JPS62239325A - optical information recording device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an optical information storage device that stores information by optical means, and particularly to an optical information storage device that can perform recording, reproduction, and erasing.

[Conventional technology]

In recent years, as information storage becomes more dense and digital, various information recording and reproducing methods are being developed. In particular, optical discs that use laser light energy for recording, erasing, and reproducing information are industrial rare metals Nci80, 1983.
As described in (Optical Disks and Materials), higher recording densities are possible than magnetic disks, and this will be a promising method for future information storage devices. Among these, a reproduction device using a laser has been put into practical use as a compact disc ('CD).

[Problem that the invention seeks to solve]

In recent years, information recording on rewritable optical discs has become popular.

There is a demand for enhanced functions such as erasing and reproduction.

An object of the present invention is to improve the recording and erasing sensitivity of a rewritable optical disc, and to increase the S/N during reproduction.

[Means for solving problems]

In the present invention, in order to improve the recording and erasing sensitivity of the optical disc, the optical disc is heated auxiliaryly by heating means other than laser light, such as high-frequency induction heating, and information is recorded, erased, and reproduced using the laser. It is done using light.

However, if the above-mentioned auxiliary heating is performed during playback using laser light, unless the amount of laser light irradiation during playback is reduced,
There is a risk of problems such as erroneous recording or erasing.

If the amount of laser light irradiation during information reproduction is reduced, there is a problem in that the S/N for reading information decreases.

In the present invention, auxiliary heating means for the optical disk other than laser light is limited to recording and erasing, and reproduction is performed by irradiating only laser light.

[Effect]

According to the present invention, since the amount of laser light irradiation during information reproduction can be increased, the S/N ratio during information reproduction is improved. Furthermore, since the optical disk is auxiliary heated during recording and erasing, the response speed of recording and erasing can be improved.

〔Example〕

FIG. 1 shows an embodiment of the present invention.

The signals and operations of each part in the figure will be explained below.

1 is a laser diode serving as a light source.

A collimation lens 2 makes the light beam of the laser diode 1 a balanced light. 3 is a polarizing beam splitter (hereinafter P
BS) transmits the output light from the collimation lens 2 and refracts the returning light from the λ/4 plate 4, which will be described below. The λ/4 plate 4 is used for phase polarization of light in order to facilitate discrimination between incident light and reflected light in the PBS 3.

Reference numeral 5 denotes an objective lens, which is used to condense the incident light L4. A coupling lens 6 receives the light beam from the PBS 3 and condenses it. coupling lens 6
is composed of, for example, two semicylindrical lenses orthogonal to each other. 7 is a photodetector.

The photodetector 7 indirectly detects the shape of the light spot of the output light L5 from the objective lens 5 by detecting the shape of the light spot of the incident light L6 from the coupling lens 6.

8 is an actuator, and the actuator 8 changes the focal position of the output light L5 of the objective lens 5 to i! according to the output of the photodetector 7. ll! ! Do 1.

Reference numeral 81 denotes a lens drive unit, which adjusts the position of the objective lens 5 based on the drive control output from the actuator 8.

9 is a disk on which information can be optically recorded, reproduced, erased, etc., and a portion thereof is shown.

The disk 9 enables information to be recorded and reproduced by irradiating a desired light spot onto the disk surface with the output light L5 from the objective lens 5.

10 is a motor, and the disk 9 is driven by the motor 10. 30 is a magnetic pole. this is.

This is an embodiment in which a high frequency induction heating source is used as a preheating means using electromagnetic waves. Magnetic lines of force passing through the disk 9 are generated from the magnet t430. The disc 9 is a disc for optical information recording to which a recording medium is added. 30' is a magnetic pole, which may be the same as the magnetic pole 30, but may also be an iron core made of a magnetic material that receives the magnetic lines of force from the magnetic pole 30. When the 6m force lines B pass through the disk 9, the disk An eddy current is generated in a portion of the disk 9, thereby causing a portion of the disk 9 to generate heat. What is the amount of heat generated at this time?

