JPH08190738A - Recording method and recording and reproducing method on master disk of information recording medium - Google Patents

Abstract

PURPOSE: To provide a preformatted information recording medium with an information recording and reproducing area to be used by the user and a format signal area for address information to be used for random access, etc., arranged in good combination. CONSTITUTION: In a recording master disk 40 for duplicating a recording medium, two master disk recording beams A and B are used, and one beam is slightly inclined to the other beam, and then they are converted on the master disk to perform recording. Alternatively, after recording a track guide, information such as position information is recorded while the device tracks along this track guide.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention records or records information on an information recording layer by optical means such as TeOx or a refractive index change recording method in a device such as a digital data file. The present invention relates to a master recording method for an information recording medium for reproducing or erasing information, and a recording / reproducing method for an information recording medium reproduced by using the master.

[0002]

2. Description of the Related Art FIG. 5 is a schematic diagram showing the structure of a conventional information recording medium. In the figure, 1 indicates an empty groove portion of the information recording / reproducing area, and 2 indicates a signal area for formatting the position information and the like. Reference numeral 3 indicates a recording / reproducing beam. The groove depth of the information recording / reproducing area and the format signal area such as position information is
The detection signal of the tracking error by the far field method is set to about λ / 8, which is the maximum.

In optically reading an information recording medium having such a structure, there is a problem that a tracking error signal and a focus error signal are adversely affected when a recording / reproducing beam crosses a format signal area. There is.

[0004]

SUMMARY OF THE INVENTION The present invention realizes a groove structure most suitable for the characteristics of information recording / reproduction, and eliminates the adverse effect on the focus and tracking error signals of the format signal area, which has been a problem in the past. The problem is solved by separating the signal area for recording from the information recording / reproducing area,
An object of the present invention is to provide a master recording method and a recording / reproducing method for an information recording medium capable of surely recording / reproducing desired information at a desired address under stable servo conditions and improving C / N.

Particularly, in a pre-formatted information recording medium, a preferable structure is provided for an information recording / reproducing area used by a user and a format signal area for address information which is a position signal used for random access. To do.

[0006]

In order to achieve the above object, the present invention is for optically recording desired information without changing the shape of the information recording layer, or for reproducing or erasing the recorded information. The information recording medium has a concentric or spiral continuous track guide having a constant depth and a groove depth different from that of the track guide, which is located between the track guides and has a half track pitch. When forming a format signal such as an address having a pit width shorter than the distance, the first master recording light beam of the two master recording light beams is focused and exposed on the master disk. To form a track guide, the second master recording light beam is passed through an optical modulator for forming information pits, and then the first master recording is performed. By exposure is converged on the master plate is inclined with respect to the incident angle of the light beam, it is to create a master disk for an information recording medium.

Further, according to the present invention, a master for reproducing the above-mentioned recording medium is recorded by using two master recording beams, or after recording a track guide, the position is controlled while tracking along the track guide. It records information such as information.

Further, the present invention forms at least two light beams, irradiates the first light beam on the track guide, and forms information pits such as addresses between the track guides irradiating the first light beam. Information is recorded, reproduced, or erased by irradiating a certain portion with a second light beam.

[0009]

With the above structure, the master of the information recording medium can be produced with a simple structure. Moreover, the format signal does not affect the focus and tracking servo,
At the time of recording / reproducing operation using the duplicated information recording medium,
The format signal does not affect the focus and tracking servo, and the C / N in the information recording / reproducing characteristics can be improved, and the information is additionally recorded / reproduced on the preformatted information recording medium. It is advantageous when

[0010]

FIG. 2 shows the relationship between the groove phase depth, the tracking error signal output by the far field method, and the address signal output recorded by the phase type. In the figure, the vertical axis represents relative output and the horizontal axis represents phase depth. The relationship between the phase depth ψ and the actual groove depth d is given by the following equation in the case of reflection reproduction, where n is the refractive index of the substrate at the used wavelength λ.

Ψ = 2nd · 2π / λ From FIG. 2, the address signal recorded in the phase type has a peak at the phase depth ψ = π radian, and the error detected by the far field method is the phase depth ψ = π / 2. 3π / 2
It peaks in radians. However, the phase of the tracking error signal is inverted at π / 2 and 3 / 2π radians. Further, the reflectance from the groove of the information recording medium has the inverse relationship with the output of the address signal as shown by the broken line in the figure, and becomes maximum at the phase depth ψ = 0.2π radian.

When a refractive index change type material such as TeOx is used for the information recording layer, it is desirable that the C / N of the information recording / reproducing signal is recorded / reproduced in the groove having a high opposite ratio. Therefore, a phase depth ψ = 0.2 π radians is desirable.

Next, considering the simplicity of the optical system, the far-field method is preferable as the tracking detection method, and the phase depth ψ = π / 2 radian is optimal in order to obtain a high relative output.

Further, in consideration of reliable access to the recording position, the format signal preferably has a high signal output, and the phase depth ψ = π radian is optimal.

