JPH06118004A - Stamper defect inspection device - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a stamper defect inspection apparatus capable of accurately performing a defect inspection of a stamper. A defect detection unit 9, a sector address decoder 10 for detecting a sector mark signal and a resync signal in addition to a sector address, and a counter circuit set at the detection time of the sector mark signal and reset at the detection time of the resync signal. A sector position information detection circuit 13 provided, a latch circuit 11 that latches defective data and sector address data, a system controller 12 that captures the latched data, and a first timer when a resync signal is not detected. End signal for resetting the counter circuit and setting the first timer with the sector mark signal, the first sector position information detecting means, and when no sector mark is detected, setting the counter circuit with the end signal for the second timer and resync signal. With the second sector position information detecting means for setting the second timer with Configured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stamper defect inspection apparatus for inspecting a stamper of an optical disc for defects.

[0002]

2. Description of the Related Art Conventionally, a stamper for an optical disc has been inspected in a preformatted portion and a data portion as part of its guarantee. In this case, in particular, the defect in the data portion greatly contributes to the error rate of the optical disc, and its details are important. FIG. 1 (this figure is also used in the embodiments described later) shows an example of a stamper defect inspection apparatus. A reflected signal from the stamper 1 is sent to a signal generation circuit 3 via an actuator section 2. The track error signal Tr, the focus error signal Fo, and the reproduction signal Rf are thereby generated. In this case, the track error signal Tr and the focus error signal Fo are transmitted to the actuator coil 5 via the compensation circuits 4a and 4b, respectively.
It is input to a and 5b, and tracking and focusing are performed. Further, the track error signal Tr and the focus error signal Fo are LPF (low pass filter) 6
a, 6b to filter the low frequency component, hold circuit 7a, 7b by timing signal T, hold the actuator coil 5 through SW8a, 8b.
a and 5b, respectively.

On the other hand, the Rf signal is input to the defect detection section 9 and the sector address decoder 10 to detect a data section defect and an address. The latch circuit 11 is used for latching defect data, sector address data, and a position within a sector, and when the defect is detected, the data is latched and taken into the system controller 12.

[0004]

In the configuration of FIG. 1 as described above, the position data of the defective portion of the data portion of the stamper 1 is obtained by latching the address (sector unit) at the time of the defect occurrence. Therefore, there is no position information within the sector, and there is insufficient data to analyze the distribution of defect data and the details of its characteristics. Also, if focus jump or track jump occurs during stamper inspection,
Defect inspection at that point becomes difficult or impossible.

Therefore, in order to solve such a problem, the track error signal Tr and the focus error signal F
o is monitored, and when it exceeds a certain value (threshold voltage), it is considered as a defect, and the low frequency components (LPFs 6a, 6) of the track error signal Tr and the focus error signal Fo in FIG.
hold the signal filtered by b)
By switching W7a and 7b, each actuator coil 5a,
It supplies to 5b and is driven and controlled not influenced by the error signal. However, such defect detection methods include
When there is a time delay, it may not be possible to prevent the transient response movement of the actuator due to drooling (pulse-shaped) of the error signal at the time of the entry of a defect, and it is an inspection in the defocus and detrack states, and accurate measurement cannot be performed. There is.

[0006]

According to a first aspect of the present invention, there is provided a defect detection section for detecting defective data in a data section of a stamper of an optical disc, and a sector mark signal as an in-sector address in addition to the sector address of the optical disc. A sector address decoder that detects a resync signal, a sector position information detection circuit that includes a counter circuit that is set at the detection time of the sector mark signal and reset at the detection time of the resync signal, the defective data and the sector address And a latch circuit for latching the address data in the sector, a system controller for fetching the data latched by the latch circuit, and resetting the counter circuit by the end signal of the first timer when the resync signal is not detected. With the sector mark signal, the first tag Position information detecting means for setting a marker, and a second sector for setting the counter circuit by the end signal of the second timer and setting the second timer by the resync signal when the sector mark is not detected. A stamper defect inspection device is constituted by the internal position information detecting means.

