WO2004021342A1 - Recording medium, and recording apparus and method - Google Patents

Abstract

A multi-value recording means which conducts a multi-value recording by irradiating an optical recording medium (1), which is formed by vertically stacking, on a substrate surface, a plurality of recording layers having different crystallization or noncrystallization temperatures, with a recording light whose intensity is modulated the information to be recorded.

Description

 TECHNICAL FIELD The present invention relates to a recording medium in which a plurality of recording layers having different temperature characteristics are formed, and a recording apparatus and method for multilevel recording of information on the recording medium.

 In addition, this application claims priority based on the Japanese Patent Application No. 2 0 0 2-2 4 9 1 5 8 filed on Aug. 28, 2002 in Japan, This application is incorporated by reference into this application. BACKGROUND ART In recent years, with the remarkable development of IT industry, there are many opportunities to handle large amounts of information in homes and the like. Along with this, there is a demand for increasing the capacity of recording media. For example, there is a method of improving the recording density by forming the recording layer of the recording medium in multiple layers and performing multi-value recording. Hereinafter, a recording and reproducing apparatus for recording information on the recording medium and reproducing the recorded information will be described. As a recording medium, a magneto-optical recording medium in which a plurality of recording layers are formed is used.

 The recording and reproducing apparatus includes a recording light irradiation unit and a recording magnetic field application unit. The recording light irradiator irradiates the recording light to a predetermined place of the magneto-optical recording medium. In the magneto-optical recording medium, the coercivity H e of each recording layer is lowered by the above-mentioned irradiation. The recording magnetic field application unit applies a recording magnetic field of an arbitrary magnitude to the place where the coercive force H c is lowered. The recording magnetic field application unit changes the magnetization state of each recording layer according to the magnitude and / or direction of the recording magnetic field to be applied. The recording / reproducing apparatus performs multi-value recording by combining the magnetization states in the perpendicular direction of each recording layer. Also, the recording / reproducing apparatus detects the magnetization state in the perpendicular direction of the recording layer using the magneto-optical effect, and reproduces the recorded information.

Next, information is recorded on an optical recording medium in which a plurality of recording layers are formed, The recording and reproducing apparatus for reproducing the

 The recording and reproducing apparatus includes a recording light irradiator, a reproduction light irradiator, and a reflected light detector. The recording light irradiation unit irradiates the recording light to a predetermined place of the optical recording medium. In the optical recording medium, the crystalline and amorphous states are selected by the temperature elevation level of the recording light to be irradiated, and the information is recorded. In the recording and reproducing apparatus, an arbitrary recording layer is crystallized by changing the focal position of the objective lens to be condensed when irradiating the recording light to the optical recording medium in the vertical direction. The recording and reproducing apparatus performs multi-value recording by combining the crystallization states in the vertical direction of each recording layer. Further, the recording and reproducing apparatus detects the crystallization state in the vertical direction of the recording layer based on the reflectance, and reproduces the recorded information.

 Incidentally, in the recording / reproducing apparatus for multi-value recording on a magneto-optical recording medium in which a plurality of recording layers are formed, as described above, the magnitude / direction of the recording magnetic field applied is changed by the recording magnetic field application unit. However, since it is technically sophisticated to rapidly change the magnitude and / or direction of the recording magnetic field, the apparatus itself becomes expensive.

 Further, in the recording / reproducing apparatus for performing multi-value recording on an optical recording medium in which a plurality of recording layers are formed, as described above, the focal position of the objective lens is changed to the vertical direction (focusing direction) of the optical recording medium. Select an arbitrary recording layer, irradiate the recording light of a predetermined level to the selected recording layer, select the crystalline and amorphous states according to the temperature rise level of the irradiated recording light, and record the information. There is. However, vertical movement of the focal position takes time for focus etc., and it takes time for recording information.

 In addition, multilayer magnetic recording is not performed on a magnetic recording medium that can miniaturize the recording marks by the optically assisted magnetic recording method. In the present invention, there is provided a recording medium in which a plurality of recording layers having different temperature characteristics are stacked, and multilevel recording is performed by irradiating a recording light having an intensity corresponding to the information to be recorded on the recording medium. It aims to provide a possible recording device and method.

The optical recording medium according to the present invention is characterized in that a plurality of recording layers having different crystallization temperatures or amorphization temperatures are stacked in the vertical direction from the substrate surface. 03 010467

3. A magnetic recording medium according to the present invention is characterized in that a plurality of recording layers having different Curie temperatures in the vertical direction from the substrate surface are laminated.