This can be controlled by the material of the disk 9, the magnitude of the eddy current, the duration of the magnetic field line's self-addition, the movement of the disk 9 (for example, the number of rotations of the disk 9), etc., so that the characteristics that cause a crystal phase change due to heating of the recording medium can be controlled. Record accordingly,
Can provide heat for functions such as erasing. Recording or erasing is performed by controlling the amount of heat generated by the disk 9 using the high-frequency induction heating method.

By setting the value below the lower limit, the amount of heat necessary for recording, erasing, etc. is further provided by the output light L5 focused on the disk 9 based on the amount of light generated from the light g1 in FIG. The power of the light source 1 required for operation can be reduced, and the heating speed of the disk 9 can also be increased. however.

During playback, the value of the incident light L6 reflected by the disk 9 based on the amount of light generated from the light source 1 is detected by the photodetector 7 to record information, for example, when the reflected light is greater than a predetermined level, the value of the incident light L6 is determined by the photodetector 7. “1”.

When the signal is low, it can be determined as '0'' and a binary signal. Therefore, it is effective to increase the S/N (signal-to-noise ratio), so the incident light L6 during playback should be minimized as much as possible. Just make it bigger.

Therefore, during reproduction, it is better to prevent the generation of eddy currents due to the lines of magnetic force B generated by the magnetic poles 30 and 30'.

Next, a recording medium that can be used for the disc 9 will be explained. The recording medium is made of a metal or alloy that has at least two types of crystal structures in a solid state, retains the crystal structure in one temperature range in the other temperature range, and/or exhibits different volume changes in the crystal state. It is characterized by: Note that any alloy that causes a change in unevenness can be used even if no crystal change occurs. On the other hand, recordable methods can be broadly divided into two types: write-once type and rewritable type. The former allows writing only once and cannot be erased, while the latter allows repeated recording and erasing. In the write-once recording method, a laser beam is used to destroy or shape the medium in the recording area to create unevenness, and for reproduction, a change in the amount of light reflected due to the interference of the laser beam at the uneven area is used for reproduction. This recording medium uses Te and its alloys,
Its dissolution.

Forming unevenness by sublimation is generally known.

This type of media involves some problems such as toxicity.

Magneto-optical materials are the mainstream for rewritable recording media. This method uses optical energy to invert and record the local magnetic anisotropy of the medium near the Curie point or the compensation point temperature, and the polarization plane of the polarized incident light at that part is caused by the magnetic Faraday effect and magnetic Kerr effect. Play with the amount of rotation. This method is being researched and developed as the most promising method for rewriting. Other rewritable systems utilize reflectance changes due to reversible phase changes between amorphous and crystalline recording media.

For example, National Technical Report Vol. 29, No. 5 (National Technical Rep.
There is a material in which a small amount of 08 and Sn are added to TeOx described in Ort Vo129, N[15] (1983).

Examples of alloys include Cu-A (1 alloy, Cu-Zn alloy,
Cu-AQZn alloy, Cu-AM-Ni alloy, Cu-AQ-Mn alloy, Cu-A
lt-F a-Cr alloy, Cu-Ga alloy, Cu-A
Q Ga alloy, Cu-In alloy, Cu-A Q
I n alloy.

Cu-G n alloy, Cu-AM-Ga alloy, Cu-S
n alloy, Cu-Ta alloy + Cu-Ti alloy.

Cu-A Q-S n alloy, Cu-Zn alloy, Cu
-9i alloy*Cu-8b alloy, Cu-Ba alloy.

Cu-B a1 alloy, Cu-Mn alloy, Cu-Pd alloy, Cu-Pt alloy, Ag Zn alloy # A g -
AQ alloy, Ag-Cd gold alloy Ag-I n alloy.

