JPS631653B2 - - Google Patents
Info
- Publication number
- JPS631653B2 JPS631653B2 JP55067632A JP6763280A JPS631653B2 JP S631653 B2 JPS631653 B2 JP S631653B2 JP 55067632 A JP55067632 A JP 55067632A JP 6763280 A JP6763280 A JP 6763280A JP S631653 B2 JPS631653 B2 JP S631653B2
- Authority
- JP
- Japan
- Prior art keywords
- track
- information
- signal
- tracking
- pit
- 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
Links
- 238000002834 transmittance Methods 0.000 claims description 9
- 230000003287 optical effect Effects 0.000 claims description 8
- 238000010586 diagram Methods 0.000 description 11
- 238000000034 method Methods 0.000 description 11
- 238000001228 spectrum Methods 0.000 description 7
- 230000001678 irradiating effect Effects 0.000 description 2
- 101150054854 POU1F1 gene Proteins 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000000737 periodic effect Effects 0.000 description 1
Classifications
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/08—Disposition or mounting of heads or light sources relatively to record carriers
- G11B7/09—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following
- G11B7/0938—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following servo format, e.g. guide tracks, pilot signals
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/007—Arrangement of the information on the record carrier, e.g. form of tracks, actual track shape, e.g. wobbled, or cross-section, e.g. v-shaped; Sequential information structures, e.g. sectoring or header formats within a track
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/08—Disposition or mounting of heads or light sources relatively to record carriers
- G11B7/09—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following
- G11B7/0901—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following for track following only
- G11B7/0904—Dithered tracking systems
Landscapes
- Optical Record Carriers And Manufacture Thereof (AREA)
- Optical Recording Or Reproduction (AREA)
Description
【発明の詳細な説明】
本発明は、記録媒体上に記録された信号を、光
スポツトを照射することにより再生する光学的再
生方式に使用される記録担体に関するもので、再
生時に光スポツトが記録軌跡に沿つて、正確に追
従走査できるよう構成したものである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a record carrier used in an optical reproduction method in which a signal recorded on a recording medium is reproduced by irradiating a light spot. It is configured to allow accurate follow-up scanning along the locus.
微少な光スポツトを、情報担体上の微小な情報
ピツト上に照射し、情報を読み出す方式の一つの
問題は、記録軌跡を光スポツトを記録軌跡に正確
に追従せしめるいわゆるトラツキングサーボ制御
が必要なことのある。かかるトラツキングが不正
確であると、隣接するトラツクとのクロストーク
が発生する為に再生信号のＳ／Ｎ比の劣化をきた
す。又情報ピツトが完全な矩型ではなく一般的に
は情報ピツトの長さ方向にトラツクの中心から離
れるに従つて短くなつている為に、トラツキング
が不正確となると情報ピツトの長さが変つたよう
に読み出されて信号のビート成分が増加したりす
る。かかるトラツキングの許容値はおよそ±（0.1
〜0.15）μｍである。 One problem with the method of reading out information by irradiating a minute light spot onto a minute information pit on an information carrier is that so-called tracking servo control is required to make the light spot accurately follow the recording trajectory. It happens. If such tracking is inaccurate, crosstalk with adjacent tracks occurs, resulting in deterioration of the S/N ratio of the reproduced signal. Also, since the information pit is not perfectly rectangular and generally becomes shorter as it moves away from the center of the track in the length direction of the information pit, the length of the information pit will change if tracking becomes inaccurate. The beat component of the signal increases as the signal is read out. The tolerance for such tracking is approximately ±(0.1
~0.15) μm.
