JPH06150319A - Recording control system for information - Google Patents

Abstract

PURPOSE:To highly accurately a recoring mark by controlling recording power and an irradiating time according to the fluctuation of an environmental temp. and the recording sensitivity of a recording medium. CONSTITUTION:A recording pulse string 21 formed by leading pulses alpha and following pulses gamma having different pulse widthes and intervals basing on a clock according to a recording code 20 is formed and a recording auxiliary pulses having a prescribed level and width are added next to the last pulse of the gamma. Then, the power of a laser is so controlled by the recording pulse string that a reproducing power Pr is set to the lowest level of and a recording power Pw is set to the high level of the power of the laser respectively and a low level recording power Pas is set to the power responding to the pulse 22. Thus, an accumulated head caused by the recording pulse is maintained constant and the width and length of the recording mark 23 are controlled highly accurately since the recording power and the irradiating time are controlled according to the environmental temp. and the sensitivity of the recording medium.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information recording control system in an information recording / reproducing apparatus for recording / reproducing on / from a recording medium, and in particular, recording of information enabling highly accurate recording control of recording marks by thermal recording. Regarding control method.

[0002]

2. Description of the Related Art With the progress of the advanced information society in recent years, there is an increasing need for a high-density and large-capacity file memory. Among them, optical recording is drawing attention as one that meets this need. . There are three types of optical recording, a read-only type, a write-once type, and a rewritable type. Among them, the magneto-optical recording is widely used as a rewritable memory as a document file or an image file. Currently, many research institutes are conducting research and development aiming to improve disk performance. One of the goals is to increase the recording capacity. At present, research has been conducted on the use of mark length recording and zone CAV recording as recording methods, recording by recording track pitches and bit pitches of disks, and using laser light sources of short wavelength. Since magneto-optical recording is basically thermo-magnetic recording, it is easily affected by environmental temperature. Therefore, the shape of the magnetic domain fluctuates, which may cause an error particularly in recording the mark length. As a conventional recording control method of this kind of information, for example, the method disclosed in Japanese Patent Laid-Open No. 3-22223 is known. In this method, the recording code sequence of the recording mark is pulsed to form a series of pulse sequences corresponding to the length of the recording code sequence, and the length and amplitude of the pulse sequence are set to the opposite phase of the recording code sequence immediately before the recording code sequence. This is a system in which the pulse train is controlled according to the length, the pulse train is divided into three parts, and the pulse width of each pulse is changed to perform recording.

[0003]

The above-mentioned prior art does not take into consideration the case where the ambient temperature fluctuates or the recording sensitivity (thermal characteristics) of the recording medium, the recording power, and the formation of the recording mark depending on the irradiation time. Since the recording mark cannot be controlled accurately, there is a problem that the recording capacity is reduced. The present invention has been made in view of the above circumstances, and an object of the present invention is to solve the above-mentioned problems in the conventional technique, and to set the recording power and the irradiation time according to the environmental temperature fluctuation and the recording sensitivity of the recording medium. By controlling
An object of the present invention is to provide an information recording control system that enables highly accurate recording mark control.

[0004]

The above object of the present invention is to record, reproduce or erase information by forming a recording area physically different from an unrecorded portion on a recording medium by using a laser beam. In the information recording control method of performing the
(Or erasing level) and a recording level composed of a plurality of levels, the plurality of recording levels are composed of a plurality of pulses, and when switching from the recording pulse to the erasing pulse, a preheat level (or an erasing level)
A lower pause period is provided, the pause period is changed according to the thermal characteristics of the recording medium, and the inflow of energy from the recording level to the preheat level (or erase level) is controlled. A recording control method or an information recording method in which information is recorded, reproduced, or erased by forming a recording area physically different from an unrecorded portion on a recording medium by using an externally applied magnetic field and a laser beam. In, the laser light level is composed of a reproduction level, a preheat level or an erasing level, and a recording level or an erasing level composed of a plurality of levels, and the recording pulse or the erasing pulse (or a recording auxiliary pulse) is composed of a plurality of pulses, When switching from the recording pulse to the erase pulse, a pause period lower than the preheat level or the erase level is provided. The information recording control method is characterized in that the pause period is changed according to the thermal characteristics of the recording medium to control the inflow of energy from the recording level to the preheat level or the erasing level.