 A recording apparatus according to the present invention is a recording light modulated on the basis of information to be recorded on an optical recording medium in which a plurality of recording layers having different crystallization temperatures or amorphization temperatures are stacked in the vertical direction from the substrate surface. And multi-value recording means for multi-value recording.

 According to the recording method of the present invention, a recording light intensity-modulated based on information to be recorded on an optical recording medium in which a plurality of recording layers having different crystallization temperatures or amorphization temperatures in the vertical direction from the substrate surface is laminated. And multi-value recording.

 A recording apparatus according to the present invention comprises: irradiating means for irradiating a recording light intensity-modulated based on information to be recorded on a recording medium in which a plurality of recording layers having different Curie temperatures are laminated in the vertical direction from the substrate surface; And recording magnetic field application means for applying a recording magnetic field of constant intensity to the place where the light source is irradiated.

 The recording method according to the present invention comprises: irradiating a recording medium in which a plurality of recording layers having a higher Curie temperature are stacked at a position which is deeper from the substrate surface in the vertical direction, recording light whose intensity is modulated based on information to be recorded; And a magnetic field applying step of applying a constant recording magnetic field to a place irradiated with the recording light whose intensity is modulated by the irradiation step. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view of an optical recording medium according to the present invention.

 FIG. 2 is a block diagram showing the configuration of a recording and reproducing apparatus for recording and reproducing information on the optical recording medium according to the present invention.

 FIG. 3 is a view showing the cross section of the optical recording medium and the direction of the magnetic moment when multi-value recording of information is performed on the optical recording medium according to the present invention by the recording / reproducing apparatus.

 FIG. 4 is a view showing the cross section of the magnetic recording medium according to the present invention along with the direction of the magnetic moment.

 FIG. 5 is a block diagram showing the configuration of a recording and reproducing apparatus for recording and reproducing information on a magnetic recording medium according to the present invention.

FIG. 6 shows that the recording / reproducing apparatus recorded multi-value information on the magnetic recording medium according to the present invention. T / JP2003 / 010467

FIG. 6 is a view showing a cross section of the optical recording medium at the time of 4th in the same time as the direction of the magnetic moment.

 FIG. 7 is a cross-sectional view of the magneto-optical recording medium according to the present invention.

 FIG. 8 is a block diagram showing the configuration of a recording and reproducing apparatus for recording and reproducing information on the magneto-optical recording medium according to the present invention.

 FIG. 9 is a view showing a cross section of the optical recording medium when multi-value information is recorded on the magneto-optical recording medium according to the present invention by the recording / reproducing apparatus, together with the direction of the magnetic moment. FIG. 10 is a view showing the cross section of the magneto-optical recording medium on which the expansion reproducing layer according to the present invention is formed, along with the direction of the magnetic moment.

 FIG. 11 is a view showing the cross section of the optical recording medium when multi-value information is recorded on the magneto-optical recording medium on which the enlargement reproduction layer according to the present invention is formed by the recording and reproducing device, along with the direction of the magnetic moment. is there.

 FIG. 12 is a diagram showing how the recording magnetic domain magnetically transferred to the expansion reproducing layer by MAMMOS is expanded and reproduced. BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

 In the optical recording medium 1 of the present invention, a plurality of recording layers having different crystallization temperatures are formed, for example, the recording layer formed at a deeper position in the vertical direction from the recording and reproducing surface of the optical recording medium 1. The crystallization temperature is high. In the optical recording medium 1, for example, as shown in FIG. 1, a first recording layer 11, a second recording layer 12, and a third recording layer 13 are stacked on a substrate 10. There is. Each recording layer is, for example, in an amorphous state at the initial stage.

The first recording layer 11 has a crystallization temperature T 1 and crystallizes when the temperature is raised to the crystallization temperature T 1 or more. The second recording layer 12 has a crystallization temperature T 2, and crystallizes when the temperature is raised to the crystallization temperature T 2 or more. The third recording layer 13 has a crystallization temperature T3 and crystallizes when the temperature is raised to the crystallization temperature T3 or more. The crystallization temperature of each recording layer is: crystallization temperature T 1 <crystallization temperature T 2 <crystallization temperature T 3. The optical recording medium 1 has different crystallization temperatures. As long as a plurality of recording layers are formed, the crystallization temperature may be lower as the recording layer is formed at a deeper position in the vertical direction from the recording and reproducing surface of the optical recording medium 1, or the recording layer may be stacked in random. May be

 The optical recording medium 1 is, for example, a CD-R (CD Recordable) or a CD-RW (CD-Rewritable) or the like in which a plurality of recording layers having different crystallization temperatures or reaction temperatures described above are formed. CD-R is a medium that can be reproduced and recorded additionally, and recording layers such as porphyrin dyes, cyanine dyes, azo dyes, dipyrromethene dyes, polymethylene dyes, naphthoquinone dyes, etc. Organic dyes are used. CD-RW is a medium on which data can be recorded, reproduced, and erased. The recording layer is made of an alloy material mainly composed of Ge, Sb, Te, etc., Ag, In, S The phase change inorganic material of the alloy material which makes b, T e a main raw material is used.

