JPH0778353A - Optical disk and optical disk device - Google Patents
Optical disk and optical disk deviceInfo
- Publication number
- JPH0778353A JPH0778353A JP5291567A JP29156793A JPH0778353A JP H0778353 A JPH0778353 A JP H0778353A JP 5291567 A JP5291567 A JP 5291567A JP 29156793 A JP29156793 A JP 29156793A JP H0778353 A JPH0778353 A JP H0778353A
- Authority
- JP
- Japan
- Prior art keywords
- recording
- layers
- optical disc
- recording layer
- 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.)
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Links
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- Optical Head (AREA)
- Optical Record Carriers And Manufacture Thereof (AREA)
Abstract
Description
【0001】[0001]
【産業上の利用分野】本発明は記録媒体の光ディスクに
光学的に情報を記録または再生する光ディスク装置に関
する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk device for optically recording or reproducing information on an optical disk as a recording medium.
【0002】[0002]
【従来の技術】以下に従来の光ディスクと光ディスク装
置について説明する。2. Description of the Related Art A conventional optical disk and optical disk device will be described below.
【0003】図17に示すように、半導体レーザ1の放
射光は、回折格子2によって0次と±1次の回折光に変
換された後、ビームスプリッター3で反射され、対物レ
ンズ4により、光ディスク5の記録層6上に絞り込ま
れ、光スポット7を形成する。次に光ディスク5で反射
した光ビーム8は、対物レンズ4を透過し、ビームスプ
リッター3に到り、これを透過した光ビーム8が光検出
器9に入る。4分割された光検出器9aからは、再生信
号とともに非点収差法でフォーカスエラー信号が検出さ
れる。トラッキングエラー信号は、光検出器9b、9c
に入射する先の±1次回折戻り光の光量差を検出する3
ビーム法によって得られる。再生信号は4分割された光
検出器9aの受光量の総和として得られる。このような
従来の光ディスク装置では、光ディスクの1面につき記
録層6は1層のみである。As shown in FIG. 17, the emitted light of the semiconductor laser 1 is converted by the diffraction grating 2 into 0th order light and ± 1st order diffracted light, which is then reflected by the beam splitter 3 and then by the objective lens 4. The light spot 7 is narrowed down on the recording layer 6 of No. 5 to form a light spot 7. Next, the light beam 8 reflected by the optical disk 5 passes through the objective lens 4, reaches the beam splitter 3, and the light beam 8 that passes through this enters the photodetector 9. From the four-divided photodetector 9a, a focus error signal is detected together with the reproduction signal by the astigmatism method. The tracking error signal is detected by the photodetectors 9b and 9c.
To detect the difference in light quantity of the ± 1st-order diffracted return light that is incident on 3
Obtained by the beam method. The reproduction signal is obtained as the sum of the amount of light received by the photodetector 9a divided into four. In such a conventional optical disc device, there is only one recording layer 6 per one side of the optical disc.
【0004】近年、光ディスク装置では短波長化、狭ト
ラック化など、高密度化の試みが盛んである。このよう
な記録面内の密度向上に加えて、記録面の垂直方向の密
度向上、すなわち、記録層を厚み方向に積層して面数を
増加することにより、記録密度の向上ができる。しかし
ながら、このような積層構造にすると、再生記録層以外
の記録層の反射光および透過光の影響があり、この欠点
のため、積層構造は採用されていない。従来の光ディス
ク装置の構成をみても、光ディスク5に設けられる記録
面数は各々表裏1面のみであり、光ディスク5の1枚に
対して設けられる記録面数は2面までである。In recent years, attempts have been actively made to increase the density of optical disc devices, such as shortening the wavelength and narrowing the track. In addition to improving the density in the recording surface, the recording density can be improved by increasing the density in the vertical direction of the recording surface, that is, by increasing the number of recording layers by laminating the recording layers in the thickness direction. However, such a laminated structure is affected by reflected light and transmitted light of recording layers other than the reproduction recording layer, and due to this drawback, the laminated structure is not adopted. Looking at the configuration of the conventional optical disk device, the number of recording surfaces provided on the optical disk 5 is only one on each side, and the number of recording surfaces provided on one optical disk 5 is up to two.
【0005】[0005]
【発明が解決しようとする課題】上述のように記録密度
を増大させるように、記録層6を光ディスク5の厚み方
向に積層すれば、記録再生しない記録層6からの干渉光
の影響を受けるという問題点を有していた。If the recording layers 6 are stacked in the thickness direction of the optical disk 5 so as to increase the recording density as described above, the recording layer 6 is affected by the interference light from the recording layer 6 which does not record or reproduce. I had a problem.
【0006】本発明は上記従来の問題点を解決するもの
で、記録再生の対象とならない記録層からの干渉光の影
響による信号混入を抑止して、大幅な記録密度を向上し
た光ディスクおよび光ディスク装置を提供することを目
的とする。The present invention solves the above-mentioned conventional problems, and suppresses signal mixing due to the influence of interference light from a recording layer that is not the target of recording / reproduction, and thus an optical disc and an optical disc apparatus having a significantly improved recording density. The purpose is to provide.
【0007】[0007]
【課題を解決するための手段】この目的を達成するため
に本発明は、光源と、記録層と透明体が交互に積層さ
れ、かつ、記録層上の記録ピットによる透過回折光のう
ち0次回折光に大略のエネルギが配分される光ディスク
と、光源からの光ビームを光ディスク上に収束する対物
レンズと、光ディスクからの反射光を受光して光ディス
ク上に記録された情報を検出する検出手段を備えたもの
である。In order to achieve this object, the present invention provides a light source, a recording layer and a transparent body which are alternately laminated, and which is the 0th order of the transmitted diffracted light by the recording pit on the recording layer. Equipped with an optical disc in which approximately energy is distributed to the folding light, an objective lens that converges a light beam from a light source onto the optical disc, and a detection unit that receives reflected light from the optical disc and detects information recorded on the optical disc. It is a thing.
【0008】[0008]
【作用】この構成において、記録再生の対象とならない
記録層からの信号混入を抑えることができて、記録層の
積層が可能となり、飛躍的に記録密度が向上することと
なる。In this structure, it is possible to suppress signal mixing from the recording layer which is not the object of recording / reproducing, and it is possible to stack the recording layers, and the recording density is dramatically improved.
【0009】[0009]
【実施例】以下、本発明の一実施例について図面を参照
しながら説明する。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.
【0010】本発明の一実施例において前述の従来例に
ついて説明した構成部分と同じ部分については、同一符
号を付し、その説明を省略する。In the embodiment of the present invention, the same parts as those described in the above-mentioned conventional example are designated by the same reference numerals, and the description thereof will be omitted.
【0011】(実施例1)図1および図2に示すよう
に、本実施例の特徴とするところは、従来例で説明した
光ディスク5を複数の記録層10を透明体11ではさん
で積層した光ディスク12とした点である。すなわち、
光ディスク12は、複数の記録層10が光ビーム8の波
長に対しては充分長い積層間隔Lだけ相互に離れて積層
配置されている。光ビーム8は記録層10のうちの幾つ
かの非合焦記録層10bを透過した後、記録再生すべき
合焦記録層10aに絞り込まれ、ここで反射された光ビ
ーム8が、往路とは逆の光路をたどり、ビームスプリッ
ター3を透過して光検出器9に入る構成とされている。
なお、図中の13は記録ピット、dは対物レンズ4側か
らみた光ディスク12の表面から合焦記録層10aまで
の深さを示す。(Embodiment 1) As shown in FIGS. 1 and 2, the feature of this embodiment is that the optical disk 5 described in the conventional example is laminated with a plurality of recording layers 10 sandwiched by a transparent body 11. The point is that the optical disk 12 is used. That is,
In the optical disc 12, a plurality of recording layers 10 are laminated and arranged at a laminating distance L sufficiently long with respect to the wavelength of the light beam 8. The light beam 8 passes through some of the non-focus recording layers 10b of the recording layers 10 and is then focused on the focused recording layer 10a to be recorded / reproduced. The light beam 8 reflected here is referred to as the outward path. It is configured to follow the reverse optical path, pass through the beam splitter 3, and enter the photodetector 9.
In the figure, 13 is a recording pit, and d is the depth from the surface of the optical disc 12 to the focused recording layer 10a as viewed from the objective lens 4 side.
【0012】以上のように構成された光ディスク装置に
ついて、以下その動作を説明する。本実施例の光ディス
ク12では、記録層10を透過するとき、記録ピット1
3による1次以上の回折光は発生しない構成となってお
り、透過する光ビーム8はほぼ0次回折光のみとなる。
なお、ここで言う0次回折光とは、透過時に回折によっ
て進行方向の変化を受けない透過光を意味している。こ
うすることにより、記録再生の対象とならない記録層1
0b、10cなどからの信号混入を抑えることが可能と
なるが、この点について以下に説明する。まず、透過光
に1次以上の回折光がある場合の弊害について述べる。
問題となるのは光ビーム8が光ディスク12に向かって
進む往路の場合において、図3に示す焦点前にある非合
焦記録層10bを透過したときの回折光の影響である。
記録ピットはトラック上にあるので、トラック間隔をピ
ッチとする回折格子の作用を持つ。そのため、図3に示
すように、回折光はすべて合焦記録層10aに合焦状態
で0次回折光による光スポット0s、1次回折光による
光スポット1s、−1次回折光による光スポット−1s
等を形成し、光スポット0s以外の1次以上の光スポッ
ト1s、−1s等は記録再生しようとする記録ピットと
関係ない位置にある記録ピットを照射する。この反射光
の一部が光検出器9に入って信号に混じるが、この信号
には記録再生すべきでない記録ピットの再生信号が含ま
れ、しかも本来の再生信号に比べて、その出力は合焦状
態で再生したものであるために無視できないほど大きく
なる。これは、0s,1s,−1s等のマルチ光スポッ
トで同時再生した状態であり、本来必要とする信号はマ
ルチスポット再生信号の中に埋もれてしまい問題であ
る。このように、透過光に高次の回折光がある場合は正
常な再生が不可能であり、正常な再生を行うためには、
厳密には透過光に高次の回折光がないと言うことが必要
条件となる。実際には高次の回折光を完全になくすこと
は困難であるが、0次回折光に対して1次以上の高次回
折光は少なくとも10%以下であることが望ましく、1
%以下であれば実際上ほぼ問題ないと言える。また、1
%以下の光ディスクの作成も可能である。The operation of the optical disk device configured as described above will be described below. In the optical disc 12 of this embodiment, when the recording pit 1 is transmitted through the recording layer 10,
The diffracted light of the first and higher orders due to 3 is not generated, and the transmitted light beam 8 is almost only the 0th order diffracted light.
