JP2719407B2 - Optical recording / reproducing method - Google Patents
Optical recording / reproducing methodInfo
- Publication number
- JP2719407B2 JP2719407B2 JP1174412A JP17441289A JP2719407B2 JP 2719407 B2 JP2719407 B2 JP 2719407B2 JP 1174412 A JP1174412 A JP 1174412A JP 17441289 A JP17441289 A JP 17441289A JP 2719407 B2 JP2719407 B2 JP 2719407B2
- Authority
- JP
- Japan
- Prior art keywords
- recording layer
- recording
- light
- groove
- layer
- 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.)
- Expired - Lifetime
Links
Description
【発明の詳細な説明】 （イ） 産業上の利用分野 本発明は光学的な情報の記録再生方法に関する。The present invention relates to a method for recording and reproducing optical information.
（ロ） 従来の技術 従来より種々の光学的な情報記録再生方法が提案され
ているが、記録可能なものとしては、光磁気ディスク、
穴（ピット）又はバブル形成を行う追記型ディスク、相
変化型ディスクが知られている。(B) Conventional technology Various optical information recording / reproducing methods have been conventionally proposed.
2. Description of the Related Art Write-once discs and phase-change discs that form holes (pits) or bubbles are known.
光磁気ディスクは記録・消去に磁場を必要とする為、
光学ヘッド系の構成が複雑となり、更に再生は反射光の
偏光面の回転角を検出することにより行うが、この偏光
面の回転角が微小である為、高い変調度を得るのが難し
い。Since magneto-optical disks require a magnetic field for recording and erasing,
The configuration of the optical head system becomes complicated, and the reproduction is performed by detecting the rotation angle of the polarization plane of the reflected light. However, since the rotation angle of the polarization plane is very small, it is difficult to obtain a high degree of modulation.
追記型のピット形成型ディスクは、レーザ光により記
録層を加熱蒸発させることにより記録層に穴（ピット）
を形成して情報を記録するものであり、またバブル形成
型ディスクはレーザ光により記録層を加熱気化させるこ
とにより記録層を変形させてバブルを形成して情報を記
録するものであり、両ディスク共、ピット部分若しくは
バブル部分が他の部分よりも反射率が低下することを利
用して、情報の再生を行うものである。これ等の方法は
記録層を加熱し高温とする為に、記録層のレーザ光の吸
収効率を高くする必要があり、その為ピット若しくはバ
ブルが形成されない部分の反射率も低くなっており、従
って高変調度、高CN（キャリア／ノイズ）比を得るのが
困難であった。In a write-once pit formation type disc, holes (pits) are formed in the recording layer by heating and evaporating the recording layer with a laser beam.
A bubble-forming disk is used to record information by forming a bubble by deforming the recording layer by heating and evaporating the recording layer with laser light to form a bubble. In both cases, information is reproduced by utilizing the fact that the reflectance of the pit portion or the bubble portion is lower than that of the other portions. In these methods, in order to heat the recording layer to a high temperature, it is necessary to increase the laser beam absorption efficiency of the recording layer, and therefore, the reflectance of a portion where pits or bubbles are not formed is also low, and accordingly, It was difficult to obtain a high modulation factor and a high CN (carrier / noise) ratio.
相変化型ディスクは、記録層の結晶状態・アモルファ
ス状態での反射率の差によって再生を行うものである
が、反射率が高い状態で20％程度、低い状態で10〜15％
と低く、従って高変調度、高CN比を得るのは困難であっ
た。The phase-change type disk performs reproduction by a difference in reflectance between the crystalline state and the amorphous state of the recording layer. The phase change type disk has a high reflectance of about 20% and a low reflectance of 10 to 15%.
Therefore, it was difficult to obtain a high degree of modulation and a high CN ratio.
（ハ） 発明が解決しようとする問題点 本発明は高反射率で高変調度が得られる光学的な記録
再生方法を可能にせんとするものである。(C) Problems to be Solved by the Invention The present invention makes it possible to provide an optical recording / reproducing method capable of obtaining a high reflectance and a high degree of modulation.