 The optical recording medium 1 is, as shown in FIG. 2, a recording light irradiator 14, a reproduction light irradiator 15, a first half mirror 16, a second half mirror 17, and an objective lens. Information is recorded by the recording and reproducing apparatus 2 provided with 18, the detecting unit 19, and the reproducing unit 20, and the recorded information is reproduced. Here, an operation of recording information on the optical recording medium 1 by the recording and reproducing apparatus 2 and reproducing the recorded information will be described.

 The recording light irradiator 14 irradiates the recording light onto the optical recording medium 1 through the first half mirror 16, the second half mirror 17 and the objective lens 18. The recording light is incident from the side of the substrate 10 of the optical recording medium 1. The recording light irradiator 14 raises the temperature of a predetermined place of the optical recording medium 1 to, for example, a crystallization temperature T 1 based on the information to be recorded. As a result, the first recording layer 11 of the optical recording medium 1 is crystallized as shown in FIG. 3 (a).

 In addition, the recording light irradiator 14 raises the temperature of a predetermined place of the optical recording medium 1 to, for example, the crystallization temperature T 2 based on the information to be recorded. As a result, the first recording layer 11 and the second recording layer 12 of the optical recording medium 1 are crystallized as shown in FIG. 3 and (b).

Furthermore, the recording light irradiator 14 raises the temperature of a predetermined place of the optical recording medium 1 to, for example, the crystallization temperature T 3 based on the information to be recorded. As a result, the first recording layer 11, the second recording layer 12, and the third recording layer 13 of the optical recording medium 1 are crystallized as shown in FIG. 3 (c). When the recording layer is crystallized in this manner, the amount of light reflected by the recording layer after crystallization (hereinafter referred to as reflectance) is smaller than the reflectance of the recording layer before the change. Therefore, as shown in FIG. 3 (d), when the recording layer is not crystallized, the reflectance is the highest, and FIG. 3 (a) _s FIG. 3 (b), FIG. The reflectance decreases in the order of c). The recording / reproducing apparatus 2 reproduces information by using the difference in reflectance. In the optical recording medium 1, the recording state as shown in FIG. 3 (a) is "1", the recording state as shown in FIG. 3 (b) is "2", and the recording as shown in FIG. 3 (c). It is assumed that the state is "3", the recording state as shown in FIG. 3 (d) is "0", and information is recorded / reproduced by four values. The following describes the playback operation.

 The reproduction light irradiator 15 irradiates the reproduction light onto the optical recording medium 1 through the first half mirror 16, the second half mirror 17 and the objective lens 18. The reproduction light is incident from the side of the substrate 10 of the optical recording medium 1. The reproduction light irradiated to the optical recording medium 1 is reflected, and is input to the detection unit 19 via the objective lens 18 and the second half mirror 17. The detection unit 19 detects the reflectance from the incident light and outputs it to the reproduction unit 20. The reproducing unit 20 reproduces the information recorded in the optical recording medium 1 based on the inputted reflectance.

 The recording / reproducing apparatus 2 configured in this way irradiates the recording light to the optical recording medium 1 in which a plurality of recording layers having different crystallization temperatures are formed, and the temperature is raised based on the information to be recorded to record the information Since the recorded information is reproduced, the information can be multi-valued recorded on the optical recording medium 1 by changing the power of the recording light to be irradiated, and the multi-valued recorded information can be multi-valued based on the reflectance. It can be played back. In the optical recording medium 1, the initial state may be a crystallized state, and recording layers having different amorphization temperatures may be stacked. In the optical recording medium 1, the recording layers may not be in direct contact with each other, and for example, a dielectric layer or a nonmagnetic layer may be formed between the recording layers.

 Next, a second embodiment will be described below.

 In the magnetic recording medium of the present invention, a plurality of magnetic recording layers having different Curie temperatures are formed. Is high.