[0005]

After the irradiation of the recording pulse is completed, the heat kept constant on the recording medium flows out to the erase pulse irradiation area. Due to the heat flowing out here, the temperature of the erase pulse irradiation area rises, the temperature of the recording pulse area irradiated next rises, and the recording mark becomes large (both the length and width of the recording mark become large). In order to suppress this thermal interference, when switching from the recording pulse to the erase pulse, a pause period lower than the preheat level or the erase level is provided, and the pause period is changed according to the thermal characteristics of the recording medium. By controlling the inflow of energy to the preheat level or the erase level and keeping the temperature of the erase pulse irradiation region constant, the length and width of the recording mark formed by the recording pulse can be controlled. In the information recording control method according to the present invention, the length and width of the formed recording mark are controlled by providing a plurality of laser light levels and changing the recording level according to the length of the recording pulse. As a result, the heat storage of the recording medium by the recording pulse irradiation is made constant. Also, with the recording level kept constant, a plurality of pulses forming the recording pulse are composed of two types of pulses, a head pulse and a rear pulse excluding the head pulse, and regarding the gap in the recording pulse,
The heat storage of the recording medium by the irradiation of the recording pulse can be made constant by configuring the gap with two kinds, that is, the gap of the head pulse, the gap of the rear pulse, and the gap in the rear pulse.

Similarly, in a recording medium which can be overwritten, reliable erasing can be performed by keeping the temperature of the erasing pulse irradiation area constant. The plurality of pulses forming the recording pulse are composed of two types of pulses, a head pulse and a rear pulse excluding the head pulse. The plurality of gaps forming the recording pulse are also the gap between the head pulse and the tail pulse (head gap). Gap between backward pulses
It is composed of two types of gaps (rear gap). The first pulse is longer than the rear pulse, and raises the temperature of the recording medium to the temperature required for recording. The head gap is provided to suppress the heat storage effect of the head pulse and the rear pulse, and keeps the temperature of the recording medium constant. In this state, by combining the rear pulse and the rear gap, it is possible to record a constant recording mark regardless of the length of the recording pulse. It can also be realized by changing the recording level of the recording pulse according to the length of the recording pulse. Furthermore, after the irradiation of the recording pulse,
The heat (or temperature) kept constant on the recording medium flows out to the erase pulse irradiation area. Because of the heat that escapes here,
The temperature of the erase pulse irradiation area rises, the temperature of the recording pulse area irradiated next rises, the recording position at the beginning of the recording pulse irradiation changes, and the recording mark becomes large.
(The length and width of the recording mark are both large). In order to suppress this "thermal interference", when switching from the recording pulse to the erase pulse, a pause period lower than the preheat level or the erase level is provided, and the pause period is changed according to the thermal characteristics of the recording medium. Reliable recording and erasing by keeping the temperature of the recording medium constant by superimposing heat from the preheat level or the erasing level with the inflow of heat from the You can

[0007]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is an explanatory diagram of a relationship between a recording method and recorded recording marks according to an embodiment of the present invention. In FIG. 1, the recording code string 20 of FIG.
With reference to the clock 30 as shown in FIG. 3, the data is output from an encoder (not shown) according to the data to be recorded. Using this recording code train 20, the recording pulse train 21 of (b) is generated in the pulse portion of the recording code train 20. The recording pulse train 21 is composed of two types of pulses, a head pulse α and a rear pulse γ excluding the head pulse α. Further, a plurality of gaps forming the recording pulse train 21 is also a gap between the head pulse and the rear pulse ( It is composed of two types of gaps: a front gap β) and a gap between rear pulses (rear gap δ). Depending on the thermal characteristics of the recording medium, the circuit scale can be reduced by matching the sum of the rear pulse γ and the rear gap δ with the cycle of the clock 30. Also, each of the above two types of pulses and gaps,
The first pulse length and the second and subsequent pulse lengths are different, and the pulse lengths of the second and subsequent pulse trains correspond to at least one pulse in the minimum change length of the recording mark, and the minimum change length of the recording mark. In order to configure a recording pulse train in which the influence of heat from other pulse trains in the vicinity of the final fall position of Etc. are set.