従来、このトラツキング制御方式として種々の
ものが考案されている。この内の１つの有力な方
式として、光ビームに微小な角度変化を与え、情
報担体上で光スポツトを情報ピツトが構成するト
ラツクに対して周期的な蛇行運動（ウオブリン
グ）をさせる方法がある。以下この方法を光ビー
ムウオブリングと呼ぶ。第１図は光ビームウオブ
リングを行なう概念図である。光ビーム５はオシ
レーター１０で発振する周波数で微小角度変化を
与えるミラー（ウオブラー）９に入射して、中間
レンズ３、対物レンズ２を透過して情報担体１上
に入射する。この時、光ビームスポツト６′は約
±0.1μｍ程度のウオブリングを行なうように前記
ミラー９を含む光学系は調整されている。情報担
体１で反射された光は半透過ミラー８で反射され
フオトデテクター１２に入射後、帯域フイルター
１１でウオブリングされた周波数をぬきだす。ぬ
きだされた信号とオシレーター１０よりの信号を
乗算器１３に入れるとトラツキング信号が得られ
る。この装置については特公昭54−15727号に詳
述してあるので具体的な構成については省略す
る。この方式の欠点は、相当高い周波数で光ビー
ムをウオブリングする装置が必要で、その周波数
を一定にするのが困難な事である。別の公知例と
して情報担体上に記録してある情報トラツクをあ
らかじめ蛇行（トラツクウオブリング）させてお
く方法がある。第２図にトラツク１６と光ビーム
スポツト１４の関係を示す。トラツク１６の蛇行
は±0.1μｍ程度であり、情報ピツト幅は0.4μｍ光
ビームスポツトはおよそ1μｍ程度であり、図面
上は誇張して図示されている。光ビームスポツト
１４の中心が第２図で示すトラツク１６のウオブ
リングの中心ａと一致している場合には第４図ａ
のようなエンベロープの再生信号となる。光ビー
ムスポツト１４の中心が第２図で示すｂまたはｃ
にある場合には情報信号出力のエンベロープは第
３図ｂ，ｃのように互に逆相出力となる。かかる
信号を基準となるウオブリング周波数の信号と乗
算してやるとトラツキング信号を得る事ができ
る。かかる装置の原理及び動作については特開昭
54−61730号あるいは特開昭50−68413号に詳述し
てある。 Conventionally, various tracking control methods have been devised. One of the most promising methods is to give a light beam a minute change in angle and cause the light spot on the information carrier to make a periodic meandering motion (wobbling) relative to the track formed by the information pit. Hereinafter, this method will be referred to as light beam wobbling. FIG. 1 is a conceptual diagram of light beam wobbling. The light beam 5 is incident on a mirror (wobbler) 9 that gives a minute angle change at a frequency oscillated by an oscillator 10, passes through an intermediate lens 3 and an objective lens 2, and is incident on the information carrier 1. At this time, the optical system including the mirror 9 is adjusted so that the light beam spot 6' wobbles by approximately ±0.1 μm. The light reflected by the information carrier 1 is reflected by the semi-transmissive mirror 8 and enters the photodetector 12, after which the wobbled frequency is extracted by the bandpass filter 11. A tracking signal is obtained by inputting the extracted signal and the signal from the oscillator 10 into a multiplier 13. This device is described in detail in Japanese Patent Publication No. 54-15727, so the detailed structure will be omitted. The disadvantage of this method is that it requires a device that wobbles the light beam at a fairly high frequency, and it is difficult to keep the frequency constant. Another known example is a method in which an information track recorded on an information carrier is made to meander in advance. FIG. 2 shows the relationship between the track 16 and the light beam spot 14. The meandering of the track 16 is approximately ±0.1 .mu.m, the width of the information pit is 0.4 .mu.m, and the width of the light beam spot is approximately 1 .mu.m, which are exaggerated in the drawing. If the center of the light beam spot 14 coincides with the wobbling center a of the track 16 shown in FIG.
The result is an envelope playback signal like this. The center of the light beam spot 14 is at b or c shown in FIG.
In this case, the envelopes of the information signal outputs are out of phase with each other as shown in FIG. 3b and c. A tracking signal can be obtained by multiplying this signal by a reference wobbling frequency signal. The principle and operation of such a device are described in Japanese Patent Application Laid-open No.
It is detailed in No. 54-61730 or Japanese Patent Application Laid-open No. 50-68413.
従来行なわれたトラツクウオブリングの方法の
欠点として情報信号出力のエンベロープが第３図
に示すごとく非対称なAM変調を受ける。このよ
うな場合には、情報出力信号内にウオブリング周
波数のスペクトラムと、情報ピツト周波数による
AM変調成分のスペクトラムの両方を含むので情
報ピツトの再生信号のＳ／Ｎ比が低下する。 A disadvantage of the conventional track wobbling method is that the envelope of the information signal output is subjected to asymmetric AM modulation as shown in FIG. In such a case, the spectrum of the wobbling frequency and the spectrum of the information pit frequency are included in the information output signal.
Since it includes both the spectrum of the AM modulation component, the S/N ratio of the reproduced signal of the information pit is lowered.
本発明は上記で述べられた欠点を除き、情報信
号出力のエンベロープを対称形のAM変調とす
る。このようにする事によりウオブリング周波数
のスペクトラムと、情報ピツト周波数のスペクト
ラムの加算として再生情報信号が得られるので、
ウオブリング周波数のスペクトラムと、情報ピツ
ト周波数のスペクトラムを単なる帯域フイルター
で分離すると、情報ピツトの再生信号のＳ／Ｎが
劣化する事はない。 The present invention eliminates the drawbacks mentioned above and provides a symmetrical AM modulation of the envelope of the information signal output. By doing this, the reproduced information signal can be obtained as the addition of the spectrum of the wobbling frequency and the spectrum of the information pit frequency.