The magnetic recording medium 3 is, for example, as shown in FIG. A layer 31, a second magnetic recording layer 32, and a third magnetic recording layer 33 are stacked. The magnetization direction of each magnetic recording layer may be either a perpendicular magnetization film or an in-plane magnetization film. Here, the former will be described as an example. First, the magnetization of each recording layer is assumed to be downward as shown in FIG. 4 in the initial state.

 The first magnetic recording layer 31 has a Curie temperature T1, and becomes paramagnetic when the temperature is raised to the Curie temperature T1 or more. The second magnetic recording layer 32 has a single temperature T 2 and becomes paramagnetic when the temperature is raised to the Curie temperature T 2 or more. The third magnetic recording layer 33 has a Curie temperature T3 and becomes paramagnetic when heated to the Curie temperature T3 or more. The Curie temperature of each magnetic recording layer is Curie temperature T 1 <curly temperature T 2 <curly temperature T 3. The magnetic recording medium 3 is, for example, a recording medium such as an HDD in which a plurality of magnetic recording layers such as CoCr or FePt having different Curie temperatures described above are formed. The magnetic recording medium 3 may have a plurality of recording layers having different Curie temperatures, and the Curie temperature is lower as the recording layer is formed at a deeper position in the perpendicular direction from the recording and reproducing surface of the magnetic recording medium 3. It may be stacked at random. The magnetic recording medium 3 has information recorded and recorded by a recording / reproducing apparatus 4 having a recording light irradiation unit 34, an objective lens 35, and a magnetic head 36, as shown in FIG. Is played. Here, an operation of recording information on the magnetic recording medium 3 by the recording / reproducing apparatus 4 and reproducing the recorded information will be described. The recording / reproducing apparatus 4 records information on the magnetic recording medium 3 by the optically assisted magnetic recording method.

 The recording light irradiator 34 irradiates the recording light onto the magnetic recording medium 3 through the objective lens 35, and raises the temperature to, for example, the Curie temperature T1 based on the information to be recorded. Although the recording light is incident from the substrate 30 side of the magnetic recording medium 3, the recording light is not limited to the incident method of the recording light, and the recording light may be incident from the magnetic head side. The magnetic head 36 applies a recording magnetic field of constant intensity at the position heated by the recording light irradiator 34. Then, the recording light irradiation unit 34 stops the irradiation of the recording light and cools it down. As a result, the magnetization of the first magnetic recording layer 31 of the magnetic recording medium 3 is reversed as shown in FIG. 6 (a).

In addition, the recording light irradiator 34 is, for example, based on Curie temperature T 2 based on the information to be recorded. Heat up to. The magnetic head 36 moves to a position heated by the recording light irradiator 34 and applies a recording magnetic field of a constant intensity. Then, the recording light irradiation unit 34 stops the irradiation of the recording light and lowers the temperature. As a result, the magnetizations of the first magnetic recording layer 31 and the second magnetic recording layer 32 of the magnetic recording medium 3 are reversed as shown in FIG. 6 (b). Furthermore, the recording light irradiator 34 raises the temperature to, for example, the Curie temperature T3 based on the information to be recorded. The magnetic head 36 moves to a position heated by the recording light irradiator 34 and applies a recording magnetic field of a constant intensity. Then, the recording light irradiation unit 34 stops the irradiation of the recording light and cools it down. As a result, the magnetization of the first magnetic recording layer 31, the second magnetic recording layer 32 and the third magnetic recording layer 33 of the magnetic recording medium 3 is reversed as shown in FIG. 6 (b). In the state shown in Fig. 6 (c), the leakage magnetic field is the largest, and the leakage magnetic field decreases in the order of Fig. 6 (b), Fig. 6 (a) and Fig. 6 (d).

 The recording / reproducing apparatus 4 reproduces information using the difference in magnitude of the leakage magnetic field. In the magnetic recording medium 3, the magnetization state as shown in FIG. 6 (a) is “1”, the magnetization state as shown in FIG. 6 (b) is “2”, and the magnetization state as shown in FIG. 6 (c) Let “3”, and let the magnetization state as shown in Fig. 6 (d) be “0”, and information be recorded / reproduced with four values.

 In the magnetized state as shown in Fig. 6 (c), the leakage magnetic field is the largest, and the leakage magnetic field decreases in the order of Fig. 6 (b), Fig. 6 (a) and Fig. 6 (d). The magnetic head 36 detects this leaked magnetic field from the substrate 30 side of the magnetic recording medium 3 and reproduces the information recorded in the magnetic recording medium 3.