FIG. 3 is a schematic view showing an example of a groove structure which satisfies the above conditions. In FIG. 1A, 10 is an information recording medium substrate, on the surface of which an information recording layer such as TeOx is formed. Reference numeral 11 is a recording area, and only the track guides 12 to 15 are shown in the drawing. Between the track guides 12 to 15 which are adjacent to each other in the radial direction, the second guides 16 to 18 shown in the drawing are provided.
The format signal area as the information section is formed in a desired section in the circumferential direction. This figure shows the case of 8 sectors / track. The format signal areas 16 to 18 may be formed by a desired number of sectors. In addition, there is also a format signal area including a track address and the like, if necessary.

FIG. 2B is an enlarged view of the area AA in FIG. 1A, and each number is assigned in the same manner as in FIG. Here, 19 is an information pit recorded in an information recording / reproducing area (information recording section), 20, 21, 22 are a recording spot, a tracking detection spot,
Indicates a playback spot.

In the information recording medium having such a structure,
The track guides 12 to 15 are formed with a phase depth ψ = π / 2 radians, and the format signal areas 16 to 18 between the track guides 12 to 15 are formed with the uneven signal of the phase depth ψ = π radians, and To provide an information recording medium satisfying all of the optimum phase depths by using an area other than the format signal areas 16 to 18 between the guides 12 to 15 as an information recording / reproducing area having a phase depth ψ = 0 radian. Is possible.

Further, in the information recording medium having such a structure, by separating the information recording / reproducing spot and the focus error and tracking error detection spots, the adverse effect of the format signal on the focus and tracking error signal is completely eliminated. It is possible to eliminate it, and it is possible to surely record / reproduce desired information at a desired address under stable servo conditions, and it is possible to record / reproduce information having a high C / N.

The recording width in the radial direction of the format signal areas 16 to 18 between the track guides 12 to 15 is as shown in FIG. 3B in order to avoid interference of the format signal with the tracking detection spot. Adjacent track guides
It is shorter than about half the distance between 12 and 15.

The recording material and the recording method are TeOx.
A method for recording or reproducing information without changing the shape of the information recording layer, such as a recording method for changing refractive index and a recording method for changing refractive index, is used. Anything that satisfies can be applied.

An example of an apparatus for producing a master of an information recording medium according to the present invention will be described with reference to FIG. The light flux from the laser light source 30 is split by the half mirror 31 into light fluxes 31a and 31b at a desired ratio. The divided light flux 31a is guided to the light modulator 32, attenuated to a desired exposure amount, reflected by the total reflection mirror 33, and further reflected by the total reflection mirror 34. After that, it is guided to a beam expander system composed of lenses 35 and 36, and after being expanded to a desired beam diameter, reflected by a total reflection mirror 37 and condensed by a recording lens 39 mounted on a voice coil 38, A spot is formed at the position A on the recording master 40. For example, the spot guide exposes the track guide.

On the other hand, the other beam 31b split by the half mirror 31 is totally reflected by the total reflection mirror 41 and intensity-modulated by the second optical modulator 42 based on desired information. Here, as the input electric signal to the optical modulator 42, the signal 48 from the signal encoder is supplied only while the gate circuit 45 is ON. On the other hand, the gate circuit 45 is controlled by a gate control circuit 46 that outputs a signal only in a desired period in synchronization with a recording system turntable drive signal 47. As the optical modulator 42, an AO optical modulator or an EO optical modulator can be used.

The output light from the second optical modulator 42 is guided to the shutter 43, guided to the total reflection mirror 44 only for a desired period, and totally reflected. The total reflection mirror 44 is installed so that the optical axis of the light beam 31b is slightly inclined with respect to the optical axis of the light beam 31a. The light beam 31b totally reflected by the total reflection mirror 44 then passes through the same optical system as the light beam 31a, is then guided to the recording lens 39, and forms a spot at a position B on the recording master 40, whereby a track is formed. Expose the format signal between the guides.

The distance L between A and B on the recording master 40 is about 0.8.
About μm is desirable, and this L is given by the following equation. L = fθ where f is the focal length of the recording lens, and θ is the angle of incidence of the light beam 31 on the recording lens. If L = 0.8 μm and f = 3 mm, then θ≈0.3 mrad.

A master recording apparatus having such an optical system can record a master of an information recording medium. The master thus recorded is developed, a metal film is vapor-deposited, a master, a mother, and a stamper are created by nickel plating, and the substrate is pressed by using this as a mold, and signals for format such as address and tracking are obtained. It is possible to form the guides at the same time.

As another recording method, it is possible to manufacture the master by recording only the track guide first and then tracking the track guide to record the format signal.

In addition to the above, various methods such as a method using plasma etching and a method using a metal film can be considered.

The reproducing optical system may have any structure as long as it has means for irradiating at least two beams to the track guide area on the information recording medium and between the track guides. Good. Although FIG. 3 shows an example in which the reproducing spot 22 exists, an erasing spot may exist, or a plurality of recording / reproducing spots may exist.