Ag-Ga alloy, Ag-AQ-Au gold alloy A! ! :
-A Q -Cn alloy, A g-A Q -A u
-Cn alloy.

Ag-An-Cd alloy, AK-Pt gold alloy A g -
8 alloy, Ag-8n alloy, Ag-Te alloy, Ag
-Ti alloy, Ag-Zr alloy, Ag-An alloy.

A g -A n alloy, Ag-Be gold alloy A g
Mg alloy, Ag-Ln alloy, Ag-Mn alloy, AQ-Fe alloy, ΔQ-Mg alloy, AM-Mn alloy.

AQ-Pd alloy, AQ-Ta alloy, A11
-T n alloy, AQ-Zn alloy, AQ-Zr alloy, N
i-sb gold alloy Ni-8i alloy, Ni-9n alloy.

Ni-Ga alloy, Mn-Ge alloy, Ni-Ga alloy, Ni-Mn alloy, Ni-5 alloy, Ni-Ti alloy,
Fa-As alloy, As-8 alloy, A5-Zn alloy,
Fa-Ba alloy, Fe-Ni alloy.

Fa-Cr alloy, Fa-P alloy, Mn-Pd alloy.

Mn-P alloy, Mn-8b alloy, Mn-8i alloy, Au-Ca alloy p Au An alloy, Au-
In alloy, Au-Ga alloy, Au-Cd alloy.

Au-Cn alloy, Au-Fn alloy, Au-
Mn alloy, Au-Zn alloy, 'Ba-Ca alloy, Bi-
pb alloy, Bi-TQn alloy Ti-Ni alloy.

N1-V alloy, Ni-Zn alloy, Cd-Li alloy.

Cd-Mg alloy, Cd-Pb alloy, Cd-8b alloy, 5
b-In alloy, Sb-In-8s alloy.

Mg-Ca alloy, Go-Cr alloy, Co-Ge
alloy, Co-Mn alloy, Go-Sb alloy, Go-V alloy, In-Mg alloy, In-Mn alloy, In-Ni alloy,
In-8n alloy, In-TQ alloy.

Li-Zn alloy, Mn-Zn alloy, Pb-T1 alloy, p
b-s alloy, pb-sb gold alloy Pd-Zn alloy, 5n-
Sb alloy, Tfi-8b alloy, 5b-Zn alloy, Ti-
Sb alloy, TQ-3n alloy.

Examples include Zr-Sn alloy, Zr-Th alloy, Ti-Zn alloy, and Ti-Zr alloy.

As examples of alloys, the following are preferred in terms of weight composition.

Ag with 30-46% Zn, 6-10% AQ, 40-60
%Cd, 20-30% In, 13-23% Ga alone,
Cu with 10-20% Al, 20-30% Ga, 20-4
0% In, 20-30% Ga, 15-35% Sn, 10
~60% Zn.

5-10% Si, 4-15% Bo, 30-45% sb alone, Au with 15-25% In, 10-15% Ga, 5
~25% Zn, 20-55% Cd.

2.5-5% AQ alone, 55-60% AQ on Ni, 4
Alloys containing 0-50% Ti alone, In-25-35
%'1'a alloy, alloy with 55% or less of pt added to Fa, Mn-5~50%Cu alloy, 5o15~25%-
In30-40%-sb alloy.

A third component and a fourth component are further added to these alloys.

The following elements other than the second component can be added as the fifth component and the like.

Ia, na, fVa, Van VIa*■a,■.

Ib-Vb, the total of one or more rare earth elements is 1
It is 5% by weight or less.

Specifically, the Ia group is Li, the a group is M g eCa,
fVa group is T x * Z r t Hf, Va group is V
.

Nb, Ta, ■a group is Cr, Mo, W, ■a group is M n
, ■groups are Co, Rh, Ir, Fa, and Ru.

Os, Ni, Pd, Pt, Ib group is Cu, Ag.

A　u　, ■b group is Zn, Cd, mb group is B, All.

