JPH05159507A - Inspecting apparatus and method for optical disc - Google Patents

Abstract

PURPOSE:To avoid damage on old data and improper writing of new data by inspecting trouble such as scratch or contamination of a write once compact disc. CONSTITUTION:When an image data read out from a film and the like through a scanner 50 is fed through a CPU 10 to a CD reproducer/recorder 20 to be additionally recorded on a write once compact disc 26, trouble such as scratch or contamination of the disc 26 is inspected. The CPU 10 controls the entire process of inspection system wherein the tracking operation, amount of reflected light from a pregroove, and detection of a protrusion in a tracking signal due to tracking error are subjected to inspection. A new image data can be recorded on the disc 26 when there is no trouble but the image data is not recorded additionally onto the disc 26 if there is a trouble.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and method for inspecting an optical disc for damage such as scratches.

[0002]

2. Description of the Related Art Compact disc ROM (CD-R), which is an optical disc of the so-called compact disc (CD) standard (Orange Book standard) manufactured by Sony Philips, has been used in the past with some steps such as premaster or prerecord. Even if there is a difference, the volume is recorded at one time 1
It was a recordable type only. With the development of technology thereafter, multi-functional discs such as a write-once type and a re-recordable type are also used. These conventional so-called one-time ROM type discs are recorded by a software supplier,
Shipped under strict quality control. Therefore, it was good to say that there was no scratch on the disc from the beginning.

However, in the case of a post-write type photo CD, when there is a vacant area in the disc which has been recorded once or when the recorded data is erased and re-recorded, the image data is generally recorded by a CD writer in a specialized laboratory. Yes, but it may be re-recorded on the disc that the user has reached.
Such a used disc may not be properly written after the new data when it is damaged by severe stains or scratches in the process of user's reproduction, use, storage or transportation. However, since the conventional CD writer is configured with only the one-time recording type compact disc in mind, the above-mentioned adverse conditions have not been sufficiently dealt with.

[0004]

When recording is performed on a compact disc having such a bad condition by using a CD writer according to the prior art, a tracking error occurs and not only a recording error of new data but also an already recorded data is recorded. The old data that was being used may have been destroyed. In addition, even if the old data is not destroyed, the data is recorded on the scratched disc, so that the disc containing the data having a high data error rate is given to the user.

The present invention overcomes the above-mentioned drawbacks of the prior art, and inspects optical discs for defects such as scratches and stains, thereby avoiding corruption of old data and improper writing of new data. An object of the present invention is to provide an optical disk inspection device and a method thereof.

[0006]

In order to solve the above problems, the present invention provides an optical disc inspection apparatus for inspecting the recording surface of a compact disc standard recordable optical disc.
Driving means for carrying the optical disc and rotating it at a predetermined speed, optical pickup means for outputting a first signal according to the amount of light reflected from the recording surface of the optical disc, and optical pickup means for following along the track of the optical disc. It has a tracking means and a computing means for identifying the disturbance of the first signal and comparing the identified disturbance with a first predetermined value to judge the quality of the optical disc. When the disturbance exceeds the first predetermined value, the optical disc is determined to be defective.

According to the present invention, an optical disc inspection method for inspecting a recording surface of a write-once optical disc of a compact disc standard includes a step of rotating the optical disc at a predetermined speed and an optical pickup along an optical disc track. Following the steps, obtaining a first signal according to the amount of light reflected from the recording surface of the optical disc, identifying a disturbance of the first signal, and comparing the identified disturbance with a first predetermined value. If the former exceeds the first predetermined value, the optical disc is determined to be defective.

