JPH1069731A - Optical recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical recording medium having two times recording capacity by making four or more in the decimal number system the numeric value expressed with four bits of the ARD term of the Q channel code in the sub-code of a read-in zone. SOLUTION: The data format of the Q channel in the read-in zone is expressed in a figure (a) and set in the ARD term of four bits in the Q channel code within a read-in track. A MODE-1 is expressed to select with the bit 1 in the right end by setting e.g. (0101) in the ARD term and a reproduced optical recording medium is expressed to be two times density with the bit 1 of the second from the left. The data format of the Q channel in a read-out zone is expressed in a Figure (b). 170 is expressed in the decimal number system with (10101010) by treating a eight-digit binary number system writing as a lump of eight bits. Accordingly, a read-out track 170 is detected by changing the track number from zero to 169.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a recording method for a read-only optical recording medium comprising phase pits as information.

[0002]

2. Description of the Related Art A conventional EFM-modulated optical recording medium composed of phase pits has a track pitch set to 1.6 μm, and the shortest mark length of a pit is 0.833 μm.
m to 0.972 μm. It is a so-called compact disk which generally has a recording capacity of about 650 MB. Recently, as the demand for an increase in the recording capacity of a read-only optical recording medium has increased, a large-capacity standard such as a DVD has been proposed. However, in order to realize this, an inexpensive short-wavelength semiconductor laser and a numerical aperture of 0.6 are required.
While securing an objective lens of zero and an inexpensive disk manufacturing process are indispensable, supply of a low-cost drive device and a disk that is considerably complicated compared with a compact disk is difficult.

[0003]

An optical recording medium having a recording capacity about twice that of a conventional compact disk can be adequately handled by a stamper and a disk forming equipment currently in operation, and is used for reproducing a conventional compact disk. The optical recording medium has a recording capacity twice as large as that of the conventional optical pickup medium when the disk structure that can use the basic structure of the optical pickup as it is can be used, so that the track number and the time and absolute time in the reproduction track are doubled. This causes inconvenience. In other words, the conventional compact disk recognizes only up to 99 tracks because the track number is a 2-digit BCD code. Similarly, the display of the elapsed time or the absolute time in the playback track is a display method that can be recognized only up to 99 minutes.

[0004]

According to a first aspect of the present invention, a recording method of a phase pit sequence formed on a transparent substrate is in accordance with EFM modulation or EFM plus modulation. In the sub-codes of the lead-in area, the lead-out area and the tone area to be formed, at least the numerical value represented by the 4 bits of the ADR term of the Q channel code in the sub-code of the lead-in area is 10
It is suggested that the number be 4 or more in the binary system.

In a second aspect of the present invention, the recording format of the pit row formed on the transparent substrate follows EFM modulation or EFM plus modulation, and the TNO, which indicates the track number in the Q channel code in the subcode of the lead-in area,
MIN and PMIN, TN indicating the track number in the Q channel code in the sub-code of the musical tone area
O, MIN representing the elapsed time on the track, AMIN representing the absolute time, and TNO, MIN and AMIN of the Q channel in the subcode of the lead-out area. TNO, MIN for elapsed time on track, and AMI for absolute time
It is proposed to record a continuous block of 8 bits for each of N.

Further, the third invention proposes that the TNO of the Q channel in the sub-code in the lead-out area is represented by a continuous block of 8 bits, and is set to 170 or more in decimal system.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION A phase pit having a mark length of 0.60 μm or more formed on an optically transparent substrate has an opening width of 0.40 μm or less and a bottom width of 0.25 μm or more.
By optimizing the optical phase depth to 3.5 times or less and 4.2 times or more, and optimizing the track pitch to 1.10 μm or more, the currently used compact disk manufacturing equipment can be used effectively. Thus, it is possible to obtain a double-density read-only optical recording medium that can be used for optical discs and can be reproduced by an optical pickup used for reproducing a compact disc. An example of such an optical recording medium will be described with reference to FIG.

FIG. 1 is a schematic cross-sectional view of a disk-shaped optical recording medium according to one embodiment of the present invention, which is cut in a radial direction. Conditions for forming phase pits on the optically transparent polycarbonate substrate 1 having a refractive index of about 1.58 are as follows:
To 0.40 μm or less, and the pit bottom width 4 to 0.2
5 μm or more, and the pit depth 5 of the pit is optically changed from 3.5 wavelength to 4.2 wavelength.
Using a laser cutting device used in the manufacture of compact disks, cutting a glass master coated with a resist of 117 nm to 141 nm thick,
A stamper is created through development, conductivity, electroforming, and polishing steps, and the polycarbonate substrate 1 is subjected to injection molding. An aluminum reflective film is formed on the side of the injection molded polycarbonate substrate 1 where the pits are formed by a sputtering device. Further, a protective coat 7 is formed by injection molding the polycarbonate substrate 1 to protect the aluminum reflective film. An aluminum reflective film is formed on the side of the injection molded polycarbonate substrate 1 where the pits are formed by a sputtering device. Further, a protective coat 7 is formed to a thickness of about 12 μm by a spin coater to protect the aluminum reflective film.