 The recording / reproducing apparatus 4 configured in this manner records information by optically assisted magnetic recording on the magnetic recording medium 3 in which a plurality of magnetic recording layers having different temperatures are formed, and the recorded information is recorded as a magnetic head 3 6 Since the reproduction is performed according to the above, it is possible to record information on the magnetic recording medium 3 in multiple levels by modulating the intensity of the recording light to be irradiated, and by detecting the leakage magnetic field output according to the magnetization state. Information can be reproduced. In the magnetic recording medium 3, the magnetic recording layers may not be in direct contact with each other, and for example, a dielectric layer or a nonmagnetic layer may be formed between the magnetic recording layers.

 Next, a third embodiment will be described below.

In the magneto-optical recording medium of the present invention, a plurality of magnetic recording layers having different Curie temperatures are formed. JP 2003/010467

For example, as the magnetic recording layer is formed at a deep position in the vertical direction from the recording and reproducing surface of the magneto-optical recording medium, the temperature is higher. ·

 For example, as shown in FIG. 7, the magneto-optical recording medium 5 includes a first magnetic recording layer 41, a second magnetic recording layer 42, and a third magnetic recording layer 43 on a substrate 40. And are stacked. The magnetization direction of each magnetic recording layer may be a perpendicular magnetization film or an in-plane magnetization film, and the former will be described as an example here. First, the magnetization of each recording layer is assumed to be downward as shown in FIG. 7 in the initial state.

 The first magnetic recording layer 41 has a Curie temperature T1, and becomes paramagnetic when heated to a temperature above T1. The second magnetic recording layer 42 has a single temperature T 2 and becomes paramagnetic when the temperature is raised to the Curie temperature T 2 or more. The third magnetic recording layer 43 has a Curie temperature T3 and becomes paramagnetic when heated to the Curie temperature T3 or more. The Curie temperature of each magnetic recording layer is such that Curie temperature T 1 <Curie temperature T 2 <Curie temperature T 3. Also, the magneto-optical recording medium 5 is, for example, a recording medium such as M〇 in which a plurality of magnetic recording layers such as T e F e C o having different Curie temperatures described above are formed. The magneto-optical recording medium 5 is only required to have a plurality of recording layers having different temperatures, and the recording layer formed at a deeper position in the vertical direction from the recording and reproducing surface of the magneto-optical recording medium 5 is The Curie temperature may be low, or may be stacked randomly. As shown in FIG. 8, the magneto-optical recording medium 5 has a recording light irradiation unit 44, a reproduction light irradiation unit 45, a first half mirror 46, a second half mirror 47, and an objective. Information is recorded by the recording and reproducing apparatus 6 including the lens 48, the recording magnetic field applying unit 49, the detecting unit 50, and the reproducing unit 51, and the recorded information is reproduced. Here, an operation of recording information on the magneto-optical recording medium 5 by the recording and reproducing device 6 and reproducing the recorded information will be described.

The recording light irradiator 44 irradiates the recording light to the magneto-optical recording medium 5 through the first half mirror 46, the second half mirror 47 and the objective lens 48, and based on the information to be recorded, For example, the temperature is raised to the Curie temperature T1. The recording light is incident from the substrate 40 side of the magneto-optical recording medium 5. The recording magnetic field application unit 49 applies a recording magnetic field of a constant intensity to the location heated by the recording light irradiation unit 44. And, Recording light irradiation The unit 44 stops the irradiation of the recording light and lowers the temperature. As a result, the magnetization of the first magnetic recording layer 41 of the magneto-optical recording medium 5 is reversed as shown in FIG. 9 (a).

 Also, the recording light irradiator 44 raises the temperature to, for example, the Curie temperature T 2 based on the information to be recorded. The recording magnetic field application unit 49 moves to a position heated by the recording light irradiation unit 44 and applies a recording magnetic field of a constant intensity. Then, the recording light irradiation unit 44 stops the irradiation of the recording light and lowers the temperature. As a result, the magnetization of the first magnetic recording layer 41 and the second magnetic recording layer 42 of the magneto-optical recording medium 5 is reversed as shown in FIG. 9 (b). Further, the recording light irradiator 44 raises the temperature to, for example, the Curie temperature T3 based on the information to be recorded. The recording magnetic field application unit 49 moves to a position heated by the recording light irradiation unit 44 and applies a recording magnetic field of a constant intensity. Then, the recording light irradiation unit 4 4 stops the irradiation of the recording light and lowers the temperature. As a result, the magnetizations of the first magnetic recording layer 41, the second magnetic recording layer 42, and the third magnetic recording layer 43 of the magneto-optical recording medium 5 are reversed as shown in FIG. 9 (c). Do. In the magneto-optical recording medium 5, the magnetization state as shown in FIG. 9 (a) is "1", the magnetization state as shown in FIG. 9 (b) is "2", and the magnetization as shown in FIG. 9 (c). Assuming that the state is “3”, and the magnetization state as shown in FIG. 9 (d) is “0”, information is recorded and reproduced by four values. The reproduction operation will be described below. The recording / reproducing apparatus 6 reproduces information from the magneto-optical recording medium 5 by the magneto-optical effect.

