JPS63313331A - Optical disk - Google Patents

Abstract

PURPOSE:To enable the inspection of optical disks of different systems by means of an inspection device of one tracking system by segmenting the optical disk to two regions; a wide region and narrow region, and recording different sets of tracking information in the respective regions. CONSTITUTION:The optical disk 1 is segmented to the relatively wide region A an the region B narrower than the region A. The region A is the region where a user records and reproduces the information and the region B is a region where the user does not usually record and reproduce the information. Wobbled pits W1 and W2 are recorded (formed) as the tracking information in the region B when grooves G or lands L are recorded (formed) as the tracking information in the region A. The recording of the track information in the region B is executed in succession to the recording of the track information of the region A and, therefore, the eccentricity, horizontal acceleration, out of roundness, etc. in the regions A and B are equaled and the inspection of the same and different tracking systems with the inspection device of the one tracking system is enabled.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an optical disc for optically recording and reproducing information.

[Summary of the invention]

In the present invention, an optical disc is divided into two areas,
First tracking information is recorded in the first area, and second tracking information different from the first tracking information is recorded in the second area.

[Background technology]

There are two types of tracking methods for optical discs.

The first method is called a continuous servo method. As shown in Figure 2, this type of disc has a group C as tracking information that guides the pickup (information detection point).
G) is formed (as a result, a land (L) is formed relatively between the groups), and either this group or the land is considered to be a track (T) on one side (in the figure, it is group G). is designated as track T), on which information is recorded. The tracking error signal is continuously generated by detecting left and right edge information of the track by a push-pull method, an auxiliary beam method, or the like.

The second method is called the sample servo method.

As shown in FIG. 3, this type of disc contains two wobbled pits W1.1 and 2.2 at positions shifted left and right from the center of the track (virtual track) T as tracking information. W
2 are formed spaced apart by a predetermined distance in the track direction. Such wobbled bits are arranged on the track at a predetermined period t2. The tracking error signal is
It is generated from the difference between the RF multiplied signal levels at the wobbled bits W□ and w2. The tracking error signal is sampled every cycle and held until the next cycle.

Since the two systems have completely different principles as described above, each requires a dedicated tracking servo circuit.

[Problem that the invention seeks to solve]

Optical discs are inspected for eccentricity, horizontal (radial) direction acceleration, roundness, etc., and only those that satisfy predetermined standard values are provided to users. Therefore, when manufacturing discs with different tracking methods, manufacturers must prepare dedicated inspection equipment for each disc, which is inconvenient.

Therefore, the present invention enables a single tracking type inspection apparatus to inspect optical disks of different types.

[Means for solving problems]

The present invention provides an optical disc that is divided into a relatively wide first area and a second area that is relatively narrow compared to the first area, and a method for making it possible to track information detection points in the first area. It is characterized in that first tracking information is recorded, and second tracking information different from the first tracking information is recorded in a second area.

[Effect]

The optical disc is divided into a relatively wide first area and a second area narrower than the first area. the first area
When tracking information is recorded in the second area, second tracking information different from the first tracking information is recorded in the second area. Therefore, the inspection device using the first tracking method can inspect the first region, and the inspection device using the second tracking method can inspect the second region.

[Example〕 FIG. 1 shows a plan view of the optical disc of the present invention.

The optical disc 1 is divided into a relatively wide area A and an area B which is narrower than the area A. Area A is an area where the user records and reproduces information, and area B is an area where the user normally does not record and reproduce information. Region B is provided on the inner periphery of region A (of course, it can also be provided on the outer periphery).

When groups or lands as shown in FIG. 2 are recorded (formed) in area A as tracking information, wobbled bits as shown in FIG. 3 are recorded (formed) as tracking information in area B, and vice versa. When wobbled bits are formed in area A, groups or lands are formed in area B.

The recording of the track information in area B is performed (formation) of the track information in area A (without once releasing the attachment to the spindle motor 2) (of course, the order may be reversed). The eccentricity, horizontal acceleration, roundness, etc. are the same in and B.