The 0th-order diffracted light referred to here means transmitted light that does not change its traveling direction due to diffraction during transmission. By doing so, the recording layer 1 that is not the target of recording and reproduction
It is possible to suppress signal mixing from 0b, 10c, etc., which will be described below. First, a description will be given of adverse effects when the transmitted light includes diffracted light of the first order or higher.
The problem is the influence of the diffracted light when passing through the non-focus recording layer 10b in front of the focus shown in FIG. 3 when the light beam 8 travels toward the optical disk 12.
Since the recording pit is on the track, it has the function of a diffraction grating with the track interval as the pitch. Therefore, as shown in FIG. 3, all the diffracted light is in the focused state on the focused recording layer 10a, a light spot 0s by the 0th order diffracted light, a light spot 1s by the 1st order diffracted light, and a light spot -1s by the -1st order diffracted light.
Etc., and the first or higher-order light spots 1s, −1s, etc. other than the light spot 0s irradiate the recording pits at positions unrelated to the recording pits to be recorded / reproduced. A part of this reflected light enters the photodetector 9 and is mixed with the signal. However, this signal includes a reproduction signal of a recording pit that should not be recorded / reproduced, and its output is better than the original reproduction signal. Since it is reproduced in a focused state, it becomes large so that it cannot be ignored. This is a state in which simultaneous reproduction is performed with multi-light spots such as 0s, 1s, and -1s, and a signal originally required is buried in the multi-spot reproduction signal, which is a problem. In this way, normal reproduction is impossible if there is a high-order diffracted light in the transmitted light, and in order to perform normal reproduction,
Strictly speaking, it is a necessary condition that transmitted light does not have high-order diffracted light. Actually, it is difficult to completely eliminate the high-order diffracted light, but it is desirable that the high-order diffracted light of 1st order or more is at least 10% or less with respect to the 0th order diffracted light.
If it is less than%, it can be said that there is practically no problem. Also, 1
It is also possible to create an optical disk of less than%.
【0013】そこで、次に、透過光に高次回折光がない
と言う条件において、他の弊害の有無に関して述べる。Therefore, next, the presence or absence of other adverse effects will be described under the condition that the transmitted light does not include high-order diffracted light.
【0014】まず、記録層10を透過する場合について
は、往路における透過光も復路における透過光も、1次
以上の回折光の発生がないことから、記録層10の記録
ピット13の情報は乗らず、記録ピット13がないと同
様であるので、何等影響はなく問題はない。First, in the case of passing through the recording layer 10, neither the transmitted light in the forward path nor the transmitted light in the return path generate the diffracted light of the first order or more, and therefore, the information of the recording pits 13 of the recording layer 10 is multiplied. No recording pit 13 is the same, so there is no effect and there is no problem.
【0015】次に記録層10の反射光について説明す
る。光ディスク12における再生信号は光検出器9の受
光量の変化として検知される。光スポット0sが合焦記
録層10a上の記録ピット13を照射したとき、反射す
る光ビーム8は記録ピット13によって回折を受け、高
次回折光の一部が対物レンズ4に入らないため、対物レ
ンズ4への総入射光量が減少し、この光量減少が検知さ
れて再生信号が得られる。したがって、上記に説明した
光量変動の他に何等かの原因によって光量変動が起きれ
ばこれが妨害信号となる。まず、図2(a)に示す焦点
ずれ状態にある非合焦記録層10bによって反射されて
対物レンズ4に向かう反射光brによる妨害信号につい
て考える。Next, the reflected light of the recording layer 10 will be described. The reproduction signal on the optical disk 12 is detected as a change in the amount of light received by the photodetector 9. When the light spot 0s irradiates the recording pit 13 on the focused recording layer 10a, the reflected light beam 8 is diffracted by the recording pit 13, and a part of the high-order diffracted light does not enter the objective lens 4, so the objective lens The total amount of light incident on the beam No. 4 decreases, and this decrease in the amount of light is detected to obtain a reproduction signal. Therefore, if the light amount variation occurs due to some cause other than the light amount variation described above, this becomes an interference signal. First, consider a disturbing signal due to the reflected light br reflected by the defocused recording layer 10b in the defocused state shown in FIG. 2A and traveling toward the objective lens 4.
【0016】非合焦記録層10b上の記録ピット13に
よる反射回折が発生し、これが対物レンズ4の入射光量
に変動をもたらして妨害信号となる。しかし、図2
(b)に模式的に示したように、光ビーム8の波長や記
録ピット13の寸法に対して記録層10の積層間隔Lを
十分大きくした条件にしておけば、光ビーム8が非合焦
記録層10bを照射するときに、光ビーム8の大きさが
記録ピット13の大きさに比べて十分大きくなり、非合
焦記録層10b上の広い範囲の多数の記録ピット13を
照射するようになる。このため、照射される記録ピット
13の数が多少変動しても、照射される数に比べれば微
々たるものとなるので、照射される記録ピット13の数
は常にほぼ一定とみなせる。したがって、非合焦記録層
10bによる反射光brの対物レンズ4に入る光量も通
常ほぼ均一となるので、実質的には検出信号への影響は
さほど大きくはならない。Reflection diffraction occurs due to the recording pits 13 on the non-focus recording layer 10b, which causes fluctuations in the amount of light incident on the objective lens 4 and becomes an interference signal. However, FIG.
As schematically shown in (b), if the lamination interval L of the recording layers 10 is set sufficiently large with respect to the wavelength of the light beam 8 and the size of the recording pit 13, the light beam 8 is out of focus. When irradiating the recording layer 10b, the size of the light beam 8 becomes sufficiently larger than the size of the recording pits 13, and a large number of recording pits 13 in a wide range on the non-focus recording layer 10b are irradiated. Become. For this reason, even if the number of irradiated recording pits 13 varies to some extent, it is insignificant compared to the number of irradiated recording pits 13. Therefore, the number of irradiated recording pits 13 can be considered to be almost constant at all times. Therefore, the amount of the reflected light br reflected by the non-focused recording layer 10b entering the objective lens 4 is usually substantially uniform, and the influence on the detection signal is not so large substantially.
【0017】たとえば、対物レンズNAを0.5、トラ
ックピッチとピットピッチを標準的な値の1.6μmと
し、記録層10の積層間隔Lを10μmとすれば、非合
焦記録層10bを照射する光ビーム8の直径Gは(数
1)となり、この直径Gの円の中には記録ピット13
は、おおよそ44個入る。For example, if the objective lens NA is 0.5, the track pitch and the pit pitch are standard values of 1.6 μm, and the stacking interval L of the recording layers 10 is 10 μm, the non-focus recording layer 10b is irradiated. The diameter G of the light beam 8 to be generated becomes (Equation 1), and the recording pit 13 is formed in the circle of this diameter G.
Is about 44 pieces.
【0018】[0018]
【数1】 [Equation 1]
【0019】ここで、たとえば、記録ピット1個分の変
化があったとすると、全体に対しては1/44=2.3
%の変動となり、実用上大きな問題とならない。記録層
10の積層間隔Lをこれ以上にすると、さらにこの値は
小さくなり、積層間隔Lを30μmとすれば、 2.3×(10/30)2 =2.3×0.11=0.2
5% となり、ほとんど問題は生じない。Here, for example, if there is a change of one recording pit, 1/44 = 2.3 to the whole.
%, Which is not a serious problem for practical use. If the stacking interval L of the recording layer 10 is made larger than this, this value becomes smaller, and if the stacking interval L is 30 μm, 2.3 × (10/30) 2 = 2.3 × 0.11 = 0. Two
It becomes 5%, and there is almost no problem.
【0020】記録層10の積層間隔Lの上限は、これを
大きくし過ぎると積層する効果が薄れるので0.8mm
程度が限界である。The upper limit of the stacking interval L of the recording layer 10 is 0.8 mm because the effect of stacking is diminished if this is set too large.
The degree is the limit.
【0021】次に、本来の信号となるべき合焦記録層1
0aによる反射光arの多重反射光の影響について説明
する。一例として、非合焦記録層10bと合焦記録層1
0aの間で反射した後、対物レンズ4に向かう光ビーム
amについてみる。非合焦記録層10bを光ビームar
は広がった状態で照射し、その後さらに広がった状態で
合焦記録層10aを照射するので、先に説明したと同様
な平均化により、実質的な影響はでない。他の多重反射
についても同様である。また、合焦記録層10aを透過
した後で非合焦記録層10cで反射し、対物レンズ4に
向かう光ビームcrについても同様である。Next, the focusing recording layer 1 to be the original signal
The influence of multiple reflection light of the reflection light ar due to 0a will be described. As an example, the non-focus recording layer 10b and the focus recording layer 1
Consider the light beam am that is directed to the objective lens 4 after being reflected between 0a. The unfocused recording layer 10b is used as a light beam ar.
Is irradiated in a spread state, and then the focused recording layer 10a is irradiated in a further spread state, and therefore, averaging similar to that described above has no substantial effect. The same applies to other multiple reflections. The same applies to the light beam cr that passes through the focused recording layer 10a, is reflected by the non-focused recording layer 10c, and travels toward the objective lens 4.
【0022】以上のように、透過光を0次のみにするこ
とができれば、光ビーム8が記録再生の対象とならない
非合焦記録層10b上の記録ピット13の影響を実質的
になくすことが可能となり、所定の記録層10に焦点を
合わせることにより、他の記録層10の影響を受けずし
て記録再生が可能となる。As described above, if the transmitted light can be only the 0th order, the influence of the recording pits 13 on the non-focus recording layer 10b, which is not the target of the recording / reproduction of the light beam 8, can be substantially eliminated. It becomes possible, and by focusing on a predetermined recording layer 10, recording and reproduction can be performed without being affected by other recording layers 10.