According to a second aspect of the present invention, in the first aspect of the present invention, when a focus jump occurs during stamper inspection, the sector address of the occurrence location and the sector position information are registered in the system controller.
A registering means and a second registering means for registering the sector address and the in-sector position information of the location where the track jump occurs during the stamper inspection in the system controller.

According to the invention of claim 3, claim 1 or 2
In the invention described above, when focus jumps or track jumps occur during reinspection of the stamper, the focus control and tracking control are set constant when the sector address and the counter circuit match, just before the occurrence of the focus jumps or track jumps. A defect inspection means for holding the time and performing the defect inspection is provided.

[0009]

According to the first aspect of the invention, in-sector position information can be obtained in addition to the ID data as position information at the time of defect detection, whereby detailed position information of the defective portion can be obtained. .

According to the second and third aspects of the present invention, a spot where a jump or a focus jump occurs at the time of stamper inspection is taken into the system controller as position information in the sector, and coincident circuit data is used as a coincidence circuit data at the time of re-inspection. By setting a few clocks before and applying the low frequency component of the error signal (before the jump) to the actuator with the matching information of the position information in the sector and the matching circuit, control can be performed without affecting the disturbance of the error signal. Becomes

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows the overall structure of a stamper defect inspection apparatus. The sector address decoder 10 is connected with an in-sector position information detection circuit 13 to which a sector mark (SM) signal and a resync (RESINC) signal are sent. The first registration means, the second registration means, and the defect inspection means are composed of a latch circuit 11 and a system controller. FIG. 2 shows the internal configuration of the in-sector position information detection circuit 13. This circuit includes a counter circuit 14, a matching circuit 15, first to third timer circuits 16 to 18, first to third F / F circuits 19 to 21, a clock generating circuit 22, an inverter 23, and an OR. Circuit 2
4, 25 and AND circuits 26, 27.

Further, the in-sector position information detection circuit 13 is
A first sector position information detecting means and a second sector position information detecting means are provided. In this case, the first sector position information detecting means resets the counter circuit 14 by the end signal of the first timer circuit 16 when the RESYNC signal is not detected, and the first timer circuit 1 by the SM signal.
Set 6. The second sector position information detecting means sets the counter circuit 14 by the end signal of the second timer circuit 17 when the sector mark is not detected, and sets the RES.
The second timer circuit 17 is set by the YNC signal. When the focus jump occurs during the stamper inspection, the first registration unit registers the sector address of the occurrence location and the in-sector position information in the system controller 12. When the track jump occurs during the stamper inspection, the second registration means registers the sector address of the occurrence location and the sector internal position information in the system controller 12. The defect inspection means, when focus jump or track jump occurs during reinspection of the stamper 1, sets the coincidence circuit 15 immediately before the occurrence of focus jump or track jump,
When the sector address and the counter circuit 14 coincide with each other, focus control and tracking control are held for a certain period of time to perform a defect inspection.

In such a configuration, by using the in-sector position information detection circuit 13 and various means as described above,
A method of detecting a defect in the stamper 1 will be described. First, before that, the pre-format configuration of the magneto-optical disk 1 (MO 90 mm size) manufactured using the stamper 1 will be described with reference to FIG. One sector is
Starting with SM (sector mark), AM (address mark) ID part (TRK No., SECT, CRC), O
DF, DATA part + RESYNC (resync), BUF
It is composed of F (buffer). The position on the magneto-optical disk by the CAV drive system is the track N of the ID.
o. , Sector no. , SM, it is possible to obtain accurate position information in the radius and circumferential directions. This allows
TRK N detected from the sector address decoder 10
o. , SECT No. At the same time, the counter circuit 14 detects the time from the SM detection.

Next, the operation of the in-sector position information detection circuit 13 will be described with reference to the configuration of FIG. 2 and the timing chart of FIG. First, the SM signal and the RESYNC signal are
It is detected by the sector address decoder 10 and sent to the in-sector position information detection circuit 13. The first F / F circuit 19 is set at the falling edge of the SM signal, and the AND of the Q output and the clock generation circuit 22 is performed by the AND circuit 26, whereby the counter circuit 14 operates. The data values D _{0 to} Dn of the counter circuit 14 are stored in the latch circuit 11
Is latched by the defect detection signal, and taken into the system controller 12 together with the ID data. Further, the reset of the counter circuit 14 is reset at the falling edge of the invert signal by the RESET signal passing through the inverter 23, and holds the RESET state until the next SM signal.

