JPH0423240A - Optical disk with guide groove - Google Patents

Abstract

PURPOSE:To widen a data recording area and to enable the continuous recording of continuous data to be performed by arranging the data recording area on a land part, and arranging pits at a pair of guide grooves on the extension of the pair of guide grooves neighboring to the right and left sides of the area. CONSTITUTION:The land part 3 demarcated by the guide groove 2 is provided, and the data recording area R is provided at the part, and the pits 4 are provided on the extension of the pair of grooves 2 neighboring to the right and left sides of the area R as a pre-formating part F. Thence, the diameter of the spot S of a laser beam is set equally to the total length of the width of the land part 3 and that of the pair of grooves 2, and the spot S is made to follow the land part 3, and address data is read by the change of reflected light on the pit 4 of the pre-formating part F, and the information of the pit 9 recorded on a following recording part R is written or read. Thereby, the data recording area can be widened, and the continuous recording of the continuous data can be performed.

Description

[Detailed Description of the Invention] Technical Field The present invention relates to write-once type, DRAW (Direct Rear)
The present invention relates to an optical disk with a guide groove used as a magneto-optical recording medium or a phase change recording medium.

BACKGROUND ART Such optical discs with guide grooves include, for example, one having a structure shown in FIG. In this disc, PMMA,
Concentric or spiral grooves are provided on the lower surface of the transparent circular substrate 1 made of P'C or the like, and the entire surface is covered with a recording layer 5 made of a magneto-optical recording medium or a phase change recording medium. A guide groove 2 and a land portion 3 are defined on the recording layer. A pre-address bit 4 (hereinafter simply referred to as a bit) is formed in advance on the land portion 3. This substrate 1 is bonded to another substrate so as to sandwich the recording layer 5, thereby forming an optical disk with guide grooves.

FIG. 6 shows a partially enlarged plan view of the optical disc with guide grooves.

The land portion 3 forms a track, and the portion indicated by F is a preformatted portion in which bit 4 is preformed corresponding to address data, and the portion indicated by R is a portion where the inverted magnetic domain or phase change domain is later formed in the racer spot. This is a recording section in which bit 9 is written as bit information.

In the writing operation of the optical disc with guide grooves, the substrate 1
A laser beam for writing is irradiated from the side, the spot is followed by a tracking servo, etc. on the land part, address data is read by the reflected light of the pit 4 of the preformat part F, and an inverted magnetic domain or a phase change domain is written in the subsequent recording part R. A pit 9 is formed to record information. Next, in the reading operation, the reading laser beam is made to follow the land portion 3, and the pit 4 of the preformat portion is
It is operated to read the address data and read the information of the pit 9 recorded in the recording section R.

This recording method is called a land recording method, and the data recording area is managed by pits on the land portions.

In particular, in magneto-optical recording, the land recording method has a high C.
/N is known to be obtained.

However, in magneto-optical recording that reads minute changes in reflected laser light, if data is overwritten on the address bits on the land portion, the data cannot be reproduced normally because the pits are not flat due to the unevenness of the pits. When a relatively long analog continuous signal such as audio data that does not require much address data is continuously recorded using an analog method (FM modulation), dropouts occur due to diffuse reflection of the laser by pits on the land.

Moreover, in this case, the CN ratio also deteriorates.

SUMMARY OF THE INVENTION [Object of the Invention] Therefore, an object of the present invention is to provide an optical disc with a guide groove that eliminates the drawbacks of the prior art and is easy to manufacture, particularly an optical disc with a guide groove using the CAV method.

[Structure of the Invention] The optical disc with a guide groove of the present invention is an optical disc with a guide groove that carries a recording layer having a land portion defined by a guide groove extending in the circumferential direction, wherein the land portion is A data recording area is arranged on the top, and a plurality of preaddress pits are arranged in the circumferential direction to form a binary pit on the same line in the disk radial direction on the extension line of a pair of guide grooves on both sides of the data recording area. It is characterized by the fact that it is distributed as much as possible.

[Operation of the Invention] With the configuration of the present invention, it is possible to ensure that the land portion of the optical disk with guide grooves is flat, and even with land recording methods such as magneto-optical recording that read minute changes in reflected laser light, signal dropout does not occur. Decrease.

Embodiment An embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a partially enlarged plan view of the optical disc with guide grooves of this embodiment, and the names of each part are the same as those of the optical disc with guide grooves in FIG. 5, and are therefore designated by the same reference numerals. The optical disc with guide grooves of this embodiment has two guide grooves as well as the conventional one.
The data recording head R is arranged on the land 3, and the preformat part F is located on the extension line of the pair of guide grooves 2 on both sides of the data recording head R.
A pit is arranged as a.

The writing and reading operations of such an optical disc with guide grooves are almost the same as those of the conventional system, or are different in the operation of reading the pits 4 of the preformat section F. That is, the diameter of the spot S of the laser beam is made approximately equal to the total length of the width of the land portion 3 and the pair of guide grooves 2 on both sides, and the spot is made to follow the land portion, and the diameter of the spot S of the laser beam is made to be approximately equal to the total length of the width of the land portion 3 and the pair of guide grooves 2 on both sides. The address data is read by changes in the reflected light, and the information in the pits 9 recorded in the subsequent recording portion R is operated to be written or read.

