JPS61184742A - Light quantity controller of optical information recording and reproducing device - Google Patents
Light quantity controller of optical information recording and reproducing deviceInfo
- Publication number
- JPS61184742A JPS61184742A JP60025953A JP2595385A JPS61184742A JP S61184742 A JPS61184742 A JP S61184742A JP 60025953 A JP60025953 A JP 60025953A JP 2595385 A JP2595385 A JP 2595385A JP S61184742 A JPS61184742 A JP S61184742A
- Authority
- JP
- Japan
- Prior art keywords
- medium
- light
- circuit
- output
- sensitivity
- 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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Abstract
Description
【発明の詳細な説明】
技術分野
本発明は、光学式情報記録再生装置の光量制御装置に関
し、特に記録時における光源の出射光量を制御する光量
制御装置に関する。TECHNICAL FIELD The present invention relates to a light amount control device for an optical information recording/reproducing device, and more particularly to a light amount control device for controlling the amount of light emitted from a light source during recording.
従来技術
光学式情報記録再生装置においては、再生時及び記録時
に、光源である例えばレーザーダイオードの出射光量が
あらかじめ定められた光量となるように、光量制御装置
により制御されている。In a conventional optical information recording/reproducing device, a light amount control device controls the amount of light emitted from a light source, such as a laser diode, at a predetermined amount during reproduction and recording.
第３図は一定のパワーで記録したときの媒体反射率と再
生信号振幅、第４図は記録パワーと再生信号振幅との関
係をそれぞれ示したものであシ、第５図は記録パワーの
差によるピット形状のでき方を示す図である。ここでは
ピット形成によって情報再生時に反射光量が増大するよ
うな媒体を例にとって説明する。第３図において媒体反
射率と再生信号振幅との関係は反射率の増加にともない
再生時の振幅が低下しているが、これは媒体感度が低下
していることによるものである。第４図において媒体感
度がａとｂの様に異なる場合を考えルト、記録パワーＩ
ｐｔで記録した場合、媒体感度の差により再生時の信号
振幅が異なり感度が高いほど振幅が大きくなることがわ
かる。これは形成されたピットがｂの側ではａに比べ小
さい為反射光ｉが少ないことによるものである。記録時
のピットの大きさはレーザーの波長と対物レンズのＮＡ
（開口数）で決まり約０．８〜１μｍであるが媒体感度
のバラツキにより、媒体感度が低いと振幅が小さくなる
と共にＣ／′Ｎが低下し、媒体感度が高いと振幅が大き
くなると共に大きなピットが形成されるためにクロスト
ークが増大するなど信号再生時の信号品質を低下させる
要因となっている。Figure 3 shows the relationship between the medium reflectance and the reproduced signal amplitude when recording with a constant power, Figure 4 shows the relationship between the recording power and the reproduced signal amplitude, and Figure 5 shows the difference in recording power. It is a figure showing how a pit shape is formed by Here, explanation will be given by taking as an example a medium in which the amount of reflected light increases during information reproduction due to the formation of pits. In FIG. 3, the relationship between the medium reflectance and the reproduced signal amplitude shows that the amplitude during reproduction decreases as the reflectance increases, but this is due to the decrease in medium sensitivity. In Fig. 4, consider the case where the medium sensitivity is different as shown in a and b.
It can be seen that when recording in pt, the signal amplitude during reproduction differs depending on the difference in medium sensitivity, and the higher the sensitivity, the larger the amplitude. This is because the formed pits are smaller on the b side than on the a side, so that the amount of reflected light i is smaller. The size of the pit during recording depends on the wavelength of the laser and the NA of the objective lens.
(numerical aperture), but due to variations in medium sensitivity, when medium sensitivity is low, the amplitude becomes small and C/'N decreases, and when medium sensitivity is high, the amplitude becomes large and C/'N decreases. The formation of pits increases crosstalk, which is a factor that degrades signal quality during signal reproduction.