At this time, when the SM signal is not detected, the second timer circuit 1 is activated by the RESYNC signal of the preceding sector.
7 is set, and the second F / F circuit 20 is set at the trailing edge (Q output) at the end of the timer. At the point B (when the OR circuit 25 is output), the first F / F circuit 19 and the second F / F circuit 20 are ORed, so that the second F / F
The circuit 20 becomes valid and the counter circuit 14 starts operating.

Next, when the RESYNC signal is not detected,
The first timer circuit 16 is set at the falling edge of the SM signal of this sector, and at the point A (when the OR circuit 24 is output), the first timer circuit 16 and the inverted signal obtained via the inverter 23 of the RESYNC signal Since the OR is taken, the counter circuit 14 is reset at the falling edge of the first timer circuit 16 at the end. Also, the first and second F / F
The circuits 19 and 20 are reset at the same time as the counter circuit 14. By the series of operations described above, the stamper 1
The defect occurrence position, that is, the sector address and the position information in the sector can be detected. The resolution of the position detection in the sector can be set by variously changing the synchronization of the clock generation circuit 22 (the description of the operation up to this point corresponds to claim 1).

Next, a processing method when a focus jump or a track jump occurs on the stamper 1 will be described. First, if focus jump or track jump occurs during the defect inspection, the ID is triggered by the occurrence point.
(Track No., Sector No.) and position data in the sector are transferred to the system controller 12 by the latch circuit 11.
It can be registered in the system controller 12 by this (the operation description up to this point is described in claim 2).
Corresponding to).

Further, in the stamper inspection, when focus jump and track jump occur, the defect inspection at that point becomes difficult or inaccurate. Therefore, the points where the focus jump and the track jump occur are registered, and the system controller 12 is set at the time of the re-inspection (the part where the jump occurs).
Is set in the coincidence circuit 15 a few clocks before the sector position data at the generation point, and the coincidence circuit 15 is set in the disable state. Next, the system controller 12 determines the track No. of the defect occurrence point.
And the sector number one before. Seek to the end point and set the end point to ENABLE. This ENABLE signal is R
Q of the third F / F circuit 21 due to the fall of the ESYNC signal
The AND with the output is taken by the AND circuit 27 and input to the EN terminal of the coincidence circuit 15. The system controller 12 sets the ENABLE signal for a time corresponding to one sector. As a setting method, a soft timer or a read timer is used. Then, when the coincidence circuit 15 is in the ENABLE state and coincides with the in-sector position data of the counter circuit 14 (this point is slightly before the jump occurrence point), the third timer circuit 18
Is turned on, which generates the timing signal T.
This timing signal T turns on the hold circuits 7a and 7b of the actuator control unit, and the SWs 8a and 8b.
Is performed and the low-frequency components of the focus error signal Fo and the track error signal Tr are applied to the actuator coils 5a and 5b, respectively, whereby stable control that is not affected by the error signal can be performed. Therefore, by performing the defect inspection of the stamper 1 in such a state, the state of the stamper surface can be inspected with high accuracy. The set time of the third timer circuit 18 is
A value corresponding to several clocks is selected on the assumption of a minute defect (the operation description up to here corresponds to claim 3).

As described above, in-sector position information can be obtained in addition to the ID data as position information at the time of defect detection, and detailed position information of the defective portion can be obtained by this, so that the stamper 1's position information can be obtained. The defect map can be analyzed accurately.

Further, the spot where the jump is generated for the focus jump or the track jump during the stamper inspection is taken into the system controller as the position information in the sector, and at the time of the re-inspection, a few clocks before the occurrence point is set as the coincident circuit data, and the sector is set. By applying the low-frequency component of the error signal (before the jump) to the actuator with the matching information of the inner position information and the matching circuit, control can be performed without affecting the disturbance of the error signal, and thus defect inspection can be performed accurately. It can be carried out.