 The reproduction light irradiator 45 irradiates the magneto-optical recording medium 5 with reproduction light through the first half mirror 46, the second half mirror 47 and the objective lens 48. The reproduction light is incident from the substrate 40 side of the magneto-optical recording medium 5. The reproduction light emitted to the magneto-optical recording medium 5 is reflected, and is incident on the detection unit 50 through the objective lens 48 and the second half mirror 47.

Here, the configuration and operation of the detection unit 50 will be described. The detection unit 50 includes a wave plate 5 0 a, a splitter 5 0 b, a first light detector 5 0 c, and a second light detector 5 0 d. The light (hereinafter referred to as "reflected light") incident from the second half mirror 47 is separated into the P-polarization component and the S-polarization component by the wave plate 50a and the beam splitter 50b. The P-polarization component is incident on a first light detector 50 c, and the S-polarization component is incident on a second light detector 5 0 c. First photodetector 5 0 c and second The photodetector 50 d detects the rotation and phase change of the polarization plane of the reflected light from each polarization component. The reproducing unit 51 reproduces the information recorded on the magneto-optical recording medium 5 according to the detection result of the detecting unit 50.

 In the magneto-optical recording medium 5 according to the present invention, as shown in FIG. 10, an auxiliary layer 52 and an enlargement reproducing layer 53 are formed between the substrate 40 and the first magnetic recording layer 41. It may be one (hereinafter referred to as magneto-optical recording medium 7). The auxiliary layer 52 is a nonmagnetic layer having no magnetic property. The enlargement reproduction layer 53 is, for example, an amorphous film of alloying a rare earth element (hereinafter referred to as RE) and a transition metal element (hereinafter referred to as TM). In such a magneto-optical recording medium 7, recorded information is reproduced by MAMMOS (Magnetic Amplifying Magneto-Optical System). The magneto-optical recording medium 7 is only required to have a plurality of recording layers having different Curie temperatures, and the recording layer formed at a position deeper in the vertical direction from the recording and reproducing surface of the magneto-optical recording medium 7 is Lee temperature may be low or may be stacked randomly.

 The magneto-optical recording medium 7 is subjected to multi-value recording and reproduction of information by the recording and reproduction apparatus 6 shown in FIG. The recording operation of the recording / reproducing apparatus 6 is the same as described above.

 Here, the reproduction operation by MAMMOS will be described below. The magneto-optical recording medium 7 is assumed to be recorded in a magnetized state as shown in FIG. 11 (a) to (c).

 As shown in FIG. 12 (a), the first magnetic recording film 41, the second magnetic recording film 42 and the third magnetic recording film 42 are formed on the expansion reproducing layer 53 through the nonmagnetic auxiliary layer 52. The magnetization state of the magnetic recording film 43 (hereinafter referred to as “magnetic recording layer m”) is magnetically transferred. In MAMMOS, recording magnetic domains are formed in the magnifying reproduction layer 53 by magnetic transfer, and the recording magnetic domains are shown in FIG. 12 (b) by the reproduction light L irradiated from the reproduction light irradiating section 45. , Reproduction light Expand to full diameter of L.

By this, it becomes possible to expand the magnetic field generated by the minute magnetic domain recorded in the magnetic recording layer m to the same level as the conventional one. The magnetic transfer from the magnetic recording layer m to the expansion reproducing layer 53 is performed by the magnetic field from the magnetic recording layer m, and the magnetic expansion on the expansion reproducing layer 53 is performed by the application of the external magnetic field Hb. After that, as shown in Fig. 12 (c), the recording / reproducing device 6 reaches the position below the recording light L with the following information: It generates a magnetic field that inverts the expanded magnetic domain, and disappears the recording magnetic domain expanded and transferred to the expanded reproducing layer 53.

