JPH10111255A - Disk-inspection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To speed up inspection by a method wherein inspection data obtained from tracks belonging to a first information track group are used as the inspection data on the tracks belonging to a second information track group adjacent thereto in the case when a high correlation is recognized between the first and second inspection data. SOLUTION: A directional position of the focus of an objective lens 23 following a prescribed land track is detected and subjected to secondary differentiation by a secondary differentiation circuit 36 and it is made a plane vibration acceleration signal. The time series data on the land track in one rotation are stored as inspection data in a data storage circuit 14. Tracking is shifted to an adjacent group in succession and the time series data in one rotation are stored as the inspection data in the data storage circuit 14. CPU 13 calculates the correlation between the two inspection data, and when the correlation is higher than a prescribed value, the inspection data on the land track are substituted for the inspection data on a groove track adjacent thereto.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a disk inspection apparatus, and more particularly to a disk inspection apparatus for inspecting mechanical characteristics of an information recording medium such as a magneto-optical disk and an optical disk.

[0002]

2. Description of the Related Art In general, an information recording medium such as a magneto-optical disk or an optical disk has a track formed of a spiral groove, and the information is formed along only one of a convex portion and a concave portion of the groove of the track. Is recorded and reproduced. Conventionally, in a disk inspection apparatus for inspecting the mechanical characteristics of such an information recording medium, for example, a run-out acceleration, a radial acceleration or a high-speed displacement, an inspection is performed only on one of a convex portion and a concave portion of a track groove. Was to do.

[0003]

However, in such a conventional disk inspection apparatus, since only one of the convex and concave portions of the track groove is inspected, more information can be obtained. For an information recording medium in which information is stored in both the convex portion and the concave portion of the track groove for storage, it is necessary to inspect both the convex portion and the concave portion, and the inspection cannot be performed in a short time. There was a point. The present invention is intended to solve such a problem, and provides a disk inspection apparatus capable of performing a high-speed mechanical characteristic inspection on a disk in which information is stored in both a convex portion and a concave portion of a track groove. It is intended to provide.

[0004]

In order to achieve the above object, a disk inspection apparatus according to the present invention provides an inspection apparatus which exhibits predetermined mechanical characteristics from predetermined tracks belonging to first and second information track groups. Detecting means for detecting data; first inspection data obtained from a predetermined track belonging to a first information track group, while inspecting mechanical characteristics based on the inspection data obtained by the detecting means; If a predetermined correlation or more is found between the track and the second inspection data obtained from the track belonging to the adjacent second information track group, the inspection of the track belonging to the second information track group is performed. Control means using, as data, test data obtained from a track belonging to a first information track group adjacent to this track It is those with a. Further, the control means, based on the inspection data obtained by the detection means,
As the mechanical characteristics, at least surface deflection acceleration, radial acceleration or high-speed displacement is inspected. Therefore, the first inspection data obtained from the predetermined track belonging to the first information track group and the second inspection data obtained from the track belonging to the second information track group adjacent to this track include: If a correlation equal to or greater than a predetermined value is found, test data obtained from a track belonging to a first information track group adjacent to this track is used as test data for a track belonging to the second information track group. .

[0005]

Next, the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of a disk inspection apparatus according to an embodiment of the present invention. In FIG. 1, reference numeral 2 denotes a light head arranged so as to be movable in a radial direction of a recording medium 1 and has a predetermined power. Light beam (laser light) 2
5, a light-emitting element (semiconductor laser: LD) 21, a light-receiving element (PIN photodiode) 22, which detects reflected light on the recording medium 1, an objective lens 23, and an actuator 3, which controls the track position and focus of the light beam. Have.

[0006] On the recording / reproducing surface of the recording medium 1, track grooves having concentric or spiral shapes and formed of lands and grooves are formed alternately in the radial direction. Here, for convenience, 1a is referred to as a land (convex portion: first track group), and 1b is referred to as a groove (concave portion: second track group). The light beam 25 applied to the recording medium 1 from the light emitting element 21 of the optical head 2 via the spectroscope (polarizing beam splitter) 24
A light spot is formed on a or the groove 1b.

The reflected light is received by a light receiving element 22 having a light receiving portion divided into a plurality (for example, four) through a spectroscope 24, and each light receiving signal is output to a signal generating circuit 4. Is done. The signal generation circuit 4 generates various servo signals such as a tracking error (TE) signal indicating a positional error between the light beam 25 and the track and a focus error (FE) signal indicating a focus error based on the received light signals. , A reproduction signal indicating information recorded on the track is generated.

