JPH04205918A - Recording method for information - Google Patents

Abstract

PURPOSE:To prevent a noise level from rising even when the rewriting of information is repeated many times by increasing the average irradiation energy near the central part of pulses forming recording marks. CONSTITUTION:The average irradiation energy near the central part of the pulses A, B which are going to form the recording marks is increased. Then, the temp. of the recording film irradiated with the central part of the recording pulses is maximized and the flow of the recording from the arc in the central part of the recording marks to the recordings on both sides arises at about the same extent if the rewriting is executed many times in this state. Since the position of the marks varies irregularly at every recording, the fluctuation in the thickness of the recording film is suppressed and the rise of the noise level is suppressed. Many times of the recording are possible in this way.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a method for recording information on a recording member capable of recording information by irradiation with an energy beam, and in particular, it relates to a method for recording information on a recording member capable of recording information by irradiation with an energy beam. The present invention relates to a method for recording information that exhibits excellent effects on phase change optical discs and the like that can be overridden for recording information.

[Conventional technology]

Conventional recording and erasing methods on rewritable recording films are capable of high-speed erasing that allows crystallization to occur in approximately the same time as the laser irradiation time for recording, as disclosed in, for example, Japanese Patent Application Laid-open No. 56-145530. When using a phase-change optical disk recording film, the power of one energy beam is
In both cases, the reading power level is changed between at least two levels higher than the read power level, that is, at least a high power level and an intermediate power level.

This method has the advantage of allowing so-called override (rewriting by overwriting), in which new information is recorded while erasing existing information.

[Problem to be solved by the invention]

When recording using the above-mentioned conventional technology, as in the 2-7 modulation markup detection recording method, information is rewritten many times using a recording waveform in which a high level portion continues as a recording signal (original signal). In this case, there was a problem in that the thickness of the recording film fluctuated due to the flow of the recording film in one direction, which increased the noise level.

SUMMARY OF THE INVENTION An object of the present invention is to solve the problems in the prior art described above and to provide a method for recording information that can be rewritten many times.

[Means to solve the problem]

In order to solve the above-mentioned problems in the prior art, in the information recording method of the present invention, the average irradiation energy near the center of the pulse for forming a recording mark is increased. At this time, near the rising edge of the recording pulse, the recording film temperature generally decreases even if the average irradiation energy of the pulse is not lowered, so the center of the area where the average irradiation energy is high is located before the center of the recording pulse. It's better to It is also possible to suddenly increase the average irradiation energy from the rising edge of the recording pulse. However, it is preferable to lower the average irradiation energy after 40% or more of the pulse width has elapsed from the rise of the recording pulse.
% or more is particularly preferable.

In-3b Te, In-5b, Ge-3b -Te
A recording medium comprising at least one type selected from recording media containing as a main component is preferable.

Here, if the pulse waveform has a high average irradiation energy at the center of the recording mark, for example, the pulse waveform can be divided into several pulse waveforms between an intermediate power level and a high power level to change the pulse density. Alternatively, the central part of the recording waveform may be changed to a higher power level than the high power level.

The above explanation of the effect was given for the case where a crystalline-amorphous phase change optical recording medium capable of high-speed crystallization is used. It is also effective for crystal-to-crystal phase change recording media, such as crystal-to-crystal phase change recording media.

In the recording waveform of the present invention, even if the power level is changed to another arbitrary power level (for example, O level or read power level) for a short time, the temperature of the recording film in the irradiated area can almost follow the change. You can expect the same results as without it.

On the other hand, it is also possible to superimpose a high-speed fluctuation that the temperature of the recording film can hardly follow on the recording waveform of the present invention, so that the change in the average power becomes the pattern described above in the present invention. .

Of course, the present invention also applies to at least one laser beam when recording is performed by irradiating the same or different patterns with two or more laser beams (two or more light spots).

Energy beams for recording are not limited to light beams such as lasers, but also low-energy beams such as electron beams and ion beams can be used depending on the properties of the reversible recording film.Furthermore, disc-shaped recording media can also be used. It is also applicable to other forms of recording media such as tapes, cards, etc.

[Function] In the present invention, by increasing the average irradiation energy at the center of the pulse forming the recording mark, the temperature of the recording film irradiated by the center of the recording pulse becomes maximum. If rewriting is performed many times in this state, the recording film will flow from the center of the recording mark to both sides to the same extent. In this case, since the position of the mark changes irregularly each time recording is performed, variations in the thickness of the recording film are suppressed and an increase in the noise level is suppressed.

〔Example〕

Hereinafter, the present invention will be explained in detail with reference to Examples.

Example 1 1 to 3 are explanatory diagrams of one embodiment of the present invention.