 The recording / reproducing apparatus 6 configured in this manner irradiates the recording light to the magneto-optical recording medium 5 in which a plurality of magnetic recording layers having different Curie temperatures are formed, and raises the temperature based on the information to be recorded. Since information is recorded by applying a recording magnetic field of a constant intensity and the magnetization state is reversed, and the recorded information is reproduced, the information is multi-valued to the magneto-optical recording medium 5 by changing the power of the recording light to be irradiated. Recording can be performed, and multi-valued recorded information can be reproduced based on the magneto-optical effect.

 In the recording / reproducing apparatus 6, a plurality of magnetic recording layers having different Curie temperatures are formed, and the recording light is irradiated to the magneto-optical recording medium 7 in which the auxiliary layer and the enlargement reproduction layer are formed above the magnetic recording layer. The temperature is raised based on the information to be recorded, a recording magnetic field of constant intensity is applied to the temperature rising location, the information is recorded by reversing the magnetization state, and the recorded information is reproduced by the MAMMOS. The information can be multi-value recorded on the magneto-optical recording medium 5 by the small recording mark size by changing 1 and information on the multi-value recording micro recording mark size can be reproduced based on the magneto-optical effect. it can. In the magneto-optical recording medium 5 and the magneto-optical recording medium 7, the respective magnetic recording layers may not be in direct contact, and for example, a dielectric layer or a nonmagnetic layer may be formed between the respective magnetic recording layers.

The present invention is not limited to the above-described embodiment described with reference to the drawings, and various modifications, substitutions or equivalents thereof may be made without departing from the scope of the appended claims and the subject matter thereof. It will be apparent to one skilled in the art that the Industrial Applicability As described above in detail, since the recording medium according to the present invention is formed by laminating a plurality of recording layers having a higher crystallization temperature in the vertical direction from the substrate surface, the light intensity modulation ( Multi-level recording can be easily performed by LIM _s Light Intensity Modulation.

In addition, as described above in detail, in the recording medium according to the present invention, since a plurality of recording layers having a higher temperature are further stacked in the vertical direction from the surface of the substrate, Magnetization states with different depths can be easily formed by intensity modulation (LIM, Light Intensity Modulation), and multi-level recording can be easily performed by applying a constant recording magnetic field thereto. Furthermore, in the recording medium according to the present invention, since the enlarged reproduction layer is formed between the substrate and the recording layer via the auxiliary layer, reproduction of the minute recording marks recorded in the recording layer is performed by MA MM OS It can be done by

 In addition, as described above in detail, the recording apparatus and method according to the present invention record on an optical recording medium in which a plurality of recording layers having higher crystallization temperatures are stacked at positions deeper in the vertical direction from the substrate surface. Since the recording light having the intensity modulated based on the information is irradiated and the multi-value recording means for multi-value recording is provided, multi-value recording can be performed by irradiating the recording light of the intensity according to the information to be recorded.

 Further, as described above in detail, in the recording apparatus and method according to the present invention, the information to be recorded on the recording medium in which a plurality of recording layers having a higher temperature are accumulated in the vertical direction from the substrate surface And the recording magnetic field applying means for applying the recording magnetic field of constant intensity to the place where the recording light is irradiated, recording of the intensity according to the information to be recorded. Light can be irradiated to form magnetization states of different depths, and multi-valued recording can be performed by applying a constant recording magnetic field thereto.

Claims

The scope of the claims

1. In an optical recording medium in which a plurality of recording layers are laminated on a substrate,

 An optical recording medium characterized in that the plurality of recording layers have different crystallization temperatures or amorphization temperatures.

 2. The plurality of recording layers are stacked on the substrate in the order of higher crystallization temperature or amorphization temperature from the side on which the recording light is incident. Optical recording media.

 3. The plurality of recording layers are stacked on the substrate in order of decreasing crystallization temperature or amorphization temperature from the side on which the recording light is incident. Optical recording media.

 4. A plurality of recording layers different in crystallization temperature or amorphization temperature from the side on which the recording light is incident are randomly stacked on the substrate. Optical recording medium.

 5. A magnetic recording medium in which a plurality of recording layers are laminated on a substrate,

 A magnetic recording medium characterized in that the plurality of recording layers have different Curie temperatures. '

 6. The magnetic recording medium according to claim 5, wherein the plurality of recording layers are stacked on the substrate in descending order of the Curie temperature from the side where the recording light is incident.

 7. The magnetic recording medium according to claim 5, wherein the plurality of recording layers are stacked on the substrate in order of decreasing Curie temperature from the side where the recording light is incident.

 8. A magnetic recording medium according to claim 5, wherein a plurality of recording layers having different Curie temperatures from the side on which the recording light is incident are randomly stacked on the substrate.

