JP2002288830A - Optical information recording method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical information recording method which can stabilize the recording operation by reducing a peak of thermal stress which is partially imposed on a recording medium, and which can increase the number of rewritable times of a rewritable recording medium, in particular, a phase change type recording medium. SOLUTION: Irradiation energy E(i)=E0 in portions i=4, 5, 6, 7, and 8 where recording marks are formed is set to the same E0 =(Pw+Pb)/2. The irradiation energy is basically made to be E(i)=E0 ×e in non-mark portions i=1, 2, 3, 9, and 10. In particular, it is constituted so that the thermal stress at the time of recording can be reduced for non-mark potions i=2 and 3 located immediately in front of the head part of a mark line i=4, by setting slightly larger irradiation energy E(i)=E0 ×a (where e<a<1) than that of the normal irradiation energy E(i)=E0 ×e (where 0<e<1), supplementing the insufficient energy.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is preferably applied to an optical information recording / reproducing apparatus represented by an optical disk apparatus, and particularly to an optical information recording / reproducing apparatus for recording an optical mark by utilizing heat generated by laser beam irradiation. Optical information recording method.

[0002]

2. Description of the Related Art Conventionally, a recording medium is irradiated with a laser beam or the like to form a hole in the recording film by the thermal action of light energy absorbed by the recording film, or to control the heating and cooling speeds to control the crystal structure. Change the direction of magnetization,
There is known a method of recording information by recording an optical mark by deforming a recording film or the like.

[0003] In recent years, this method has been applied to optical disk devices and magneto-optical disk devices and has been put to practical use. These devices are characterized by their high recording density and large memory capacity, and are used as external information recording devices. It was started.

[0004] The memory capacity of the optical disk device is 13 in diameter.
300MB (megabyte) to 5 on one side of 0mm disk
Larger capacity since the age of 00MB
It is desired to have a memory capacity of 000 MB or more, and the recording line density and the track density have been improved.

In general, simply shortening the period of the recording position or narrowing the track pitch increases signal interference with adjacent marks and deteriorates a reproduction signal. Therefore, the spot diameter of the recording / reproduction light beam is reduced. Need to
This time, there arises a problem that the design margin of the optical system of the recording / reproducing apparatus is reduced.

[0006] As an optical information recording method capable of solving such contradictory problems and improving the information recording density, a recording method described in JP-A-4-49525 is conventionally known. That is, when sequentially recording the presence / absence of a mark on a medium according to input information, when shifting from a state without a mark to a state with a mark, recording is performed with a larger recording energy than during normal mark recording.

According to this method, when marks are continuously recorded, the later the mark is recorded, the more excessively wide the recording is caused by the residual heat from the previous mark, and the track density is reduced. Mark interference) can be resolved, and the track density can be improved.

[0008]

However, on the other hand,
In the portion where the recording energy is concentrated, the thermal stress applied to the recording medium increases, and partial degradation accumulates. In particular, in the case of a phase change recording medium, there is a disadvantage that the number of rewritable times is easily reduced. .

This will be described in more detail with reference to FIG. FIG. 3 shows a conventional example in which the recording method described in Japanese Patent Application Laid-Open No. 4-49525 is applied to phase change recording, and the NRZI (Non-Return-to-Zero-Inv.
(erted) The relationship between the data (a) in the channel bit sequence, the logic signal (b), and the recording mark (c) is shown. Chan
The nelbit sequence is not necessarily random, and the number of times that the same bit state appears continuously is 3 to 14 times or 2 to 7 times in accordance with the recording characteristics.
In some cases, the lower and upper limits are limited.

The recording light pulse (d) is emitted from a light source such as a semiconductor laser in synchronization with the bit clock of the input data signal. Information is recorded in a highly reflective crystalline state. Incidentally, as an example of a recording method suitable for phase change recording, there is a method using pulsed light as disclosed in Japanese Patent Application Laid-Open No. 8-221557. The recording power Pw is higher than the erasing power Pe, and the bias power Pb is set lower than the erasing power Pe in order to promote rapid cooling immediately after the irradiation of the recording power Pw and efficiently form an amorphous mark. You. Furthermore, the first mark bit is set so that the irradiation energy (the product of the power value and the duration) of the light beam is larger than the other mark bits. The erase power is held constant over the entire bit time to provide enough time to replenish enough energy for the erase and promote crystallization.

According to such a conventional technique, a short recording mark is emphasized and recorded by the excessive recording energy at the head of the mark row, so that the recording characteristics are excellent. As the recording energy increases, the thermal stress caused by the presence or absence of the optical mark is increased, and in the case of a rewritable and recordable phase change medium, the number of times of rewriting is reduced.

According to the present invention, it is possible to stabilize a recording operation by reducing a peak of a thermal stress which is partially applied to a recording medium, and to increase the number of times of rewriting of a rewritable recording medium, particularly, a phase change recording medium. It is an object of the present invention to provide a method for recording optical information that can be performed.