（ニ） 問題点を解決するための手段 本発明は、上面に溝が形成されている透明基板上に記
録層、反射層が順に形成されている光記録媒体を用いた
光学式記録再生方法である。そして記録時には、前記光
記録媒体の前記溝が形成されている部分と前記溝が形成
されていない部分とに跨って前記透明基板側より前記記
録層に光を照射して該記録層の屈折率を変化させること
により情報の記録を行う。(D) Means for Solving the Problems The present invention relates to an optical recording / reproducing method using an optical recording medium in which a recording layer and a reflection layer are formed in this order on a transparent substrate having a groove formed on the upper surface. is there. During recording, the recording layer is irradiated with light from the transparent substrate side over a portion where the groove is formed and a portion where the groove is not formed in the optical recording medium, and the refractive index of the recording layer is changed. The information is recorded by changing.
また、再生時には、前記光記録媒体に前記透明基板側
より光を照射して、前記溝が形成されている部分上の記
録層を通過して前記反射層で反射される光と、前記溝が
形成されていない部分上の記録層を通過して前記反射層
で反射される光との間に生じる、前記記録層の屈折率変
化に起因して発生する位相差を利用した干渉に基く光の
強弱を検出して再生を行うことを特徴とする。Further, at the time of reproduction, the optical recording medium is irradiated with light from the transparent substrate side, and passes through a recording layer on a portion where the groove is formed and is reflected by the reflection layer; Light generated based on interference using a phase difference generated due to a change in the refractive index of the recording layer, which is generated between the light reflected by the reflection layer and the light passing through the recording layer on the portion where the light is not formed. The reproduction is performed by detecting the strength.
（ホ） 作用 記録層を通過する光と、通過しない光の間に大きな位
相差を与えることができれば、高変調度の記録再生がで
きることになる。本発明に於いては記録層の屈折率を変
化させることにより、斯る位相差を与えている。(E) Function If a large phase difference can be given between light passing through the recording layer and light not passing through, recording and reproduction with a high modulation degree can be performed. In the present invention, such a phase difference is provided by changing the refractive index of the recording layer.
記録層についてはフォトンモード、ヒートモードを問
わず屈折率が変化する物質を利用できるが特にヒートモ
ード型の記録層とした場合には、従来のピット若しくは
バブル形成型の如く記録層を強く加熱する必要がないの
で吸収率を低くすることができ、その結果反射率を大き
くすることができ、高変調度を得ることができる。For the recording layer, a substance whose refractive index changes regardless of the photon mode or the heat mode can be used. In particular, in the case of a heat mode type recording layer, the recording layer is strongly heated like a conventional pit or bubble formation type. Since there is no need, the absorptance can be reduced, and as a result, the reflectivity can be increased and a high degree of modulation can be obtained.
（ヘ） 実施例 第１図に示す実施例は、溝（グループ）部に記録する
実施例であり、ディスク（Ｄ）は透明基板（１）、記録
層（２）、反射膜（３）、保護膜（４）より構成されて
いる。透明基板（１）には溝（1a）が形成されており、
この溝部（1a）の記録層（２）に対して記録が行われ
る。適当な光学系にて収束された読出しビーム光（Bo）
は記録層（２）部分と非記録層部分に跨って照射され
る。(F) Embodiment The embodiment shown in FIG. 1 is an embodiment in which recording is performed in a groove (group) portion, and a disc (D) is composed of a transparent substrate (1), a recording layer (2), a reflection film (3), It is composed of a protective film (4). A groove (1a) is formed in the transparent substrate (1),
Recording is performed on the recording layer (2) in the groove (1a). Read beam light (Bo) converged by appropriate optical system
Is irradiated over the recording layer (2) portion and the non-recording layer portion.