Ga, In, and lVb groups include C, Si, Go, and Sn.

The pb and vb groups are P, Sb, and Bi, and the rare earth elements are Y.

La, Ca, Sm, Gd, Tb, D)'*Lu is preferred, and 0.1 to 5% by weight is particularly preferred.

The above recording medium has a first temperature (high temperature) higher than room temperature in a solid state and a second temperature (low temperature) lower than the first temperature.
In an alloy having different crystal structures, the alloy has an alloy composition in which at least a portion of its surface forms a crystal structure different from that obtained by non-quenching at the low temperature by rapid cooling from the high temperature.

This alloy has at least two types of spectral reflectance at the same temperature by heating and cooling treatment in a solid state, and the spectral reflectance can be changed reversibly. That is, the alloy according to the present invention has phases with different crystal structures in at least two temperature ranges in a solid state, and among these, the high-temperature phase is quenched and the non-quenched standard state is a low-temperature state. The spectral reflectance is different, and the spectral reflectance changes reversibly by heating and cooling in a high sum temperature range and heating and cooling in a low sum temperature range.

The principle of this reversible change in reflectance of the recording alloy will be explained with reference to FIG. The figure is a phase diagram of an X-Y binary alloy, in which a solid solution exists and c an intermetallic compound. A
Taking an alloy having the composition B as an example, this alloy has a single b phase, a (b+c) phase, and an (a+c) phase in a solid state. The crystal structure is a.

Each of b and c is different in a single phase state, and the optical properties, such as spectral reflectance, are different in each of these single phase and mixed phase. Although the TI humidity temperature of such alloys is generally room temperature, the (a+c) phase is stable. When this is heated and rapidly cooled to the T4 temperature, the b phase is rapidly cooled to the TI humidity temperature. This b
The phase may transform into a new phase (for example b') during quenching, and since this state is different from the (a+c) phase, the spectral reflectance will also be different. When this rapidly cooled phase (or b' phase) alloy is heated to T2 temperature below Ta temperature and cooled, (a +
c) It transforms into a phase and the 1-spectral reflectance returns to its initial state. By repeating such two heating and cooling processes, it is possible to reversibly change the 1-spectral reflectance.

(Alloy composition) The recording alloy must have a different crystal structure at high and low temperatures, and the rapidly cooled crystal structure must be formed by rapid cooling from a high temperature. The resulting phase must be able to change to a crystalline structure at a low temperature by heating at a predetermined temperature.In this way, the cooling rate is required to obtain a crystalline structure different from that at a low temperature by rapid cooling from a high temperature. as 1
It is preferable that such a change in crystal structure occurs at a temperature of 0''C/sec or higher or 108°C/sec or higher.

The recording alloy is preferably made of an alloy of at least one element selected from group Ib elements of the periodic table and at least one element selected from group elements ub group, nib group, IVb group, and Vb group.

(Manufacturing method) In order to obtain reflectance variability, the recording alloy must be capable of forming a supercooled phase by heating and rapidly cooling the material. In order to create and store information at high speed, it is desirable to use a non-bulk material with a high rapid heating and cooling effect and a small heat capacity.In other words, the energy applied to a desired minute area allows the depth of only the desired area to be reduced. It is desirable that the foil is non-bulk and has a volume that can change to a crystal structure different from the standard crystal structure throughout. Therefore, in order to produce high-density information in a desired micro area, a non-bulk foil with a small heat capacity @ , fine copper wire or powder is preferable, and for producing information in a minute area with a recording density of 20 megabits/aJ or more, 0.01 to 0.2 μm.
Generally, intermetallic compounds are difficult to plastically work, so it is best to have a film thickness of 1.115.11! I. As a method for forming thin wires or powder, it is effective to directly rapidly cool and solidify the material from the gas or liquid phase to form it into a predetermined shape. These methods include PVD method (vapor deposition, sputtering method, etc.)
.

