JPS6122450A - Information recording medium and its recording and reproducing method - Google Patents

Abstract

PURPOSE:To attain surely recording and reproduction to a desired address under the stable servo condition by separating a format signal area into information recording and reproducing areas to solve the adverse effect on a tracking error signal. CONSTITUTION:Desired numbers of sectors are formed on format signal areas 16-18. An information bit recorded on the information recording and reproducing area is shown in caption 19, the recording spot is in 20, the tracking detection spot is in 21 and the reproducing spot is in 22. Track guides 12-15 are formed with phase depth PSI=PI/2(R), format signal areas 16-18 between the guides 12-15 are formed by a rugged signal of position depth PSI=PI(R) and areas other than format signal areas 16-18 between the track guides 12-15 are used as information recording and reproducing areas with phase depth PSI=0(R), then an information recording medium satisfying all the optimum phase depths is obtained. The C/N is improved at the recording/reproduction of information without giving the effect of a format signal to the focus and tracking servo.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an information recording medium, such as a digital data file, for recording information in an information recording layer by optical means, or for reproducing or erasing recorded information. and its recording and reproducing method.

Conventional Structure and Its Problems A schematic diagram of the structure of a conventional information recording medium is shown in FIG. In the figure, ■ is the empty groove in the information recording/reproducing area, and ■ is the position information 4.
The signal area for which format.

Show. ■The flea shows the recording/reproducing beam. The groove depth of the information recording/reproducing area and the formatting signal area such as position information is approximately λ/8 at which the tracking error detection signal by the far field method is the maximum.

When optically reading an information recording medium configured in this manner, there is a problem in that when a recording/reproducing beam crosses a formatting signal area, it adversely affects a tracking error signal and a focus error signal.

Purpose of the Invention The present invention realizes a groove configuration that is optimal for information recording and reproducing characteristics, and also solves the conventional problem of adverse effects on focus and tracking error signals in the formatting signal area by changing the formatting signal area to the information recording and reproducing area. and minute 11ff
The solution is to ensure that the desired information is recorded and reproduced at the desired address under stable servo conditions, and that the C/
It is an object of the present invention to provide an information recording medium and a method for recording and reproducing the same, in which N can be improved. In particular, in a pre-formatted information recording medium, it provides a suitable configuration of an information recording/reproducing area used by the user and a signal area for formatting position information, etc. used for random access etc. .

Structure of the Invention In order to achieve the above object, the present invention forms continuous track guides having a constant depth in a concentric or spiral shape, and stores information such as position information in the circumferential direction between radially adjacent track guides. A second information section is formed for this purpose.

Moreover, the present invention forms at least two or more beams, and provides a first beam to continuous track guides having a constant depth in a concentric or spiral shape, and a circumference between the track guides adjacent in the radial direction. The second information section formed in the direction is irradiated with a second light beam with a required spot size, respectively.

Therefore, the format signal does not affect the focus or tracking servo, and it is possible to improve the C/N in the recording and reproducing characteristics of information, especially on preformatted information recording media. Add information,
This is advantageous when playing.

DESCRIPTION OF THE EMBODIMENTS FIG. 2 shows the relationship among the phase depth of the groove, the tracking error signal output by the far field method, and the address signal output recorded by the phase type. In the same figure, the vertical axis is relative output,
The horizontal axis indicates 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 reflective reproduction, where n is the refractive index of the substrate at the wavelength λ used.

ψ-2nd・2π/λ From Figure 2, the address signal recorded by the phase type peaks at the phase depth ψ-π radian, and the error detected by the far-field method is the phase depth ψ-π/2.3π. /
It peaks at 2 radians.

However, the phase of the tracking error signal is reversed at π/2.3/2π radians. Further, the reflectance from the groove portion of the information recording medium has an inverse relationship to the address signal output, as shown by the broken line in the figure, and reaches a maximum at the phase depth ψ−〇 and 2π radians.

When a refractive index variable material such as TeOx is used as the information recording layer, it is desirable that the information recording/reproducing signal be recorded and reproduced in a groove portion with a high C/N ratio. Therefore, a phase depth ψ=0.2π radians is desirable.

