JP6832524B2 - Optical disk inspection method - Google Patents

Description

The present disclosure relates to an inspection method for inspecting whether or not an optical disc is in a state where data can be normally recorded or reproduced.

Optical discs capable of recording information (data) have become widespread and widely used. Patent Document 1 discloses a defect detection method for an optical disc, which detects defects such as scratches or stains adhering to the surface of the optical disc.

Japanese Unexamined Patent Publication No. 10-40546

The present disclosure provides an inspection method capable of inspecting with high accuracy whether or not an optical disc is in a state where data can be normally recorded or reproduced.

The inspection method of the present disclosure is a recording type optical disc inspection method, wherein the optical disc has a recording layer including a plurality of recording units which are units for performing error correction when data is recorded, and the inspection is performed. The method is a condensing step of condensing a laser beam on the recording layer, an acquisition step of acquiring an electric signal corresponding to the laser light reflected by the recording layer, and an electric signal in the acquired electric signal. A determination step for determining the presence or absence of an abnormality in the optical disc and an output step for outputting the determination result by specifying the first period in which the signal level of the optical disc is lower than a predetermined value for each second period corresponding to the recording unit. And include.

The inspection method of the present disclosure can inspect with high accuracy whether or not the optical disk is in a state where data can be normally recorded or reproduced.

FIG. 1 is an external perspective view of the information recording system according to the embodiment. FIG. 2 is an external perspective view of the magazine. FIG. 3 is an exploded perspective view of the magazine. FIG. 4 is a schematic cross-sectional view showing the structure of the recording layer of the optical disc. FIG. 5 is a plan view showing the structure of the recording layer of the optical disc. FIG. 6 is a block diagram showing a functional configuration of the information recording system according to the embodiment. FIG. 7 is a flowchart of an optical disc inspection method. FIG. 8 is a diagram for explaining a method of specifying the first period of the second control unit. FIG. 9 is a first schematic diagram showing a recording layer in which laser light is focused. FIG. 10 is a second schematic view showing a recording layer in which laser light is focused. FIG. 11 is a schematic diagram for explaining a method of estimating the presence or absence of scratches or deposits long in the radial direction.

Hereinafter, embodiments will be described in detail with reference to the drawings as appropriate. However, more detailed explanation than necessary may be omitted. For example, detailed explanations of already well-known matters and duplicate explanations for substantially the same configuration may be omitted. This is to avoid unnecessary redundancy of the following description and to facilitate the understanding of those skilled in the art.

It should be noted that the inventors provide the accompanying drawings and the following description in order for those skilled in the art to fully understand the present disclosure, which are intended to limit the subject matter described in the claims. is not it. The attached drawings are schematic views and are not necessarily exactly illustrated. Further, in the attached drawings, substantially the same configurations are designated by the same reference numerals, and duplicate description may be omitted or simplified.

(Embodiment)
[Overview of information recording system]
First, the outline of the information recording system according to the embodiment will be described. FIG. 1 is an external perspective view of the information recording system according to the embodiment.

As shown in FIG. 1, the information recording system 200 includes an information recording device 100, an information terminal 110, and a display device 120.

The information recording device 100 is a data archiver that stores data using a plurality of optical discs. The information terminal 110 and the display device 120 are user interfaces in the information recording system 200, and the user uses the information terminal 110 and the display device 120 to read out the information recorded in the information recording device 100 and the information recording device. It is possible to give an instruction to record information to 100.

Specifically, the information recording device 100 includes a magazine stocker 10, a plurality of magazines 20, a picker 30, a carrier 40, a plurality of disk drives 50, and a control device 60.

The magazine 20 is a housing that accommodates a plurality of optical discs. FIG. 2 is an external perspective view of the magazine 20, and FIG. 3 is an exploded perspective view of the magazine 20.

As shown in FIGS. 2 and 3, the magazine 20 has a magazine tray 21 in which a plurality of optical discs 80 are stacked in the vertical direction, and a case 22 in which the magazine tray 21 is accommodated. For example, 12 optical discs 80 are housed in one magazine tray 21.

The optical disc 80 is a disk-shaped recording medium. In the embodiment, the optical disc 80 is a recording type (additional writing type) optical disc, and for example, about 100 GB of data is recorded on each optical disc. The write-once type optical disc 80 is a recording medium for additionally recording information, and once recorded data cannot be rewritten.