There are CVD methods, molten metal quenching methods in which molten metal is rotated at high speed and made of a member with high thermal conductivity, especially by pouring the molten metal onto the circumferential surface of a metal roll and rapidly solidifying it, and ft electroplating chemical plating methods. When using a film or powder material, it is effective to form it directly on the substrate or to apply it and adhere it to the substrate. When coating, it is best to use a binder that does not cause a reaction even when the powder is heated.Also, to prevent oxidation of the material due to heating, it is also possible to coat the surface of the material, the film formed on the substrate, or the surface of the coating layer. It is valid.

The foil or thin wire is preferably formed by a molten metal quenching method, and preferably has a thickness or straightness of 0.1 mm or less.

In particular, in order to produce foil or fine wire with a crystal grain size of 0.1 μm or less, a thickness or diameter of 0.05 μm or less is preferable.

The powder is preferably formed by an atomization method in which molten metal is sprayed with a gaseous or liquid refrigerant and then poured into water to be rapidly cooled.The particle size is preferably 0.1 μm or less, particularly ultrafine powder with a particle size of 1 μm or less. is preferred.

The film can be formed by vapor deposition, sputtering, CVD electroplating, chemical plating, etc., as described above.

In particular, sputtering is preferable to form a film with a thickness of 0.1 μm or less, and sputtering allows easy control of the target alloy composition.

(Structure) The recording alloy must have a different crystal structure at high and low temperatures, and must have a supercooled phase composition in which the crystal structure at high temperatures is maintained at low temperatures by rapid cooling from high temperatures; The supercooled phase is preferably an intermetallic compound having a C5-CQ type or DOs type ordered lattice, as an example, and the alloy of the present invention has a crystal structure of a lattice. Alloys that mainly form intermediate compounds are preferred.

In particular, a composition in which the entire alloy forms an intermetallic compound is preferred. This intermetallic compound is called an electronic compound, and especially 3/2
Electron compounds (average outer shell electron concentration o/a of 3/2) have good alloy compositions.

Further, the recording alloy preferably has an alloy composition having an in-phase transformation, for example, a eutectoid carbon layer or an encapsulated transformation, and an alloy having a large difference in spectral reflectance can be obtained by quenching from a high temperature and non-quenching.

The optical recording alloy is preferably an alloy having ultrafine crystal grains, and the crystal grain size is particularly preferably 0.1 μm or less.

That is, the crystal grains are preferably smaller than the wavelength of visible light, but may be smaller than the wavelength of semiconductor laser light.

(Characteristics) The recording material can be formed to have at least two types of spectral reflectance in the visible light region at the same temperature. That is, it is necessary that the spectral reflectance of a material having a crystal structure (structure) formed by rapid cooling from a high temperature is different from that of a material having a crystal structure (structure) formed by non-quenching.

In addition, the difference in spectral reflectance obtained by quenching and non-quenching is preferably 5% or more, particularly preferably 10% or more.0 If the difference in spectral reflectance is large, it is easy to visually identify the color, It has remarkable effects in various applications described later.

As a light source for spectrally reflecting, electromagnetic waves other than visible light can be used, and infrared rays, ultraviolet rays, etc. can also be used.

Other properties of recording alloys include electrical resistivity.

The refractive index of light, the polarization rate of light, the transmittance of light, etc. can be changed reversibly in the same way as the spectral reflectance, making it possible to record various information,
It can be used to reproduce recorded information.

Since the spectral reflectance is related to the surface roughness of the alloy, it is preferable that at least the intended portion has a mirror surface so as to have 10% or more in the visible light region as described above.

When the recording alloy is heated and rapidly cooled, its physical or electrical properties such as AM wave spectral reflectance, electrical resistivity, refractive index, polarization rate, and transmittance are changed by partially or entirely changing the crystal structure. It can be used as an information recording element by utilizing the change in characteristics.