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

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

FIG. 3 shows a schematic diagram of a groove structure that is an embodiment of the present invention that satisfies the above conditions. In the same figure (a), 10 is an information recording medium substrate, on the surface of which an information recording layer such as l"eQx is formed, 11 is a recording area, and only track guides 12 to 15 are shown in the figure. Between each track guide 12 to 15 adjacent in the radial direction, a formatting area as a second information section indicated by 16 to 18 in the figure is formed in a desired section in the circumferential direction. This figure shows the case of 8 sectors/track.The signal areas 16 to 18 for formats 1 to 1 may be formed as many as the desired number of sectors.Also, if necessary, the signal areas 16 to 18 for formats 1 to 1 may be formed for formats including track addresses, etc. There is also a signal area. Figure (b) is an enlarged view of the A-A area in figure (a), and each number is assigned in the same way as in figure (a). Here, Reference numeral 19 indicates information bits recorded in the information recording/reproducing area (one section of information recording), and 20, 21, and 22 indicate each recording spot 1-, tracking detection slot 1-1, and reproduction spot 1-.

In the information recording medium having such a configuration, the track guides 12 to 15 are formed with a phase depth of ψ-π/2 radians, and the formatting signal areas 16 to 18 between the track guides 12 to 15 are formed with a phase depth of ψ= By forming a concavo-convex signal of π radian and using the area other than the formatting signal areas 16 to 18 between each track guide 12 to 15 as an information recording/reproducing area with a phase depth of φ-0 radian, all of the above-mentioned optimal phase depths can be achieved. Providing satisfactory information recording media
It becomes possible to

Furthermore, in an information recording medium having such a configuration, by separating the information recording and reproducing spot from the focus error and tracking error detection spot, it is possible to completely eliminate the negative influence of the format signal on the focus and tracking error signal. This makes it possible to reliably record and reproduce desired information at a desired address under stable servo conditions, and to record and reproduce information with a high C/N.

In implementing the present invention, each track guide 12 to 1
The recording width in the radial direction of the formatting signal areas 16 to 18 between the adjacent track guides 12
It is preferable that the interval is narrower than the interval between 15 to 15.

Further, the recording material and recording method are not limited to T'OOX and the refractive index change recording method, which are one embodiment of the present invention, but any material can be used as long as it satisfies the object of the present invention.

An example of an apparatus for producing a master disc of an information recording medium according to the present invention will be explained using FIG. 4. The light beam from the laser light source 30 is divided into light beams (31a) and (31b) by a half mirror 31 at a desired ratio.

The divided light flux (31a) is guided to a light modulator 32, attenuated to a desired exposure amount, and then passed through a total reflection mirror 3.
3, further reflected by the total reflection mirror 34, guided to a beam evangelizer system composed of lenses 35 and 36, expanded to a desired beam diameter, and then reflected by the total reflection mirror 31, The light is focused by the recording lens 39 mounted on the voice coil 38, and the recording master 4
Form a spot at a position above 0. For example, the aforementioned guide rack is exposed using this spot.

On the other hand, the other beam (3
1b) is totally reflected by a total reflection mirror 41 and intensity-modulated by a second optical modulator 42 according to desired information.Here, the input electric signal to the optical modulator 42 is a signal 48 from a 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 which outputs a signal only for a desired period in synchronization with the turntable drive signal 41 of the recording system. 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 by a shutter 43, guided to a total reflection mirror 44 only for a desired period, and totally reflected. Total reflection mirror 44 has a luminous flux <3
1b)' is installed so that the optical axis of the light beam (31a) is slightly inclined compared to the optical axis of the light beam (31a). After passing through the system, the recording lens 3
9, a spot is formed at position B on the recording master 40, and a format signal is exposed between the tracker guides.

The distance between A-8 on the recording master 40 is 111! H! is about 0.8
It is desirable that the value is on the order of μm, and ρ is given by the following equation.

ρ −f θ Here, f is the recording lens's fishing distance, and θ is the luminous flux (31b)
is the angle of incidence on the recording lens. Ω-08μm, f=3
If in, θ=0.3srad.

Ru.

A master disc recording device having such an optical system can record the master disc of the information recording medium of the present invention B.

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

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

The reproducing optical system may have any configuration as long as it has means for irradiating at least two beams onto the track guide area on the information recording medium and between the track guides. Although FIG. 3 shows an example in which there is a U reproduction spot 22, there may be an additional erasure spot, or there may be a plurality of recording and reproduction spots.

