KR970010942B1 - Optical recording medium - Google Patents

Optical recording medium Download PDF

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KR970010942B1
KR970010942B1 KR1019890005695A KR890005695A KR970010942B1 KR 970010942 B1 KR970010942 B1 KR 970010942B1 KR 1019890005695 A KR1019890005695 A KR 1019890005695A KR 890005695 A KR890005695 A KR 890005695A KR 970010942 B1 KR970010942 B1 KR 970010942B1
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South Korea
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film
recording
reproducing
magneto
recording medium
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KR1019890005695A
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Korean (ko)
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KR900017035A (en
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안동훈
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엘지전자 주식회사
구자홍
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    • GPHYSICS
    • G11INFORMATION STORAGE
    • G11BINFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B11/00Recording on or reproducing from the same record carrier wherein for these two operations the methods are covered by different main groups of groups G11B3/00 - G11B7/00 or by different subgroups of group G11B9/00; Record carriers therefor
    • G11B11/10Recording on or reproducing from the same record carrier wherein for these two operations the methods are covered by different main groups of groups G11B3/00 - G11B7/00 or by different subgroups of group G11B9/00; Record carriers therefor using recording by magnetic means or other means for magnetisation or demagnetisation of a record carrier, e.g. light induced spin magnetisation; Demagnetisation by thermal or stress means in the presence or not of an orienting magnetic field
    • GPHYSICS
    • G11INFORMATION STORAGE
    • G11BINFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/62Record carriers characterised by the selection of the material
    • G11B5/73Base layers, i.e. all non-magnetic layers lying under a lowermost magnetic recording layer, e.g. including any non-magnetic layer in between a first magnetic recording layer and either an underlying substrate or a soft magnetic underlayer
    • GPHYSICS
    • G11INFORMATION STORAGE
    • G11BINFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B2220/00Record carriers by type
    • G11B2220/20Disc-shaped record carriers
    • G11B2220/25Disc-shaped record carriers characterised in that the disc is based on a specific recording technology
    • G11B2220/2525Magneto-optical [MO] discs

Abstract

A photo magnetic recording medium capable of recording and storing a stable bit and reproducing a signal of good quality by using magnetic films for recording and reproducing different from each other and forming magnetic film of high permeability therebetween is disclosed. In the photo magnetic recording medium, an interference film(22) is formed on a substrate(21). A reproducing film(23) is formed on the interference film(22). A recording film(25) is formed on the reproducing film(23). The reproducing film(23) and recording film(25) are formed by magnetic films of materials different from each other A protective film(26) is formed on the recording film(25). A copy film(24) is formed between the reproducing film(23) and recording film(25) and copies a signal.

Description

광자기 기록매체Magneto-optical recording media

제 1 도는 종래 전형적인 광자기 디스크의 구조도.1 is a structural diagram of a conventional typical magneto-optical disk.

제 2 도는 본 발명과 관련된 도면으로 다층 기록막의 구조도.2 is a structural diagram of a multilayer recording film in accordance with the present invention.

제 3 도는 본 발명에 의한 광자기 디스크의 구조도.3 is a structural diagram of a magneto-optical disk according to the present invention.

제 4 도는 본 발명에 의한 광자기 디스크의 C/N대 기록파워 선도.4 is a C / N band recording power diagram of a magneto-optical disk according to the present invention.

제 5 도는 본 발명에 의한 기록막 및 재생막의 MH 히스데리시스 루우프를 보인 선드.Fig. 5 shows a Sun showing MH hysteresis loops of a recording film and a reproducing film according to the present invention.

본 발명은 정보기록용 광자기 기록매체에 관한 것으로, 특히 기록 및 재생에 서로 상이한 자성박막을 사용함과 아울러 그 사이에 고투자율의 연질자성박막을 형성함으로써 안정된 비트(Bit)의 기록 및 보존이 가능하며 재생시에는 보다 높은 신호품질을 얻을 수 있도록 한 광자기 기록매체에 관한 것이다.The present invention relates to a magneto-optical recording medium for information recording. In particular, by using different magnetic thin films for recording and reproducing, and forming a high magnetic permeability soft magnetic thin film therebetween, stable recording and storage of bits are possible. The present invention relates to a magneto-optical recording medium capable of obtaining higher signal quality during reproduction.

정보의 기록밀도가 증가됨에 따라 종래 사용되던 자기기록매체는 반자계 헤드/매체간의 접촉에 따른 주행특성의 악화등의 문제로 기록밀도를 높이는데 한계가 있었으며, 이러한 문제를 해결하기 위하여 등장한 것이 광자기 기록매체이다.As the recording density of information increases, the conventional magnetic recording media has a limitation in increasing the recording density due to the deterioration of driving characteristics due to the contact between the diamagnetic heads and the media, and has emerged to solve such problems. It is a magnetic recording medium.