さて、再生を行う際、非記録部分の読出しビーム反射
光が強となり、記録部分の読出しビーム反射光が弱とな
るように再生するものとする。溝の深さをβ、未記録状
態時の記録層の屈折率をｎ、記録状態時の屈折率を
ｎ′、基板の屈折率をno、レーザ光の真空中での波長を
λとすると、未記録状態（第１図ａ）に於て、溝即ち記
録層（２）を通過する反射光（B1）と、溝と溝の間即ち
非記録層部を通過する反射光（B2）との位相差が半波長
の偶数倍の時に反射光は強くなる。即ち、 （βno−βｎ）×２＝λ/2・2m …… （m:整数） 一方、記録状態（第１図ｂ）に於いて、記録層（２）
の記録部分（2a）を通過する反射光（B1）と非記録層部
を通過する反射光（B2）との位相差が半波長の奇数倍の
時に反射光は弱くなる。即ち、 （βno−βｎ′）×２＝λ/2・（2m′＋１） …… （ｍ′：整数） 屈折率の変化△ｎは、式より △ｎ＝ｎ′−ｎ＝λ/4β・｛２（ｍ−ｍ′）−１｝ …… 最も簡単な例としてｍ＝１、ｍ′＝０とすると △ｎ＝λ/4β …… 従って、例えば、波長が決っている場合には、未記録
状態で式を満たすｎ、noを選択し、式により屈折率
変化△ｎに合わせてβを決定すれば記録再生が可能とな
る。Now, when reproducing, it is assumed that reproduction is performed so that the read beam reflected light of the non-recorded portion becomes strong and the read beam reflected light of the recorded portion becomes weak. When the depth of the groove is β, the refractive index of the recording layer in the unrecorded state is n, the refractive index in the recorded state is n ′, the refractive index of the substrate is no, and the wavelength of the laser beam in vacuum is λ, In an unrecorded state (FIG. 1a), reflected light (B 1 ) passing through the groove, ie, the recording layer (2), and reflected light (B 2 ) passing between the grooves, ie, passing through the non-recording layer portion. The reflected light becomes strong when the phase difference from is greater than half the wavelength. That is, (βno−βn) × 2 = λ / 2 · 2m (m: integer) On the other hand, in the recording state (FIG. 1B), the recording layer (2)
When the phase difference between the reflected light (B 1 ) passing through the recording portion (2a) and the reflected light (B 2 ) passing through the non-recording layer portion is an odd multiple of half a wavelength, the reflected light becomes weak. That is, (βno−βn ′) × 2 = λ / 2 · (2m ′ + 1) (m ′: integer) The change Δn in the refractive index is given by Δn = n′−n = λ / 4β · {2 (m−m ′) − 1}... As the simplest example, if m = 1 and m ′ = 0, Δn = λ / 4β... Therefore, for example, if the wavelength is determined, In the recording state, if n and no satisfying the expression are selected, and β is determined according to the refractive index change Δn by the expression, recording / reproduction becomes possible.
屈折率変化△ｎが制御可能であるならば、初めにβを
決定して、それから、式が成立する様に△ｎを決定し
ても良い。更にλを自由に選択できるのであれば、△
ｎ、βに合せて、λを決定しても良い。If the refractive index change Δn is controllable, β may be determined first, and then Δn may be determined such that the equation holds. Furthermore, if λ can be freely selected, △
λ may be determined according to n and β.
本発明の記録層（２）の材料としては例えば、フォト
クロミック材料を利用することができる（参考文献：光
メモリジポンジウム′86論文集ページ75〜80）。As a material of the recording layer (2) of the present invention, for example, a photochromic material can be used (Reference: Optical memory dipondium '86, pages 75-80 of the collection of papers).
（ト） 発明の効果 以上述べた本発明に依れば、記録層にピット若しくは
バブルを形成しないので高温に加熱する必要がなく従っ
て吸収率が低い即ち反射率が高いものを利用することが
でき、更に、位相差を利用しており、しかも前記位相差
を利用するための２つの光は共に記録層上に形成された
反射層での反射光であるため、強度が略等しくなり、高
い変調度を得ることが可能となる。(G) Effects of the Invention According to the present invention described above, since no pits or bubbles are formed in the recording layer, it is not necessary to heat the recording layer to a high temperature, and therefore, a material having a low absorptivity, that is, a high reflectance can be used. Further, since the phase difference is utilized, and the two lights for utilizing the phase difference are both reflection lights from the reflection layer formed on the recording layer, the intensity is substantially equal, and the high modulation is achieved. It is possible to gain a degree.