【0023】次に対物レンズ4の性能との関連に関して
説明する。本実施例の光ディスク12は、記録層10の
積層間隔Lは広いほど、他の記録層10からの信号混入
が少なくなって有利であるが、その反面、光ディスク1
2の表面から合焦記録層10aまでの深さdが合焦する
記録層10の違いによって変化する。対物レンズ4は光
ディスク12の所定の厚み(約1.2mm)に合わせて
設計されており、この厚みのときは十分満足すべき性能
を発揮するが、厚みが変化すると、光ビーム8を十分絞
り込めないと言う問題が生じる。これは球面収差が大き
くなることに起因し、球面収差を抑制できれば、絞り込
み性能の劣化を防ぐことができる。球面収差は主に光ビ
ーム8の光軸中心部と周辺部とを通る光ビームの光路長
の差に起因するので、例えば、図4に示すように、プリ
ズムを用いたビーム変換手段14を設けて、光ビーム8
を例えばリング状にして、周辺部のみに光ビーム8を通
す、あるいは周辺部の光量を多くすれば、このリング領
域内での対物レンズ4と光ディスク12で構成される光
学系の光路長差は著しく小さくなり、絞り込み性能の改
善ができる。なお、この方法は超解像法になっているの
で、収束スポットの短径化も同時に図れる。Next, the relationship with the performance of the objective lens 4 will be described. In the optical disc 12 of the present embodiment, the wider the lamination interval L of the recording layers 10 is, the less signals are mixed from other recording layers 10, which is advantageous.
The depth d from the surface of No. 2 to the focused recording layer 10a changes depending on the difference of the focused recording layer 10. The objective lens 4 is designed in accordance with a predetermined thickness (about 1.2 mm) of the optical disk 12, and exhibits satisfactory performance at this thickness, but when the thickness changes, the light beam 8 is sufficiently narrowed. There is a problem that you can not put it. This is because the spherical aberration becomes large, and if the spherical aberration can be suppressed, it is possible to prevent deterioration of the focusing performance. Since the spherical aberration is mainly caused by the difference in the optical path length of the light beam passing through the central portion and the peripheral portion of the optical beam 8, the beam converting means 14 using a prism is provided as shown in FIG. 4, for example. Light beam 8
If, for example, is made into a ring shape and the light beam 8 is passed through only the peripheral portion, or if the amount of light in the peripheral portion is increased, the optical path length difference between the optical system composed of the objective lens 4 and the optical disk 12 in this ring area is It becomes significantly smaller and the narrowing performance can be improved. Since this method is a super-resolution method, the diameter of the convergent spot can be shortened at the same time.
【0024】また、他の方法として図5に示すように、
光路長変更手段15を用いることもできる。光路長変更
手段15はたとえば、対物レンズ4と光ディスク12の
間に配設され、等しい屈折率のくさび状の2枚のガラス
の斜面側を対向させた構成とし、一方のガラスをその斜
面に沿って移動させれば、光路長変更手段15の厚みw
を変えることができるので、合焦記録層10aの変更に
伴う深さdの変化を補正することが可能となり、対物レ
ンズ4の絞り込み性能の劣化を防止することができる。
また、光路長変更手段15は光ビーム8が非平行な部分
であれば、どこに配設してもよくて、対物レンズ4と光
ディスク12の間に限られたものでなく、例えば、図6
に示すように、半導体レーザ1の放射光をコリメータレ
ンズ16を使用して、平行またはほぼ平行な光ビーム8
にする光学系については、半導体レーザ1とコリメータ
レンズ16の間に光路長変更手段15を配設しても同様
の効果が得られる。As another method, as shown in FIG.
The optical path length changing means 15 can also be used. The optical path length changing means 15 is, for example, disposed between the objective lens 4 and the optical disk 12, and is constituted by two wedge-shaped glasses having the same refractive index with their slope sides facing each other, and one glass is provided along the slope. If the optical path length changing means 15 is moved, the thickness w
It is possible to correct the change of the depth d due to the change of the focus recording layer 10a, and it is possible to prevent the deterioration of the narrowing performance of the objective lens 4 because it can be changed.
Further, the optical path length changing means 15 may be disposed anywhere as long as the light beam 8 is a non-parallel portion, and is not limited to between the objective lens 4 and the optical disk 12, and for example, as shown in FIG.
As shown in FIG. 3, the emitted light of the semiconductor laser 1 is converted into a parallel or nearly parallel light beam 8 by using a collimator lens 16.
With respect to the optical system described above, the same effect can be obtained by disposing the optical path length changing means 15 between the semiconductor laser 1 and the collimator lens 16.
【0025】上述のように本実施例は、記録ピット13
による透過光に対して1次以上の回折光がない構成とし
ていることにより、再生層以外の記録層10からの影響
を低減することが可能となり、積層構造の問題点が解決
できる。本実施例と似た概念で記録密度の向上を図る方
法として、波長多重法がある。波長多重法は一層のみで
形成される記録材に、多数の異なる波長で重ねて記録
し、これを異なる波長で再生すれば、それぞれの波長に
対して、再生信号が独立に得られるというものであり、
使用波長数分の高密度化が可能となり、記録材として、
有機色素を使う方法、ケミカルホールバーニング法など
が研究されている。その他、多重記録方法として光の偏
向方向を変えて記録再生する方法が提案されている。こ
れらの方法に対して、本実施例は、多層の記録層10を
用いるもので、光ビーム8の波長が一定であっても、ま
た光偏向方向が一定であっても可能であり、簡易な構成
で記録密度の向上ができる。As described above, in this embodiment, the recording pit 13
By adopting a configuration in which there is no diffracted light of the first or higher order with respect to the transmitted light, it is possible to reduce the influence from the recording layer 10 other than the reproducing layer, and solve the problem of the laminated structure. A wavelength multiplexing method is a method for improving the recording density with a concept similar to that of the present embodiment. The wavelength division multiplexing method is that when a recording material formed of only one layer is overlaid with a number of different wavelengths and then recorded at different wavelengths, a reproduced signal can be obtained independently for each wavelength. Yes,
It is possible to increase the density for the number of wavelengths used, and as a recording material,
Methods such as organic hole dyeing and chemical hole burning are being studied. In addition, as a multiplex recording method, a method of recording / reproducing by changing the deflection direction of light has been proposed. In contrast to these methods, the present embodiment uses the multi-layer recording layer 10, and it is possible even if the wavelength of the light beam 8 is constant or the light deflection direction is constant, which is simple. The structure can improve the recording density.
【0026】上記実施例1の光ディスク12は光ビーム
8のピット回折光のうち0次回折光のみ透過することに
特徴があるが、次に、これを実現する光ディスク12の
実施例について説明する。The optical disk 12 of the first embodiment is characterized in that only the 0th order diffracted light of the pit diffracted light of the light beam 8 is transmitted. Next, an embodiment of the optical disk 12 which realizes this will be described.
【0027】(実施例2)以下に記録層として光吸収体
を用いた再生専用型の光ディスクについて説明する。(Embodiment 2) A read-only optical disc using a light absorber as a recording layer will be described below.
【0028】図7に示すように、記録層10の厚みを一
定にして記録層10の透過率が全面にわたって一定とな
るようにし、さらに、記録層10の両側の透明体11の
屈折率をほぼ等しくなるよう設定する。記録ピット13
は記録層10に凹凸を与えることによって作製する。こ
うして、記録層10の記録ピット13の部分の透過光T
Pと記録ピット13のない部分の透過光TLの位相の違
いをみると、平面U1から平面U2までの光路長比較で
は両者が等しくなるので、位相の違いは発生しないこと
になる。また、透過率も一定であるから、透過光の振幅
も一定となる。透過光の回折は光の振幅、位相のいずれ
かが透過によって変化すれば生ずるが、本実施例では、
透過光TP、TLの両者に変化がないので光の回折は生
じず、透過光は0次回折光のみとなる。したがって、透
過光は記録ピット13の有無を感知せず、記録ピット1
3がないのと同様である。一方、反射光の光路長は記録
ピット13の部分の反射光RPと記録ピット13のない
部分の反射光RLでは記録ピット13の深さVの2倍分
異なるので位相が変化し、1次以上の回折光が発生し、
この回折光の記録ピット情報が含まれ、ピット情報を得
ることができる。記録層10の作製方法としては、光吸
収体としてアルミニウム等の金属を適度な透過率の得ら
れる膜厚にして蒸着、スパッタ等によって形成すること
ができる。As shown in FIG. 7, the thickness of the recording layer 10 is made constant so that the transmittance of the recording layer 10 becomes constant over the entire surface, and the refractive indexes of the transparent bodies 11 on both sides of the recording layer 10 are almost the same. Set to be equal. Recording pit 13
Is produced by giving unevenness to the recording layer 10. Thus, the transmitted light T of the recording pit 13 of the recording layer 10
Looking at the phase difference between P and the transmitted light TL in the portion where the recording pit 13 is not present, the two are the same in the comparison of the optical path lengths from the plane U1 to the plane U2, and therefore no phase difference occurs. Also, since the transmittance is constant, the amplitude of transmitted light is also constant. Diffraction of transmitted light occurs if either the amplitude or the phase of the light changes due to the transmission, but in this embodiment,
Since there is no change in both the transmitted light TP and TL, the light is not diffracted, and the transmitted light is only the 0th order diffracted light. Therefore, the transmitted light does not detect the presence or absence of the recording pit 13, and the recording pit 1
Similar to the lack of 3. On the other hand, the optical path length of the reflected light differs by twice the depth V of the recording pit 13 between the reflected light RP of the recording pit 13 and the reflected light RL of the portion without the recording pit 13, so that the phase changes, Diffracted light of
The recording pit information of this diffracted light is included, and the pit information can be obtained. As a method for producing the recording layer 10, a metal such as aluminum may be formed as a light absorber by vapor deposition, sputtering, or the like so as to have a film thickness capable of obtaining an appropriate transmittance.
【0029】(実施例3)以下に記録層として誘電体を
用いた再生専用型の光ディスクについて説明する。(Embodiment 3) A read-only type optical disc using a dielectric as a recording layer will be described below.