[0021]

According to the first aspect of the present invention, a defect detecting section for detecting defective data in a data section of a stamper of an optical disk and a sector mark signal or a resync signal as an in-sector address in combination with a sector address of the optical disk are detected. A sector address decoder, a sector position information detection circuit having a counter circuit which is set at the time of detecting the sector mark signal and reset at the time of detecting the resync signal, the defective data, the sector address and the sector address A latch circuit for latching data,
A system controller in which the data latched by the latch circuit is fetched, and when the resync signal is not detected, the counter circuit is reset by the end signal of the first timer and the sector mark signal is used to reset the counter circuit by the first signal.
A first sector position information detecting means for setting a timer, and a second sector for setting the counter circuit by the end signal of the second timer when the sector mark is not detected and setting the second timer by the resync signal Since the stamper defect inspection device is configured by the inner position information detecting means, the position information in the sector can be obtained in addition to the ID data as the position information at the time of detecting the defect, thereby obtaining the detailed position information of the defective portion. Therefore, it is possible to accurately analyze the defect map and the like.

According to a second aspect of the present invention, in the first aspect of the present invention, when a focus jump occurs during a stamper inspection, the sector address of the occurrence location and the intra-sector position information are registered in the system controller. Since the registration means and the second registration means for registering the sector address of the location where the track jump occurs during the stamper inspection and the position information in the sector to the system controller are provided, the focus during the stamper inspection is provided. With respect to jumps and track jumps, the spot where jumps occur can be taken into the system controller as in-sector position information, whereby defect information can be registered in the system.

According to a third aspect of the present invention, in the first or second aspect of the invention, when focus jumps or track jumps occur at the time of reinspection of the stamper, immediately before the occurrence points are set in the coincidence circuit and the sector address is set. When the counter circuit and the counter circuit coincide with each other, a defect inspection means is provided for holding the focus control and the tracking control for a certain period of time to perform a defect inspection. By applying the low-frequency component of the error signal (before jumping) to the actuator using the internal position information and the matching information of the matching circuit, control can be performed without affecting the disturbance of the error signal, which enables accurate defect inspection. It can be done well.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of a stamper defect inspection apparatus that is an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration within a sector position information detection circuit.

FIG. 3 is a schematic diagram showing a sector configuration example in a magneto-optical disk.

FIG. 4 is a timing chart.

[Explanation of symbols]

 9 Defect Detection Section 10 Sector Address Decoder 11 Latch Circuit 12 System Controller 13 In-Sector Position Information Detection Circuit 14 Counter Circuit 15 Matching Circuit

Claims (3)

[Claims] 1. A defect detection unit for detecting defective data in a data portion of a stamper of an optical disc, a sector address decoder for detecting a sector mark signal or a resync signal as an in-sector address in addition to a sector address of the optical disc, and the sector. An in-sector position information detection circuit including a counter circuit that is set at the time of detecting a mark signal and reset at the time of detecting the resync signal; and a latch circuit that latches the defective data, the sector address, and the in-sector address data. A system controller in which the data latched in the latch circuit is fetched, and the counter circuit is reset by the end signal of the first timer when the resync signal is not detected, and the first timer is set by the sector mark signal. First
Position information detecting means in the sector, and second position information detecting means in the sector which sets the counter circuit by the end signal of the second timer and sets the second timer by the resync signal when the sector mark is not detected. A stamper defect inspection apparatus comprising: 2. When a focus jump occurs during stamper inspection, a sector address of the occurrence location and in-sector position information are registered in the system controller.
2. A registration means, and a second registration means for registering a sector address of a location where the track jumps and position information within the sector in the system controller when a track jump occurs during stamper inspection. Stamper defect inspection device. 3. When focus jump or track jump occurs during reinspection of the stamper, the focus control and tracking control are set constant when the sector address and the counter circuit match, immediately before the occurrence of focus jump or track jump. The stamper defect inspection apparatus according to claim 1 or 2, further comprising a defect inspection means for holding the time to perform a defect inspection.