The picker 30 selects one magazine 20 from the plurality of magazines 20 housed in the magazine stocker 10 and pulls out the magazine tray 21 of the selected magazine 20. Further, the picker 30 holds the pulled-out magazine tray 21 and conveys it to the vicinity of the plurality of disk drives 50. The picker 30 has a separator 31 that separates a plurality of optical discs 80 housed in the magazine tray 21 so as not to come into contact with each other.

The carrier 40 receives the plurality of optical discs 80 separated by the separator 31 from the separator 31 in the separated state, and inserts the plurality of optical discs 80 into the insertion openings 51 of the plurality of disk drives 50 one by one.

The disk drive 50 is a device that records information on the optical disk 80 and reproduces the optical disk 80. The disk drive 50 is a slot-in type disk drive for loading the optical disk 80 without using a tray. The plurality of disk drives 50 are stacked in the vertical direction (height direction). The total number of the plurality of disk drives 50 included in the information recording device 100 is equal to the total number of optical discs 80 accommodated in the magazine 20, and is 12 in the embodiment.

The control device 60 is a control device that controls the operation of each device such as the picker 30, the carrier 40, and the disk drive 50.

The information recording device 100 as described above inspects a plurality of magazines 20 before the start of use. Specifically, the information recording device 100 inspects the optical disc 80 in the magazine 20 for scratches or deposits in a state where it has not been recorded.

[Optical disk structure]
Next, the structure of the recording layer of the optical disk 80 will be described. FIG. 4 is a schematic cross-sectional view showing the structure of the recording layer of the optical disc. FIG. 5 is a plan view showing the structure of the recording layer of the optical disc.

As described above, the optical disc 80 is a recording type (additional type) optical disc. As shown in FIG. 4, the optical disc 80 has three recording layers on the upper surface and the lower surface, respectively. The optical disk 80 has three recording layers of Layer0 (L0 in FIG. 4), Layer1 (L1 in FIG. 4), and Layer2 (L2 in FIG. 4) on the upper surface side, and Layer0, Layer1, and Layer2 are also provided on the lower surface side. It has three recording layers.

Further, as shown in FIG. 5, in one recording layer, a groove (groove) is formed in a spiral shape from the vicinity of the center, and one of the groove and the land (the region between the grooves) has a recording mark. It is said that the track 81 is formed. Both the groove and the land may be the track 81.

The track 81 is divided into a plurality of ECC (Error Correcting Code) blocks 82. In other words, the plurality of ECC blocks 82 form a spiral track in the recording layer. The ECC block 82 is an example of a recording unit, and is a unit in which error correction is performed when data is recorded.

The track 81 (groove) has a fine wobbling structure along the track 81, and the disk drive 50 can recognize the wobbling structure as address information in the optical disc 80. According to the wobbling structure, the disk drive 50 can stably identify the address even on the optical disk 80 before the data is recorded.

[Functional configuration of information recording system]
Next, the functional configuration of the information recording system 200 will be described. FIG. 6 is a block diagram showing a functional configuration of the information recording system 200.

As shown in FIG. 6, the information recording system 200 includes an information recording device 100, an information terminal 110, and a display device 120. The information terminal 110 is, for example, a personal computer, and the display device 120 is, for example, a liquid crystal display.

Further, the information recording device 100 mainly includes a disk drive 50 and a control device 60. First, the detailed configuration of the disk drive 50 will be described. The disk drive 50 includes an optical head 52, a spindle motor 53, a servo control unit 54, an address identification unit 55, a binarization processing unit 56, a laser drive unit 57, a first control unit 58, and a first unit. It is provided with a storage unit 59.

The optical head 52 collects the laser light on the recording layer of the optical disc 80, and receives the laser light reflected by the recording layer of the optical disc 80. Further, the optical head 52 converts the received laser light into an electric signal and outputs the light. The optical head 52 outputs a wobble signal, a servo error signal, and a data signal as electric signals. Specifically, the optical head 52 is an optical pickup device, and has a laser light source that emits a laser beam and a photodetector (photodiode) that converts the laser beam into an electric signal.

The wobble signal is a signal corresponding to the wobbling structure of the optical disk 80, and is a signal indicating the address of the position (condensing position) where the laser light is focused in the track 81. The servo error signal is a signal for focusing the laser beam on the recording layer and making the focusing position follow the track 81. The data signal is a signal indicating the data recorded on the track 81.

