JPH0714170A - Optical disk device - Google Patents
Optical disk deviceInfo
- Publication number
- JPH0714170A JPH0714170A JP15162893A JP15162893A JPH0714170A JP H0714170 A JPH0714170 A JP H0714170A JP 15162893 A JP15162893 A JP 15162893A JP 15162893 A JP15162893 A JP 15162893A JP H0714170 A JPH0714170 A JP H0714170A
- Authority
- JP
- Japan
- Prior art keywords
- optical disk
- recording
- reproducing
- recording mark
- difference
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Landscapes
- Optical Recording Or Reproduction (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、光ディスク再生方法に
関し、特に相変化光ディスクにおける再生方法に関する
ものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk reproducing method, and more particularly to a reproducing method for a phase change optical disk.
【０００２】[0002]
【従来の技術】レーザ光を用いた光ディスク記録方法は
大容量記録が可能であり、非接触で高速アクセスできる
ことから、大容量メモリとして実用化が始まっている。
光ディスクはコンパクトディスクやレーザディスクとし
て知られている再生専用型、ユーザで記録ができる追記
型、及びユーザで繰り返し記録ができる書き替え型に分
類される。追記型・書き替え型の光ディスクはコンピュ
ータの外部メモリ、あるいは文書・画像ファイルとして
使用されようとしている。2. Description of the Related Art An optical disk recording method using a laser beam is capable of large-capacity recording and can be accessed at high speed in a non-contact manner.
Optical discs are classified into read-only types known as compact discs and laser discs, write-once types that can be recorded by the user, and rewritable types that can be repeatedly recorded by the user. The write-once / rewritable optical disk is about to be used as an external memory of a computer or as a document / image file.
【０００３】現在用いられている光ディスク装置では、
光ディスクで変調を受けて反射されたレーザ光から再生
信号が検出されている。たとえば、再生専用型では、デ
ィスク上に形成された凹凸のピットからの反射光量変化
を利用して再生信号を取り出している。追記型では、レ
ーザ光照射によって形成された微小ピットあるいは相変
化に伴う反射光量変化を再生に利用している。また、書
き替え型の一つである光磁気ディスクでは、記録膜が持
つ磁気光学効果を利用して記録膜の磁化状態が偏光面の
変化として読み出される。もうひとつの書き替え型であ
る相変化光ディスクでは追記型と同様、相変化に起因し
た反射光量変化あるいは光学的な位相差を再生に用いる
ことが可能である。（例えば、「光ディスク技術」ラジ
オ技術社） 特に、相変化光ディスクについては、例えば、特開平２
−７３５３７号公報によれば、記録部分と消去部分間で
光学的位相差として約（−π／２）あるいは（π／２）
を有する相変化記録媒体が容易に実現可能であることが
示されている。In the currently used optical disk device,
A reproduction signal is detected from the laser light that is modulated and reflected by the optical disc. For example, in the read-only type, a reproduced signal is taken out by utilizing a change in the amount of reflected light from the pits of irregularities formed on the disc. In the write-once type, minute pits formed by laser light irradiation or changes in reflected light amount due to phase changes are used for reproduction. In a rewritable magneto-optical disk, the magnetization state of the recording film is read out as a change of the polarization plane by utilizing the magneto-optical effect of the recording film. As with the write-once type, another rewritable type phase change optical disk can use the change in the amount of reflected light or the optical phase difference due to the phase change for reproduction. (For example, "Optical Disc Technology" Radio Technology Co., Ltd.) Particularly, regarding a phase change optical disc, for example, Japanese Patent Laid-Open No. Hei 2
According to Japanese Patent Laid-Open No. -73537, the optical phase difference between the recording portion and the erasing portion is about (-π / 2) or (π / 2).
It has been shown that a phase change recording medium having a can be easily realized.