[0013]

According to the first aspect of the present invention,
An optical element for recording information by irradiating a modulated light beam to a position having a predetermined period Δx along an information track of an optical information recording medium provided at a predetermined pitch to form an optical mark or not. In the information recording method, the positions at which the presence or absence of the optical mark is formed are sequentially described as:.
.., Δ (i−1), δ (i), δ (i + 1),... Mark formation state 1 and mark non-formation state When represented by 0,
Light beam irradiation energy E at each mark formation position i
The (i), E (i) = E 0 × δ (i) + E 0 × e × (1-δ (i)) ( _{where, 0 <e <1, E} 0 is the predetermined irradiation energy value)
Δ (i) = 0 and δ (i) = 0
When (i + 1) = 1 or δ (i + 2) = 1, the setting is made such that E (i) = E ₀ × a (where e <a <1).

[0014] Accordingly, a predetermined period Δx irradiation energy shown for each E (i) is kept at the same irradiation energy E (i) = E ₀ is the portion of the mark forming status 1, the one preceding mark the mark train immediately before Energy E ₀ × larger than the original irradiation energy E (i) = E ₀ × e in the formation state 0 portion
a, the recording power can be compensated for in the non-mark portion before the leading mark without concentrating the recording power on the leading portion of the mark row. The applied thermal stress can be reduced, and the number of rewrites can be increased.

According to a second aspect of the present invention, in addition to the optical information recording method of the first aspect, the light beam irradiation energy E (i) at each mark forming position i is set to δ (i) = 0 and Even when δ (i + 2) = 1, the setting was made so that E (i) = E ₀ × a.

Therefore, in addition to the first aspect of the present invention, not only the immediately preceding mark formation state 0 portion immediately before the mark row but also the two previous mark formation state 0 portion have the original irradiation energy. Since the energy E ₀ × a larger than E (i) = E ₀ × e is applied, the recording power is not concentrated on the head portion of the mark row, and the non-mark portion before the head mark is further reduced. Can compensate for the energy shortage, thereby reducing the thermal stress applied to the optical information recording medium during recording and increasing the number of rewrites.

According to a third aspect of the present invention, in the optical information recording method according to the first or second aspect, the irradiation light when E ₀ × e and E ₀ × a are given as the irradiation energy E (i). continuous during a predetermined period △ x, duration illumination light for illuminating the within a predetermined period △ x, at a high power level in a pulsed manner when applying a predetermined irradiation energy value E ₀ as the irradiation energy E (i) And a period for maintaining the power level at a low level.

Therefore, in realizing the first or second aspect of the present invention, the mark forming state 1 is recorded with a pulse light having a high power level and a low power level, thereby improving the recording characteristics. Can be kept.

According to a fourth aspect of the present invention, in the optical information recording method according to the third aspect, a predetermined irradiation as the irradiation energy E (i) is performed at the first mark formation position of a mark row in which the mark formation state 1 is continuous. Irradiation light for giving the energy value E ₀ is continuous at the energy level of E ₀ × e during the predetermined period Δx.

Therefore, it is basically the same as the third aspect of the present invention. In particular, regarding the formation of the first mark of a mark row, the irradiation energy value E ₀ is the same as that of the other marks, and E ₀ × e. By applying the energy as a continuous energy for a predetermined period 所 定 x at a given energy level, it becomes more suitable for recording on an optical information recording medium in which the mark length is likely to be long, and the number of times of rewriting of the optical information recording medium is reduced. Can be increased.

[0021] The invention according to claim 5 is the invention according to claims 1 to 4.
In the optical information recording method according to any one of the above, the optical information recording medium is a phase change recording medium.

Therefore, by applying the present invention to a phase change recording medium which is a rewritable optical information recording medium,
The number of rewrites can be increased.

[0023]

FIG. 1 shows a first embodiment of the present invention.
It will be described based on. The optical information recording method according to the present embodiment is applied, for example, as an information recording method for a rewritable phase-change recording medium as an optical information recording medium. In this case, similarly to the case shown in FIG. 3, a modulated light beam is irradiated to a position having a predetermined period Δx along an information track of a phase change type recording medium provided at a predetermined pitch to form an optical mark. An optical information recording method for recording information by forming the presence or absence of the information is assumed.