If the spectrum of the wobbling frequency and the spectrum of the information pit frequency are separated by a simple bandpass filter, the S/N of the reproduced signal of the information pit will not deteriorate.
以下図に基づいて本発明の原理を説明する。第
４図は本発明に基づいた情報信号の記録状態を示
す概略図である。情報ピツト１８は、一定のトラ
ツク２０上に配置されている。この情報ピツト１
８は、情報ピツト１８のない部分に対し、光学的
な位相差を有する。情報ピツト１８の形成するト
ラツク２０に対し一定の周波数で蛇行するトラツ
キング用のトラツク１７は、トラツク２０に対し
振幅が0.1μｍ以上で、かつ、トラツク２０のトラ
ツクピツチの半分以下である。トラツキング用ト
ラツク１７の幅はトラツク２０のトラツクピツチ
の半分以下からなる。トラツキング用トラツク１
７は、他の部分に比べ反射率又は透過率が異つて
いる。このような記録担体より光ビームスポツト
１９で公知の手段により再生された情報出力信号
は、第５図に示すようになる。第５図に於て、高
周波成分は情報ピツト１８による回折で検出され
たものであり、低周波成分は主としてトラツキン
グ用トラツク１７による反射率又は透過率の差と
して検出された信号である。光ビームスポツト１
９とトラツキング用トラツク１７の関係は重要な
パラメーターとなる。即ちトラツキング用トラツ
ク１７が光ビームスポツト１９の直径よりも細い
場合には、トラツキング用トラツク１７による変
調が、反射率又は透過率の差によるもの以外にト
ラツキング用トラツク１７による回折の項が無視
できなくなる。従つてトラツキング用トラツク１
７の幅は、できるだけ幅広い方が情報出力信号の
対称性を良くする。 The principle of the present invention will be explained below based on the figures. FIG. 4 is a schematic diagram showing the recording state of an information signal based on the present invention. The information pits 18 are arranged on a certain track 20. This information pit 1
8 has an optical phase difference with respect to the portion without the information pit 18. The tracking track 17 that meanders at a constant frequency with respect to the track 20 formed by the information pit 18 has an amplitude of 0.1 μm or more and less than half the track pitch of the track 20. The width of the tracking track 17 is less than half the track pitch of the track 20. Tracking track 1
7 has a different reflectance or transmittance compared to other parts. The information output signal reproduced from such a record carrier by the light beam spot 19 by known means is as shown in FIG. In FIG. 5, the high frequency component is detected by diffraction by the information pit 18, and the low frequency component is a signal detected mainly as a difference in reflectance or transmittance by the tracking track 17. Light beam spot 1
9 and the tracking track 17 is an important parameter. That is, when the tracking track 17 is thinner than the diameter of the light beam spot 19, the modulation by the tracking track 17 is due to the difference in reflectance or transmittance, and the term of diffraction by the tracking track 17 cannot be ignored. . Therefore, tracking track 1
The wider the width of 7, the better the symmetry of the information output signal.
第６図は、本発明に基づく第２の方法を示す概
略図である。情報ピツト２３は、一定のトラツク
２４上に配置されている。この情報ピツト２３
は、情報ピツト２３のない部分に対し、反射率又
は透過率が異つている。トラツキング用トラツク
２２は、情報ピツトの形成するトラツク２４に対
し一定の周波数で蛇行している。トラツキング用
トラツク２２は、トラツク２４に対し振幅が0.1μ
ｍ以上でかつトラツク２４のトラツクピツチの半
分以下である。トラツキング用トラツク２２の幅
は、トラツク２４のトラツクピツチの半分以下か
らなる。また、トラツキング用トラツク２２は、
他の部分に対し、光学的な位相差を有している。
光ビームスポツト２１で、公知の手段により再生
される情報信号出力は第７図に示すようになる。
第７図に於て、高周波成分は情報ピツトにより主
として反射率又は透過率の差として検出されたも
のであり、低周波成分はトラツキング用トラツク
により光の回折により検出されたものである。 FIG. 6 is a schematic diagram illustrating a second method according to the invention. The information pits 23 are arranged on a certain track 24. This information pit 23
The reflectance or transmittance is different from the part without the information pit 23. The tracking track 22 meanders at a constant frequency with respect to the track 24 formed by the information pit. The tracking track 22 has an amplitude of 0.1μ with respect to the track 24.
m or more and less than half the track pitch of the track 24. The width of the tracking track 22 is less than half the track pitch of the track 24. In addition, the tracking track 22 is
It has an optical phase difference with respect to other parts.
The information signal output reproduced by the known means at the light beam spot 21 is as shown in FIG.
In FIG. 7, the high frequency component is detected mainly as a difference in reflectance or transmittance by the information pit, and the low frequency component is detected by the diffraction of light by the tracking track.