An example of a reproduction optical system will be explained using FIG. 5.

A semiconductor laser array 50 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 in the same direction as the optical axis of the optical system. On the other hand, the beam emission position of the single light emitting point (50B) on the same plane is located a little away from the optical axis in the direction of 45 degrees, for example.
The beam exit direction is arranged at an angle of 1 with respect to the optical axis. The emitted light from this semiconductor laser array 50 is expanded to a desired beam diameter by a collimating lens 51, passes through a polarizing beam splitter 52, a λ/4 plate 5, a metal plate 3, and is transferred to an information recording medium 55 by a reproducing lens 54. Then, the light is focused at a position slightly distant from the center of the optical axis (for example, 0.8 μTrL in each of the circumferential and radial directions). The reflected light from the information recording medium returns along the same optical path as the long sword, and passes through the λ/4 plate 5.
The light from the sheet metal 3 is totally reflected by the polarizing beam splitter 52, passes through the astigma focus lenses 56 and 57, and is focused onto the photoelectric conversion element 58. Photoelectric conversion element 5
8 is constituted by, for example, a four-division PIN photodiode and an independent PIN 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 a 4-split PIN photodetector to detect focus and tracking error signals. On the other hand, the beam that irradiates between the track guides has an independent P
The light is focused on the IN photodiode and used for recording/reproducing information and reproducing format signals.

In this example, a beam passing through the center of the optical axis is used to record information.
It is also possible to use it as a reproduction beam.

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

No matter what kind of optical system it is, as long as it is a recording/reproducing optical system that has means for irradiating a beam between the track guide and the track kite, and means for independently detecting each beam, the present invention is applicable. It is applicable.

Effects of the Invention As described above, according to the present invention, in an optical disk system having an information recording/reproducing or erasing function, especially when additionally recording or reproducing information on a preformatted information recording medium, the format signal is It becomes possible to provide an optimal configuration of an information recording medium and its recording and reproducing method in terms of C/N in information recording and reproducing characteristics without affecting focus and tracking servo.

Furthermore, especially when using an optical disk system as a data file for a computer, it is very important to reliably record information at the address specified by the host computer. The present invention guarantees more reliable operation against disturbances because the tracking and focus error detection signals are not affected by the format signal at all during address detection in the format signal.

[Brief explanation of the drawings] Fig. 1 is a schematic diagram of a conventional information recording medium, Fig. 2 shows the phase depth of the groove, the tracking error signal, the reflectance from the groove,
3 is a schematic diagram of an information recording medium according to an embodiment of the present invention; FIG. 4 is a diagram showing the configuration of the recording optical system of the master of the information recording medium of the present invention; Fifth
The figure is a configuration diagram of a reproducing optical system of an information recording medium according to the present invention. 10... Information recording medium substrate, 11... Recording area, 1
2.13゜14.15...Track guide, 16,1
7.18...Formatting signal area (second information section), 19...Information bit, 20...Recording spot, 21...Tracking detection spot, 22...
Reproduction spot, 30... Laser light source, 31... Half mirror 132... Optical modulator, 42... Second optical modulator, 50... Semiconductor laser array, 50A...
・Light-emitting point, 50B... Other light-emitting point, 58... Photoelectric conversion element agent Yoshihiro Morimoto (Figure 1, Figure 2), Figure 3 (b) Figure 4, Figure 5

Claims (1)

[Claims] 1. An information recording medium having an information recording layer for optically recording desired information or for reproducing or erasing recorded information, which has a concentric or spiral shape with a constant depth. 1. An information recording medium characterized in that a continuous track guide having a length is formed, and a second information section for positional information etc. is formed in the circumferential direction between the radially adjacent track guides. 2. The second track guide between adjacent track guides in the radial direction
2. The information recording medium according to claim 1, wherein a recording section for desired information is formed outside the information section. 3. The information recording according to claim 1 or 2, wherein the recording width of the second information section is formed narrower than the interval between track guides adjacent in the radial direction. Medium. 4. Forming at least two or more beams, the first beam is formed in a continuous track guide having a constant depth in a concentric or spiral shape, and the beam is formed in the circumferential direction between radially adjacent track guides. A method for recording and reproducing information on an information recording medium, characterized in that the second information section is irradiated with a second light beam with a required spot size.