광자기 기록매체는 재생만 가능한 CD, VD, CD-ROM 등의 재생전용 광디스크가 현재 널리 보급되고 있는 단계에 있으며, 대용량 파일링 시스템(Filing System)용으로 1회 기록용(WORM type) 디스크가 실용화되는 단계에 와있다.Magneto-optical recording media are in the stage of widespread use of reproducing optical discs such as CDs, VDs, and CD-ROMs.WORM type discs have been put to practical use in large-scale filing systems. I am at the stage of becoming.

그러나 궁극적으로 기존의 자기기록매체가 갖고 있는 소거/재생기능의 소거 가능형 광디스크는 이제 연구단계에 있으며, 최근 샘플 등이 만들어지고 있는 실정이다.Ultimately, however, erasable optical discs having an erase / playback function of existing magnetic recording media are in the research stage, and samples have recently been produced.

소거 가능형 광디스크는 광자기 타입과 상변이 타입의 2가지로 크게 분류되고 있으나, 제 1 세대의 소거 가능형 광디스크로서는 광자기 타입이 유망하다.Erasable optical discs are broadly classified into two types, a magneto-optical type and a phase change type. However, a magneto-optical type is promising as the first generation of erasable optical discs.

광자기 디스크 재료로서는 초기에는 MnBi 등의 다결정 재료등이 연구되었으나 결정입계에서 기인되는 노이즈 등에 의해 충분한 크기의 신호 품질을 얻을 수 없었다.Initially, as the magneto-optical disk material, polycrystalline materials such as MnBi and the like have been studied, but signal quality of sufficient magnitude could not be obtained due to noise caused by grain boundaries.

따라서 비정질 조직의 회토류 천이금속의 합금이 광자기 디스크 재료로서 기대되고 있다.Therefore, an alloy of rare earth transition metal of amorphous structure is expected as a magneto-optical disk material.

종래 기술에 의해 제조되는 전형적인 광자기 디스크는 제 1 도에 도시한 바와 같이 글래스 혹은 PC, PMMA 등을 이용한 기판(1) 위에 Si3N4, SiO, AlN 등의 유전물질을 이용한 간섭막(2)이 형성되고, 그 위에 Tb, Gd 등의 회토류 금속과 Fe, Co 등의 천이금속을 합금한 기록층(3)이 형성되며, 그위에 간섭막(2)과 동일한 재료로서 보호막(4)이 형성된 구조로 되어 있다.A typical magneto-optical disk manufactured by the prior art is an interference film 2 made of a dielectric material such as Si 3 N 4 , SiO, AlN, etc. on a substrate 1 using glass or PC, PMMA, or the like as shown in FIG. ) Is formed, and a recording layer 3 is formed thereon alloying a rare earth metal such as Tb and Gd and a transition metal such as Fe and Co. The protective film 4 is made of the same material as the interference film 2 thereon. This structure is formed.

일반적으로 기록막 재생에 사용되는 레이저 빔은 기판(1)측으로부터 입사되며, 동시에 외부 자계에 의해 기록층(3)에는 자구(磁區)가 형성되며 이 자구방향에 따라 정보가 기록된다.In general, a laser beam used for reproducing a recording film is incident from the substrate 1 side, and at the same time a magnetic domain is formed in the recording layer 3 by an external magnetic field, and information is recorded according to the magnetic domain direction.

재생시에는 편광된 빛이 자화의 방향에 따라 편광편 축이 회전하는 커(Kerr) 효과를 이용한다.At the time of reproduction, the Kerr effect is used in which the polarized light axis rotates according to the direction of magnetization of the polarized light.

정보기록의 단위가 되는 자구의 안정된 형성을 위해서는 기록재료의 조자력이 충분히 커야 하고, 또한 작은 에너지로서도 반응할 수 있도록 충분히 큐리 온도가 낮아야 하며, 기록된 비트를 재생할 때 재생선호의 C/N비는 커 회전각 θk에 비례한다.For stable formation of magnetic domains that are the information recording units, the coercive force of the recording material must be large enough, and the Curie temperature must be low enough to react with small energy, and the C / N ratio of the reproduction preference when reproducing the recorded bits. Is proportional to the rotation angle θ k.

그러나 종래의 재료, 즉 Tb, Gd 등의 회토류와 Fe, Co 등의 전이금속의 합금으로서는 적절한 기록강도와 안정성 그리고 충분히 큰 재생품질을 얻을 수 없는 문제점이 있었다.However, conventional alloys, such as alloys of rare earths such as Tb and Gd and transition metals such as Fe and Co, have problems in that proper recording strength and stability and a sufficiently large reproduction quality cannot be obtained.