【0030】図7に示すように、記録層10と透明体1
1の界面S1、S2では屈折率の違いに起因する光の反
射が生じる。記録層10の厚みaが光の波長程度に薄く
なると界面s1、s2の反射光の多重干渉効果を生かし
て、よく知られている反射防止膜、多層膜フィルター等
と同等の原理により比較的大きな反射率を得ることがで
きる。ここで、記録層10の厚みaと記録層10を挟む
透明体11の屈折率をどの部分においても一定となる条
件にする。誘電体を用いた記録層10の反射率、透過率
は界面S1、S2の両側の屈折率が関係し、本実施例の
場合、記録ピット13の部分と記録ピット13がない部
分の屈折率は同じであるので、透過光TPと透過光TL
はその振幅、位相共に同じになるため、記録ピット13
による回折は発生せず、上述の実施例2と同様に透過光
は0次回折光のみとすることができ、実施例2と同様な
効果が得られる。また、反射光については、実施例2と
同様に記録ピット13の深さvによる光路長差ができ、
記録ピット情報を得ることができる。反射率、透過率は
記録層10と透明体11の屈折率、厚みで決定されるの
で、本実施例のように記録層10の両側の媒質すなわち
透明体11の屈折率が等しいときは、記録層10と透明
体11の屈折率が異なれば、反射が生じる。記録層10
と透明体11の屈折率が異なるほど反射率が大きくな
り、本実施例では5%程度以上が望ましいが、こうする
ためには、記録層10の屈折率は透明体11の屈折率の
1.1倍以上または0.9倍以下が望ましい。これを満
たす誘電体としては、たとえばTiO2 、ZnS、Ce
O2 、ZrO2 等がある。以上の説明では記録層10は
誘電体を1層としたが複数層にしても同様の効果が得ら
れ、設計の自由度がさらに大きくなる。As shown in FIG. 7, the recording layer 10 and the transparent body 1
At the interfaces S1 and S2 of No. 1, light is reflected due to the difference in refractive index. When the thickness a of the recording layer 10 is reduced to about the wavelength of light, the multiple interference effect of the reflected light at the interfaces s1 and s2 is utilized to make it relatively large due to the same principle as that of well-known antireflection films, multilayer filters, and the like. The reflectance can be obtained. Here, the condition is such that the thickness a of the recording layer 10 and the refractive index of the transparent body 11 sandwiching the recording layer 10 are constant in any part. The reflectance and the transmittance of the recording layer 10 using a dielectric material are related to the refractive indices on both sides of the interfaces S1 and S2. In this embodiment, the refractive index of the recording pit 13 and the portion without the recording pit 13 is Since it is the same, transmitted light TP and transmitted light TL
Has the same amplitude and phase, so recording pit 13
Diffraction due to is not generated, and the transmitted light can be only the 0th-order diffracted light as in the above-described second embodiment, and the same effect as in the second embodiment can be obtained. Further, regarding the reflected light, an optical path length difference due to the depth v of the recording pit 13 is generated as in the second embodiment,
The recording pit information can be obtained. Since the reflectance and the transmittance are determined by the refractive index and the thickness of the recording layer 10 and the transparent body 11, when the medium on both sides of the recording layer 10, that is, the transparent body 11 has the same refractive index as in the present embodiment, recording is performed. If the layer 10 and the transparent body 11 have different refractive indices, reflection occurs. Recording layer 10
The refractive index of the transparent body 11 increases as the refractive index of the transparent body 11 differs from that of the transparent body 11, and in the present embodiment, about 5% or more is desirable. To achieve this, the refractive index of the recording layer 10 is 1. It is preferably 1 time or more or 0.9 times or less. Examples of dielectrics satisfying this are TiO 2 , ZnS, and Ce.
O 2 , ZrO 2 and the like. In the above description, the recording layer 10 has one dielectric layer, but the same effect can be obtained even if the recording layer 10 has a plurality of layers, and the degree of freedom in design is further increased.
【0031】(実施例4)以下に記録消去型の光ディス
クについて説明する。(Embodiment 4) A recording / erasing type optical disk will be described below.
【0032】図8(a)に示すように、照射光強度の違
いによって透過率の変わる第1の層17と第2の層18
の2層を近接させて配設した記録層19を透明体11で
挟持した構成である。照射光強度Aに対しては、第1の
層17の透過率がT1A、第2の層18の透過率がT2
Aとなり、他の照射光強度Bに対しては、第1の層17
の透過率がT1B、第2の層18の透過率がT2Bとな
る構成の光ディスクは、Pで示した部分を照射光強度A
で、Qで示した部分を照射光強度Bで照射すると、Pの
部分の第1、第2の層17、18の透過率はT1A、T
2Aとなり、Qの部分の第1、第2の層17、18の透
過率はT1B、T2Bとなる。ここで、界面S1、S2
での光照射光強度A、Bに対する反射率をR1a、R2
a、R1b、R2bとし、例えばR1a>R2a、R1
b<R2bとすれば、Pの部分での反射は透明体11と
第1の層17との界面S1で大きく、Qの部分では第1
の層17と第2の層18との界面S2で大きくなる。
(なお、図中では第1の層17と第2の層18を比べて
反射率の大きい方に斜線を付している。)反射光R1
a、R2bについてみると、Pの部分とQの部分では第
1の層17の厚み分の反射面の段差H1が生じており、
これが記録ピットが形成されたと同等な効果を持つこと
になる。また、照射光強度BでPの部分を照射すると、
先に形成された段差H1が消失するので、照射強度を変
えることにより、記録消去が可能となる。As shown in FIG. 8A, the first layer 17 and the second layer 18 whose transmittance changes depending on the difference in irradiation light intensity.
The recording layer 19 in which the two layers are arranged close to each other is sandwiched between the transparent bodies 11. For the irradiation light intensity A, the transmittance of the first layer 17 is T1A and the transmittance of the second layer 18 is T2.
A, and for other irradiation light intensities B, the first layer 17
Of the optical disk having a transmittance of T1B and a transmittance of the second layer 18 of T2B.
When the portion indicated by Q is irradiated with the irradiation light intensity B, the transmittances of the first and second layers 17 and 18 in the portion P are T1A and T1.
2A, and the transmittances of the first and second layers 17 and 18 in the Q portion are T1B and T2B. Here, the interfaces S1 and S2
The reflectance for the light irradiation light intensities A and B at R1a and R2
a, R1b, R2b, for example, R1a> R2a, R1
If b <R2b, the reflection at the P portion is large at the interface S1 between the transparent body 11 and the first layer 17, and at the Q portion, the first reflection occurs.
It becomes larger at the interface S2 between the layer 17 and the second layer 18.
(Note that, in the drawing, the first layer 17 and the second layer 18 are compared and the one with the higher reflectance is shaded.) Reflected light R1
Regarding a and R2b, a step H1 of the reflecting surface corresponding to the thickness of the first layer 17 is generated in the P portion and the Q portion,
This has the same effect as the formation of the recording pit. Further, when the P portion is irradiated with the irradiation light intensity B,
Since the step H1 previously formed disappears, it is possible to erase the recording by changing the irradiation intensity.
【0033】一方、これに対する透過光については、P
の部分とQの部分の記録層19の全体の透過率をTP、
TLとすると、 TP=T1A×T2A TL=T1B×T2B であるから T1A×T2A=T1B×T2B という条件にすると、0次以外の回折光の発生はなく、
透過光は段差H1を感知しないので、再生しない他の記
録層からのクロストークはほとんどなく、合焦点記録層
の記録再生消去が可能となる。On the other hand, regarding the transmitted light to this, P
The total transmittance of the recording layer 19 in the portions of and is TP,
If TL, TP = T1A × T2A TL = T1B × T2B Therefore, under the condition of T1A × T2A = T1B × T2B, no diffracted light other than the 0th order is generated,
Since the step H1 is not sensed by the transmitted light, there is almost no crosstalk from other recording layers that do not reproduce, and recording / reproduction / erasure of the focused recording layer becomes possible.
【0034】(実施例5)以下に記録層として誘電体を
用いた記録消去型の光ディスクについて説明する。(Embodiment 5) A recording / erasing type optical disk using a dielectric as a recording layer will be described below.
【0035】本実施例の構成は図8(a)で説明した実
施例4と同様であり、記録層に誘電体を用いて、照射光
強度の違いによって屈折率の変わる第1の層17と第2
の層18の2層を近接させて配設した記録層19を透明
体11で挟持した構成である。照射光強度Aに対して
は、第1の層17の屈折率がN1A、第2の層18の屈
折率がN2Aとなり、他の照射光強度Bに対しては、第
1の層17、第2の層18の屈折率がN1B、N2Bと
なる構成の光ディスクでは、Pの部分を照射光強度A
で、Qの部分を照射光強度Bで照射すると、Pの部分の
第1、第2の層17、18の屈折率はN1A、N2Aと
なり、Qの部分の第1、第2の層17、18の屈折率は
N1B、N2Bとなる。ここで、界面S1、S2の光照
射強度A、Bに対する反射率をR1a、R2a、R1
b、R2bとすれば、これらは界面S1、S2、S3の
両側の屈折率と厚みとで決まることになる。R1a、R
2a、R1b、R2bの関係を実施例4と同様にR1a
>R2a、R1b<R2bとすればR1aとR2bのペ
アで記録ピットの形成、記録消去ができる。The structure of this embodiment is the same as that of the embodiment 4 described with reference to FIG. 8A, and a dielectric is used for the recording layer, and the first layer 17 whose refractive index changes depending on the difference in irradiation light intensity. Second
The recording layer 19 in which the two layers 18 of 18 are disposed close to each other is sandwiched between the transparent bodies 11. For the irradiation light intensity A, the refractive index of the first layer 17 is N1A, and the refractive index of the second layer 18 is N2A. For the other irradiation light intensity B, the first layer 17, In the optical disc having a structure in which the refractive index of the second layer 18 is N1B and N2B, the P portion is irradiated with the irradiation light intensity A.
When the Q portion is irradiated with the irradiation light intensity B, the refractive index of the first and second layers 17 and 18 of the P portion becomes N1A and N2A, and the first and second layers 17 and 18 of the Q portion are The refractive indexes of 18 are N1B and N2B. Here, the reflectances of the interfaces S1 and S2 with respect to the light irradiation intensities A and B are R1a, R2a, and R1.
b and R2b are determined by the refractive index and the thickness on both sides of the interfaces S1, S2 and S3. R1a, R
The relationship between 2a, R1b, and R2b is R1a as in the fourth embodiment.
When> R2a and R1b <R2b, recording pits can be formed and recording / erasing can be performed with a pair of R1a and R2b.