A focus servo loop is constituted by the gain setting circuit 5, the phase compensation circuit 6 and the AF driver 7. The actuator 3 is servo-controlled by the AF driver 7 based on a focus error signal from the signal generation circuit 4. Controls the focus of the light beam 25, and a desired focus can be obtained at the land 1 a and the groove 1 b of the recording medium 1.

A gain setting circuit 8, a phase compensating circuit 9, a polarity inverting circuit 10, and an AT driver 11
A tracking servo loop is formed, and the irradiation position of the light beam 25 is slightly controlled in the radial direction by servo-controlling the AT driver 11 based on the tracking error signal from the signal generation circuit 4. 1a and a desired position (the center of the track) of the groove 1b. By performing the focus control and the tracking control in parallel, the light beam 25 is emitted to a predetermined land 1a or the groove 1b.
b.

Reference numeral 12 detects a reproduction signal from the signal generation circuit 4 and performs predetermined signal processing, thereby outputting binarized information indicating information recorded on the lands 1a and the grooves 1b, and outputting the binarized information. It is a reproduction signal detection circuit that outputs amplitude information and integration information. Reference numeral 13 denotes the reproduction signal detection circuit 12 and the data storage circuit (EP-ROM) 1
And a CPU (control means) for controlling each unit based on various information from the CPU 4.

In particular, the CPU 13 determines whether the track position irradiated with the light beam 25 is the land 1a or the groove 1b based on the address information obtained from the binarized information, and indicates the land result indicating this determination result. The groove information is output to the polarity inversion circuit 10. In general,
In the land 1a and the groove 1b, predetermined unit recording areas called sectors are continuously provided in the track direction, and address information indicating the track is assigned to each of these sectors and recorded.

Therefore, for example, the address (ID) information of the sector on the land 1a is set to an odd number, while
When the address information of the upper sector is set to an even number, by determining the odd / even number of the obtained address information,
The track position irradiated with the light beam 25 is the land 1
a or the groove 1b can be recognized, and land / groove information can be generated. In accordance with the land / groove information, the polarity determination circuit 10 determines the polarity (control direction) of the track servo loop to the AT driver 11.
Is switched.

The CPU 13 calculates a radial position where the light beam 25 is radiated based on the address information described above, and reads a power value of the light beam 25 stored in the EP-ROM 14 in advance according to the radial position. To the LD driver 16. As a result, a light beam 25 having an appropriate power according to the radial position of the recording medium 1 or the information track group is output. The actuator 3 is provided with a focus position sensor 31 for detecting the position of the objective lens 23 in the focus direction and a tracking position sensor 32 for detecting the position of the objective lens 23 in the tracking direction. Used for inspection.

The focus position sensor signal from the focus position sensor 31 is input to a secondary differentiating circuit 36 via a filter 33, where the signal is secondarily differentiated to generate a plane deflection acceleration signal, and an A / D conversion circuit is provided. The data is output to the data storage circuit 14 through 38. Tracking position sensor 3
The tracking position sensor signal from
Is input to a secondary differentiating circuit 37, where the signal is secondarily differentiated to generate a radial acceleration signal, which is output to the data storage circuit 14 via the A / D conversion circuit 38.

The focus position sensor 31, the track position sensor 32, the filters 33 to 35, and the secondary differentiating circuits 36 and 37 output inspection data indicating predetermined mechanical characteristics from predetermined tracks belonging to each information track group. Detection means for detecting is configured. Reference numeral 15 denotes a display circuit for displaying a test result of the mechanical characteristics of the storage medium 1 according to a test output from the CPU 13.

Next, the operation of the present invention will be described with reference to FIG. After the recording medium 1 is loaded in the apparatus, the recording medium 1
After reaching a predetermined number of revolutions, the optical head 2 inside the apparatus moves to the initial position of the servo start-up, and the servo adjustment is performed by following the light spot on a predetermined land track. Here, as the servo adjustment, for example, the above-described gain and offset adjustment of the focus servo loop and the gain and offset adjustment of the tracking servo loop are performed. After the servo adjustment, the ID portion (formatted ID portion) written in advance on the medium is reproduced, and after determining which land is present, the optical head 2 is moved to the area to be inspected and Follow the land track.
The following inspection operation is performed on a predetermined land track.