The signal evaluation of the optical recording medium manufactured through the above-described steps was performed. The optical pickup used for the evaluation is a combination of a 780 nm semiconductor laser used for a compact disc and an objective lens having a numerical aperture of 0.45. The pit signal recorded on the optical recording medium of the present invention complies with the EFM modulation. The signal amplitude of 3T with respect to the signal amplitude of 11T is reduced to less than half that of a normal compact disk in any of the optical recording media manufactured in this embodiment. However, in any optical recording medium, the amplitude of 3T can be increased by adding an inexpensive amplitude equivalent circuit, and signal quality satisfying the compact disk standard (block error rate of 3% or less) can be easily obtained. . Double density E on polycarbonate substrate
Q composed of a phase pit sequence recorded according to FM modulation
A recording method of a channel will be described.

FIG. 2A shows the data format of the Q channel in the lead-in area. PO is POIN
T and M are MIN, S is SEC, FR is FRAME, PM
Represents PMIN, PS represents PSEC, and PF represents PFRAME. When MODE-1 is used in a conventional compact disc, the 4-bit ADR term in the Q channel code in the lead-in track is set to (0001). For example, instead of (0001), (0101) is used. AD
By setting it to the R term, the rightmost bit 1 becomes MODE.
It indicates that -1 has been selected, and the second bit 1 from the left indicates that the optical recording medium to be reproduced has double density. In the conventional compact disk, the TNO indicating the track number expresses 8 bits in a 2-digit BCD code. However, in the present invention, the 8-digit binary notation of the TNO is treated as a block of 8 bits to express up to 255. Becomes possible.

FIG. 2B shows the data format of the Q channel in the lead-out area. In order to represent the lead-out track on a conventional compact disc, AA, ie, (1)
However, as described in the present invention, by treating an 8-digit binary notation as a block of 8 bits, (10101010) becomes 1 in decimal notation.
70 will be shown. Therefore, if the track number is 0
From 169 to lead-out track 1
70 can be detected. Of course, the number of the lead-out track may be designated by a number different from the conventional TNO (10101010). That is, it is possible to specify a number between 170 and 255, inclusive.

[0012] Further, the conventional MIN and AMIN are 74 minutes at the maximum in the conventional case, but the display of 148 minutes at the maximum is required for the double density disc. FIG. 3 shows the data format of the Q channel in the tone area according to the present invention. AM is AMI according to Red Book
N and AS represent ASEC, and AF represents AFRAME. TN
By treating the 8-digit binary notation of O as one block of 8 bits, the maximum track number of "255" can be set to T
NO can be designated by consecutive 8 bits “11111111”. The track number of "198" of double density is shown in FIG.
"11000110". In this case, the lead-out track is set to (11000011), that is, 19
It will be specified by a number 9 or more. Similarly, as shown in FIG. 4, with regard to MIN and AMIN, display of up to 255 minutes is possible by treating a 2-digit BCD as a block of 8 bits. In the embodiment, “01111000” is shown up to 120 minutes. 255 minutes
11111111 ". As described in detail above, by setting ADR to (0101), MO
It is possible to display up to 255 by designating that it is a double density optical recording medium of DE-1, and by treating a 2-digit BCD code representing TNO, MIN, PMIN and AMIN as a continuous block of 8-bit data. become.

[0013]

According to the optical recording medium of the present invention, it is possible to supply an optical recording medium having a recording capacity twice as large as that of a conventional compact disk, in which equipment for manufacturing a conventional compact disk can be effectively used. By changing the description of the Q channel in the sub-code composed of the pit train, the elapsed time, the absolute time, and the track number in the reproduction track can be handled in the same manner as a conventional compact disk having a track pitch of 1.60 μm. It is.

[Brief description of the drawings]

FIG. 1 is an enlarged schematic sectional view of a portion of an optical recording medium of the present invention cut in a radial direction.

FIG. 2 is a diagram showing a Q channel data format in a lead-in area and a Q channel data format in a lead-out area of the optical recording medium of the present invention.

FIG. 3 is a diagram showing data of a track number of a Q channel in a musical sound area of an optical recording medium according to the present invention.

FIG. 4 is a diagram showing MIN and AMIN data of a Q channel in a musical sound area of the optical recording medium of the present invention.

[Description of Signs] 1 Polycarbonate substrate 2 Aluminum reflective film 3 Pit opening width 4 Pit bottom width 5 Pit depth 6 Track pitch 7 Protective coat

Claims (3)

[Claims] 1. The recording format of a phase pit row formed on a transparent substrate is in accordance with EFM modulation or EFM plus modulation, and the recorded pit row forms a sub-code of a lead-in area, a lead-out area, and a musical tone area. At least the numerical value represented by the 4 bits of the ADR term of the Q channel code in the sub-code of the lead-in area is 10
An optical recording medium characterized by being 4 or more in binary. 2. A recording format of a pit row formed on a transparent substrate follows EFM modulation or EFM plus modulation, and TNO, MIN, and P indicating a track number in a Q channel code in a subcode of a lead-in area.
MIN, TNO representing the track number in the Q channel code in the sub-code of the musical tone area, MIN representing the elapsed time on the track, and AMIN representing the absolute time
And TNO representing the track number of at least the Q channel code in the sub-code of the musical tone area among the TNO, MIN and AMIN of the Q channel in the sub-code of the lead-out area, MIN representing the elapsed time on the track, and representing the absolute time 2. The optical recording medium according to claim 1, wherein each of the AMINs is recorded in a continuous block of 8 bits. 3. The optical recording medium according to claim 2, wherein the TNO of the Q channel in the subcode in the lead-out area is represented by a continuous block of 8 bits, and is 170 or more in decimal notation.