The spindle motor 53 rotates the optical disc 80 under the control of the servo control unit 54. Based on the servo error signal output from the optical head 52, the servo control unit 54 controls the laser beam to focus on the recording layer and the focused position to follow the track 81. Further, the servo control unit 54 controls the rotation speed of the spindle motor 53. The servo control unit 54 is controlled by, for example, the first control unit 58.

The address specifying unit 55 identifies the address of the focused position of the laser light in the recording layer based on the wobble signal. Specifically, the address identification unit 55 includes an ADC (Analog Digital Converter) circuit. The ADC circuit has HPF (High Pass Filter) processing that suppresses DC fluctuations, LPF (Low Pass Filter) processing that removes high-frequency noise unnecessary for reproduction of the wobble signal, and amplitude of the wobble signal. Performs analog signal processing such as AGC (Auto Gain Control) processing that suppresses fluctuations.

Further, the address specifying unit 55 further includes a PLL (Phase Locked Loop) circuit and a demodulation circuit. The ADC circuit uses the clock signal supplied from the PLL circuit to digitize the wobble signal after analog signal processing. The PLL circuit generates and outputs a clock signal synchronized with the wobble signal from the digitized and BPF-processed wobble signal. The demodulation circuit demodulates the address information from the sampled wobble signal with reference to the clock signal output from the PLL circuit. As a result, the address of the focused position of the laser in the recording layer is specified.

The binarization processing unit 56 performs a process of binarizing the data signal output from the optical head 52. Specifically, the binarization processing unit 56 includes an ADC circuit. The ADC circuit performs analog signal processing such as HPF processing that suppresses DC fluctuations, LPF processing that removes high-frequency noise unnecessary for binarization, and AGC processing that suppresses amplitude fluctuations of data signals. I do.

Further, the binarization processing unit 56 further includes a PLL circuit, an adaptive filter, and a demodulation circuit. The ADC circuit digitizes the data signal using the clock signal supplied from the data PLL circuit. The digitized data signal is filtered by an adaptive filter and then converted into binarized data by a demodulation circuit. Although the details are not shown, the binarized data is subsequently subjected to error correction processing and the like.

The laser drive unit 57 causes the optical head 52 to emit laser light under the control of the first control unit 58. Specifically, the laser drive unit 57 is a drive circuit for a semiconductor laser. The laser driving unit 57 may be included in the optical head 52.

The first control unit 58 controls each component included in the disk drive 50 and communicates with the control device 60. Specifically, the first control unit 58 is realized by a processor, a microcomputer, a dedicated circuit, or the like. The first control unit 58 may be realized by a combination of two or more of a processor, a microcomputer, and a dedicated circuit. Although details are not shown, a communication interface (communication circuit) is interposed between the first control unit 58 and the control device 60.

The first storage unit 59 is a storage device that stores a control program or the like executed by the first control unit 58. Specifically, the first storage unit 59 is realized by a semiconductor memory or the like.

Next, the control device 60 will be described. The control device 60 includes a second control unit 61 and a second storage unit 62.

The second control unit 61 controls the operation of each device such as the picker 30, the carrier 40, and the disk drive 50, based on, for example, an instruction from the information terminal 110. Specifically, the second control unit 61 is realized by a processor, a microcomputer, a dedicated circuit, or the like. The second control unit 61 may be realized by a combination of two or more of a processor, a microcomputer, and a dedicated circuit. Although details are not shown, a communication interface (communication circuit) is interposed between the second control unit 61 and the information terminal 110.

Further, the second control unit 61 inspects the optical disc 80 for scratches or deposits before the information recording device 100 starts to be used, that is, in a state where the optical disc 80 in the magazine 20 has not been recorded. .. Details of such an inspection will be described later.

The second storage unit 62 is a storage device that stores a control program or the like executed by the second control unit 61. This control program includes a program for inspecting the optical disk 80 (magazine 20). Specifically, the second storage unit 62 is realized by a semiconductor memory or the like.

[Optical disc inspection method]
Next, an inspection method of the optical disc 80 in the magazine 20 performed by the control device 60 (second control unit 61) will be described. FIG. 7 is a flowchart of an inspection method for the optical disc 80. The flowchart of FIG. 7 shows an inspection method performed on one optical disk 80 after the second control unit 61 controls the picker 30 and the carrier 40 to insert the optical disk 80 into the disk drive 50.