【０００４】従来より、相変化光ディスクでは、記録部
分と消去部分の反射光量の差を再生信号として検出して
いた。しかしながら、記録部分と消去部分に反射光量に
差があることは、両者での吸収率に差があることであ
り、オーバライト時には、この吸収率差に起因した昇温
の差が原因となる記録マーク歪が発生していた。このマ
ーク歪を解消するには、吸収率差を制御したディスクと
することが必要であり、その場合、記録部分と消去部分
間の反射率差が小さくなるため、再生においては、反射
光量差ではなく、光学的な位相差を利用する方法が非常
に有効である。Conventionally, in the phase change optical disk, the difference in the reflected light amount between the recorded portion and the erased portion is detected as a reproduction signal. However, the difference in the amount of reflected light between the recorded portion and the erased portion means that there is a difference in the absorptance between the two, and during overwriting, the difference in the temperature rise caused by this difference in the absorptance causes the recording. Mark distortion was occurring. In order to eliminate this mark distortion, it is necessary to use a disc with a controlled absorptance difference. In that case, the difference in reflectance between the recorded portion and the erased portion will be small, and therefore the difference in the reflected light amount during reproduction will not However, the method of utilizing the optical phase difference is very effective.
【０００５】例えば、図４に示す従来から用いられてい
る再生系の再生信号検出器４１から得られる再生信号４
０は、相変化光ディスク２０の記録マーク部分２０１と
消去部分２０２間の位相差に応じてレベルが変化し、位
相差πで最大値をとる変化となる。典型的な再生信号４
０は図５に示した形である。位相差が小さい場合には、
再生信号レベルはかなり小さくなってしまう。エッジ検
出信号６はこの再生信号を微分処理することにより得ら
れるが、位相差が小さい場合には再生信号のＳ／Ｎが低
下し、エラーとなりやすいという課題があった。For example, the reproduction signal 4 obtained from the reproduction signal detector 41 of the conventional reproduction system shown in FIG.
The value of 0 changes according to the phase difference between the recording mark portion 201 and the erased portion 202 of the phase change optical disc 20, and has a maximum value at the phase difference π. Typical playback signal 4
0 is the shape shown in FIG. If the phase difference is small,
The reproduction signal level becomes considerably low. The edge detection signal 6 is obtained by differentiating the reproduced signal, but when the phase difference is small, the S / N of the reproduced signal is lowered, and there is a problem that an error is likely to occur.
【０００６】[0006]
【発明が解決しようとする課題】本発明の目的は、位相
差が小さい光ディスクであっても、再生信号を劣化させ
ることのない光ディスク装置を提供することであって、
簡単な構成により、光学的な位相差を利用して、相変化
光ディスクのマークエッジ記録におけるエッジ検出再生
に優れた新規の相変化光ディスク装置を提供することに
ある。SUMMARY OF THE INVENTION It is an object of the present invention to provide an optical disc device which does not deteriorate a reproduction signal even if the optical disc has a small phase difference.
It is an object of the present invention to provide a novel phase change optical disk device having a simple configuration and excellent in edge detection and reproduction in mark edge recording of a phase change optical disk by utilizing an optical phase difference.
【０００７】[0007]
【課題を解決するための手段】本発明の光ディスク装置
は、光ディスクのトラック方向に対して、２分割された
再生用検出器を有し、前記検出器の両出力が差動増幅器
に接続されるとともに、前記検出器の両出力が加算器に
接続され、前記加算器出力が微分回路に接続され、前記
差動増幅器出力と前記微分回路出力が増幅器に接続さ
れ、前記増幅器の出力を記録マークのエッジ検出信号と
することを特徴とする光ディスク装置である。The optical disk device of the present invention has a reproduction detector divided into two in the track direction of the optical disk, and both outputs of the detector are connected to a differential amplifier. At the same time, both outputs of the detector are connected to an adder, the adder output is connected to a differentiating circuit, the differential amplifier output and the differentiating circuit output are connected to an amplifier, and the output of the amplifier is recorded. The optical disk device is characterized by using an edge detection signal.