An example of this reproducing optical system will be described with reference to FIG. Here, 50 is a semiconductor laser array, which has, for example, two light emitting points, the light emitting point 50A is located at the center of the optical axis, and the beam emission direction is also the same as the optical axis of the optical system. on the other hand,
The other emission points 50B on the same plane are arranged such that the beam emission direction is inclined by θ with respect to the optical axis, for example, the beam emission position is located slightly away from the optical axis in the direction of 45 degrees. The light emitted from the semiconductor laser array 50 is expanded to a desired beam diameter by the collimator lens 51, then passes through the polarization beam splitter 52 and the λ / 4 plate 53, and is reproduced on the information recording medium 55 by the reproducing lens 54. The light is focused at a position slightly apart from the center of the optical axis (for example, 0.8 μm in the circumferential direction and 0.8 μm in the radial direction). Light reflected from the information recording medium returns along the same optical path as when it is incident, is totally reflected by the polarization beam splitter 52 by the action of the λ / 4 plate 53, passes through the astigmatic focus lenses 56 and 57, and is a photoelectric conversion element. 58
Focused on top. The photoelectric conversion element 58 is, for example, a 4-division P
It is composed of an IN photodiode. In this case, the beam irradiating the track guide passes through the center of the optical axis of the optical system and is focused on the four-division PIN photodetector to detect focus and tracking error signals. On the other hand, the beam irradiated between the track guides is condensed on an independent PIN photodiode and used for recording / reproducing information and reproducing a format signal. Alternatively, a beam passing through the center of the optical axis can be used as an information recording / reproducing beam.

Further, it is possible to use an independent semiconductor laser without using the semiconductor laser array 50, and it is also possible to split the beam of one semiconductor laser.

Any optical system is applicable to the present invention as long as it is a recording / reproducing optical system having a means for irradiating a beam between track guides and a means for independently detecting each beam. It is possible.

[0032]

As described above, according to the present invention, in an optical disc system having a recording / reproducing or erasing function of information, a format signal is recorded especially when information is additionally recorded or reproduced on a preformatted information recording medium. Does not affect the focus and tracking servo, and it is possible to provide an optimum information recording configuration and its recording / reproducing method in terms of C / N in the recording / reproducing characteristics of information.

Further, particularly when the optical disk system is used as a data file of a computer or the like, it is very important to surely record the information at the address designated by the host computer. According to the present invention, in address detection in the format signal, the tracking and focus error detection signals are not affected by the format signal at all, so that a more reliable operation can be guaranteed against disturbance.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a recording optical system for a master of an information recording medium according to the present invention.

FIG. 2 is a diagram showing a relationship between a phase depth of a groove and a relative output of a tracking error signal, a reflectance from a groove, and an address signal.

FIG. 3 is a schematic diagram of an information recording medium according to the present invention.

FIG. 4 is a configuration diagram of a reproduction optical system of an information recording medium based on the present invention.

FIG. 5 is a schematic diagram of a conventional information recording medium.

[Explanation of symbols]

10 Information recording medium substrate 11 Recording area 12, 13, 14, 15 Track guide 16, 17, 18 Format signal area (second information section) 19 Information pit 20 Recording spot 21 Tracking detection spot 22 Playback spot 30 Laser light source 31 Half mirror 32 Optical modulator 40 Recording master A position B position 42 Second optical modulator 50 Semiconductor laser array 50A Light emitting point 50B Other light emitting point 58 Photoelectric conversion element

Claims (3)

[Claims] 1. An information recording medium for optically recording desired information without changing the shape of the information recording layer, or reproducing or erasing the recorded information, has a concentric or spiral constant depth. And a continuous track guide having a groove depth different from that of the track guide and having a pit width shorter than a half of the track pitch. In order to realize the formation of and, the first master recording light beam of the two master recording light beams is condensed and exposed on the master disk to form a track guide, and the second master recording light beam is formed. After passing through the light modulator for forming the information pits, the light beam is tilted with respect to the incident angle of the first master recording light beam and collected on the master. A master recording method for an information recording medium, which comprises forming a master for an information recording medium by exposing it to light. 2. A track guide is recorded by one master recording light beam, and then the master recording light beam is tracked along the recorded track guide while the other master recording light beam forms an information pit. The master recording method for an information recording medium according to claim 1, wherein the master is recorded and exposed on the master after passing through a light modulator for recording. 3. A continuous concentric or spiral constant depth for optically recording desired information without changing the shape of the information recording layer, or for reproducing or erasing the recorded information. A track guide and a format signal such as an address, which is located between the track guides and has a groove depth different from that of the track guide and a pit width shorter than a half of the track pitch, are formed. A recording / reproducing method for an information recording medium, comprising forming at least two light beams,
Or the information is recorded, reproduced, or the like. A recording / reproducing method for an information recording medium characterized by erasing.