[0008]

According to the present invention, when image data is recorded on a write-once type optical disc, the presence or absence of an obstacle such as dirt or scratches that hinders the recording and reproduction of data is inspected before the data recording. The inspection items are tracking operation,
This is the protrusion of the tracking signal due to the decrease in the amount of reflected light on the disk surface and the tracking error.
This is done along the pre-groove of the unrecorded track on the disc. If there is no problem as a result of the inspection, new image data can be recorded on the disk to be inspected. According to one embodiment,
When the trouble is detected, the disc to be inspected is ejected and new image data is not recorded on the disc.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an optical disc inspection apparatus and method according to the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 shows an embodiment of an optical disk recording apparatus for realizing an optical disk inspection method according to the present invention. This optical disk recording apparatus records an image signal obtained from an image data source such as a scanner 50 and / or a hard disk apparatus 12 on, for example, a so-called photo CD standard write-once compact disk (CD) 26 manufactured by Kodak Phillips. It is a device. The scanner 50 is an image reading device that reads a color image recorded on, for example, a color negative film (not shown) at a high resolution, and the entire system is installed in, for example, a photo CD software supplier's laboratory. In this embodiment, the compact disc 26 is a write-once or re-recording type optical disc.
That is, both a one-time recording type and a so-called re-recording type that can be erased and reused are included. This is for example a scanner
It is brought into the laboratory from the customer together with the negative film to be read by 50. Therefore, in many cases, the compact disc 26 has an area 26a (FIG. 2) in which image data has already been recorded, and a pre-groove (not shown) is formed in the unrecorded area 26b. There is.

The compact disc 26 is a CD reproducing / recording device.
It is detachably set to 20. The CD playback / recording device 20
This is a device for recording image data on the compact disk 26 and for reproducing it. The playback function is not necessary. Therefore, the reproducing / recording device 20 has an optical pickup 21 as shown in FIG.
The recording surface 26d of the compact disc 26 is irradiated with 60, and the reflected light from the recording surface 26d is received and a corresponding electric signal is output to the signal line 62. The reproducing / recording device 20 also has a function of inspecting the recording surface of the disk 26 for any obstacles 27 such as stains and scratches which may interfere with recording or reproducing use. This function is realized by a control calculation unit 64 that performs analysis and calculation described later based on the reflected light amount signal 62 output from the optical pickup 21. The playback / recording device 20
When the disk 26 to be inspected has a fault 27, it has a function of ejecting the disk 26. For this purpose a recording / playback device 20
Has a disc ejecting mechanism 66.

The reproducing / recording device 20 has a spindle motor 68, and an output shaft 70 on which the disc 26 is detachably mounted. The spindle motor 68 is driven by the motor drive circuit 72 and rotates it at a constant angular velocity at a constant speed. In the optical pickup 21, the focus servo (automatic focus control) mechanism 74 focuses the light beam 60 on the recording surface 26d, receives the reflected light from the recording surface 26d, and records by the tracking servo (track automatic tracking) mechanism 76. Face 26
Tracked along a pit row or pre-groove (not shown) of d. The tracking servo mechanism 76 also has a transfer mechanism that movably carries the pickup 21 and transfers it in the radial direction of the disk 26. These mechanisms 66,
72, 74 and 76 are collectively controlled by the control calculation unit 64. Preferably, the control calculation unit 64 is realized by a processing system such as a personal computer.

The preferred embodiment of the apparatus also includes a separate CD.
A recording device 30 is provided and is also connected to the central processing unit 10 by a connection line 87 of a SCSI interface. The recording device 30 is a device for recording image data on another compact disc 36. The compact disc 36 is preferably a virgin disc having no data recorded in the entire recording area. This recording device 30 is a disc
This is a recording device for recording all the image data on the virgin disk 36 when there is a fault 27 in 26 and recording cannot be performed in this.

Prior to recording on the disk 26, the present apparatus
Check whether there is any obstacle 27 on the recording surface of the disk 26.
In order to control the entire system and perform the recording of this image data and the inspection of faults, the apparatus has a central processing unit 10. The central processing unit 10 including the peripheral devices to be described later is advantageously realized by a general-purpose processing system such as a commercially available personal computer in this embodiment. The central processing unit 10 is interfaced with the CD reproducing / recording device 20 and the scanner 50 by connecting lines 82 and 85 by a small computer system interface (SCSI), respectively. The central processing unit 10 controls the entire system as well as a process for recording an image, for example, a scanner.
It also has functions such as reading image data from 50, image color correction and gradation correction, compression encoding of image data, and conversion processing to a recording format of the compact disc standard. A hard disk device 12 is connected to the central processing unit 10 in order to hold these image data.