As a means of recording information, electrical energy in the form of voltage and current, electromagnetic waves (visible light, radiant heat, infrared, ultraviolet,
Light from photographic flash lamps, electron beams, laser beams from proton at argon lasers, semiconductor lasers, high-voltage spark discharges, etc.) can be used, and in particular, changes in spectral reflectance caused by the irradiation can be used to emit light. It is preferable to use it as a recording medium. By using an optical disc recording medium as a recording platform, it can be used for read-only type, additional recording type, and rewritable type disc devices, and is particularly effective in rewritable type disc devices. The recording method may be either a method of continuously applying energy in a pulsed manner or a method of applying energy continuously; in the former case, it is possible to record as a digital signal.

An example of the principle of recording and reproduction when the recording alloy is used in the recording medium of an optical disk is as follows.

First, the recording medium is locally heated and then rapidly cooled to maintain the crystal structure in the high temperature region in the low temperature region to record predetermined information, or the high temperature phase is used as a base to locally heat the recording medium. During high-temperature curing, information can be recorded locally by heating a low-temperature phase, and by irradiating the recorded portion with light and detecting the difference in optical characteristics between the heated portion and the non-heated portion, information can be reproduced. Furthermore, the recorded information can be erased by heating the portion recorded as information at a temperature lower than the heating temperature at the time of recording. When the light is a laser beam, a short wavelength laser is preferred. Since the reflectance of the heated portion and the non-heated portion of the present invention is large at wavelengths around 500 nm or 800 nm, it is preferable to use laser light having such wavelengths for reproduction.
The same laser source is used for recording and reproducing, and for erasing, another laser beam with a lower energy density than that used for recording is irradiated.

Further, a disk using a recording alloy as a recording medium has a great advantage in that it can be visually determined whether information is recorded or not.

That is, this recording alloy is formed as a thin film recording medium 90 on a substrate 91 as shown in FIG. By applying high thermal energy, it transforms into the second phase, and the reflectance changes from 1 to 2 as shown in Figure 4. To the 0th order, apply relatively long low thermal energy with a pulse width of 18. As a result, it reversibly transforms into the first phase, and the reflectance changes from 2 to 1 at this time. This reflectance change is shown in FIG. 1, in which a light beam L5 with low thermal energy P+t that does not contribute to the phase transformation shown in FIG. 3(A) is spot-radiated onto the recording medium 1, and the reflected light is electrically detected. Light detection method 7
The optical head generates a short, high thermal profile necessary to effect a second phase change.
for recording the temperature profile of , giving a lower thermal profile for a longer time than this, for erasing the first temperature profile that causes the change to the first phase, and for increasing the temperature by irradiating with thermal energy that does not directly contribute to the phase change. Allocate the profile as optical energy for reading.

It has been revealed that the recording characteristics of the phase transformation type recording alloy allow writing with a pulse width on the order of 0.1 μS, and compared to conventional systems, it has a rewriting function that is not found in conventional pit systems. In addition, it is promising as a high-density recording material because it has a longer recording life than the amorphous/crystalline modified type that has a 4I conversion function.

Phase change recording alloys have higher mechanical strength and elongation than conventional materials, so they are highly flexible and can be used by vapor deposition or sputtering on thin-walled disks, tapes, cards, etc. This is especially convenient. The method for recording and erasing information for each of these types of information needs to be determined based on the amount of information required, the image of the device, etc., and in particular, it is necessary to adopt a method based on the characteristics of the material.

In this regard, since recording alloys have high thermal conductivity, it is effective to apply a pulse of high thermal energy for a short time to record on a minute area during recording, thereby achieving high-speed writing.

During erasing, when light energy with a pulse width τE shown in FIG. 3A is applied using a semiconductor laser with an oscillation wavelength of 830 nm, the reflectance decreases from the recorded layer 2 to the erased state 1. At this moment, the amount of heat input to the recording medium 91 coated with the optical recording alloy film increases, so if the temperature rises to the second temperature profile, there is a risk of rewriting. Therefore, such an erasing method using light energy is not necessarily optimal.