Under such a premise, in the present embodiment,
.., I−
.., Δ (i−1), δ (i), δ (i + 1),... Mark formation state 1 and mark non-formation state When represented by 0,
Light beam irradiation energy E at each mark formation position i
The (i), E (i) = E 0 × δ (i) + E 0 × e × (1-δ (i)) ( _{where, 0 <e <1, E} 0 is the predetermined irradiation energy value)
Δ (i) = 0 and δ (i) = 0
When (i + 1) = 1, the setting is made so that E (i) = E ₀ × a (where e <a <1). At the same time, δ (i) = 0 and δ (i + 2) =
Also in the case of 1, the setting is made so that E (i) = E ₀ × a. further,
A predetermined irradiation energy value E as the irradiation energy E (i)
_A setting is made such that pulsed light having a period of 50% duty, for example, in which the irradiation light when giving ₀ is pulsed at a high power level Pw and held at a low power level Pb within a predetermined period Δx, for example, is used. Have been.

[0025] Thus, in this embodiment, as the irradiation energy _E (i) = E ₀ of the portion i = 4,5,6,7,8 forming a recording _{mark, E 0 = (Pw + Pb} ) / 2 It has been. On the other hand, the non-mark part i = 1, 2, 2,
In 3, 9, and 10, the irradiation energy E (i) = E ₀
Xe, but in the present embodiment, the non-mark part i = 2, 3 located immediately before the head part i = 4 of the mark string
The is set as the original radiation energy E (i) = E ₀ × larger irradiation energy E than _{e (i) = E 0 ×} a. These irradiation energies E (i) = E ₀ ×
Irradiation light for giving e, E ₀ × a is set to have a pulse waveform that is continuous for a predetermined period Δx.

That is, when the example shown in FIG. 1 is applied to the above equation, E (1) = E ₀ × e ← δ (1) = 0 E (2) = E ₀ × a ← δ (2) = 0 and, [delta] (4) = According to _{1 E (3) = E 0} × a ← δ (3) = 0, and, [delta] (4) = According to _{1 E (4) = E 0} ← δ (4) = 1 According to _{E (5) = E 0 ←} δ (5) = According to _{1 E (6) = E 0} ← δ (6) = According to _{1 E (7) = E 0} ← δ (7) = According to 1 E (8) _{= E 0 ← δ (8)} = 1 in accordance _{E (9) = E 0 ×} e ← δ (9) = 0 E (10) by _{= E 0 × e ← δ (} 10) by = 0 ... it becomes.

As described above, according to the present embodiment, i =
4 is recorded with the same irradiation energy as the other mark bits such as i = 5, 6, 7, and 8, and the erasure of one or two bits before the first mark bit is performed. Since the recording is performed by increasing the energy from Pe to Pa, the recording power Pw does not concentrate on the head of the mark, and compensates for the insufficient energy during the erasing period before the head mark. The thermal stress is small, and the number of rewrites is 2
About twice as much.

A second embodiment of the present invention will be described with reference to FIG. This embodiment is basically the same as the first embodiment, but in the present embodiment, the non-mark portion i = 3 located immediately before the head portion i = 4 of the mark sequence.
Is set as the irradiation energy E (i) = E ₀ × a which is larger than the original irradiation energy E (i) = E ₀ × e, and for the leading part i = 4 in the mark row, other marks are used. The irradiation energy is the same as that of the portion i = 5, 6, 7, and 8, but recording is performed by a continuous recording light pulse for a predetermined period Δx at an energy level of E ₀ × e = Pe.

That is, when the example shown in FIG. 2 is applied to the above equation, E (1) = E ₀ × e ← δ (1) = 0 E (2) = E ₀ × e ← δ (2) = E (3) = E ₀ × a ← δ (3) = 0 by 0 and E (4) = E ₀ ← δ (4) = 1 by δ (4) = 1 E (5) = E ₀ E (6) = E ₀ ← due to δ (5) = 1 E (7) = E ₀ ← due to δ (7) = 1 E (8) = E ₀ ← δ (8) = by _{1 E (9) = E 0} × e ← δ (9) = 0 in accordance _{E (10) = E 0 ×} e ← δ (10) = According to 0 ... become.

In terms of power level, E (4) = Pe
= E (5) = E (6) = E (7) = E (8) = (Pw + Pb) /
It becomes 2.

As described above, according to the present embodiment, the first mark bit such as i = 4 in the mark sequence is set to i = 5,
Recording is performed with the same irradiation energy as other mark bits such as 6, 7, and 8, and recording is performed at the same power level as the erasing power Pe with the portion i = 4 of the first mark bit. The power Pw is not concentrated at the head of the mark row, and is particularly suitable for recording on a medium in which the recording mark is likely to be long, such as a phase change recording medium in the present embodiment. Heat stress is small, and the number of rewrites is 2
Can be improved more than twice.

[0032]

Next, in order to specifically show the effect of the present invention, an embodiment in which the number of times of rewriting is compared is shown below.