First, the second control unit 61 collects the laser light on the recording layer of the optical disk 80 by controlling the laser drive unit 57 and the servo control unit 54 via the first control unit 58 (S11). At this time, the second control unit 61 controls the servo control unit 54 via the first control unit 58 to rotate the spindle motor 53, so that the beam spot of the laser light focused on the recording layer is transferred to the optical disk 80. It is made to follow the track 81 of the recording layer of.

Next, the second control unit 61 acquires a data signal corresponding to the laser beam reflected by the recording layer (S12). In the state where the data is recorded on the recording layer, the data signal is a signal whose signal level fluctuates according to the recorded data, but this inspection method is performed on the optical disc 80 in which the data has not been recorded. .. When the data is not recorded, the data signal usually has a substantially constant signal level, but if there are scratches or deposits on the surface of the optical disk 80, the amount of reflection of the laser beam decreases, so the signal level becomes low. descend. That is, the period during which the signal level of the data signal is low can be regarded as the period during which there are scratches or deposits.

Therefore, in the data signal acquired in step S12, the second control unit 61 specifies a first period in which the signal level of the data signal becomes lower than a predetermined value for each second period corresponding to the ECC block 82 ( S13). FIG. 8 is a diagram for explaining a method for specifying the first period.

In FIG. 8, the data signal being inspected is illustrated. As described above, the beam spot of the laser beam focused on the recording layer travels along the track 81 due to the rotation of the optical disc. If there are scratches or deposits on the target portion of the surface of the optical disk 80, the signal level of the data signal is lowered while the beam spot hits the portion of the track 81 that overlaps the target portion. In Figure 8, in the first period T _1, the signal level of the data signal is lower than a predetermined value.

It is considered that the longer the length of the first period T ₁ , the larger scratches or deposits are present on the surface of the optical disc 80. Therefore, when the _{length of the first period T 1} is longer than the predetermined period, an inspection method for determining that the optical disc 80 is abnormal (unusable) can be considered. This is because there is a possibility that data cannot be normally recorded or reproduced on such an optical disc 80 due to scratches or deposits as an obstacle.

However, the optical disc 80 determined to be unusable by such an inspection method may actually be usable. Specifically, as shown in FIG. 8, when the first period T ₁ spans two second period T ₂₁ and second period T ₂₂ , that is, two ECC blocks 82 with scratches or deposits. This is the case when it exists across.

As described above, the ECC block 82 is a unit in which error correction is performed when data is reproduced. If an area free of scratches or deposits is secured in one ECC block 82, error correction is possible, and usually there is no problem in data reproduction. In the example of FIG. 8, the first period T ₁ includes the first period T ₁₁ belonging to the second period T ₂₁ corresponding to one ECC block 82 and the second period T _{22 corresponding to the other ECC block 82.} It includes a first time period _{T 12} that belongs. In such a case, if _{each of the length of the first period T 11 and} the length of the first period T ₁₂ is less than a predetermined length, there is usually no problem in recording the data.

Therefore, in step S13, the second control unit 61 does not specify the first period regardless of the ECC block 82, but specifies the first period in the data signal for each second period corresponding to the ECC block 82. .. In the example of FIG. 8, the second control unit 61 identifies the first period T _{11 included in the second period T 21} and specifies the first period T ₁₂ included in the second period T ₂₂ .

The start point and the end point (the boundary between the two ECC blocks 82) of the second period of the data signal can be specified based on the address output from the address specifying unit 55. Whether or not the data signal is equal to or less than a predetermined value can be specified by, for example, a comparator circuit or the like. The predetermined value is, for example, 50% of the maximum value of the signal level of the data signal, but is not particularly limited.

Then, the second control unit 61 _{determines whether or not each of the length of the first period T 11 and} the length of the first period T ₁₂ is equal to or longer than a predetermined length (S14). The length of the first period can be measured by, for example, a time counter or the like. The predetermined length is, for example, a length corresponding to an amount of information of 600 bytes. Since the length of the second period corresponds to the amount of information of 64KByte, the predetermined length is about 1% of the length of the second period. The predetermined length is not particularly limited, but may be a length corresponding to a predetermined amount of information for which error correction is permitted.

When the second control unit 61 determines that at least one _{of the length of the first period T 11 and} the length of the first period T ₁₂ is equal to or longer than a predetermined length (Yes in S14), the optical disk 80 has an abnormality. (S15). That is, it is determined that the optical disk 80 has large scratches or deposits that cannot normally record or reproduce data.