【０００８】本発明の光ディスク装置で記録・再生する
光ディスクとしては、相変化光ディスクが適している。A phase change optical disk is suitable as an optical disk for recording / reproducing with the optical disk device of the present invention.
【０００９】[0009]
【実施例】本発明について、図面を参照して説明する。
図１に示すように、再生信号検出器１に入射する光量の
総和を再生信号とするとともに、相変化光ディスク２０
のトラック方向に対して２分割された再生信号検出器１
０１および１０２の出力を差動増幅器２に入力し、両者
の差をとる方法を追加する。この時、この差動増幅器２
の出力として得られる再生信号１０は、図２に示すよう
に記録マーク２０１のエッジ部分で極大値、あるいは極
小値となる。この再生信号１０は記録マークと消去部分
の位相差がπ／２のとき最大となり、また、そのピーク
は、記録マークエッジに再生用レーザ光の中心が位置し
たときに得られる。一方、再生信号検出器１０１および
１０２の出力は、加算器３にも入力される。この加算器
３の出力である再生信号１１は従来の再生方法の場合と
同様であり、図２に示すように図５の再生信号４０と同
等である。この信号は微分回路４によって微分処理され
たのち、増幅器５によって、差動増幅器２の出力と合成
され、最終的には図２（ｄ）の波形、すなわちエッジ検
出信号６となる。本発明の再生方法を採用することによ
って、再生しようとする相変化光ディスクの記録点と消
去部分の光学的位相差がπよりも小さい場合であって
も、マークエッジに対応した十分な再生信号が得られ
る。エッジ検出に最適の再生方法である。DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described with reference to the drawings.
As shown in FIG. 1, the total amount of light incident on the reproduction signal detector 1 is used as a reproduction signal, and the phase change optical disc 20 is used.
Playback signal detector 1 divided into two in the track direction
A method of inputting the outputs of 01 and 102 to the differential amplifier 2 and taking the difference between the two is added. At this time, this differential amplifier 2
As shown in FIG. 2, the reproduction signal 10 obtained as the output of the above becomes the maximum value or the minimum value at the edge portion of the recording mark 201. The reproduction signal 10 becomes maximum when the phase difference between the recording mark and the erased portion is π / 2, and its peak is obtained when the center of the reproducing laser beam is located at the recording mark edge. On the other hand, the outputs of the reproduction signal detectors 101 and 102 are also input to the adder 3. The reproduced signal 11 which is the output of the adder 3 is the same as in the case of the conventional reproducing method, and is equivalent to the reproduced signal 40 of FIG. 5 as shown in FIG. This signal is differentiated by the differentiating circuit 4 and then combined with the output of the differential amplifier 2 by the amplifier 5 to finally become the waveform of FIG. 2D, that is, the edge detection signal 6. By adopting the reproducing method of the present invention, even if the optical phase difference between the recording point and the erased portion of the phase change optical disk to be reproduced is smaller than π, a sufficient reproduction signal corresponding to the mark edge can be obtained. can get. This is the best playback method for edge detection.
