimum threshold period, and if the result of this determination is less than the minimum threshold period, it is determined that the optical disc has wobble;
As a result of the determination, if it is not less than the minimum threshold period, it is determined whether or not the maximum wobble NG period exceeds the maximum threshold period. As a result, if the maximum wobble NG period exceeds the maximum threshold period, the optical disc Judge that there is no wobble,
If the maximum threshold period is not exceeded as a result of the determination, whether or not a value obtained by subtracting the maximum wobble NG period from the maximum threshold period is equal to or greater than a value obtained by subtracting the minimum threshold period from the minimum wobble NG period. As a result, if it is equal to or larger than the value obtained by subtracting the minimum threshold period from the minimum wobble NG period, it is determined that the optical disc has wobble,
If the result of the determination is not equal to or less than the minimum wobble NG period minus the minimum threshold period, it is determined that the optical disc has no wobble;
Thereafter, the type of the optical disc determined to have wobble is determined to be an optical disc on which data can be written, and the type of optical disc determined to have no wobble is determined to be a read-only optical disc. An optical disc device characterized. When determining the type of the optical disc,
After the wobble NG cycle mode calculation unit calculates the LTH wobble NG cycle and the HTL wobble NG cycle, and the wobble NG cycle setting unit sets the minimum wobble NG cycle and the maximum wobble NG cycle, respectively. ,
The disc discriminating means is
It is determined whether the minimum wobble NG period is less than the minimum threshold period, and as a result, if the minimum wobble NG period is less than the minimum threshold period, it is determined that the optical disc has wobble,
As a result of the determination, if it is not less than the minimum threshold period, it is determined whether or not the maximum wobble NG period exceeds the maximum threshold period. As a result, if the maximum wobble NG period exceeds the maximum threshold period, the optical disc Judge that there is no wobble,
As a result of the determination, if not exceeded, it is determined whether a value obtained by subtracting the maximum wobble NG period from the maximum threshold period is equal to or greater than a value obtained by subtracting the minimum threshold period from the minimum wobble NG period. As a result, when it is equal to or greater than the minimum wobble NG period minus the minimum threshold period,
The calculation means for each wobble NG cycle mode calculates the LTH wobble NG cycle and the HTL wobble NG cycle, and the wobble NG cycle setting means resets the minimum wobble NG cycle and the maximum wobble NG cycle. Thereafter, it is repeated a predetermined number of times whether or not the value obtained by subtracting the maximum wobble NG cycle set again from the maximum threshold cycle is equal to or greater than the value obtained by subtracting the minimum threshold cycle from the reset minimum wobble NG cycle. ,
As a result of the determination, if it is determined that the value obtained by subtracting the maximum wobble NG period from the maximum threshold period is equal to or greater than the value obtained by subtracting the minimum threshold period from the minimum wobble NG period, there is a wobble. And
If it is determined that the value obtained by subtracting the maximum wobble NG period from the maximum threshold period is not less than a predetermined number of times that the value obtained by subtracting the minimum threshold period from the minimum wobble NG period is determined as having no wobble;
Thereafter, the type of the optical disc determined to have wobble is determined to be an optical disc on which data can be written, and the type of optical disc determined to have no wobble is determined to be a read-only optical disc. 2. The optical disk apparatus according to claim 1, wherein

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