FIG. 2 shows RF waveforms obtained in the order of A to F when the recording portion of the optical disk with guide grooves shown in FIG. 1 is moved from left to right in the figure by a laser beam spot S. If even one pit exists in the spot S, the reading laser reflected light is disturbed and its intensity decreases, and when a pair of pits on both sides of the land portion exist in the spot S, the intensity of the reading laser reflected light decreases. It will be the lowest. For example, if the RF waveform in Figure 2 is to be binarized and a threshold is set as shown by the dashed-dotted line in Figure 2, only when there is a pair of pits on both sides of the land will be identified, and this will be identified by the address It shall be applied to O of the data. Then, the address data corresponding to the waveform of FIG. 2 from 8 to F becomes 011 ], 01.

Identifies only when there is a pair of bits on both sides of the land,
If this is applied to address data 0 and bits are formed on both sides of the land portion, 16 tracks having different address data from 0 to F as shown in FIG. 3 are obtained. Different sets of pits 4 are shown on extension lines of the pair of guide grooves 2 on both sides of the land portion 3, and the pits of the guide groove between the pair of land portions 3 are shared by the pair of lands. Such a plurality of address data is an example of modulation as 4-bit hexadecimal data according to the code table shown in FIG. 4, and the code table shown in FIG. 4 shows an example of the arrangement of pits in the preformat part of the intra-sector format.

In a CAV disk, address data is always assigned to bits in sectors arranged in the radial direction of the disk in ascending or descending order. For example, in FIG. They appear sequentially at the beginning of the sector, and repeat the array 0 to F to indicate that the CAV disk is being formatted.

Therefore, as shown in the figure, this embodiment can be used for recording one frame of image on one track of a CAV disc, for example, and one bit is arranged for one track almost at the leading end, and a plurality of bits It takes advantage of the fact that the tracks are arranged in a radial direction and the address data is arranged so that it changes continuously by a predetermined value. Address data can be read based on crosstalk signals corresponding to changes in laser light reflected by pits on guide grooves provided on both sides of the land portion. Since the pits of the guide groove are shared by adjacent tracks, a pair of bits in a CLV disk will be misaligned.

In this embodiment, when address data is recorded and reproduced using a pair of bits in the guide grooves on both sides of the land portion, if the C/N ratio of the address data is 60 dB (bit), the C/N ratio of the entire system is 48 dB. The ratio is obtained.

According to this embodiment, all the land portions have a mirror surface, and dropouts due to pits will not occur.

In addition to this embodiment, it is possible to record and reproduce address data using a row of bits in the guide groove on one side of the land, but the amplitude would be approximately 112, the modulation degree would be 1/2, and the CN
The ratio is about 12 dB, which is worse than address data recorded on normal land portions. For this reason, it is possible to reduce the recording density and increase the pit diameter in the guide groove, but compared to the modulation method that uses multiple pit diameters for reading and writing, according to this embodiment, the pit diameter for reading and writing is By making the diameters the same, deterioration in modulation degree can be reduced. Although the above embodiment uses a 1-beam system, it is also possible to operate with a 3-beam system.

Effects of the Invention As described above, according to the optical disc with guide grooves of the present invention, the data recording area is arranged on the land part, and the pits are arranged on the extension line of the pair of guide grooves on both sides of the data recording area. All data recording areas on the unit have a mirror surface. Therefore, the data recording area is expanded, and it becomes possible to continuously record continuous data such as analog audio signals, which conventionally could not be continuously recorded (written) due to the address area.

[Brief explanation of the drawing]

FIG. 1 is a partially enlarged plan view showing pre-address pits on the surface of an optical disk with guide grooves according to the present invention, and FIG. 2 is a graph showing an RFi shape corresponding to the pre-address pits in FIG. 1.
FIG. 3 is a partially enlarged plan view of 16 pairs of bridle pits on the surface of an optical disk with guide grooves according to an embodiment of the present invention;
The figure shows a hexadecimal code table corresponding to the pre-address pit shown in Fig. 3, Fig. 5 is an enlarged perspective view of a cutout part of a conventional optical disc with guide grooves, and Fig. 6 shows pre-address pits on the surface of a conventional optical disc with guide grooves. It is a partially enlarged plan view showing. Explanation of symbols of main parts 1...Transparent substrate 2...Guide groove 3...Land portion 4...Briard swivel/soto 5... Recording layer 9... Recorded bi-soto F... Preformat section R... Recording section

Claims (1)

[Claims] An optical disc with a guide groove carrying a recording layer having a land defined by a guide groove extending in the circumferential direction, wherein a data recording area is disposed on the land, and a pair of guide grooves are provided on both sides of the data recording area. 1. An optical disc with a guide groove, characterized in that pre-address pits forming binary pits on the same line in the radial direction of the disc are disposed on an extension line of the guide groove in a plurality of digits in the circumferential direction.