Light beam diameter: half-value beam diameter 0.9 μm (condensed at a wavelength of 780 nm and a numerical aperture of 0.50) Optical recording medium: rewritable phase-change recording medium CD-RW formed on a polycarbonate substrate having a diameter of 120 mm Conditions: Light beam scanning speed: 4.8 m / sec Laser recording power: Pw = 14 mW, Pe = 7.0 mW, Pa = 9.0 mW, Pb = 0.7 mW Period of mark position Δx: 0.28 μm Track pitch: 1 .6 μm recording signal: Channel bit string of EFM modulation (mark / non-mark length 3T to 11T)

[0034]

[Table 1]

According to the present embodiment, an example of a phase change type recording medium will be described. However, a remarkable effect of dramatically improving the number of rewritable times is obtained. Also, each channel forming a mark
Since the light energy is made uniform between the bits, even when the reflected light is detected and the address is read from the meandering guide groove, the recording signal light mixed into the irradiation light becomes almost equal in bit units, and the meandering groove The signal is stabilized, and the reproduction reliability of the address is improved. Such effects can be obtained not only in the phase change type recording medium but also in other optical information recording media which record by a thermal action such as a magneto-optical recording medium.

[0036]

According to the invention of claim 1, wherein, according to the present invention, the irradiation energy E indicated in a predetermined cycle [Delta] x (i) is kept at the same irradiation energy E (i) = E ₀ is the portion of the mark forming status 1, mark The previous mark formation state 0 immediately before the row
Is irradiated with an energy E ₀ × a which is larger than the original irradiation energy E (i) = E ₀ × e, so that the recording power is not concentrated on the head of the mark row and the recording power is higher than the head mark. The lack of energy can be compensated for by the non-marked portion, so that the thermal stress applied to the optical information recording medium during recording can be reduced and the number of rewrites can be increased.

According to the invention of claim 2, according to claim 1,
In addition to the invention described above, the mark immediately before the mark row
Mark formation not only in the mark formation state 0 but also two marks before
In the state 0, the original irradiation energy E (i) = E₀× e
Larger energy E than ₀To irradiate xa
So that the recording power is even higher
Non-mark part before the first mark without concentrating on
Can compensate for the lack of energy, and
Reduces thermal stress on optical information recording media,
The number of replacements can be increased.

According to the third aspect of the present invention, in order to realize the first or second aspect of the present invention, the mark forming state 1 is recorded by a pulse light having a high power level and a low power level. Thereby, good recording characteristics can be maintained.

According to the fourth aspect of the present invention, it is basically the same as the third aspect of the present invention, but in particular, with respect to the formation of the first mark in the mark row, the other mark portions and the irradiation energy value E ₀ is the same, and is applied as continuous energy for a predetermined period Δx at an energy level of E ₀ × e, so that it is more suitable for recording on an optical information recording medium in which the mark length tends to be long. In addition, the number of times of rewriting of the optical information recording medium can be increased.

According to a fifth aspect of the present invention, in the optical information recording method according to any one of the first to fourth aspects,
By applying the present invention to a phase change recording medium which is a rewritable optical information recording medium, the number of times of rewriting can be increased.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an information recording method according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram showing an information recording method according to a second embodiment of the present invention.

FIG. 3 is an explanatory diagram showing a conventional information recording method.

Claims (5)

[Claims] An information is formed by irradiating a modulated light beam to a position having a predetermined period Δx along an information track of an optical information recording medium provided at a predetermined pitch to form an optical mark. In the optical information recording method for recording the information, the positions for forming the presence or absence of the optical mark are sequentially arranged in the order of:
.., δ (i−1), δ (i), δ (i + 1),..., i−1, i, i + 1,.
, The light beam irradiation energy E at each mark forming position i.
The (i), E (i) = E 0 × δ (i) + E 0 × e × (1-δ (i)) ( _{where, 0 <e <1, E} 0 is the predetermined irradiation energy value)
Δ (i) = 0 and δ (i) = 0
An optical information recording method, wherein, when (i + 1) = 1, E (i) = E ₀ × a (where e <a <1). 2. The light beam irradiation energy E (i) at each mark forming position i is δ (i) = 0 and δ (i + 2)
2. The optical information recording method according to claim 1, wherein E (i) = E ₀ × a is set even when = 1. 3. The irradiation energy E (i) is E ₀ ×
e, the irradiation light when giving E ₀ × a is equal to the predetermined period Δx
The irradiation light when a predetermined irradiation energy value E ₀ is given as the irradiation energy E (i) within the predetermined period Δx, and a period in which the irradiation light is pulsed at a high power level and a low power level 3. The optical information recording method according to claim 1, wherein the optical information recording method further comprises: 4. The illuminating light E ₀ × e becomes energy level when applying a predetermined irradiation energy value E ₀ Examples irradiation energy E (i) at the beginning of the mark forming position of the mark train mark formation condition 1 is continuous 4. The optical information recording method according to claim 3, wherein the optical information recording method is continuous during the predetermined period Δx. 5. The optical information recording method according to claim 1, wherein said optical information recording medium is a phase change recording medium.