【0036】透過光については、Pの部分、Qの部分の
その透過光路長OPP、OPQは OPP=N1A×H1+N2A×H2 OPQ=N1B×H1+N2B×H2 となるので、 OPP=OPQ すなわち、 N1A×H1+N2A×H2=N1B×H1+N2B×
H2 に示す条件にしておけば記録層19のPの部分とQの部
分での透過光の光路長は同等となるので、両者の位相の
変化の違いは発生しない。このため、実施例4と同様
に、透過光は界面S1と界面S2の段差を感知しないの
で、ここに形成される記録ピットによって生ずる±1次
以上の回折光の発生もない。Regarding the transmitted light, the transmitted light path lengths OPP and OPQ of the P portion and the Q portion are OPP = N1A × H1 + N2A × H2 OPQ = N1B × H1 + N2B × H2, so OPP = OPQ, that is, N1A × H1 + N2A × H2 = N1B × H1 + N2B ×
Under the condition indicated by H2, the optical path lengths of the transmitted light in the P portion and the Q portion of the recording layer 19 are equal, and therefore the difference in phase change between the two does not occur. For this reason, as in the case of the fourth embodiment, since the transmitted light does not sense the step between the interface S1 and the interface S2, there is no generation of diffracted light of ± 1st order or more caused by the recording pits formed here.
【0037】また、Pの部分の第2の層18の照射光強
度Aのときの屈折率N2AとQの部分の第1の層17の
照射光強度Bのときの屈折率N1Bを透明体11の屈折
率に等しくすれば、図8(b)に示すように、Pの部分
の第2の層18と透明体11の界面S3とQの部分の第
1の層17と透明体11の界面S1が光学的にはなくな
るので、Pの部分の透過光TPの界面S3による反射光
とQの部分の界面S1による反射光R1bが消失するこ
とにより、これによるノイズ成分が消え、より良好な再
生信号を得ることができる。Further, the refractive index N2A at the irradiation light intensity A of the second layer 18 in the P portion and the refractive index N1B at the irradiation light intensity B of the first layer 17 in the Q portion are set to the transparent body 11. 8B, the interface S3 between the second layer 18 at the P portion and the transparent body 11 and the interface between the first layer 17 at the Q portion and the transparent body 11 as shown in FIG. 8B. Since S1 does not exist optically, the reflected light by the interface S3 of the transmitted light TP in the P portion and the reflected light R1b by the interface S1 in the Q portion disappear, so that the noise component due to this disappears and better reproduction is achieved. You can get a signal.
【0038】(実施例6)以下に記録層の間に中間透明
体を配設した記録消去型の光ディスクについて説明す
る。(Embodiment 6) A recording / erasing type optical disc having an intermediate transparent body disposed between recording layers will be described below.
【0039】図9(a)に示すように本実施例は、前述
実施例5の構成の第1の層17と第2の層18の間に透
明物質製の中間透明体20を配設した記録層21とした
構成である。In this embodiment, as shown in FIG. 9A, an intermediate transparent body 20 made of a transparent material is arranged between the first layer 17 and the second layer 18 of the construction of the above-mentioned fifth embodiment. The recording layer 21 is provided.
【0040】照射光強度の違いによって実施例5と同様
に第1、第2の層17、18の透過率が変化するとし、
中間透明体20の光学特性の変化はないとする。本実施
例では、たとえば、Pの部分での反射は透明体11と第
1の層17との界面S1で大きく、Qの部分では中間透
明体20と第2の層18との界面S3で大きくする。こ
うして、段差H3の記録ピットを形成することができ
る。本実施例では、中間透明体20を設けることによっ
て、記録ピットの深さと第1、第2の記録層17、18
の厚みとの相互依存性を除くことができ、記録ピットの
深さと第1、第2の記録層17、18の厚みの設定の自
由度が増すことができる。透過率の差を用いて記録ピッ
トを形成するときは、第1、第2の層17、18の透過
率の条件は前述の N1A×H1+N2A×H2=N1B×H1+N2B×
H2 となる。誘電体を用いて第1、第2の層17、18を構
成する場合の条件は前述の OPP=OPQ となる。また、図8(b)で説明した実施例5と同様
に、Pの部分の第2の層18の屈折率N2AとQの部分
の第1の層17の屈折率N1Bを透明体11および中間
透明体20の屈折率に等しくすれば、図9(b)に示す
ように、Pの部分の第2の層18と透明体11および中
間透明体20との界面、Qの部分の第1の層17と透明
体11および中間透明体20との界面が光学的にはなく
なるので、この部分による反射光が消失し、より良好な
再生信号を得ることができる。It is assumed that the transmittances of the first and second layers 17 and 18 are changed by the difference in the irradiation light intensity as in the case of Example 5,
It is assumed that there is no change in the optical characteristics of the intermediate transparent body 20. In this embodiment, for example, the reflection at the portion P is large at the interface S1 between the transparent body 11 and the first layer 17, and at the portion Q is large at the interface S3 between the intermediate transparent body 20 and the second layer 18. To do. In this way, the recording pit with the step H3 can be formed. In this embodiment, by providing the intermediate transparent body 20, the depth of the recording pit and the first and second recording layers 17 and 18 are
Of the recording pits and the thickness of the first and second recording layers 17 and 18 can be set more freely. When the recording pit is formed using the difference in transmittance, the conditions for the transmittance of the first and second layers 17 and 18 are N1A × H1 + N2A × H2 = N1B × H1 + N2B ×
It becomes H2. The condition for forming the first and second layers 17 and 18 using a dielectric material is OPP = OPQ described above. In addition, as in Example 5 described in FIG. 8B, the refractive index N2A of the second layer 18 in the P portion and the refractive index N1B of the first layer 17 in the Q portion are set to the transparent body 11 and the intermediate portion. If it is made equal to the refractive index of the transparent body 20, as shown in FIG. 9B, the interface between the second layer 18 in the P portion and the transparent body 11 and the intermediate transparent body 20, and the first portion in the Q portion. Since the interface between the layer 17 and the transparent body 11 and the intermediate transparent body 20 is optically eliminated, the reflected light at this portion disappears and a better reproduced signal can be obtained.
【0041】(実施例7)以下に反射率を異にした記録
層を有する光ディスクについて説明する。(Embodiment 7) An optical disk having recording layers having different reflectances will be described below.
【0042】図10に示すように、光ビーム8が光ディ
スク22に対して下方から入射するとして記録層23に
光ビーム8の入射側から順番に1番目を記録層23a、
2番目を記録層23b、3番目を記録層23cとする
と、2番目の記録層23bへの照射光量t1が1番目の
記録層23aでの反射光量R1と吸収光量だけ減ってし
まうので、記録層23bでの反射光量R2もこの分が減
り、光検出器に戻る光量も減ってしまう。同様に、3番
目の記録層23cへの照射光量t2と反射光量R3も減
り、記録層23の層数が増すにつれて、この減少量が大
きくなる。また、記録層23を反射した後、光検出器に
戻る過程での他の記録層23の透過によっても光量の減
少が生じるので、半導体レーザから遠い記録層23ほど
光検出器への戻り光量がさらに減少することになる。し
たがって、半導体レーザから遠い位置の記録層23ほど
その反射率を大きくした構成とすることにより、光検出
器への戻り光量の減少を防止できる。As shown in FIG. 10, it is assumed that the light beam 8 is incident on the optical disc 22 from below, and the first recording layer 23a is arranged on the recording layer 23 in order from the incident side of the light beam 8.
If the second recording layer 23b and the third recording layer 23c are used, the irradiation light amount t1 to the second recording layer 23b is reduced by the reflected light amount R1 and the absorbed light amount at the first recording layer 23a. The amount R2 of reflected light at 23b is also reduced by this amount, and the amount of light returning to the photodetector is also reduced. Similarly, the amount t2 of irradiation light and the amount R3 of reflected light to the third recording layer 23c also decrease, and the amount of decrease increases as the number of recording layers 23 increases. In addition, since the amount of light also decreases due to the transmission of the other recording layer 23 in the process of returning to the photodetector after being reflected from the recording layer 23, the amount of light returning to the photodetector increases as the recording layer 23 is farther from the semiconductor laser. It will be further reduced. Therefore, by decreasing the reflectance of the recording layer 23 at a position farther from the semiconductor laser, the amount of light returning to the photodetector can be prevented from decreasing.
【0043】(実施例8)以下に記録層として磁気光学
効果を利用する光磁気材料を用いた光ディスクについて
説明する。(Embodiment 8) An optical disk using a magneto-optical material utilizing the magneto-optical effect as a recording layer will be described below.
【0044】図11に示すように、光ビーム8が非合焦
記録層10bを照射するときについてみると、非合焦記
録層10bに入射する光ビーム8が矢印Aで示した方向
に偏光しているとすると、未記録部24の透過光の偏光
方向は変化せず、矢印Aで示した方向そのままである
が、記録ピット13の部分では偏光方向が矢印Bで示し
た方向に回転変化する。記録ピット13の部分と未記録
部24での違いはこの偏光方向のみであり、光ビーム8
の振幅、位相の違いは両者にないので、光の回折は生じ
ない。また、反射光についても、前述透過光と同様に記
録ピット13の部分の偏光方向の変化のみであり、光の
回折は生じない。透過光と反射光の全体としては偏光方
向が変化し、これは、記録ピット13の部分と未記録部
24の面積比と照射光の強度分布で決まる。ここで記録
層10間の積層間隔を大きくとって光ビーム8で照射さ
れる非合焦記録層10b上の記録ピット13の数を十分
多くすると、すでに説明したように、その数が多数であ
るので、記録ピット13による光ビーム8全体の偏光方
向に対する影響は平均化されて、実際上この偏光方向は
常に一定とみなして差し支えない。こうして、光ビーム
8全体の偏光方向は記録部分の偏光方向と未記録部24
の偏光方向の間のある特定の方向を向くことになる。再
生信号は光ビーム8全体の変化で決定されるので、光ビ
ーム8全体の偏光方向の一定なる変化は再生信号にDC
成分が乗るのみとなるので、再生信号には影響を及ぼさ
ず問題とならない。このように、光磁気材料の記録層の
場合は、記録層10の積層間隔を波長あるいは記録ピッ
ト寸法に対して十分大きくすれば、非合焦記録層10b
の透過、反射での回折はないので、再生信号への非記録
再生層の影響を抑止できて記録再生密度の向上ができ
る。As shown in FIG. 11, when the light beam 8 irradiates the unfocused recording layer 10b, the light beam 8 incident on the unfocused recording layer 10b is polarized in the direction indicated by the arrow A. If so, the polarization direction of the transmitted light of the unrecorded portion 24 does not change and remains in the direction indicated by the arrow A, but the polarization direction of the recording pit 13 is rotationally changed in the direction indicated by the arrow B. . The only difference between the recording pit 13 and the unrecorded portion 24 is this polarization direction.