In the gap portion of the recording code string 20, as shown in FIG.
The recording auxiliary pulse 22 shown in FIG. The recording auxiliary pulse 22 is provided with a certain rest gap Ts from the trailing edge of the recording code train 20 so that the heat from the last trailing edge of the recording pulse train hardly changes the temperature at the leading edge of the next recording pulse train. It is for The above-mentioned rest gap Ts is
It can be set arbitrarily using a delay line or the like. FIG. 1D shows a change in laser power according to a recording code sequence when a laser (not shown) is driven by using the recording pulse train 21 and the recording auxiliary pulse 22 described above, the horizontal axis represents time, and the vertical axis represents time. It was expressed by taking the laser power. The lowest level of laser power is the reproduction power (Pr) during reproduction, the high level of recording is the recording power (Pw) of the recording pulse train 21, and the low level of recording is the recording power (Pas) of the recording auxiliary pulse 22. Figure 1 (e)
Further, the situation in which the temperature of the recording medium is controlled by the laser power is shown by taking time on the horizontal axis and temperature on the vertical axis. Depending on the temperature distribution, the recording mark 2 as shown in FIG.
3 is formed. Since the temperature on the recording medium is kept constant, the length of the recording mark 23 can be controlled with high accuracy according to the recording pulse train 21. Further, since the temperature on the recording medium is kept constant, the width of the recording mark 23 is controlled within a certain fixed range. Therefore, as shown in FIG.
The amplitude of the recording portion of the reproduction signal 24 becomes constant.

By discriminating the reproduced signal 24 at its center or at a certain level, a reproduced code string 25 as shown in FIG. 1 (h) is generated. According to the above-mentioned embodiment, since the heat storage of the recording medium by the irradiation of the recording pulse can be made constant, it is possible to obtain the effect that the length and width of the recording mark formed by the recording pulse can be controlled. . FIG. 2 is an explanatory diagram of a relationship between a recording method and a recorded recording mark according to another embodiment of the present invention. In FIG. 2, the recording code string 20 of (b) is output according to the data to be recorded from an encoder (not shown) with the clock 30 of (a) as a reference. Using this recording code train 20, the recording pulse train 21a of (c) is generated in the pulse portion of the recording code train 20. The recording pulse train 21a is composed of two types of pulses, a head pulse synchronized with the clock 30 and a rear pulse excluding the head pulse. The plurality of gaps forming the recording pulse train 21a are synchronized with the gap of the clock 30. The pulse portion of the recording code string 20 can be arbitrarily set to an integral multiple of the clock 30 or a fraction of an integer. In addition, the recording pulse train 21b of FIG.
The recording pulse train 21a includes a rear pulse portion and a gap. The recording auxiliary pulse 22 of FIG. 2E is the same as that of FIG. Using the recording pulse trains 21a and 21b and the recording auxiliary pulse 22, the change according to the recording code train of the laser power when a laser (not shown) is driven, the horizontal axis represents time, and the vertical axis represents laser power, It is shown in FIG.

The lowest level of laser power is the reproduction power (Pr) during reproduction, and the high level of recording is the recording pulse train 21.
Recording power (Pw2) of b, recording intermediate level is recording power (Pw1) of the recording pulse train 21a, and low recording level is recording power (Pas) of the auxiliary recording pulse 22. The recording power (Pw2) and the recording power (Pw1) may be reversed depending on the thermal characteristics of the recording medium. As a result, a recording mark 23 similar to that shown in FIG. 1 can be formed. Also according to the above embodiment, since it becomes possible to keep the heat storage of the recording medium by the recording pulse irradiation constant,
The effect that the length and width of the recording mark formed by the recording pulse can be controlled is obtained. Figure 3
It is explanatory drawing about the relationship of the recording system and the recorded recording mark which concern on the other Example of this invention. The recording code string 20 of FIG. 3B is output from an encoder (not shown) according to the data to be recorded with the clock 30 of FIG. 3A as a reference. Using the recording code string 20 and the clock 30, (c)-
The recording pulse trains 21A to 21D of (f) are formed. Here, the recording pulse train 21A has two pulses of the clock 30 as the pulse length, and the recording pulse trains 21B to 21D have one period of the clock 30 as the pulse length. Here, the recording pulse train 21A coincides with the rising position of the recording code train 20,
The recording pulse train 21B coincides with the falling position of the recording pulse train 21A. The recording pulse trains 21C and 21D coincide with the falling positions of the recording pulse trains 21B and 21C.