The present apparatus also has a display device (CRT) 40 for visually displaying the state of the system and an image to be processed, and an operating device 18 for inputting an operator's instruction. Connected to device 10. The operation device 18 includes an instruction for an operator to read a negative image by the scanner 50, an instruction and conditions for image processing, an instruction for executing an inspection of the compact disc 26, and a reproducing / recording device 20 or a recording device. 30 has a key for inputting various instructions to the system, such as instructions for recording image data on the disk 26 or 36.

In the operating state, the negative film (not shown) brought into the laboratory is set in the scanner 50, and the compact disc 26 brought in together with it is set in the reproducing / recording device 20. Then, the operator instructs the operation device 18 to read an image of a desired frame on the negative film. The frame of the image to be read is designated by the operation device 18. In response to this, the central processing unit 10 controls the scanner 50, and the latter reads the image carried by the film. The image data representing the read image is transferred to the central processing unit 10 via the connection line 85, and the central processing unit 10
Then, image processing such as color correction, gradation correction, and data compression is performed and stored in the hard disk 12 (step 202, FIG. 5). At that time, the central processing unit 10 calculates the amount of compressed image data for each frame, and
The total amount of image data to be recorded in the 26 unrecorded areas 26c is calculated (204). Therefore, the central processing unit 10 instructs the reproducing / recording device 20 to inspect the disc 26 (206). That is, the central processing unit 10 inspects the compact disc 26 before recording new image data on the disc 26, and confirms that there is no obstacle in recording and subsequent reproduction.

In response to this, the reproducing / recording device 20 enters the inspection routine 208 (FIG. 8). In response to the inspection instruction 206, the control calculation unit 64 controls the motor drive circuit 72 to rotate the disk 26 at a constant angular velocity at a constant speed. With this,
By controlling the focus servo mechanism 74, the focus servo of the optical pickup 21 is closed (220). At that time, the track servo is kept open.

The write-once compact disc 26 brought into the laboratory by the customer generally has data already recorded in a partial area 26a thereof, as shown in FIG. Recording and reproduction of the disk 26 are performed along a spiral track from the center to the outer periphery. Therefore, the control calculation unit 64 uses the tracking servo mechanism 76.
The optical pickup 21 is moved toward the outer periphery from the center of the disk 26 by controlling the blank start position 26c, that is, the boundary 26c between the image data recorded area 26a and the unrecorded green area 26b.
To detect. The transport of the optical pickup 21 is stopped on that track (222). At that time, the control calculation unit 64 calculates the target position 26e of the inspection end from the image data amount to be newly recorded to be received from the central processing unit 10. This position 26e
Is the position where the data of the new image read by the scanner 50 is recorded and the final position, that is, the unrecorded area 26b
It is the most advanced position for. For example, in a compact disc 26 capable of recording 100 Mbytes of image data, if 48 Mbytes of image data for 8 frames are recorded continuously in the unrecorded area 26b from the boundary portion 26c, the track position of the recording end portion 26e is calculated. To do.

The signal obtained by the optical pickup 21 in the track servo open state is the same as that at the time of complete tracking error. The acquisition signal of the optical pickup 21 in this state is affected by pits and pregrooves of the recording data and becomes an irregular high frequency signal as shown in FIG. In the figure, the optical pickup 21 has a disc 26
The signal obtained for one rotation of
Indicates the amount of reflected light, and the lower waveform 120 indicates the tracking signal. The same applies to FIGS. 5 and 6.

When the optical pickup 21 is moved to the blank start position 26c, the control calculation unit 64 controls the tracking servo mechanism 76 to close the tracking servo and set the still mode (224). As we all know,
Playback or recording of the compact disc 26 is performed in a spiral pit row or pre-groove from the center to the outer periphery. Usually, one round of the pit row is called a track. In this still mode, the optical pickup 21
In the scanning of 1, the pre-groove of the disk 26 is made one round, then one track is jumped back to the original position, and the same pre-groove is tracked a plurality of times.

The control calculation unit 64 first checks whether or not the tracking operation of the inspection position is normally performed (226). The tracking of the unrecorded area 26b is performed along the pregroove formed on the disk 26. If the tracking operation is normal, the process proceeds to the next inspection step 228, but if abnormal, a defective message is generated (246) and no further inspection is performed.