In this regard, when using an Ar/laser with a wavelength of around 35gr1m, the reflectance increases when changing from the recording state of 2 to the erasing state of 1, so the above problem can be avoided. However, A
R+ lasers are larger and more expensive than semiconductor lasers, and are disadvantageous in terms of equipment.

The present invention aims to reduce the capacity of the above-mentioned semiconductor laser light source by generating high-frequency eddy current in a recording medium and generating heat.

FIG. 5 explains the heat generation effect of the disk 9 and a structural example based on the principle of high-frequency induction heating. Figure 5 (A
), 9 indicates a part of the disk, and 90 is a recording medium using the above-mentioned recording alloys. 91 is a substrate, which may be made of glass, plastic, or a core; 320 is a power controller, which controls the amount of heat generated and the duration of generation for generating eddy current in the disk 9;
This is to determine the timing of generation, etc., and to control the output of the power supply 321 at the next stage.

322 is ttts for passing the output current of the electric IW 321 to the coils 311, 312, 313 and 314. Coils 311 and 312 are part of the upper core 301
In this example, the coils 313 and 314 are wound around one leg of the body. By supplying high frequency current tl[321 to the coils 311, 312, 313 and 314,
Generates magnetic field lines B. Upper core 301. Both lower cores 302 may be made of a magnetic material with high magnetic permeability, such as a ferrite core. Also, by configuring the lower core 302 in the same manner as the upper core 301, the lines of magnetic force B can be added between both cores. Figure 5 (A
) Upper core 301. lower core 302 and coil 311,
312, 313, 314 are magnetic poles 30 and 30' in FIG.
Since the magnetic force, I&B, penetrates the disk 9 in a reciprocating manner, an eddy current is generated in the recording medium 90 made of an alloy. FIG. 5(B) shows an outline of the eddy current generated in the recording medium when high-frequency magnetic lines of force B pass through the disk 9. The lines of magnetic force B are the lines of magnetic force that pass from the top surface of the disk to the bottom surface Bn, and conversely from the bottom surface to the top surface. The lines of magnetic force passing through are shown as BS.

Eddy current Iao is generated by magnetic field line BN, and magnetic field line Bg
This causes an eddy current Iao'.

Since the eddy currents Iao and Iao' are generated by Biot-Savart's right-handed screw law, they are in the direction of the arrow in the figure, and the amount of eddy current generated is large at the midpoint between the two lines of magnetic force. The Joule heat generated in the zero heat generating part Wp, where the part indicated by Wp is the main heat generating part, depends on the resistance and eddy current values of the recording medium 90. 10-6 to 10 when used
-6Ω1, the thickness is 0.1 μm, and the irradiation spot area is 1 μm×10 μm, then the resistance R in this range is 0.1 to 1Ω.

This resistance is measured at the transformation temperature of the recording alloy from the second phase to the first phase (
Since approximately 3 mW of power is experimentally required to heat the erase temperature to 150°C, the required electric current is as follows.

FIG. 6 shows a recording medium 90 connected to a transparent conductive protective film substrate 91.
．． It has a structure in which heat is generated by passing the lines of magnetic force B in the thickness direction of the alloy 1 through magnetic poles 30 and 30', which are coded with 91' and placed on the upper and lower surfaces thereof, as in FIG. 5. Since the overall thickness of a record carrier having such a structure can be made extremely thin on the order of microns, it is possible to realize not only recording alloy disks but also cards and tapes. By such a method, the recording medium 90 made of an optical recording alloy can be heated to undergo the above-described transformation between the first phase and the second phase. 321 is a power source that generates a high frequency current, and the output current of the power source 321 generates magnetic lines of force B at the magnetic poles 30 and 30' in the same manner as described in FIG. 9 is a disk.