First, an example of a cross-sectional view of the structure of a disk used in the information recording method of the present invention will be described with reference to FIG. First, a 513N4 protective film 2 having a thickness of about 1100 nm was formed by magnetron sputtering on a polycarbonate substrate 1 having a guide groove (track) and having a diameter of 13 mm and a thickness of 1.2 cm. Next, Ge13Sbff was deposited on the Si and N4 protective films 2 in the same sputtering device. Recording film 3 having a composition of Ts, .
was deposited to a thickness of about 30 nm. Next, a Si, N, protective film 4 was formed to a thickness of about 220 nm in the same sputtering apparatus again. Furthermore, 1100 nm of Ni--Cr reflection 115 was applied thereon in the same sputtering apparatus. Thereafter, another disk having the same structure was bonded thereon with an adhesive layer 6 interposed therebetween.

Next, the recording method of the present invention will be explained using FIGS. 1 (1) to (4).

First, the G e 13 S b zo T f3 s
□ Initialization is performed by rotating an optical disk with a recording film at t800 rpm and irradiating the recording track with semiconductor laser light (continuous light with a wavelength of 830 nm) at an intermediate power level (Ps) while performing automatic focusing and tracking. I did it. Then, perform automatic focusing and tracking at the readout power level (PR) on the initialized recording track, and while checking the recording location, adjust the laser power up and down as shown in the recording waveform in Figure 1 (1). Recording was done by doing this. Here, 2
A -7 modulation mark edge detection recording method was used. In the case of such a modulation method, a high power level (Po) may be maintained for a long time. That is, in the conventional method, all recording pulses B are maintained at a high power level (PH). When rewriting is performed many times with such a recording waveform, a flow occurs in one direction in the portion of the recording film irradiated with this pulse, causing a change in the thickness of the recording film. Therefore, in the present invention, in order to prevent this, the average irradiation energy at the center of the recording pulse is increased as shown in FIG. 1(2). In this example, for the sake of clarity, the average irradiation energy within the time period in which the recording pulse A is divided into three equal parts and the recording pulse B is divided into five equal parts is shown. Here, the recording pulse was divided into several pulses so that the average irradiation energy at the center was high, but it is not necessary to divide all pulses; for example, the shortest recording pulse may not need to be divided depending on the case. . And, Figure 1 (1
) When rewriting is performed using a recording pulse train such as that shown in FIG. When rewriting is performed many times in this state, the recording film flows from the hottest part (A) on the recording film [FIG. 1 (4)] to the coldest parts (A) and (T). Due to this.

There was no change in recording film thickness due to flow, and the increase in noise level due to multiple rewriting was suppressed.

There are several other methods of dividing a long pulse, but in all cases it is necessary to increase the average irradiation energy at the center of the recording pulse. This average irradiation energy is an average value within an arbitrary unit time, and since the thermal conductivity and the like vary depending on the film sample, the average time width may be changed as appropriate each time.

FIGS. 3 and 4 show examples of other recording waveforms for increasing the average irradiation energy near the center of the recording pulse. In this example, instead of keeping the power level constant and dividing the recording pulse into several pulses, we use a high power level (PH) and an intermediate power level (PH) so that the average illumination energy is higher near the center of the recording pulse. A similar effect is obtained by holding each power level for a certain period of time at different power levels between PM and PM.

In addition, near the rising edge of the recording pulse, the recording film temperature generally decreases even if the average irradiation energy of the pulse is not lowered, so as shown in Figure 5, the center of the area where the average irradiation energy is high is It is better to have it before the center of the pulse. It is also possible to suddenly increase the average irradiation energy from the rise of the recording pulse. However, the average irradiation energy is preferably lowered after 40% or more of the pulse width has elapsed from the rise of the recording pulse, particularly preferably after 50% or more of the pulse width has elapsed.

〔Effect of the invention〕

According to the present invention, even when information is rewritten many times using a recording waveform in which a high level portion continues as a recording signal (original signal), as in the case of the 2-7 modulation match detection recording method, recording is possible. Since the flow of the membrane in one direction can be suppressed, the noise level no longer increases due to rewriting.

Further, the recording method of the present invention is effective not only for disk-shaped recording media but also for other forms of recording media such as tape-shaped and cart-shaped recording media.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the recording method according to the present invention, FIG. 2 is a cross-sectional view of the structure of the disk used in the present invention, and FIGS. FIG. 3 is a diagram showing an example of increasing the average irradiation energy. 1.1'...polycarbonate substrate, 2,2'...
Si, N, protective film, 3.3' ・=Ge, , Sb, , T
e... 1st figure '62 mouth 3rd figure 4 figure HA β ′! i3 S Figure 1111 Gen1 Town hn

Claims (1)

[Claims] 1. Using an information recording medium, when recording on the information recording medium, the power of the energy beam is changed over time to at least two levels, high and medium, with a power greater than the irradiation energy beam power during reproduction. In the information recording method of recording information by irradiating the
An information recording method characterized by recording with a waveform in which the average irradiation energy near the center of a pulse forming a recording mark is high.