When the tracking of the pre-groove of at least one rotation of the disk 26 is normal, the control calculation unit 64
Detects a decrease in the amount of reflected light for the same pregroove (228). That is, the recording surface 26d of the disc 26 shown in FIG.
Measure the lowest value of 154 of the amount of reflected light from 150 (228). C
The D reproducing / recording device 20 compares the measured value 154 with a predetermined set value by the analysis processing described later (230).
This measurement and comparison may be repeated for multiple revolutions of disk 26. If the comparison result is good, the process moves to the next tracking error protrusion detection 232. If the comparison result is bad, a bad message is generated 282 and the inspection routine 208 is exited.

The amount of light reflected from the recording surface 26d of the disk 26 received by the optical pickup 21 is maintained at a stable level as shown by the waveforms 130 and 140 in FIG. 5 when the disk 26 has no obstacles 27 such as scratches and dirt. To do. However, when the obstacle 27 is present, the level drop point 154 occurs as shown in the waveform of FIG. In that case, a corresponding decrease in the level of the tracking signal 164 often occurs. The left and right waveforms in the figure are disturbed because the amount of reflected light received by the optical pickup 21 is disturbed by the influence of the pregroove when the optical pickup 21 jumps one track by the still operation and returns to the original starting point of the same track. Is shown. Therefore, when the optical pickup 21 does not perform the still operation, the waveform is not disturbed.

The decrease amount of the reflected light level due to the obstacle 27 on the recording surface 26d is quantitatively analyzed by the control calculation unit 64 as follows. In the light quantity measured by the optical pickup 21 during the tracking close operation, or the voltage conversion value thereof, the quantity of light reflected from the disk 26, that is, the optical pickup
The 0 level of the amount of light incident on 21 (170 in FIG. 6) is set to HF GND,
Average amount of reflected light per track with this HF GND as the reference value 15
7 is HFa, and the lowest reflected light quantity 154 is HFd. The recording / reproducing apparatus 20 compares the calculation result HFn obtained from the following relational expression HFn = (HFa-HFd) / HFa (1) with a predetermined set value (23
0) If the difference between the two is within a predetermined range, the inspection result is determined to be good. If the calculation result HFn is outside this range,
Consider it defective. The set value for determining the quality is determined by an empirical rule.

The control calculation unit 64 continues the still operation of the optical pickup 21, but if the comparison result in step 230 is good, it detects the tracking error protrusion 164 for the same pre-groove (232). The detection 232 of the tracking error protrusion is also performed in the same manner as the detection 228 of the decrease in the amount of reflected light 228, and the comparison 234 with the set value is performed.

The analysis regarding the set value of the tracking error protrusion is performed as follows. When the tracking operation along the pre-groove is normal, the signal picked up by the optical pickup 21 is a stable signal as shown in the lower part of FIG.
It becomes 0. However, when there is the obstacle 27, an unstable point 164 occurs as shown in FIG. The amplitude of this unstable part 164
TEd is quantitatively analyzed in the same manner as in the case of the detection 228 and 230 of the decrease in the amount of reflected light described above, and the quality is determined. As shown in FIG. 4, when the average value of the amplitude of the tracking signal 120 when the track servo is open is TEp,
The recording / reproducing apparatus 20 obtains the calculation result TEn based on the formula TEn = (TEp-TEd) / TEp (2) shown below. If the value TEn is within the predetermined range, it is determined to be normal, and if it is out of the range, it is determined to be abnormal. The set value for determining pass / fail is determined by an empirical rule, as in the case of detecting the decrease in the amount of reflected light. According to one embodiment,
This reference value was set to a value substantially equal to 1/3 of the average amplitude value TEp of the envelope of the track error signal 120.

The influence of the damage 27 such as scratches and dirt on the recording surface 26d of the disk 26 on the data signal is that when the disk 26 is a one-time ROM, the signal is normally recorded.
It only lowers the overall level during playback. However, when the disc 26 is a write-once type, it is affected not only during reproduction but also during data recording. The form of influence is
This is equivalent to the apparent reduction in the light amount of the pickup 21 due to the light blocking effect of the obstacle 27. Due to this effect, uncertain recording of signals, such as defective recording position due to defective focusing, occurs. It is empirically known that these effects are influenced by obstacles with a synergistic effect in the case of the write-once disc as compared with the disc which is shipped in the recorded state. Therefore, in the case of a write-once disc,
More strict inspection for the presence of obstacles is required.