Since there is no difference in amplitude and phase between the two, light diffraction does not occur. Further, as for the reflected light, only the change in the polarization direction of the recording pit 13 is caused as in the case of the transmitted light, and the light is not diffracted. The polarization directions of the transmitted light and the reflected light are changed as a whole, and this is determined by the area ratio of the recording pit 13 and the unrecorded portion 24 and the intensity distribution of the irradiation light. Here, if the number of recording pits 13 on the non-focus recording layer 10b irradiated with the light beam 8 is made sufficiently large by increasing the stacking interval between the recording layers 10, as described above, the number is large. Therefore, the influence of the recording pits 13 on the polarization direction of the entire light beam 8 is averaged, and in practice this polarization direction can be regarded as always constant. Thus, the polarization direction of the entire light beam 8 is the same as the polarization direction of the recorded portion and the unrecorded portion 24.
Will be oriented in a certain direction between the polarization directions of. Since the reproduction signal is determined by the change in the entire light beam 8, a constant change in the polarization direction of the entire light beam 8 causes a DC change in the reproduction signal.
Since only the component is added, it does not affect the reproduced signal and is not a problem. As described above, in the case of the recording layer made of the magneto-optical material, the non-focus recording layer 10b can be obtained by setting the lamination interval of the recording layers 10 sufficiently large with respect to the wavelength or the recording pit size.
Since there is no diffraction due to transmission or reflection, the influence of the non-recording / reproducing layer on the reproduction signal can be suppressed and the recording / reproducing density can be improved.
【0045】(実施例9)以下に多層の記録層と従来の
記録層を混在積層した構成の光ディスクについて説明す
る。(Embodiment 9) An optical disc having a structure in which multiple recording layers and conventional recording layers are mixed and laminated will be described below.
【0046】図12に示すように、記録層10に高次透
過光を発生する従来の記録層25を付加した光ディスク
26としたとき、従来の構成の記録層25では通常、高
次透過光が発生し、これが再生信号に対して妨害信号と
なる。そこで、光ビーム8の入射側には多層の記録層1
0を配設し、光ビーム8の透過側には従来の記録層25
を配設すれば従来の記録層25の透過光が悪影響を及ぼ
すことがないので、両者を共存して使用することが可能
となる。ただし、従来の記録層25は1層のみ使用し、
アモルファスー結晶間の状態変化を利用した相変化記録
層などを用いる。As shown in FIG. 12, when an optical disk 26 is formed by adding a conventional recording layer 25 for generating high-order transmitted light to the recording layer 10, a high-order transmitted light is normally generated in the recording layer 25 having the conventional structure. Occurs, which becomes an interfering signal with respect to the reproduced signal. Therefore, the multilayer recording layer 1 is provided on the incident side of the light beam 8.
0 is provided, and the conventional recording layer 25 is provided on the transmission side of the light beam 8.
By disposing the above, since the transmitted light of the conventional recording layer 25 does not have an adverse effect, both can be used together. However, only one conventional recording layer 25 is used,
A phase change recording layer or the like that utilizes the state change between amorphous and crystal is used.
【0047】(実施例10)以下に光ディスクの製造方
法について説明する。前述実施例の図1および図2に説
明したように、光ディスク12は記録層10と透明体1
1を交互に積層した構成で、記録層10の相互間の積層
間隔Lは10μm程度から数百μm程度と比較的薄いも
のであり、また、積層間隔Lはできる限り一定となるこ
とが望ましいので、透明体11の厚みを均一に作成する
ことが重要となる。そこで、図13に示すように、記録
層27の相互間に厚みを厳密に規定したスペーサ28を
はさみこみ、スペーサ28の厚みで記録層27の積層間
隔Lを規定する。その後、透明体29を流し込んで固め
る等の方法で光ディスク30を作成する。なお、図14
に示すように、スペーサ28は同心円状または放射状に
配置する方法もある。(Embodiment 10) An optical disk manufacturing method will be described below. As described in FIGS. 1 and 2 of the above-described embodiment, the optical disc 12 includes the recording layer 10 and the transparent body 1.
In the configuration in which the recording layers 10 are alternately laminated, the lamination interval L between the recording layers 10 is relatively thin, about 10 μm to several hundreds μm, and the lamination interval L is preferably as constant as possible. It is important to make the thickness of the transparent body 11 uniform. Therefore, as shown in FIG. 13, a spacer 28 having a strictly defined thickness is sandwiched between the recording layers 27, and the stacking interval L of the recording layers 27 is defined by the thickness of the spacer 28. Then, the optical disk 30 is prepared by a method of pouring the transparent body 29 and hardening it. Note that FIG.
There is also a method of arranging the spacers 28 concentrically or radially as shown in FIG.
【0048】また、記録層27の相互間の積層間隔Lを
規定するのに、記録層27上に液状の樹脂を滴下した後
に、光ディスク30を回転させて、樹脂を均一に薄く塗
布する、いわゆるスピンコートによって透明体29を形
成する方法もある。In order to define the stacking interval L between the recording layers 27, after the liquid resin is dropped on the recording layer 27, the optical disc 30 is rotated to apply the resin uniformly and thinly. There is also a method of forming the transparent body 29 by spin coating.
【0049】(実施例11)以下に両面貼合せ型の光デ
ィスクの再生について説明する。(Embodiment 11) The reproduction of a double-sided bonded type optical disc will be described below.
【0050】図18に示すように、従来の両面貼合せ型
の光ディスク31は、2個の片面ディスク31A、31
Bの片面に記録層を各々形成し、両記録層を向い合わせ
て貼合せた2面の記録層を有する構成で、光ディスク3
1の再生において、片面ディスク31Aの記録層を再生
するときは光ビームを片面ディスク31A側より照射
し、片面ディスク31Bの記録層を再生するときは光ビ
ームを片面ディスク31B側より照射しなければならな
いので、一方の記録層を再生した後、もう一方の記録層
を再生するのに光ディスク31を反転する作業が必要で
あった。したがって、両面記録層を人手を介さずに連続
再生するためには、ガイド33を設けて光ディスク31
の両面に光ヘッド32を移送するヘッド移動手段を用い
ていた。また、図19に示すように、光ディスク31の
両側にそれぞれ光ヘッド34を設けた両面配置ヘッド手
段を用いていた。As shown in FIG. 18, the conventional double-sided bonding type optical disc 31 includes two single-sided discs 31A and 31A.
The optical disc 3 has a structure in which recording layers are formed on one side of B, and two recording layers are laminated by facing both recording layers.
In the reproduction of No. 1, the light beam must be emitted from the single-sided disc 31A side when reproducing the recording layer of the single-sided disc 31A, and the light beam must be emitted from the single-sided disc 31B side when reproducing the recording layer of the single-sided disc 31B. Therefore, it is necessary to invert the optical disc 31 to reproduce the other recording layer after reproducing the one recording layer. Therefore, in order to continuously reproduce the double-sided recording layer without human intervention, the guide 33 is provided and the optical disc 31 is provided.
Head moving means for moving the optical head 32 to both sides of the above was used. Further, as shown in FIG. 19, a double-sided arrangement head means in which optical heads 34 are provided on both sides of the optical disc 31 is used.
【0051】本実施例の光ディスク、例えば図15に示
すように、記録層35A、35Bに凹凸を与えて記録ピ
ットを形成し、接合材36で貼合せ、透明体11で挟持
した光ディスク37では、光ビーム8が途中の記録層3
5Aを透過しても再生できるので、上方より光ビーム8
を照射しても記録層35Aおよび記録層35Bを再生す
ることができる。したがって、従来の光ディスクでは、
必要であった光ディスクの反転なしで両面の記録層35
A、35Bを再生することが可能となり、従来例のよう
に両面配置ヘッド手段やヘッド移動手段が不要となる。As shown in FIG. 15, the optical disc 37 of the present embodiment, for example, an optical disc 37 in which recording layers 35A and 35B are provided with irregularities to form recording pits, which are bonded by a bonding material 36 and sandwiched by the transparent body 11, The recording layer 3 where the light beam 8 is in the middle
Even if it passes through 5A, it can be reproduced, so
The recording layer 35A and the recording layer 35B can be reproduced by irradiating. Therefore, in the conventional optical disc,
Recording layers 35 on both sides without reversing the required optical disk
It becomes possible to reproduce A and 35B, and the double-sided arrangement head means and head moving means are not required unlike the conventional example.
【0052】また、図16(a)や図16(b)に示し
たように、2層構造にした記録層38や光磁気材料を用
いた記録層39をそれぞれ接合材36で貼合せ、透明体
11で挟持した光ディスク40や光ディスク41につい
ても、上述の光ディスク37と同様に再生でき、同様な
効果が得られる。なお、透明体11と接合材36の屈折
率は高次の透過光を防止するためにほぼ等しい構成とし
ている。As shown in FIGS. 16 (a) and 16 (b), a recording layer 38 having a two-layer structure and a recording layer 39 made of a magneto-optical material are adhered with a bonding material 36, respectively, and are transparent. The optical disc 40 and the optical disc 41 sandwiched by the body 11 can be reproduced in the same manner as the optical disc 37 described above, and the same effect can be obtained. The transparent body 11 and the bonding material 36 have substantially the same refractive index in order to prevent higher-order transmitted light.
【0053】[0053]
【発明の効果】以上の説明からも明らかなように本発明
は、光源と、記録層と透明体が交互に積層され、かつ記
録層上の記録ピットによる透過回折光のうち0次回折光
に大略のエネルギが配分される光ディスクと、光源から
の光ビームを光ディスク上に収束する対物レンズと、光
ディスクからの反射光を受光して光ディスク上に記録さ
れた情報を検出する検出手段を備えた構成により、記録
再生の対象とならない記録層からの干渉光の影響による
信号混入を抑止して、大幅な記録密度を向上した優れた
光ディスクおよび光ディスク装置を実現できるものであ
る。As is apparent from the above description, the present invention generally uses a light source, a recording layer and a transparent body alternately laminated, and is generally a 0th-order diffracted light among the transmitted diffracted light by the recording pits on the recording layer. Of the optical disc, the objective lens that converges the light beam from the light source onto the optical disc, and the detection means that receives the reflected light from the optical disc and detects the information recorded on the optical disc. It is possible to realize an excellent optical disc and optical disc device in which signals are prevented from being mixed due to the influence of interference light from a recording layer that is not a target of recording / reproduction and a large recording density is improved.