【００１０】次に、本発明に係る光ディスク再生方法お
よび光ディスク再生装置の性能を把握するために、相変
化光ディスクの情報再生をおこなった。図３にディスク
の断面図を示す。使用した相変化光ディスクの構成は１
３０ｍｍ直径のポリカーボネート基板２１上にＺｎＳ−
ＳｉＯ2 下地保護膜２２、ＧｅＳｂＴｅ記録膜２３、Ｚ
ｎＳ−ＳｉＯ2 上部保護膜２４、Ａｌ−Ｔｉ反射膜２５
を順次スパッタリング法で連続成膜したものである。記
録トラック２６のピッチは、１．６μｍである。レーザ
波長８３０ｎｍにおける記録マークと消去部分の光学的
位相差は、各層の膜厚を調整して、π／３となる構成と
した。具体的には、ＺｎＳ−ＳｉＯ2 下地保護膜を９０
ｎｍ厚、Ｇｅ2 Ｓｂ2 Ｔｅ5 記録膜を３７ｎｍ厚、Ｚｎ
Ｓ−ＳｉＯ2 上部保護膜を３３ｎｍ厚、Ａｌ−Ｔｉ反射
膜を６０ｎｍ厚とした。波長８３０ｎｍのレーザを搭載
した光ヘッドを用いて、ディスクを線速１１．３ｍ／ｓ
で回転し、半径３０ｍｍのトラックにある１セクタに
３．７ＭＨｚ、Ｄｕｔｙ５０％の信号を記録した。従来
例である図４と同等の再生系を用いたときの再生信号は
Ｃ／Ｎ４５ｄＢであったが、本発明に係る図１と同等の
再生方法を用いた場合、Ｃ／Ｎは４８ｄＢに改善され、
また、再生波形もマークエッジが強調された形となっ
た。Next, in order to understand the performance of the optical disk reproducing method and the optical disk reproducing apparatus according to the present invention, information reproduction of the phase change optical disk was performed. FIG. 3 shows a sectional view of the disc. The structure of the phase change optical disk used is 1
ZnS-on a polycarbonate substrate 21 having a diameter of 30 mm.
SiO 2 base protection film 22, GeSbTe recording film 23, Z
nS-SiO 2 upper protective film 24, Al-Ti reflective film 25
Are sequentially formed by a sputtering method. The pitch of the recording tracks 26 is 1.6 μm. The optical phase difference between the recording mark and the erased portion at the laser wavelength of 830 nm was π / 3 by adjusting the film thickness of each layer. Specifically, the ZnS—SiO 2 underlayer protective film is
nm, Ge 2 Sb 2 Te 5 recording film 37 nm thick, Zn
33nm The S-SiO 2 upper protecting film thickness was 60nm thick the Al-Ti reflecting film. Using an optical head equipped with a laser with a wavelength of 830 nm, the disk is drawn at a linear velocity of 11.3 m / s.
, And a signal of 3.7 MHz and a duty of 50% was recorded in one sector on a track having a radius of 30 mm. The reproduction signal when the reproduction system equivalent to that of FIG. 4 which is the conventional example is used is C / N 45 dB, but when the reproduction method equivalent to that of FIG. 1 according to the present invention is used, the C / N is improved to 48 dB. Is
Also, the reproduced waveform has a shape in which the mark edge is emphasized.
【００１１】[0011]
【発明の効果】以上説明したように、本方法の採用によ
り、記録マークと消去部分間の光学的位相差が小さいデ
ィスクであっても、良好なエッジ検出が可能であり、相
変化光ディスク作成上のマージンが広がり、成膜に対す
る制限がなくなる。また、媒体設計上の自由度が増すと
いうメリットがある。As described above, by adopting this method, good edge detection is possible even in the case of a disc having a small optical phase difference between the recording mark and the erased portion, and it is possible to produce a phase change optical disc. , The margin is widened and there is no limitation on film formation. Further, there is an advantage that the degree of freedom in medium design is increased.
【図１】光ディスク装置の構成を示した説明図である。FIG. 1 is an explanatory diagram showing a configuration of an optical disc device.
【図２】光ディスクの再生方法を示した説明図である。FIG. 2 is an explanatory diagram showing a reproducing method of an optical disc.
【図３】光ディスクの断面構造を示した説明図である。FIG. 3 is an explanatory diagram showing a cross-sectional structure of an optical disc.
【図４】従来の光ディスク装置の構成を示した説明図で
ある。FIG. 4 is an explanatory diagram showing a configuration of a conventional optical disc device.
【図５】従来の光ディスクの再生方法を示した説明図で
ある。FIG. 5 is an explanatory view showing a conventional optical disc reproducing method.