On the other hand, when the second control unit 61 _{determines that both the length of the first period T 11 and} the length of the first period T ₁₂ are less than a predetermined length (No in S14), the optical disk 80 has an abnormality. It is determined that there is no such thing (S16). That is, it is determined that the optical disk 80 has no large scratches or deposits that cannot normally record or reproduce data.

Finally, the second control unit 61 outputs the determination result (S17). The determination result is output to, for example, the information terminal 110. As a result, for example, an image showing a determination result (inspection result) is displayed on the display device 120.

According to the inspection method as described above, it is possible to inspect with high accuracy whether or not the optical disk 80 is in a state where data can be normally recorded or reproduced.

[Modification 1]
As described above, the optical disc 80 has three recording layers on the upper surface and the lower surface, respectively. That is, the optical disc 80 has a structure in which a plurality of recording layers are laminated. Here, for example, when inspecting one surface of the upper surface and the lower surface of the optical disk 80, the laser light may be focused on one of the three recording layers. At this time, the laser light may be focused on any of the three recording layers. 9 and 10 are schematic views showing a recording layer in which laser light is focused.

In FIG. 9, the laser beam is focused on Layer 0, which is the recording layer farthest from the optical head 52 among the plurality of recording layers, and in FIG. 10, Layer 2 is the recording layer closest to the optical head 52 among the plurality of recording layers. The laser beam is focused on.

Here, the beam spot diameter r1 on the surface of the optical disc 80 when the laser light is focused on the Layer 0 is smaller than the beam spot diameter r2 on the surface of the optical disc 80 when the laser light is focused on the Layer 2. .. As shown in FIGS. 9 and 10, since the deposit 70 adheres to the surface of the optical disk 80, the smaller the beam spot diameter on the surface, the higher the accuracy of the inspection for the presence or absence of the deposit 70. That is, as shown in FIG. 10, the laser beam is focused on the recording layer closest to the optical head 52 among the plurality of recording layers included in the optical disk 80, so that the inspection accuracy can be improved.

[Modification 2]
It is desirable that the optical disk 80 has no scratches or deposits that hinder the recording or reproduction of data. Therefore, in the inspection of the optical disc 80, the same number of second periods as the number of ECC blocks 82 included in one recording layer are specified, and all the specified second periods are included in the second period. Ideally, the condition that one period is less than a predetermined length is satisfied. In a double-sided recording type optical disc such as the optical disc 80, it is ideal that the above conditions are satisfied in each of the recording layer on the upper surface side and the recording layer on the lower surface side.

However, if some of the specified second periods do not meet the conditions, that is, the optical disk 80 is presumed to be unusable for recording due to scratches or deposits (hereinafter referred to as ECC block 82). , Described as a defective ECC block), the optical disk 80 can be used as long as the address of the defective ECC block is stored and recording in the defective ECC block is avoided. In other words, the defective ECC block is an ECC block corresponding to a second period including a first period having a predetermined length or longer.

Therefore, the second control unit 61 may determine the presence or absence of an abnormality in the optical disk 80 based on the number of second periods including the first period having a predetermined length or longer, that is, the number of defective ECC blocks. Specifically, the second control unit 61 is when the number of the second period (the number of defective ECC blocks in the recording layer) including the first period of a predetermined length or more in the data signal is a predetermined number or more. It may be determined that the optical disk 80 has an abnormality.

The predetermined number may be determined according to, for example, the recording capacity. The predetermined number is set so that, for example, the total recording capacity of the defective ECC blocks is less than 10% of the maximum recording capacity of one optical disc 80.

[Modification 3]
The second control unit 61 may determine that the optical disc 80 has an abnormality when it is estimated that there are long scratches or deposits in the radial direction of the optical disc 80. FIG. 11 is a schematic diagram for explaining a method of estimating the presence or absence of scratches or deposits long in the radial direction. Although the track 81 shown in FIG. 11 is actually spiral, it is simplified for the sake of explanation.

In FIG. 11, the ECC block group 83 is composed of a plurality of ECC blocks 82 included in the portion of the track 81 on the first circumference from the center (innermost circumference) of the optical disk 80. The ECC block group 84 is composed of a plurality of ECC blocks 82 included in the portion of the track 81 on the m-th lap from the center of the optical disk 80, and the ECC block group 85 is included in the portion on the n-th lap from the center of the track 81. It consists of a plurality of ECC blocks 82. Note that l, m, and n are natural numbers that are different from each other.