【図1】本発明の実施例1の光ディスク装置の概略構成
図FIG. 1 is a schematic configuration diagram of an optical disk device according to a first embodiment of the present invention.
【図2】同光ディスク装置の記録層における光の透過、
反射の説明図FIG. 2 shows transmission of light through a recording layer of the optical disc device,
Illustration of reflection
【図3】同記録層上の記録ピットによる回折の説明図FIG. 3 is an explanatory diagram of diffraction by recording pits on the recording layer.
【図4】同実施例のビーム変換手段を設けた光ディスク
装置の概略構成図FIG. 4 is a schematic configuration diagram of an optical disk device provided with a beam converting means of the embodiment.
【図5】同実施例の光路長変更手段を設けた光ディスク
装置の概略構成図FIG. 5 is a schematic configuration diagram of an optical disk device provided with an optical path length changing unit of the same embodiment.
【図6】同光路長変更手段を設けた光ディスク装置の他
の実施例の要部構成図FIG. 6 is a configuration diagram of a main part of another embodiment of an optical disc device provided with the optical path length changing means.
【図7】本発明の実施例2の光ディスクの構成断面略図FIG. 7 is a schematic sectional view of the configuration of an optical disc according to a second embodiment of the present invention.
【図8】本発明の実施例4の光ディスクの構成断面略図FIG. 8 is a schematic sectional view showing the configuration of an optical disc according to Example 4 of the present invention.
【図9】本発明の実施例6の光ディスクの構成断面略図FIG. 9 is a schematic sectional view showing the configuration of an optical disc according to Example 6 of the present invention.
【図10】本発明の実施例7の光ディスクの記録層にお
ける光の透過、反射の説明図FIG. 10 is an explanatory diagram of light transmission and reflection in the recording layer of the optical disc of Example 7 of the present invention.
【図11】本発明の実施例8の光ディスクの記録ピット
の偏光の説明図FIG. 11 is an explanatory diagram of polarization of recording pits of the optical disc of Example 8 of the present invention.
【図12】本発明の実施例9の光ディスクの構成断面略
図FIG. 12 is a schematic sectional view showing the configuration of an optical disc according to Example 9 of the present invention.
【図13】本発明の実施例10の光ディスクの製造方法
におけるスペーサの配置状態を示した断面略図FIG. 13 is a schematic cross-sectional view showing the arrangement state of spacers in the optical disc manufacturing method according to example 10 of the present invention.
【図14】同スペーサの他の配置状態を示した要部断面
図FIG. 14 is a sectional view of an essential part showing another arrangement state of the spacer.
【図15】本発明の実施例11の光ディスクの構成断面
略図FIG. 15 is a schematic sectional view showing the structure of an optical disc according to Example 11 of the present invention.
【図16】同実施例の他の光ディスクの断面略図FIG. 16 is a schematic sectional view of another optical disc in the same example.
【図17】従来の光ディスク装置の概略構成図FIG. 17 is a schematic configuration diagram of a conventional optical disc device.
【図18】従来の両面貼合せ型の光ディスクに用いる光
ディスク装置の要部構成図FIG. 18 is a configuration diagram of main parts of a conventional optical disk device used for a double-sided bonded optical disk.
【図19】同光ディスクに用いる他の光ディスク装置の
要部構成図FIG. 19 is a configuration diagram of a main part of another optical disk device used for the optical disk.
1 半導体レーザ(光源) 4 対物レンズ 9 光検出器(検出手段) 10、19 記録層 11 透明体 12 光ディスク 14 ビーム変換手段 15 光路長変更手段 17 第1の層 18 第2の層 20 中間透明体 28 スペーサ DESCRIPTION OF SYMBOLS 1 semiconductor laser (light source) 4 objective lens 9 photodetector (detection means) 10, 19 recording layer 11 transparent body 12 optical disk 14 beam conversion means 15 optical path length changing means 17 first layer 18 second layer 20 intermediate transparent body 28 Spacer
───────────────────────────────────────────────────── フロントページの続き (72)発明者 西内 健一 大阪府門真市大字門真1006番地 松下電器 産業株式会社内 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Kenichi Nishiuchi, 1006, Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.
Claims (25)
録層を有し、光の振幅または位相変化により記録された
前記記録層の記録ピットによる透過回折光のうち0次回
折光に大略のエネルギが配分されることを特徴とする光
ディスク。1. A 0-th order diffracted light of a transmitted diffracted light by a recording pit of the recording layer recorded by the amplitude or phase change of light, having a plurality of recording layers in which recording layers and transparent bodies are alternately arranged. An optical disc characterized in that almost all energy is distributed.
に対して離れて位置する記録層ほど反射率を高くした請
求項1記載の光ディスク。2. The optical disc according to claim 1, wherein the recording layer located farther from the incident direction of the light beam irradiating the optical disc has a higher reflectance.
備えた請求項1記載の光ディスク。3. The optical disk according to claim 1, further comprising a spacer that defines a mutual distance between the recording layers.
に対して最も離れた位置に記録ピットによる高次回折光
がある記録層を有する請求項1記載の光ディスク。4. The optical disc according to claim 1, further comprising a recording layer having a high-order diffracted light by recording pits at a position farthest from the incident direction of the light beam for irradiating the optical disc.
が相変化記録層である請求項4記載の光ディスク。5. The optical disc according to claim 4, wherein the recording layer on which the high-order diffracted light due to the recording pit is present is a phase change recording layer.
屈折率の透明体とを交互に積層し、記録層と記録層の間
隔を使用波長の10倍以上としたことを特徴とする光デ
ィスク。6. A recording layer made of a magneto-optical material and a transparent body having a substantially uniform refractive index are alternately laminated, and the distance between the recording layers is 10 times or more the wavelength used. Optical disc.
録ピットの部分と前記記録ピットがない部分の透過率を
ほぼ等しくした記録層と透明体とを交互に積層し、前記
記録層を挟む両側の前記透明体の屈折率をほぼ等しく
し、記録層と記録層の間隔を使用波長の10倍以上とし
たことを特徴とする光ディスク。7. A recording pit is formed by providing projections and depressions, and a recording layer and a transparent body in which the transmittance of the recording pit portion and the portion without the recording pit are substantially equal are alternately laminated, and the recording layer is formed. An optical disk characterized in that the transparent bodies on both sides of the sandwich are made substantially equal in refractive index, and the distance between the recording layers is 10 times or more the wavelength used.
録層を備えた請求項7記載の光ディスク。8. The optical disc according to claim 7, further comprising a recording layer formed of a light absorber having a constant transmittance.
記録層を備えた請求項7記載の光ディスク。9. The optical disk according to claim 7, further comprising a recording layer formed of a dielectric having a refractive index different from that of the transparent body.
9倍以下または1.1倍以上である請求項9記載の光デ
ィスク。10. The refractive index of the recording layer is 0.
The optical disc according to claim 9, which is 9 times or less or 1.1 times or more.
層を備えた請求項9記載の光ディスク。11. The optical disc according to claim 9, further comprising a recording layer formed by laminating a plurality of dielectrics.
の透過率がT1A、T2Aになり、照射光強度Bに対し
ては第1、第2の層の透過率がT1B、T2Bになる第
1の層と第2の層より各々構成される記録層が T1A×T2A=T1B×T2B となる条件を満たし、透明体を挟んで複数積層され、記
録層と記録層の間隔を使用波長の10倍以上としたこと
を特徴とする光ディスク。12. The transmittances of the first and second layers are T1A and T2A for the irradiation light intensity A, and the transmittances of the first and second layers are T1B for the irradiation light intensity B. , The recording layer composed of the first layer and the second layer of T2B satisfy the condition of T1A × T2A = T1B × T2B, and a plurality of layers are laminated with a transparent body sandwiched between them. Is an optical disc having a wavelength of 10 times or more.
挟まれた中間透明体により構成される記録層と透明体と
を交互に積層し、照射光強度Aに対しては第1、第2の
層の透過率がT1A、T2Aになり、照射光強度Bに対
しては第1、第2の層の透過率がT1B、T2Bになる
とき、 T1A×T2A=T1B×T2B となる条件を満たし、かつ、前記中間透明体と前記透明
体の屈折率がほぼ等しく、記録層と記録層の間隔を使用
波長の10倍以上としたことを特徴とする光ディスク。13. A recording layer composed of first and second layers and an intermediate transparent body sandwiched between the first and second layers, and a transparent body are alternately laminated to obtain an irradiation light intensity A. When the transmittances of the first and second layers are T1A and T2A and the transmittances of the first and second layers are T1B and T2B for the irradiation light intensity B, T1A × T2A = T1B × An optical disk characterized in that the condition of T2B is satisfied, the refractive indexes of the intermediate transparent body and the transparent body are substantially equal to each other, and the distance between recording layers is 10 times or more the wavelength used.
射光強度Aに対しては第1、第2の層の屈折率がN1
A、N2Aになり、照射光強度Bに対しては第1、第2
の層の屈折率がN1B、N2Bになる第1の層と第2の
層より各々構成される記録層が N1A×H1+N2A×H2=N1B×H1+N2B×
H2 となる条件を満たし、透明体を挟んで複数積層され、記
録層と記録層の間隔を使用波長の10倍以上としたこと
を特徴とする光ディスク。14. The thickness of the first and second layers is H1 and H2, and the refractive index of the first and second layers is N1 with respect to the irradiation light intensity A.
A, N2A, and the first and second with respect to the irradiation light intensity B
The recording layer composed of the first layer and the second layer having the refractive indices of N1B and N2B is N1A × H1 + N2A × H2 = N1B × H1 + N2B ×
An optical disc, wherein a plurality of layers satisfying the condition of H2, are laminated with a transparent body sandwiched therebetween, and the distance between recording layers is 10 times or more the wavelength used.
体の界面の反射率と、第1の層と第2の層の界面の反射
率とを比較して、前者が小さいときは照射光強度Aに対
する第1の層の屈折率と照射光強度Bに対する第2の層
の屈折率とをほぼ透明体の屈折率に等しくし、後者が小
さいときはそれぞれ反対の層の屈折率を透明体の屈折率
に等しくした請求項14記載の光ディスク。15. Compared with the irradiation light intensity A, the reflectance at the interface between the first layer and the transparent body and the reflectance at the interface between the first layer and the second layer are compared, and the former is smaller. When the latter is small, the refractive index of the first layer with respect to the irradiation light intensity A and the refractive index of the second layer with respect to the irradiation light intensity B are made substantially equal to the refractive index of the transparent body. The optical disk according to claim 14, wherein the index is equal to the refractive index of the transparent body.