When the above-mentioned series of inspections for one track is normally completed, the control calculation section 64 confirms whether or not the optical pickup 21 has reached the previously calculated target position 26e of the end of recording. 236). If the end position 26e has not been reached, open the tracking servo here (23
8) The optical pickup 21 is moved to the next inspection position, that is, the unrecorded track (240), and the process returns to step 224 of the tracking servo close and still mode. Control then repeats steps 224 through 236 again. When the recording end target position 26e is reached in the judgment step 236 in the process, a good message indicating that the inspection result is good is generated (242), and the inspection routine is ended. This inspection result “good” is transferred from the reproducing / recording device 20 to the central processing unit 10, and the processing unit 10 confirms the result (210).

In this example, since the inspection result is good,
The central processing unit 10 shifts to the next process 214, and additionally records new image data in the unrecorded area 26b of the disk 26 to be inspected. This image data is previously read from the negative film by the scanner 50 and is stored in the hard disk device 12. The central processing unit 10 reads this from the hard disk device 12, converts it into a recording format of a compact disk, and transfers it to the reproducing / recording apparatus 20. The reproducing / recording device 20 writes this image data in the unrecorded area 26b. In this way, if the write-once compact disc 26 provided by the customer is inspected and there is no problem in recording new image data, new image data is additionally written on the disc 26.

By the way, the control calculation unit 64 determines whether the determination step 2
Recording surface 26d of the disc 26 at 26, 230 or 234
If the fault 27 is detected in the first line and it is determined to be defective, a defective message is generated 282 and the inspection routine 208 is skipped. Upon receipt of the defective message from the recording / reproducing device 20, the central processing unit 10 confirms it (210), ejects the disk 26 to be inspected from the recording / reproducing device 20 (212), and completes all steps. .. This ejection is performed by the disc ejection mechanism 66 under the control of the control calculation unit 64. The reason why the rejected disc 26 is ejected in this manner is to maintain compatibility with the conventional CD player in this system.

The disk brought in by the customer in this way
If 26 is determined to be defective, new image data may not be written to the inspected disk 26, and both the old and new image data may be recorded by the recording device 30 on the virgin disk 36 prepared by the laboratory. .. In that case,
The central controller 10 controls the reproducing / recording device 20 to read all the data recorded therein from the disc 26, transfer this data to the recording device 30 and record it on a new disc 36. Unlike the case of recording, reading from the disk 26 has a high tolerance for noise, so there is a normal level of failure.
If 27, in most cases, there is no problem. Subsequent to recording on the blank disc 36, the central processing unit 10 reads out the image data accumulated in the hard disk device 12, converts it into a recording format of a compact disc, and writes it on the disc 36 by the recording device 30. Thus obstacles
Image data of both old and new was written on the compact disc 36 without 27. This is given to the customer along with the negative film that he has deposited.

As described above, the inspection routine 208 is divided into the tracking operation, the detection of the decrease in the reflected light amount of the track formed by the pre-groove, and the detection of the tracking error protrusion.
Type of inspection is done as one set. This set of inspections may be configured to be performed on the pregrooves of the disk 26 to be inspected for each circumference at intermittent positions at appropriate intervals. It is not necessary to inspect all the tracks in the unrecorded area 26b from the boundary 26c on the recording surface 26d to the target recording end position 26e.
This is because the obstacle 27 such as a scratch that hinders the use of the disk is expected to have a certain size in a normal case.
The intermittent distance is determined by a rule of thumb. In addition, the inspection at the intermittent position has an effect of reducing the time required for the inspection.

[0032]

As described above, according to the present invention, it is possible to inspect the optical disc to be inspected for a failure prior to additional recording of data. Therefore, even if the disc to be inspected is defective, it is possible to prevent damage to the data recorded on the disc and inappropriate writing of new data.