본 발명자는 종래의 문제점을 해결하기 위해 기록막을 다층화함으로써 좋은 특성을 가진 광디스크를 제조하고자 하는 연구를 시도한 바 있다,The present inventor has attempted to manufacture an optical disk having good characteristics by multilayering the recording film in order to solve the conventional problems.

즉, 제 2 도에 도시한 바와 같이 기록막(3)과 재생막(5)을 각각 설치한 광디스크를 제조하였으며, 기록막(3)으로서는 높은 보자력, 낮은 큐리온도를 가진 재료를 사용하고 재생막(5)으로서는 높은 커각 θk를 가진 재료를 사용하였다.That is, as shown in FIG. 2, an optical disc provided with the recording film 3 and the reproducing film 5, respectively, was manufactured. As the recording film 3, a material having high coercivity and a low Curie temperature was used. As the material (5), a material having a high cut angle θk was used.

그러나 이러한 2층막은 막의 상호간의 교환 결합력 또는 정자(靜磁) 결합력을 이용하고 있어 그 효과가 실제 광자기 디스크로서 사용하기에는 미흡하다는 결론에 도달하였다.However, these two-layer films use exchange-bonding or sperm-bonding strengths of the membranes, and the result is concluded that the effect is insufficient to be used as an actual magneto-optical disk.

본 발명의 목적은 기록의 안정성 및 재생시의 높은 신호 품질을 얻을 수 있도록 한 광자기 기록매체를 제공하는데 목적이 있는 것이다.An object of the present invention is to provide a magneto-optical recording medium capable of obtaining recording stability and high signal quality during reproduction.

이러한 본 발명의 목적을 달성하기 위하여 기관위에 형성한 간섭막과, 상기 간섭막위에 서로 상이한 재질의 자성박막으로 각각 형성한 기록막과 재생막과, 상기 기록막과 재생막에 형성된 보호막 및, 상기 기록막과 재생막 사이에 형성되어 신호를 전사하는 전사막으로 구성됨을 특징으로 하는 광자기 기록매체가 제공된다.In order to achieve the object of the present invention, an interfering film formed on an engine, a recording film and a reproducing film each formed of magnetic thin films of different materials on the interfering film, a protective film formed on the recording film and a reproducing film, and Provided is a magneto-optical recording medium, which is formed between a recording film and a reproduction film, and is composed of a transfer film for transferring a signal.

상기 전사막은 NiFe합금, FeAlSi합금, Co, Fe계 비정질 합금등으로 이루어진다.The transfer film is made of NiFe alloy, FeAlSi alloy, Co, Fe-based amorphous alloy and the like.

이하 본 발명에 의한 광자기 기록매체를 첨부도면에 도시한 실시예에 따라서 상세히 설명한다.Hereinafter, a magneto-optical recording medium according to the present invention will be described in detail according to the embodiment shown in the accompanying drawings.

제 3 도는 본 발명에 의한 광자기 기록매체의 일 실시예를 도시하는 것으로 이에 도시한 바와 같이 기판(2l) 위에 간섭막(22), 재생막(23), 전사막(24), 기록막(25) 및 보호막(26)이 순차적으로 형성된 구조로 되어 있다.3 shows an embodiment of the magneto-optical recording medium according to the present invention. As shown therein, the interference film 22, the reproducing film 23, the transfer film 24, the recording film ( 25 and the protective film 26 are formed sequentially.

상기 전사막(24)의 재료로서는 앞에서 언급한 바와 같이 자기적으로 연한 성질을 가지는 고투자율 재료, 즉 NiFe합금(Permalloy), FeAlSi합금 또는 Co, Fe계 비정질 합금등을 사용한다.As the material of the transfer film 24, as described above, a high permeability material having magnetically soft properties, that is, NiFe alloy (Permalloy), FeAlSi alloy or Co, Fe-based amorphous alloy, or the like is used.

그리고 전사막(24)은 150∼200Å 정도의 두께로 형성한다.And the transfer film 24 is formed in the thickness of about 150-200 micrometers.

전사막(24)은 상기 범위에서 전사효과가 가장 우수하며, 그 범위를 벗어나면 전사효과가 저하된다.The transfer film 24 is the most excellent transfer effect in the above range, the transfer effect is lowered outside the range.

본 발명에 의한 광자기 기록매체를 일 실시예를 들어 보다 구체적으로 설명하면, 상기 기록막(25)에 Tb23Fe77을 사용하고 재생막(23)에 Gd24Fe76을 사용하며 전사막(24)으로는 NiFe합금을 사용하였다.The magneto-optical recording medium according to the present invention will be described in more detail with reference to one embodiment. Tb 23 Fe 77 is used for the recording film 25 and Gd 24 Fe 76 is used for the reproducing film 23. 24) NiFe alloy was used.