第１図は本発明に係る光学式の記録再生方法の説明に供
する図である。 （１）……透明基板、（２）……記録層、（３）……反
射膜、（４）……保護膜。FIG. 1 is a diagram for explaining an optical recording / reproducing method according to the present invention. (1) a transparent substrate; (2) a recording layer; (3) a reflective film; and (4) a protective film.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 久米 実 大阪府守口市京阪本通２丁目18番地 三 洋電機株式会社内 (72)発明者 松浦 宏太郎 大阪府守口市京阪本通２丁目18番地 三 洋電機株式会社内 (56)参考文献 特開 昭54−1002（ＪＰ，Ａ) 特開 昭51−148323（ＪＰ，Ａ) 特開 昭49−9259（ＪＰ，Ａ) 特開 昭61−130094（ＪＰ，Ａ) 特開 昭55−45166（ＪＰ，Ａ) ──────────────────────────────────────────────────続 き Continuing on the front page (72) Minoru Kume, 2-18-18 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (72) Kotaro Matsuura 2-3-18 Keihanhondori, Moriguchi-shi, Osaka (56) References JP-A-54-1002 (JP, A) JP-A-51-148323 (JP, A) JP-A-49-9259 (JP, A) JP-A-61-130094 (JP) JP, A) JP-A-55-45166 (JP, A)
Claims (1)
録層、反射層が順に形成されている光記録媒体を用いた
光学式記録再生方法であって、記録時、前記光記録媒体
の前記溝が形成されている部分と前記溝が形成されてい
ない部分とに跨って前記透明基板側より前記記録層に光
を照射して該記録層の屈折率を変化させることにより情
報の記録を行い、再生時、前記光記録媒体に前記透明基
板側より光を照射して、前記溝が形成されている部分上
の記録層を通過して前記反射層で反射される光と、前記
溝が形成されていない部分上の記録層を通過して前記反
射層で反射される光との間に生じる、前記記録層の屈折
率変化に起因して発生する位相差を利用した干渉に基く
光の強弱を検出して再生を行うことを特徴とする光学式
記録再生方法。1. An optical recording / reproducing method using an optical recording medium in which a recording layer and a reflection layer are sequentially formed on a transparent substrate having a groove formed on the upper surface, wherein the optical recording medium is used for recording. Recording information by irradiating the recording layer with light from the transparent substrate side to change the refractive index of the recording layer over a portion where the groove is formed and a portion where the groove is not formed. During reproduction, irradiates the optical recording medium with light from the transparent substrate side, passes light through the recording layer on the portion where the groove is formed and is reflected by the reflective layer, and the groove The light based on the interference utilizing the phase difference generated between the light reflected by the reflective layer and the light passing through the recording layer on the portion where the is not formed, which is caused by the change in the refractive index of the recording layer An optical recording / reproducing method, wherein the reproduction is performed by detecting the strength of the image.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1174412A JP2719407B2 (en) | 1989-07-06 | 1989-07-06 | Optical recording / reproducing method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1174412A JP2719407B2 (en) | 1989-07-06 | 1989-07-06 | Optical recording / reproducing method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0340222A JPH0340222A (en) | 1991-02-21 |
| JP2719407B2 true JP2719407B2 (en) | 1998-02-25 |
Family
ID=15978103
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1174412A Expired - Lifetime JP2719407B2 (en) | 1989-07-06 | 1989-07-06 | Optical recording / reproducing method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2719407B2 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5527661A (en) * | 1992-11-25 | 1996-06-18 | Matsushita Electric Industrial Co., Ltd. | Optical information recording medium |
| TWI292910B (en) | 2001-06-11 | 2008-01-21 | Sony Corp | |
| JPWO2003003361A1 (en) * | 2001-06-27 | 2004-10-21 | ソニー株式会社 | Optical recording medium |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5545166A (en) * | 1978-09-25 | 1980-03-29 | Matsushita Electric Ind Co Ltd | Recording and reproducing method for optical information |
-
1989
- 1989-07-06 JP JP1174412A patent/JP2719407B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0340222A (en) | 1991-02-21 |
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