FIG. 7 shows an embodiment of the configuration of the power supply controller 320 and power supply 321 shown in FIG.

320 is the power controller part a Pw, PE
are the recording command pulse and the erasure command pulse, respectively, and the first
In the output light L5 shown in the figure, the recording command and erasing command are performed simultaneously with the above-mentioned command pulses Pw and PE. However, the control of the light source 1 in FIG. 1 is not illustrated. O
R is an OR gate, and command pulse Pw or P[
The output ON becomes the operation permissible output only when this occurs. E
H is a high frequency oscillator, which is used as a clock for the high frequency power supply.

FF is a flip-flop, and its outputs Q and ζ- are alternately generated in accordance with a clock generated by a high frequency oscillator Es. However, the output Q or τ is generated only when the output of the OR gate OR is ON to allow operation, that is, when recording or erasing is performed. 321 is a high frequency inverter serving as a power source portion in FIG. 5, and Eo is a DC power source for generating a high frequency current. Cs is a capacitor.

It absorbs harmonics and stabilizes the DC output voltage so that the voltage of the DC power supply ED remains constant.
1e T Rz is a semiconductor valve, for example (such as a Trangistau electrostatic thyristor).
z*T Rz constitutes a switching circuit in which either one of them is conductive or non-conductive. D.I., D.I.
is a diode.

This was used as a protection element as a surge absorber for a semiconductor valve T Rt t T Ra. TF is an isolation transformer, and magnetic pole 3 serves as a load for tttwX.
0 and is used to match the level of load current I'L. Matching of the load current IL can be performed by changing the turns ratio of the isolation transformer TF. C1 is a capacitor for controlling the waveform of load current IL. It is also possible to increase the load current I2 by varying the capacitance of the capacitor C2 and achieving resonance with the inductive load impedance of the magnetic pole. By energizing the load device IL to the magnetic pole 30, a desired eddy current can be generated in the recording medium.

Furthermore, in the present invention, the recording medium has been described as being applied to a rotating disk, but it may also be a tape or a card using an optical recording medium.

In addition, for recording media with high resistance, high frequency M
Fl! Heating may be applied, and in this case, the magnetic poles described in this embodiment may be of any type as long as they generate high-frequency radio waves.

〔Effect of the invention〕

According to the present invention, the recording medium can be heated by generating eddy current during recording and erasing, and the capacity of the light source can be reduced.

Furthermore, since information is read only by irradiation with a light source during reproduction, the S/N ratio can be increased.

Further, by using a semiconductor valve as a high frequency power source used to generate eddy current, the device can be made stationary, and moreover, it can be made smaller and lighter.

It also has the effect of increasing reliability.

[Brief explanation of drawings]

FIG. 1 is an overall explanatory diagram of the present invention. Figure 2 shows the temperature characteristics of the recording medium. Figure 3 shows the irradiation power for recording and erasing the recording medium. Figure 4 shows an example of the spectral reflectance of the recording medium. Figure 5 shows the recording medium. FIG. 6 shows an example of the structure of a disk, and FIG. 7 shows a power supply configuration for generating high-frequency current. 1...Light source, 9...Disk, 30...Magnetic pole, 3
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Claims (1)

[Claims] 1. In an optical information recording device equipped with a recording medium that records, reproduces, or erases information by irradiating it with optical energy, preheating by electromagnetic waves is not performed at least during reproduction. An optical information recording device characterized by: 2. In the optical information recording device according to item 1, a semiconductor laser is used as a light source as a means for irradiating optical energy, and high-frequency induction heating or high-frequency dielectric heating is performed for preheating by electromagnetic waves. Optical information recording device. 3. An optical information recording device according to item 1, characterized in that the recording medium of the optical information recording device uses a material whose crystal phase changes from a crystalline state to another crystalline state depending on the presence or absence of recording. 4. An optical information recording device according to item 2, further comprising a semiconductor bulb as a means for preheating using electromagnetic waves.