Here, when at least one defective ECC block is contained in each of the ECC block group 83, the ECC block group 84, and the ECC block group 85, a radial deposit 71 (or a scratch) is present. It is estimated that there is.

Therefore, when the second control unit 61 determines that each of the ECC block group 83, the ECC block group 84, and the ECC block group 85 contains at least one defective ECC block, the optical disk 80 is determined to have an abnormality. You may judge.

Specifically, in the acquired data signal, the second control unit 61 includes a period corresponding to the first lap portion of the track 81, a period corresponding to the m lap portion of the track 81, and the track 81. When each of the periods corresponding to the nth lap includes a second period including the first period having a predetermined length or more, it may be determined that the optical disk 80 has an abnormality. The period corresponding to the first lap portion of the track 81, the period corresponding to the m lap portion of the track 81, and the period corresponding to the nth lap portion of the track 81 in the data signal are respectively. It can be specified based on the address output from the address specifying unit 55.

As a result, the second control unit 61 can determine that the optical disc 80, which is presumed to have long scratches or deposits in the radial direction, has an abnormality.

Further, the l-th, m-th, and n-th laps of the track 81 are set at equal intervals, for example, and if l <m <n, ml is equal to n-m. Each of ml and nm is, for example, an integer of 1 or more. As described above, the second control unit 61 is the first of the data signals having a predetermined length or more for each of the N periods corresponding to the tracks of N laps that are not adjacent to each other and are selected at equal intervals. When at least one second period including the period is included, it may be determined that the optical disk 80 has an abnormality (N is an integer of 2 or more).

When the second control unit 61 determines that each of at least two ECC block groups (for example, ECC block group 84 and ECC block group 85) contains at least one defective ECC block, the optical disk is used. It may be determined that there is an abnormality in 80. That is, in the acquired data signal, the second control unit 61 has a period corresponding to the m-th lap from the center of the optical disc 80 in the track 81, and the nth lap from the center of the optical disc 80 in the track 81. When each of the periods corresponding to the portions includes the second period including the first period having a predetermined length or more, it may be determined that the optical disk 80 has an abnormality.

[Modification example 4]
In the above inspection method, the determination result is output for each optical disc 80, but the determination result may be output for each magazine 20. That is, the presence or absence of abnormality (usability) may be determined for each magazine 20.

Here, among the plurality of optical discs 80 housed in the magazine 20, scratches or deposits are likely to occur on the upper surface of the first optical disc located at the top. This is because the upper surface of the first optical disc easily comes into contact with the case 22. Similarly, scratches or deposits are likely to occur on the lower surface of the second optical disc located at the bottom of the plurality of optical discs 80 housed in the magazine 20. This is because the lower surface of the second optical disc easily comes into contact with the magazine tray 21.

Therefore, when the presence or absence of an abnormality is determined for each magazine 20, instead of all the optical discs 80 in the magazine 20 being inspected, only the first optical disc and the second optical disc may be inspected. .. More specifically, only the recording layer on the upper surface side of the first optical disc and the recording layer on the lower surface side of the second optical disc may be the subject of the inspection.

In this case, in the inspection, the laser beam is focused on the recording layer on the upper surface side of the first optical disc and the recording layer on the lower surface side of the second optical disc. That is, for one magazine 20, only two recording layers are subject to inspection. Any of the above-mentioned methods may be used for determining the presence or absence of an abnormality.

Then, when at least one of the first optical disk and the second optical disk is determined to be abnormal, a determination result indicating that the magazine 20 is abnormal is output.

In this way, by selectively inspecting only the recording layer on the upper surface side of the first optical disc and the recording layer on the lower surface side of the second optical disc, it is possible to efficiently determine the presence or absence of an abnormality in the magazine 20. it can.

[Effects, etc.]
As described above, the above embodiment relates to a method for inspecting a recordable optical disc 80. The optical disk 80 has a recording layer including a plurality of ECC blocks 82, which are units for performing error correction when data is recorded. The ECC block 82 is an example of a recording unit. The inspection method includes a condensing step (S11) of condensing the laser light on the recording layer and an acquisition step (S12) of acquiring a data signal corresponding to the laser light reflected by the recording layer. In the inspection method, in the acquired data signal, the first period in which the signal level of the data signal becomes lower than a predetermined value is specified for each second period corresponding to the ECC block 82 (S13), whereby the optical disk 80 A determination step (S14 to S16) for determining the presence or absence of an abnormality and an output step (S17) for outputting the determination result are included. The data signal is an example of an electrical signal.