１、４１、１０１、１０２ 再生信号検出器 ２ 差動増幅器 ３ 加算器 ４ 微分回路 ５、４２ 増幅器 ６ エッジ検出信号 ７ レーザ光 ８ 集光レンズ １０、１１、４０ 再生信号 ２０ 相変化光ディスク ２１ 基板 ２２ 下地保護膜 ２３ 記録膜 ２４ 上部保護膜 ２５ 反射膜 ２６ 記録トラック ２０１ 記録マーク部分 ２０２ 消去部分 1, 41, 101, 102 reproduction signal detector 2 differential amplifier 3 adder 4 differentiating circuit 5, 42 amplifier 6 edge detection signal 7 laser light 8 condenser lens 10, 11, 40 reproduction signal 20 phase change optical disk 21 substrate 22 Base protective film 23 Recording film 24 Upper protective film 25 Reflective film 26 Recording track 201 Recording mark part 202 Erasing part
Claims (2)
分割された再生用検出器を有し、前記検出器の両出力が
差動増幅器に接続されるとともに、前記検出器の両出力
が加算器に接続され、前記加算器出力が微分回路に接続
され、前記差動増幅器出力と前記微分回路出力が増幅器
に接続され、前記増幅器の出力を記録マークエッジ検出
信号とすることを特徴とする光ディスク装置。1. The optical disc track direction is 2 with respect to the track direction.
A divided reproduction detector is provided, and both outputs of the detector are connected to a differential amplifier, both outputs of the detector are connected to an adder, and the adder output is connected to a differentiating circuit. An optical disk device, wherein the differential amplifier output and the differential circuit output are connected to an amplifier, and the output of the amplifier is used as a recording mark edge detection signal.
ることを特徴とする請求項１記載の光ディスク装置。2. The optical disk device according to claim 1, wherein the optical disk is a phase change optical disk.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15162893A JP2601142B2 (en) | 1993-06-23 | 1993-06-23 | Optical disk drive |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15162893A JP2601142B2 (en) | 1993-06-23 | 1993-06-23 | Optical disk drive |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0714170A true JPH0714170A (en) | 1995-01-17 |
| JP2601142B2 JP2601142B2 (en) | 1997-04-16 |
Family
ID=15522700
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP15162893A Expired - Fee Related JP2601142B2 (en) | 1993-06-23 | 1993-06-23 | Optical disk drive |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2601142B2 (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR19990058975A (en) * | 1997-12-30 | 1999-07-26 | 구자홍 | How to record and erase the ball |
| WO2000057407A1 (en) * | 1999-03-19 | 2000-09-28 | Hitachi, Ltd. | Optical information reproducing device |
| US6226251B1 (en) | 1997-08-29 | 2001-05-01 | Samsung Electronics Co., Ltd. | Signal detection method of a phase-change optical disk |
| US6577573B2 (en) | 2001-06-25 | 2003-06-10 | Hitachi, Ltd. | Optical information reproducing method in which either a first edge signal or a second edge signal is selected depending on a length of a mark on an optical information medium |
-
1993
- 1993-06-23 JP JP15162893A patent/JP2601142B2/en not_active Expired - Fee Related
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6226251B1 (en) | 1997-08-29 | 2001-05-01 | Samsung Electronics Co., Ltd. | Signal detection method of a phase-change optical disk |
| KR19990058975A (en) * | 1997-12-30 | 1999-07-26 | 구자홍 | How to record and erase the ball |
| WO2000057407A1 (en) * | 1999-03-19 | 2000-09-28 | Hitachi, Ltd. | Optical information reproducing device |
| US6430131B1 (en) * | 1999-03-19 | 2002-08-06 | Hitachi, Ltd. | Optical information reproducing device |
| US6577573B2 (en) | 2001-06-25 | 2003-06-10 | Hitachi, Ltd. | Optical information reproducing method in which either a first edge signal or a second edge signal is selected depending on a length of a mark on an optical information medium |
| US6717898B2 (en) | 2001-06-25 | 2004-04-06 | Hitachi, Ltd. | Optical information reproducing method for reproducing information by generating a signal representing a center of a mark |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2601142B2 (en) | 1997-04-16 |
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