A boundary area C is formed between areas A and B, and no track information is recorded in area C.

In other words, the track information of area B and the track information of area A are not continuous as tracks. As a result, area B
Prevents the spot light tracing the track of area A (or A) from continuing to trace the track of area A (or B) and the data at that time being mistakenly detected as data of area B (or A). be done.

FIG. 4 is a block diagram of an optical disc inspection device. When the input means 11 is operated to command the start of inspection, the control circuit 9, which is made up of, for example, a microcomputer, controls the spindle motor 2 via the spindle servo circuit 8,
Rotate the optical disc 1. At this time, a pulse generator (PG) 3 attached to the spindle motor 2 generates pulses synchronized with the rotation.

Data regarding the tracking method in area A of the optical disc 1 mounted is inputted from the input means 11. If the input method is the same as the tracking method in the tracking servo circuit 6, the control circuit 9 controls the slider servo circuit 5 to move the pickup 4 to a predetermined position in the area A. If the input method is different from the method in the tracking servo circuit 6, the pickup 4 is moved to a predetermined position in area B.

Of course, it is also possible to input an area of the same tracking method as the tracking servo circuit 6 through the input means 11, and move the pickup 4 to the input area. Alternatively, the pickup 4 can be automatically moved to one of areas A and B without any particular input, and if the tracking servo is applied there, the inspection described below will be executed, and if the servo is not applied, the pickup 4 can be moved to the other area. It is also possible to predetermine a sequence.

When the pickup 4 is placed at a predetermined position, the control circuit 9 controls the focus servo circuit 7 to close the focus servo loop. Further, the tracking servo circuit 6 is controlled, and the tracking servo loop is closed. As a result, the spot light (information detection point) on the optical disk 1 traces the track.

The control circuit 9 detects one revolution of the optical disc 1 based on the pulse output from the pulse generator 3, and also detects the error voltage of the slider servo loop during one revolution of the optical disc 1.

As shown in FIG. 5, this error voltage exhibits two peak values, large and small, during one rotation of the optical disc 1.

The difference between the high level peak value 2 and the low level peak value V corresponds to the amount of eccentricity. The control circuit 9 uses this value ■
, and v2, the amount of eccentricity is calculated and displayed on a display means 10 such as a CRT or a printer.

The horizontal (radial) direction acceleration is obtained by calculating the differential value at the zero cross of the error signal in FIG. Further, the roundness can be obtained by correcting the error voltage at a predetermined rotation angle of the optical disc 1 by the amount corresponding to the track pitch. These calculations, corrections, etc. are also performed by the control circuit 9, and the results are displayed on the display means 10.

〔effect〕

As described above, the present invention divides an optical disc into a relatively wide first area and a second area that is relatively narrow compared to the first area, and makes it possible to track information detection points in the first area. Since the first tracking information for the inspection is recorded and the second tracking information different from the first tracking information is recorded in the second area, a single tracking type inspection device can perform the same inspection and inspection. It becomes possible to perform inspections using different tracking methods.

[Brief explanation of drawings]

FIG. 1 is a plan view of the optical disc of the present invention, FIG. 2 is an explanatory diagram of tracks using the continuous servo system, FIG. 3 is an explanatory diagram of tracks using the sample servo system, and FIG. 4 is a block diagram of the inspection device. , FIG. 5 is a waveform diagram of the error voltage of the slider servo. 1... Optical disk 2... Spindle motor 3... Pulse generator 4... Pick up 5... Slider servo circuit 6... Tracking servo circuit 7... Focus servo circuit 8... Spindle servo Circuit 9...Control circuit 10...Display means 11...Input means or higher

Claims (1)

[Claims] first tracking for making it possible to track an information detection point in the first area by dividing it into a relatively wide first area and a second area that is relatively narrow compared to the first area; An optical disc characterized in that information is recorded, and second tracking information different from the first tracking information is recorded in the second area.