According to such an inspection method, the presence or absence of obstacles or deposits is determined for each ECC block 82, and therefore, it is possible to inspect with high accuracy whether or not the optical disk 80 is in a state where data can be normally recorded. Can be done.

Further, in the determination step, it may be determined that the optical disk 80 has an abnormality when the length of the first period included in the second period is equal to or longer than a predetermined length in the acquired data signal.

Thereby, in the above inspection method, for example, the ECC block 82 can inspect the optical disk 80 in consideration of whether or not the error can be corrected when the data is recorded.

Further, as in the second modification, in the determination step, the presence or absence of an abnormality in the optical disk may be determined based on the number of the second period including the first period having a predetermined length or longer in the acquired data signal. Good.

Thereby, the above-mentioned inspection method can inspect the optical disc 80 in consideration of the required recording capacity, for example.

Further, as in the modification 3, the plurality of ECC blocks 82 form a spiral track 81 in the recording layer, and in the determination step, in the acquired data signal, m (m) from the center of the optical disk 80 of the track 81. m is a natural number) The period corresponding to the lap portion and the period corresponding to the n (n is a natural number different from m) lap portion from the center of the optical disk 80 of the track 81 are each having a predetermined length or more. When the second period including the first period of the above is included, it may be determined that the optical disk 80 has an abnormality.

As a result, the above inspection method can determine that the optical disc 80, which is presumed to have long scratches or deposits in the radial direction, has an abnormality.

Further, as in the first modification, the optical disk 80 has a structure in which a plurality of recording layers are laminated, and in the condensing step, the recording layer closest to the optical head 52 that emits laser light among the plurality of recording layers. The laser beam may be focused on the light.

As a result, the beam spot diameter on the surface of the optical disk 80 becomes smaller. Therefore, the above-mentioned inspection method can inspect the presence or absence of deposits with high accuracy.

Further, as in the modified example 4, the inspection method is a plurality of optical discs 80 housed in the magazine 20 in a state of being stacked in the vertical direction, and each of the plurality of optical discs 80 having recording layers on both the upper surface and the lower surface. Of these, only the first optical disc located at the top and the second optical disc located at the bottom may be targeted. In the condensing step, the laser beam may be condensing on the recording layer on the upper surface side of the first optical disc and the recording layer on the lower surface side of the second optical disc. In the output step, when at least one of the first optical disk and the second optical disk is determined to be abnormal in the determination step, a determination result indicating that the magazine is abnormal may be output.

As a result, only the recording layer of the optical disc 80 to which scratches or deposits 70 are easily attached is selectively inspected. Therefore, the above inspection method can efficiently determine the presence or absence of an abnormality in the magazine 20.

Further, the inspection method may be performed on the optical disc 80 for which no data has been recorded.

As a result, the above inspection method can determine the presence or absence of scratches or deposits on the optical disc 80 for which data has not been recorded.

Further, as described above, the ECC block 82 is an example of a recording unit. That is, the recording unit may be an ECC block.

As a result, the above inspection method can inspect each ECC block 82 for the presence or absence of obstacles or deposits.

(Other embodiments)
As described above, embodiments have been described as examples of the techniques disclosed in this application. However, the technique in the present disclosure is not limited to this, and can be applied to embodiments in which changes, replacements, additions, omissions, etc. are made as appropriate. In addition, it is also possible to combine the components described in the above-described embodiment to form a new embodiment.

Therefore, other embodiments will be collectively described below.

In the above embodiment, the inspection method is executed by the second control unit included in the control device, but may be executed by the first control unit included in the disk drive. Further, each process included in the inspection method may be shared by each component included in the information recording device.

Further, in the above embodiment, even if the components such as the first control unit and the second control unit are configured by dedicated hardware or realized by executing a software program suitable for each component. Good. Each component may be realized by a program execution unit such as a CPU or a processor reading and executing a software program recorded on a recording medium such as a hard disk or a semiconductor memory.

Further, the inspection method of the above embodiment can be applied to various recording type optical discs. For example, it can be applied to recordable discs such as AD (archival disc (registered trademark)), BD (Blu-ray disc (registered trademark)), DVD, and CD. Further, the disc to be inspected may be a double-sided recording type or a single-sided recording type.