挟まれた中間透明体により構成される記録層と透明体と
を交互に積層し、第1、第2の層の厚みがH1、H2
で、照射光強度Aに対しては第1、第2の層の屈折率が
N1A、N2Aであり照射光強度Bに対しては第1、第
2の層の屈折率がN1B、N2Bであるとき N1A×H1+N2A×H2=N1B×H1+N2B×
H2 となる条件を満たし、前記中間透明体と前記透明体の屈
折率がほぼ等しく、記録層と記録層の間隔を使用波長の
10倍以上としたことを特徴とする光ディスク。16. A recording layer and a transparent body composed of first and second layers and an intermediate transparent body sandwiched between the first and second layers are alternately laminated to form first and second layers. Thickness is H1, H2
With respect to the irradiation light intensity A, the refractive indices of the first and second layers are N1A and N2A, and with respect to the irradiation light intensity B, the refractive indices of the first and second layers are N1B and N2B. When N1A × H1 + N2A × H2 = N1B × H1 + N2B ×
An optical disk, wherein the condition of H2 is satisfied, the refractive indices of the intermediate transparent body and the transparent body are substantially equal to each other, and the distance between the recording layers is 10 times or more the used wavelength.
体の界面の反射率と、第2の層と中間透明体の界面の反
射率とを比較して、前者が小さいときは照射光強度Aに
対する第1の層の屈折率と照射光強度Bに対する第2の
層の屈折率とをほぼ前記透明体および前記中間透明体の
屈折率に等しくし、後者が小さいときはそれぞれ反対の
層の屈折率を前記透明体および前記中間透明体の屈折率
に等しくした請求項16記載の光ディスク。17. When the former is small, the reflectance of the interface between the first layer and the transparent body and the reflectance of the interface between the second layer and the intermediate transparent body are compared with respect to the irradiation light intensity A. Makes the refractive index of the first layer for the irradiation light intensity A and the refractive index of the second layer for the irradiation light intensity B substantially equal to the refractive indexes of the transparent body and the intermediate transparent body, and when the latter is small, respectively. The optical disk according to claim 16, wherein the refractive index of the opposite layer is equal to the refractive index of the transparent body and the intermediate transparent body.
れ、前記光源からの光ビームの振幅あるいは位相の変化
によって記録された前記記録層上の記録ピットによる透
過回折光のうち0次回折光に大略のエネルギが配分され
る光ディスクと、前記光源からの光ビームを前記光ディ
スク上に収束する対物レンズと、前記光ディスクからの
反射光を受光して、前記光ディスク上に記録された情報
を検出する検出手段を備えたことを特徴とする光ディス
ク装置。18. A light source, a recording layer and a transparent body are alternately laminated, and the 0th time of the transmitted diffraction light by the recording pit on the recording layer recorded by the change of the amplitude or phase of the light beam from the light source. An optical disc in which approximately energy is distributed to the folding light, an objective lens that converges a light beam from the light source onto the optical disc, and reflected light from the optical disc is received to detect information recorded on the optical disc. An optical disc device comprising:
れてなる光ディスクと、前記光源からの光ビームを前記
光ディスク上に収束する対物レンズと、前記光ビームの
透過光路長を変える光路長変更手段と、前記光ディスク
からの反射光を受光して前記光ディスク上に記録された
情報を検出する検出手段を備え、前記光路長変更手段を
前記光ビームの非平行部に配設したことを特徴とする光
ディスク装置。19. A light source, an optical disc in which recording layers and transparent bodies are alternately laminated, an objective lens for converging a light beam from the light source onto the optical disc, and an optical path for changing a transmission optical path length of the light beam. A length changing means and a detecting means for receiving reflected light from the optical disc to detect information recorded on the optical disc, wherein the optical path length changing means is arranged in a non-parallel portion of the light beam. Characteristic optical disk device.
クの中間に配設した請求項19記載の光ディスク装置。20. The optical disk device according to claim 19, wherein the optical path length changing means is arranged between the objective lens and the optical disk.
向となるように対向させて配設し、互いの位置をずらす
ことにより光ビームの透過光路長を変える構成とした光
路長変更手段を備えた請求項19記載の光ディスク装
置。21. An optical path length changing structure in which two wedge-shaped transparent bodies are arranged so as to face each other with their slopes facing in opposite directions, and the transmission optical path length of a light beam is changed by shifting their positions. 20. The optical disk device according to claim 19, further comprising means.
れてなる光ディスクと、前記光源からの光ビームをリン
グ状の光ビームに変換するビーム変換手段と、前記光ビ
ームを前記光ディスク上に収束する対物レンズと、前記
光ディスクからの反射光を受光して、前記光ディスク上
に記録された情報を検出する検出手段を備えたことを特
徴とする光ディスク装置。22. A light source, an optical disk in which recording layers and transparent bodies are alternately laminated, beam conversion means for converting a light beam from the light source into a ring-shaped light beam, and the light beam on the optical disk. An optical disc apparatus comprising: an objective lens that converges to an optical disc; and a detection unit that receives reflected light from the optical disc and detects information recorded on the optical disc.
トを形成し、前記記録層の記録ピットの部分と記録ピッ
トがない部分の透過率をほぼ等しくしたディスクを接合
材で2枚接合し、前記ディスクと前記接合材の屈折率を
ほぼ等しくした構成の両面貼合せ型の光ディスクと、前
記光源からの光ビームを前記光ディスク上に収束する対
物レンズと、前記光ディスクからの反射光を受光して、
前記光ディスク上に記録された情報を検出する検出手段
を備え、前記光ディスクの2つの記録層を前記光ディス
クの反転なしで、1方向のみの光ビームの照射により再
生することを特徴とする光ディスク装置。23. Two discs are bonded with a bonding material by forming a recording pit by providing unevenness on the light source and the recording layer, and making the transmittances of the recording pit portion and the portion without the recording pit of the recording layer approximately equal. Then, a double-sided bonding type optical disc having a structure in which the refractive index of the disc and the bonding material are substantially equal to each other, an objective lens for converging a light beam from the light source onto the optical disc, and a reflected light from the optical disc are received. do it,
An optical disk device comprising a detection means for detecting information recorded on the optical disk, and reproducing the two recording layers of the optical disk by irradiating a light beam in only one direction without inverting the optical disk.
かに記載の光ディスクを備えた請求項23記載の光ディ
スク装置。24. An optical disk device according to claim 23, comprising the optical disk according to any one of claims 12, 13, 14, and 16.
スクを備えた請求項23記載の光ディスク装置。25. The optical disk device according to claim 23, further comprising an optical disk using a magneto-optical material as a recording layer.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP5291567A JPH0778353A (en) | 1992-11-26 | 1993-11-22 | Optical disk and optical disk device |
Applications Claiming Priority (5)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP31683192 | 1992-11-26 | ||
JP15470193 | 1993-06-25 | ||
JP5-154701 | 1993-06-25 | ||
JP4-316831 | 1993-06-25 | ||
JP5291567A JPH0778353A (en) | 1992-11-26 | 1993-11-22 | Optical disk and optical disk device |
Related Child Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP2001165955A Division JP2002015458A (en) | 1992-11-26 | 2001-06-01 | Optical disk and optical disk device |
Publications (1)
Publication Number | Publication Date |
---|---|
JPH0778353A true JPH0778353A (en) | 1995-03-20 |
Family
ID=27320707
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP5291567A Pending JPH0778353A (en) | 1992-11-26 | 1993-11-22 | Optical disk and optical disk device |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH0778353A (en) |
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH0954972A (en) * | 1995-08-15 | 1997-02-25 | Nec Corp | Optical head device |
WO2002067250A1 (en) * | 2001-02-22 | 2002-08-29 | Matsushita Electric Industrial Co., Ltd. | Optical disk unit |
WO2004036569A1 (en) * | 2002-10-16 | 2004-04-29 | Matsushita Electric Industrial Co., Ltd. | Information recording medium, process for producing the same and optical information recording and reproducing device |
WO2004036559A1 (en) * | 2002-10-15 | 2004-04-29 | Matsushita Electric Industrial Co., Ltd. | Multi-layer information medium, reproduction method and reproduction device thereof |
US7116631B2 (en) | 1995-04-07 | 2006-10-03 | Matsushita Electric Industrial Co., Ltd. | Optical information recording medium manfacturing method therefor, manufacturing apparatus therefor, and optical information recording and reproducing apparatus |
CN1314024C (en) * | 2001-06-04 | 2007-05-02 | 松下电器产业株式会社 | Optical pickup head and information recording/ reproducing apparatus |
JP2009070557A (en) * | 2008-11-17 | 2009-04-02 | Panasonic Corp | Optical pickup head device and optical information device |
-
1993
- 1993-11-22 JP JP5291567A patent/JPH0778353A/en active Pending
Cited By (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7116631B2 (en) | 1995-04-07 | 2006-10-03 | Matsushita Electric Industrial Co., Ltd. | Optical information recording medium manfacturing method therefor, manufacturing apparatus therefor, and optical information recording and reproducing apparatus |
US7136349B2 (en) | 1995-04-07 | 2006-11-14 | Matsushita Electric Industrial Co., Ltd. | Multi-layer optical information recording medium with pits or grooves |
JPH0954972A (en) * | 1995-08-15 | 1997-02-25 | Nec Corp | Optical head device |
WO2002067250A1 (en) * | 2001-02-22 | 2002-08-29 | Matsushita Electric Industrial Co., Ltd. | Optical disk unit |
US7158452B2 (en) | 2001-02-22 | 2007-01-02 | Matsushita Electric Industrial Co., Ltd. | Focus control for optical disk unit |
CN1314024C (en) * | 2001-06-04 | 2007-05-02 | 松下电器产业株式会社 | Optical pickup head and information recording/ reproducing apparatus |
WO2004036559A1 (en) * | 2002-10-15 | 2004-04-29 | Matsushita Electric Industrial Co., Ltd. | Multi-layer information medium, reproduction method and reproduction device thereof |
WO2004036569A1 (en) * | 2002-10-16 | 2004-04-29 | Matsushita Electric Industrial Co., Ltd. | Information recording medium, process for producing the same and optical information recording and reproducing device |
JP2009070557A (en) * | 2008-11-17 | 2009-04-02 | Panasonic Corp | Optical pickup head device and optical information device |
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