상기 전사막(24)은 스퍼터링을 이용하여 플라스틱 기판(21) 위에 간섭막(22)으로서 Si3N4를 약 800Å점도 형성시킨 후 재생막(23)으로서는 GdFe합금 타게트를 이용하여 약 150Å 형성시키고 이후에 전사막(24)으로시 NiFe막을 170Å 형성시키고 이후에 기록막(25)으로시 TbFe를 450Å 형성시키며 보호막(26)으로서 간섭막과 같이 Si3N4를 800Å 정도 형성시킬 수 있다.The transfer film 24 was formed by sputtering on the plastic substrate 21 to form Si 3 N 4 as an interfering film 22 at about 800 kV and then formed as a regeneration film 23 by using a GdFe alloy target. Thereafter, 170 Å of Si NiFe film is formed by the transfer film 24, 450 Å TbFe is formed later by the recording film 25, and Si 3 N 4 may be formed as a protective film 26 by about 800 Si like the interference film.

상기한 바와 같은 본 발명에 의한 광디스크는 제 4 도와 같이 기록 파워가 약 4mW 정도로 감도가 좋았으며, C/N비는 57dB이상을 얻을 수 있었다.As described above, the optical disk according to the present invention had a high sensitivity of about 4 mW and a C / N ratio of 57 dB or more, as shown in FIG.

제 5 도는 본 발명에 의한 광자기 디스크의 MH히스테리시스 루우프(Hysteresis Loop)를 보인 것으로 두층에 의한 루우프의 변화를 알 수 있다. 기록에는 보자력이 커서 작은 자구가 안정되게 존재하는 것이 필요한데 본 발명에 의한 구조의 디스크로서 1mm 이하의 비트가 안정되게 형성되는 것을 알 수 있다.5 shows the MH hysteresis loop of the magneto-optical disk according to the present invention, and the change in the loop due to the two layers can be seen. The recording requires a large coercive force so that a small magnetic domain exists stably, but it can be seen that a bit of 1 mm or less is stably formed as a disk of the structure according to the present invention.

이상에서 설명한 바와 같은 본 발명은 기록막 및 재생막에 각각 다른 재질을 사용하고 또한 그 사이에 고투자율의 연자성 박막의 전사막을 형성함으로써 기록막의 비트가 재생막에 쉽게 전사될 수 있게 하여 종래의 광자기 디스크로서는 얻을 수 없었던 기록의 안정성 및 재생시의 높은 신호 품질을 얻을 수 있으며, 두 층사이의 연자성 박막의 전사막이 기록층에서 발생되는 플럭스(Flux)를 보다 효과적으로 재생층에 전사시킬 수 있으므로 고품질의 광자기 디스크 제조가 가능하게 된다.As described above, the present invention uses a different material for the recording film and the reproducing film, and also forms a transfer film of a soft magnetic thin film having a high permeability therebetween so that the bits of the recording film can be easily transferred to the reproducing film. It is possible to obtain recording stability and high signal quality at the time of reproducing which cannot be obtained with a magneto-optical disk, and the transfer film of the soft magnetic thin film between the two layers can transfer the flux generated in the recording layer to the reproduction layer more effectively. Therefore, high quality magneto-optical disks can be manufactured.

Claims (2)

기판위에 형성한 간섭막과, 상기 간섭막 위에 서로 상이한 재질의 자성박막으로 각각 형성한 기록막과 재생막고, 상기 기록막과 재생막에 형성된 보호막 및, 상기 기록막과 재생막 사이에 형성되어 신호를 전사하는 전사막으로 구성됨을 특징으로 하는 광자기 기록매체.An interference film formed on the substrate, a recording film and a reproducing film each formed of magnetic thin films of different materials on the interference film, a protective film formed on the recording film and the reproducing film, and a signal formed between the recording film and the reproducing film Magneto-optical recording medium, characterized in that consisting of a transfer film for transferring. 제 1 항에 있어서, 상기 전사막이 NiFe합금, FeAlSi합금, Co, Fe계 비정질 합금등으로 이루어진 것을 특징으로 하는 광자기 기록매체.The magneto-optical recording medium according to claim 1, wherein the transfer film is made of NiFe alloy, FeAlSi alloy, Co, Fe-based amorphous alloy, or the like.
KR1019890005695A 1989-04-29 1989-04-29 Optical recording medium KR970010942B1 (en)

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KR900017035A KR900017035A (en) 1990-11-15
KR970010942B1 true KR970010942B1 (en) 1997-07-02

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KR1019890005695A KR970010942B1 (en) 1989-04-29 1989-04-29 Optical recording medium

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