The recording auxiliary pulse 22 shown in FIG. 3G is the same as that shown in FIG. Using the recording pulse trains 21A to 21D and the recording auxiliary pulse 22 described above, the change in the laser power according to the recording code train when a laser (not shown) is driven is shown in FIG. The vertical axis represents the laser power. Lowest level of laser power, reproduction of the reproduction power (Pr), a recording level corresponding to the recording pulse train 21A~21D, the recording power (P _A ~P _D), a low recording level recording power of the recording auxiliary pulse 22 Pas. As described above, the recording power equivalent to the recording code string 20.
By sequentially changing the level, the temperature on the recording medium can be kept constant as in the temperature distribution shown in FIG. As a result, the recording mark as shown in FIG. 1 can be formed. According to each of the above-described examples, the recording power and the irradiation time can be controlled according to the recording sensitivity (thermal property) of the recording medium, so that the compatibility with the recording medium can be improved and the recording mark can be controlled with high accuracy. The effect is to improve the reliability and storage capacity of the recording / reproducing apparatus. It should be noted that all of the above-mentioned embodiments are examples of the present invention,
It goes without saying that the present invention should not be limited to this.

[0012]

As described above in detail, according to the present invention, highly precise recording mark control is possible by controlling the recording power and the irradiation time according to the environmental temperature fluctuation and the recording sensitivity of the recording medium. This has the remarkable effect of realizing the information recording control method.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a relationship between a recording method and a recorded recording mark according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a relationship between a recording method and a recorded recording mark according to another embodiment of the present invention.

FIG. 3 is an explanatory diagram of a relationship between a recording method and a recorded recording mark according to still another embodiment of the present invention.

[Explanation of symbols]

20: Recording code string, 21, 21a, 21b and 21A
21D: recording pulse train, 22: recording auxiliary pulse, 2
3: recording mark, 24: reproduction signal, 25: reproduction code string,
30: clock, Ts: pause gap, α: head pulse, β: head gap, γ: rear pulse, δ: rear gap.

Front page continuation (72) Inventor Takeshi Maeda 1-280, Higashi Koikekubo, Kokubunji, Tokyo Inside Hitachi Central Research Laboratory (72) Inventor Hiroyuki Doninaga 1-280, Higashi Koikeku, Kokubunji, Tokyo Hitachi Central Research Co., Ltd. In-house (72) Inventor Toshimitsu Kaku 2880, Kozu, Odawara-shi, Kanagawa Hitachi Storage Systems Division (72) Inventor, Seiichi Mita 2880, Kozu, Odawara, Kanagawa Hitachi Systems Storage Systems Division (72) Inventor Kazuo Shigematsu 2880 Kozu, Odawara City, Kanagawa Stock Company, Hitachi Ltd. Storage Systems Division

Claims (4)

[Claims] 1. An information recording control method for recording, reproducing, or erasing information by forming a recording area physically different from an unrecorded portion on a recording medium by using laser light, wherein the laser is used. The light level is the reproduction level,
It is composed of a preheat level (or erase level) and a recording level composed of multiple levels, and the multiple recording levels are composed of multiple pulses, and the preheat level is used when switching from the recording pulse to the erase pulse.
(Or erasing level), a quiescent period lower than that is provided, and the quiescent period is changed according to the thermal characteristics of the recording medium to control the inflow of energy from the recording level to the preheat level (or erasing level). Recording control method for characteristic information. 2. An information recording method for recording, reproducing or erasing information by forming a recording area physically different from an unrecorded portion on a recording medium by using an externally applied magnetic field and a laser beam. , The laser light level consists of a reproduction level, a preheat level or an erasing level, and a recording level or an erasing level consisting of multiple levels, and the recording pulse or erasing pulse (or recording auxiliary pulse) consists of multiple pulses, When switching from the pulse to the erase pulse, a pause period lower than the preheat level or the erase level is provided, and the pause period is changed according to the thermal characteristics of the recording medium to change the energy from the recording level to the preheat level or the erase level. An information recording control method characterized by controlling inflow. 3. The recording level or the erasing level (or preheat level) is composed of one level, respectively, and a plurality of pulses constituting a recording pulse are composed of a head pulse and a rear pulse excluding the head pulse, and 3. The information recording control system according to claim 1, wherein the gap in the recording pulse is composed of a gap between the head pulse and the rear pulse and a gap between the rear pulses. 4. The recording level is lowered as the length of the recording pulse becomes longer, and the erasing level is raised as the length of the erasing pulse becomes longer, so that accurate recording is performed when the energy on the recording medium becomes constant. 3. The information recording control method according to claim 1, wherein the recording control method is performed.