本発明の第２の方法によると光ビームスポツト
２１の大きさと情報信号ピツト２３の大きさが同
程度の寸法となる場合が多く、従つて情報信号ピ
ツトの回折効果が無視できなくなつてくる。この
場合、本発明による第１の方法よりも情報ピツト
の再生信号のＳ／Ｎは劣化する事が予想される
が、かかる場合に於ても従来のトラツクウオブリ
ングによる方法よりもＳ／Ｎ比の良好なものを得
る事ができる。 According to the second method of the present invention, the size of the light beam spot 21 and the size of the information signal pit 23 are often about the same size, so that the diffraction effect of the information signal pit cannot be ignored. In this case, it is expected that the S/N of the reproduced signal from the information pit will be worse than in the first method according to the present invention, but even in such a case, the S/N ratio will be lower than in the conventional method using track wobbling. You can get a good one.
第１図は従来のビームウオブリング方式の光学
系を示すブロツク図、第２図は従来公知であるト
ラツクウオブリングの信号ピツトの配置を示す
図、第３図は従来のトラツクウオブリングによる
情報出力信号の様子を示す図、第４図は本発明に
よる光学的位相差を有する情報信号ピツトと反射
率又は透過率の異るトラツキング用トラツクの配
置を示す図、第５図は、本発明による情報出力信
号の波形を示す図、第６図は本発明の他の実施例
による、反射率又は透過率の異る情報ピツトと光
学的位相差を有するトラツキング用トラツクの配
置を示す図、第７図は本発明の他の実施例による
情報出力信号の波形を示す図である。
１７，２２……トラツキング用トラツク、１
８，２３……信号ピツト、１９，２１……光スポ
ツト、２０，２４……信号トラツク。
Fig. 1 is a block diagram showing a conventional beam wobbling optical system, Fig. 2 is a diagram showing the arrangement of signal pits of a conventionally known track wobbling system, and Fig. 3 is a diagram showing information output by a conventional track wobbling system. FIG. 4 is a diagram showing the arrangement of information signal pits having an optical phase difference according to the present invention and tracking tracks having different reflectances or transmittances; FIG. 5 is a diagram showing the information signal pit according to the present invention. FIG. 6 is a diagram showing the waveform of the output signal, and FIG. 7 is a diagram showing the arrangement of information pits having different reflectances or transmittances and tracking tracks having an optical phase difference according to another embodiment of the present invention. FIG. 6 is a diagram showing a waveform of an information output signal according to another embodiment of the present invention. 17, 22...tracking track, 1
8, 23... Signal pit, 19, 21... Light spot, 20, 24... Signal track.
Claims (1)
ようトラツキング用トラツクを設け、前記情報ト
ラツクとトラツキング用トラツクをその一方のト
ラツクが光の反射率または透過率の変化として検
出される時、他方のトラツクは主として光の回折
により検出されるよう構成したことを特徴とする
光学的情報記録担体。1. A tracking track is provided to meander periodically with respect to the information signal track, and when one track is detected as a change in light reflectance or transmittance, the other track is detected as a change in light reflectance or transmittance. An optical information recording carrier characterized in that it is configured to be detected mainly by diffraction of light.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6763280A JPS56163534A (en) | 1980-05-20 | 1980-05-20 | Optical information recording carrier |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6763280A JPS56163534A (en) | 1980-05-20 | 1980-05-20 | Optical information recording carrier |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS56163534A JPS56163534A (en) | 1981-12-16 |
| JPS631653B2 true JPS631653B2 (en) | 1988-01-13 |
Family
ID=13350547
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP6763280A Granted JPS56163534A (en) | 1980-05-20 | 1980-05-20 | Optical information recording carrier |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS56163534A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0283048U (en) * | 1988-12-12 | 1990-06-27 | ||
| JPH0543882Y2 (en) * | 1988-11-02 | 1993-11-05 |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5297125A (en) * | 1989-08-25 | 1994-03-22 | Sony Corporation | Optical recording medium and information recording apparatus for recording bursts of low-pass filtered reproduce-only information in a wobbling pre-groove on the optical recording medium |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS54130102A (en) * | 1978-03-16 | 1979-10-09 | Philips Nv | Method of writing information* recording carrier* recorded record carrier* and information writing and reading device |
-
1980
- 1980-05-20 JP JP6763280A patent/JPS56163534A/en active Granted
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS54130102A (en) * | 1978-03-16 | 1979-10-09 | Philips Nv | Method of writing information* recording carrier* recorded record carrier* and information writing and reading device |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0543882Y2 (en) * | 1988-11-02 | 1993-11-05 | ||
| JPH0283048U (en) * | 1988-12-12 | 1990-06-27 |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS56163534A (en) | 1981-12-16 |
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