First, the operation for inspecting the surface runout acceleration will be described. Here, the focus direction position of the objective lens 23 following the predetermined land track is detected by using the focus direction position sensor 31 of the actuator 3. The focus position sensor signal from the focus position sensor 31 is passed through a filter 33 to the second differentiating circuit 3.
The signal is secondarily differentiated at 6 to generate a plane deflection acceleration signal, which is further input to the data storage circuit 14 via the A / D conversion circuit 38 and stored as inspection data.

In the inspection, time series data of one rotation of the land track is stored in the data storage circuit 14 as inspection data when a predetermined land track is followed in the surface deflection acceleration signal. Further, peak detection is performed on the surface deflection acceleration signal obtained from the remaining other tracks, and it is determined whether the signal exceeds a predetermined inspection level.
Subsequently, tracking is performed on a groove adjacent to the predetermined land track from which the time-series data has been previously taken, and the time-series data of the surface runout acceleration signal for one rotation is stored as inspection data in the data storage circuit 14, and the CPU 13 Then, the correlation between the inspection data of the adjacent land track and the groove track is calculated, and if the correlation between the two is higher than a predetermined value, the inspection data of the subsequent groove track is the inspection data of the land track adjacent to the groove track. Substitute with

FIGS. 2A and 2B are explanatory diagrams showing an example of sampling the waveform level for one rotation of the track between adjacent land tracks and groove tracks. FIG. 2A shows the waveform level of a signal obtained from the land track, and FIG. ) Shows the waveform level of the signal obtained from the groove track adjacent to the land track (a). FIG. 3 is an explanatory diagram showing the correlation of inspection data between adjacent land tracks and groove tracks. The horizontal axis represents the waveform level of a signal obtained from the land track, and the vertical axis represents the land track (horizontal axis). It shows the waveform level of the signal obtained from the groove track.

When a time series of inspection data as shown in FIG. 2, that is, surface runout acceleration data as shown in FIG. 2, is sampled from a predetermined land track and a groove track adjacent thereto as one track rotation, the CPU 13
Calculates a correlation between the two as shown in FIG. 3 based on both the inspection data. For example, as shown in FIG. 2, when the values of data Ai and Bi sampled at the same timing i from the same track circumferential position are Dli and Dgi, in FIG. 3, these Dli and Dgi are plotted on the vertical and vertical axes. On the axis, correlation data at timing i is obtained. In this way, the correlation between the two is calculated based on the correlation data obtained from all the inspection data, and when the correlation is higher than a predetermined value (when the correlation width is narrow), the inspection data of the groove track is converted. The inspection data of the adjacent land track is substituted.

Next, the operation for inspecting the radial acceleration will be described. Here, the tracking direction position of the objective lens following the predetermined land is detected by using the tracking direction position sensor 32 of the actuator 3. The tracking position sensor signal from the tracking position sensor 32 is passed through a filter 34 to a second differentiating circuit 3.
The signal is secondarily differentiated at 7 to become a radial acceleration signal, which is further input to the data storage circuit 14 via the A / D conversion circuit 38 and stored as inspection data.

In the inspection, time series data of one rotation of the land track is stored in the data storage circuit 14 as inspection data when a predetermined land track is followed in the radial acceleration signal. Further, peak detection is performed on the radial acceleration signals obtained from the remaining other tracks, and it is determined whether or not a signal exceeds a predetermined inspection level. Subsequently, tracking is performed on the groove adjacent to the predetermined land track from which the time-series data has been previously taken, and the time-series data of the radial acceleration signal for one rotation is stored in the data storage circuit 14 as inspection data, and the CPU 13 Calculates the correlation between the inspection data of the adjacent land track and the groove track, and if the correlation is high, the inspection data of the subsequent groove track is replaced with the inspection data of the land track adjacent to the groove track. I do.

Next, the operation for inspecting a high-speed displacement will be described. Here, the FE from the signal generation circuit 4
Signal or TE signal while following a predetermined land.
Among the sudden residual signals of several KHz or more contained in the E signal or the TE signal, the duration of the high speed displacement exceeding a predetermined level is detected by a power counter or the like in the CPU 13. For example, when inspecting a high-speed displacement based on a TE signal, the TE signal from the signal generation circuit 4 is input to the filter 35,
This output is stored as test data in the data storage circuit 14 via the A / D conversion circuit 38, and the CPU 13 detects the high-speed displacement continuation period.