[Brief description of drawings]

FIG. 1 is a functional block diagram showing a system configuration of an embodiment of an optical disc inspection apparatus according to the present invention.

2 is a plan view conceptually showing a recording state of image data on an example of an inspected disc inspected by the disc inspection system shown in FIG. 1. FIG.

FIG. 3 is a functional block diagram illustrating a specific configuration of the CD recording / reproducing device in the embodiment shown in FIG.

4 is a diagram showing an example of a reflected light amount and a tracking signal acquired by the optical pickup in the track servo open state in the CD reproducing / recording device of the disc inspection system shown in FIG.

FIG. 5 is a diagram showing an example of a reflected light amount and a tracking signal which are acquired by the optical pickup in the same CD reproducing / recording apparatus when there is no obstacle on the disk recording surface in the track servo close state.

FIG. 6 is a diagram showing an example of a reflected light amount and a tracking signal which are obtained by the optical pickup in the same CD reproducing / recording device when the disc recording surface has an obstacle in a track servo closed state.

FIG. 7 is a flowchart showing the operation of the disk inspection system shown in FIG.

8 is a flowchart showing details of an inspection routine in the flowchart of FIG.

[Explanation of symbols]

 10 Central processing unit 20 CD recording / playback device 21 Optical pickup 26 Write-once compact disc 30 CD recording device 36 New write-once compact disc 40 Monitor display 50 Scanner 64 Control calculation unit 66 Disc ejection mechanism 74 Focus servo mechanism 76 Tracking servo Mechanism 110, 130, 150 Reflected light intensity signal 120, 140, 160 Tracking signal

Claims (8)

[Claims] 1. An optical disk inspection apparatus for inspecting a recording surface of a write-once optical disk of a compact disk standard, said apparatus comprising drive means for carrying said optical disk and rotating said optical disk at a predetermined speed. Optical pickup means for outputting a first signal in accordance with the amount of reflected light from the optical disc, tracking means for causing the optical pickup means to follow along the track of the optical disc, and disturbance of the first signal is identified and the identification is performed. The optical disc is compared with a first predetermined value to determine whether the optical disc is good or bad, and the arithmetic means is configured to detect the optical disc when the identified disturbance exceeds a first predetermined value. A device for inspecting an optical disc, which is characterized in that 2. The inspection apparatus according to claim 1, wherein the apparatus includes means for identifying a tracking error from a first signal obtained from the optical pickup means while being tracked by the tracking means, The calculating means compares the identified tracking error with a second predetermined value, and determines that the optical disc is defective when the identified tracking error exceeds a second predetermined value. Optical disk inspection device. 3. The optical disk inspection apparatus according to claim 1, wherein the tracking unit repeatedly tracks the same track on the disk. 4. The inspection apparatus according to claim 1, wherein the apparatus has an ejecting unit that ejects the disc from the inspecting device when the computing unit determines that the disc is defective. Optical disc inspection device. 5. The inspection apparatus according to claim 3, wherein the disturbance of the first signal includes a lowering portion of the reflected light amount.
The optical disc inspection apparatus is characterized in that the arithmetic unit determines that the optical disc is defective when the degree of deterioration of the reduced portion exceeds a first predetermined value. 6. The inspection apparatus according to claim 2, wherein the second predetermined value is an average amplitude value of an envelope envelope formed by the first signal in a state where the tracking unit is not tracking. An optical disk inspection apparatus having a value substantially equal to 1/3. 7. An optical disc inspection method for inspecting a recording surface of a write-once optical disc of a compact disc standard, the method comprising a step of rotating the optical disc at a predetermined speed, and an optical pickup along a track of the optical disc. To obtain a first signal corresponding to the amount of light reflected from the recording surface of the optical disc, a step of identifying a disturbance of the first signal, and a step of identifying the identified disturbance as a first predetermined value. And comparing the identified disturbances with a first predetermined value, the optical disc is determined to be defective. 8. The inspection method according to claim 7, further comprising: identifying a tracking error from a first signal obtained from the optical pickup while the optical pickup is being tracked. Comparing the identified tracking error with a second predetermined value, and determining that the optical disk is defective when the identified tracking error exceeds a second predetermined value. Inspection method.