Further, the order of the plurality of processes in the inspection method described in the above embodiment is an example. The order of the plurality of processes may be changed, or some of the plurality of processes may be executed in parallel.

Moreover, the comprehensive or specific aspect of the present disclosure is not limited to the inspection method, and may be realized as a system or an apparatus. In addition, a comprehensive or specific embodiment of the present disclosure may be realized by a recording medium such as an integrated circuit, a computer program or a computer-readable CD-ROM.

For example, the present disclosure may be realized as a disk drive, an information recording device, or an information recording system described in the above embodiment. Further, the present disclosure may be realized as a program for causing a computer to execute the above inspection method, or may be realized as a non-temporary recording medium in which the program is recorded.

As described above, an embodiment has been described as an example of the technique in the present disclosure. To that end, the accompanying drawings and detailed description are provided.

Therefore, among the components described in the attached drawings and the detailed description, not only the components essential for solving the problem but also the components not essential for solving the problem in order to exemplify the above technology. Can also be included. Therefore, the fact that those non-essential components are described in the accompanying drawings or detailed description should not immediately determine that those non-essential components are essential.

Further, since the above-described embodiment is for exemplifying the technique in the present disclosure, various changes, replacements, additions, omissions, etc. can be made within the scope of claims or the equivalent thereof.

The present disclosure is useful as a method for inspecting a recordable optical disc.

10 Magazine stocker 20 Magazine 21 Magazine tray 22 Case 30 Picker 31 Separator 40 Carrier 50 Disk drive 51 Insertion port 52 Optical head 53 Spindle motor 54 Servo control unit 55 Address identification unit 56 Binarization processing unit 57 Laser drive unit 58 First control Unit 59 First storage unit 60 Control device 61 Second control unit 62 Second storage unit 70 Adhesion 71 Adhesion 80 Optical disc 81 Track 82 ECC block 83, 84, 85 ECC block group 100 Information recording device 110 Information terminal 120 Display device 200 Information recording system

Claims (7)

This is a method for inspecting recordable optical discs.
The optical disc has a recording layer including a plurality of recording units, which are units for performing error correction when data is recorded.
The inspection method is
A condensing step that condenses the laser light on the recording layer,
An acquisition step of acquiring an electric signal corresponding to the laser beam reflected by the recording layer, and
In the acquired electric signal, the presence or absence of abnormality of the optical disk is determined by specifying the first period in which the signal level of the electric signal is lower than a predetermined value for each second period corresponding to the recording unit. Judgment step and
And an output step of outputting a determination result only contains,
The inspection method is a first of a plurality of optical discs housed in a magazine in a vertically stacked state, each having a recording layer on both the upper surface and the lower surface, and is located at the top of the plurality of optical discs. This is done only for the optical disc and the second optical disc located at the bottom.
In the focusing step, the laser beam is focused on the recording layer only for the recording layer on the upper surface side of the first optical disk and the recording layer on the lower surface side of the second optical disk.
In the output step, when at least one of the first optical disk and the second optical disk is determined to be abnormal in the determination step, an inspection of the optical disk that outputs the determination result indicating that the magazine is abnormal. Method. In the determination step, when the length of the first period included in the second period is equal to or longer than a predetermined length in the acquired electric signal, it is determined that the optical disk has an abnormality. The method for inspecting an optical disc described in 1. The determination step according to claim 1, wherein the presence or absence of an abnormality in the optical disc is determined based on the number of the second periods including the first period having a predetermined length or longer in the acquired electric signal. Optical disc inspection method. The plurality of recording units form a spiral track in the recording layer.
In the determination step, in the acquired electric signal, the period corresponding to the portion of the track on the m (m is a natural number) lap from the center of the optical disc, and n (m) from the center of the optical disc of the track. n is a natural number different from m) When each of the periods corresponding to the lap portion includes the second period including the first period having a predetermined length or more, it is determined that the optical disk has an abnormality. The method for inspecting an optical disc according to claim 1. The optical disc has a structure in which a plurality of recording layers are laminated.
The method for inspecting an optical disc according to any one of claims 1 to 4, wherein in the condensing step, the laser beam is focused on the recording layer closest to the optical head that emits the laser beam among the plurality of recording layers. .. The optical disc inspection method according to any one of claims 1 to 5 , wherein the inspection method is performed on the optical disc for which data has not been recorded. The method for inspecting an optical disc according to any one of claims 1 to 6 , wherein the recording unit is an ECC (Error Correcting Code) block.

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