As an inspection, time series data of one revolution of the land track is stored in the data storage circuit 14 when a predetermined land track follows the TE signal. For the TE signals obtained from the remaining tracks, the CPU 13 detects the high-speed displacement duration and determines whether or not the duration exceeds a predetermined inspection level. Subsequently, tracking is performed on a groove adjacent to a predetermined land track for which time-series data has been taken earlier,
The time-series data of the TE signal for one rotation is stored as inspection data in the data storage circuit 14, and the CPU 13 calculates the correlation between the inspection data on the adjacent land track and the groove track. Subsequent inspection data for inspecting the high-speed displacement continuation time in the groove track is replaced with inspection data of a land track adjacent to the groove track.

As described above, various inspection data are obtained from a predetermined land track and a groove track adjacent thereto, and a correlation between these time-series data is calculated. In this method, inspection data obtained from a land track adjacent to the groove track is used as inspection data for a groove track, so that a disk having information stored in both a land track and a groove track can be inspected at high speed for mechanical characteristics. Can be implemented. In the above description, the case where the inspection data of the groove track is replaced with the inspection data of the land track has been described. However, the present invention is not limited to this.
The inspection data of the land track may be replaced with the inspection data of the groove track.

[0026]

As described above, according to the present invention, detecting means for detecting inspection data having predetermined mechanical characteristics from predetermined tracks belonging to the first and second information track groups is provided. Inspection of mechanical characteristics such as surface runout acceleration, radial acceleration or high-speed displacement based on the inspection data obtained by the means, and a first inspection obtained from a predetermined track belonging to the first information track group. The data and the second
If a predetermined correlation or more is recognized with the second inspection data obtained from the track belonging to the information track group, the inspection data of the track belonging to the second information track group is determined as the inspection data of the track belonging to the second information track group. First
Inspection data obtained from tracks belonging to the information track group is used. Therefore, when the information is stored in both the convex and concave portions of the track groove as in the related art, the convex and concave portions of the track groove are compared with the case where both the convex and concave portions are inspected, respectively. Inspection of the mechanical characteristics can be performed at high speed with respect to the disc in which the information is stored in both of them.

[Brief description of the drawings]

FIG. 1 is a block diagram of a disk inspection apparatus according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing an example of sampling waveform levels for one rotation of a track between adjacent land tracks and groove tracks.

FIG. 3 is an explanatory diagram showing a correlation between inspection data and an adjacent land track and a groove track.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Recording medium, 1a ... Land, 1b ... Groove, 2 ... Optical head, 21 ... Light emitting element, 22 ... Light receiving element, 23 ... Objective lens, 24 ... Spectroscope, 25 ... Light beam, 3 ... Actuator, 31 ... Focus Position sensor, 32: Tracking position sensor, 33 to 35: Filter, 36, 37 ...
Second-order differentiator circuit, 38 A / D conversion circuit, 4 signal generation circuit, 5, 8 gain setting circuit, 6, 9 phase compensation circuit,
7: AF driver, 10: polarity inversion circuit, 11: AT driver, 12: reproduction signal detection circuit, 13: CPU, 14
... data storage circuit, 15 ... display circuit, 16 ... LD driver.

Claims (2)

[Claims] 1. A method according to claim 1, wherein the first and second information track groups having the same circular shape or spiral shape as the information tracks on the recording medium and provided alternately in the radial direction are mechanically provided. A disk inspection apparatus for inspecting characteristics, detecting means for detecting inspection data indicating predetermined mechanical characteristics from predetermined tracks belonging to the first and second information track groups, and detecting the inspection data obtained by the detecting means. The mechanical characteristics are inspected based on the first inspection data obtained from a predetermined track belonging to the first information track group, and the first inspection data obtained from a track belonging to a second information track group adjacent to the track. If a predetermined correlation or more is found with the second inspection data, the inspection data of a track belonging to the second information track group is checked. As data, disk inspection apparatus characterized by a control means using test data obtained from the track belonging to the first information track group adjacent to the track. 2. A disk inspection apparatus according to claim 1, wherein said control means inspects at least surface runout acceleration, radial acceleration or high-speed displacement as mechanical characteristics based on the inspection data obtained by said detection means. A disk inspection device characterized by the above-mentioned.