 9. A magnetic recording medium according to claim 5, wherein a magnifying reproduction layer is formed between the substrate and the recording layer via an auxiliary layer.

1 0. Multiple recording layers with different crystallization or amorphization temperatures in the vertical direction from the substrate surface What is claimed is: 1. A recording apparatus comprising: multi-level recording means for irradiating a recording light intensity-modulated based on information to be recorded onto a plurality of optical recording media stacked, and performing multi-level recording.

 1 1. In the optical recording medium, the plurality of recording layers are stacked on the substrate in the order of higher crystallization temperature or amorphization temperature,

 The recording apparatus according to claim 10, wherein said multi-value recording means irradiates recording light from the substrate side of said optical recording medium.

 1 2. In the optical recording medium, the plurality of recording layers are stacked on the substrate in the order of low crystallization temperature or low amorphization temperature,

 The recording apparatus according to claim 10, wherein said multi-value recording means irradiates recording light from the substrate side of said optical recording means.

 1 3. In the optical recording medium, a plurality of recording layers having different crystallization temperatures or amorphization temperatures are randomly stacked on the substrate,

 The recording apparatus according to claim 10, wherein said multi-value recording means irradiates recording light from the substrate side of said optical recording medium.

 1 4. The recording light whose intensity is modulated based on the information to be recorded is irradiated to the optical recording medium in which a plurality of recording layers having different crystallization temperatures or amorphization temperatures are stacked in the vertical direction from the substrate surface. A recording method characterized in that a value is recorded.

 In the optical recording medium, the plurality of recording layers are stacked on the substrate in the order of higher crystallization temperature or amorphization temperature,

 15. A recording method according to claim 14, wherein the recording light is irradiated from the substrate side of the optical recording medium.

 In the recording medium, the plurality of recording layers are stacked on the substrate in the order of low crystallization temperature or amorphization temperature,

 15. A recording method according to claim 14, wherein the recording light is irradiated from the substrate side of the optical recording medium. .

 In the optical recording medium, a plurality of recording layers having different crystallization temperatures or amorphization temperatures are randomly stacked on the substrate,

15. A recording method according to claim 14, wherein the recording light is irradiated from the substrate side of the optical recording medium.

8. A recording medium in which a plurality of recording layers having different Curie temperatures are stacked in the vertical direction from the substrate surface is irradiated with the recording light whose intensity is modulated based on the information to be recorded, and the recording light is irradiated. And a recording magnetic field application unit that applies a recording magnetic field of a constant intensity to a place where the recording medium is located.

 The recording medium is a magneto-optical recording medium or a magnetic recording medium which is stacked on the substrate in the order of higher Curie temperature,

 The recording apparatus according to claim 18, wherein the recording light is irradiated from the substrate side of the magneto-optical recording medium or the magnetic recording medium.

 2 0. The recording medium is a magneto-optical recording medium or a magnetic recording medium which is stacked on the substrate in the order of low Curie temperature,

 The recording apparatus according to claim 18, wherein the recording light is irradiated from the substrate side of the magneto-optical recording medium or the magnetic recording medium.

 The recording medium is a magneto-optical recording medium or a magnetic recording medium in which a plurality of recording layers having different Curie temperatures are stacked on a random basis on the substrate.

 The recording apparatus according to claim 18, wherein the recording light is irradiated from the substrate side of the magneto-optical recording medium or the magnetic recording medium.

 2 2. A recording medium in which a plurality of recording layers having different Curie temperatures are stacked in the vertical direction from the substrate surface is irradiated with the recording light whose intensity is modulated based on the information to be recorded; And a magnetic field applying step of applying a constant recording magnetic field to the place where the recording light is irradiated.

2 3. The recording medium is a magneto-optical recording medium or a magnetic recording medium which is stacked on the substrate in the order of higher Curie temperature,

 The recording method according to claim 22, wherein the irradiating step irradiates the recording light from the substrate side of the magneto-optical recording medium or the magnetic recording medium.

The recording medium is a magneto-optical recording medium or a magnetic recording medium stacked on the substrate in the order of low Curie temperature,

 The recording method according to claim 22, wherein the irradiating step irradiates the recording light from the substrate side of the magneto-optical recording medium or the magnetic recording medium.

In the recording medium, a plurality of recording layers having different Curie temperatures run on the substrate. The magneto-optical recording medium or the magnetic recording medium stacked on a dam;

 The recording method according to claim 22, wherein the irradiating step irradiates the recording light from the substrate side of the magneto-optical recording medium or the magnetic recording medium.