一方、９Ｎを改善し信号振幅の確保を考えると、媒体感
度のバラツキによる信号振幅のバラツキを少なく抑える
為に、第４図において、記録パワーをＩｐ＋よりも工Ｐ
２に設定すれば、媒体感度のバラツキに対して再生時の
信号振幅のバラツキを抑えることができるが、第５図に
示すように、工Ｐｌでは（ａ）のようになっていたピッ
トがＩＰ！では（ｂ）のように大きくなるので、ピット
間がつまシ分解能が低下し、クロストークも増えること
からトラックピッチ及びピット間隔を広げる必要が有り
、記録密度が減少する。以上の事から、記録容量を確保
するために、媒体感度のバラツキを抑えてやる必要があ
り、媒体製造時の歩留まりを低下させる要因となってい
た。On the other hand, when considering improving 9N and ensuring signal amplitude, in order to minimize the variation in signal amplitude due to variation in medium sensitivity, in Fig. 4, the recording power is set to
If set to 2, it is possible to suppress variations in signal amplitude during reproduction due to variations in medium sensitivity, but as shown in Fig. 5, the pits as shown in (a) in IP ! In this case, since the size becomes large as shown in (b), the resolution between pits decreases and crosstalk increases, so it is necessary to widen the track pitch and pit interval, and the recording density decreases. From the above, in order to secure the recording capacity, it is necessary to suppress variations in medium sensitivity, which has been a factor in reducing yield during medium manufacturing.
先述した従来の光量制御装置においては、あらかじめ定
められた記録パワーになるように出射光量が制御されて
いたので、媒体感度にバラツキがあると記録時に安定し
たピット形状が得られず、ピットが小さくなることによ
る９Ｎの低下、ピットが大きくなることによるクロスト
ークの増大及び分解能の低下等の悪影響があるために、
信号品質を確保するために媒体感度の許容範囲が広くと
れないという欠点があった。In the conventional light amount control device mentioned above, the amount of emitted light is controlled to achieve a predetermined recording power, so if there are variations in media sensitivity, a stable pit shape cannot be obtained during recording, resulting in small pits. There are negative effects such as a decrease in 9N due to the increase in the size of the pit, an increase in crosstalk due to the increase in the size of the pit, and a decrease in resolution.
The drawback is that a wide tolerance range for medium sensitivity cannot be achieved in order to ensure signal quality.
発明の目的
本発明は、上述した従来のものの欠点を除去すべくなさ
れたもので、媒体感度のバラツキに対しても安定なピッ
トサイズを得ることによ’）、”／’Ｈの向上、クロス
トークの低減及び分解能の向上を可能とした光量制御装
置を提供することを目的とする。OBJECTS OF THE INVENTION The present invention has been made to eliminate the above-mentioned drawbacks of the conventional ones, and by obtaining a stable pit size even with variations in medium sensitivity, it is possible to improve An object of the present invention is to provide a light amount control device that can reduce talk and improve resolution.
発明の構成
本発明による光量制御装置は、記録媒体の記録面を経た
光を受光しその光量に応じた出力を発生する光検出器と
、あらかじめ設定された値を記憶しておきその記憶値の
中から上記光検出器の出力に応じた値の出力を発生する
記憶回路とを備え、この記憶回路の出力に応じて光源の
出射光量を制御することを特徴としている。Structure of the Invention The light amount control device according to the present invention includes a photodetector that receives light that has passed through the recording surface of a recording medium and generates an output according to the amount of light, and a photodetector that stores a preset value and stores the stored value. It is characterized in that it includes a memory circuit that generates an output of a value corresponding to the output of the photodetector, and controls the amount of light emitted from the light source in accordance with the output of the memory circuit.
実施例 以下、本発明について図面を参照して説明する。Example Hereinafter, the present invention will be explained with reference to the drawings.
第１図は本発明の一実施例の構成図である。媒体１から
の反射光ｌＯは対物レンズ２．ビームスプリッタ３、を
経て光検出器５に入射される。光検出器５からは、入射
光量に応じた信号が出力され、この出力信号は前置増幅
回路６によシ増幅され、〜も二ンバータフによりアナロ
グ−ディジタル変換される。〜勺コンバータ７でディジ
タル化された信号はＲＯＭ等を用いた記憶回路８に入力
される。記憶回路８には、媒体反射率と媒体感度に対す
る同一サイズのピット形成の為のレーザーパワー強度値
があらかじめ記憶されており、当該記憶回路８は入力信
号に応じた値のパワー強度値を出力する。光ビーム駆動
回路９は記憶回路８の出力に応じた光ビームパワーとな
るようにレーザー光源９を駆動する。FIG. 1 is a block diagram of an embodiment of the present invention. The reflected light lO from the medium 1 is reflected by the objective lens 2. The beam passes through a beam splitter 3 and enters a photodetector 5. A signal corresponding to the amount of incident light is output from the photodetector 5, and this output signal is amplified by a preamplifier circuit 6, and analog-digital converted by a two-inverter. The signal digitized by the digital converter 7 is input to a storage circuit 8 using a ROM or the like. The storage circuit 8 stores in advance laser power intensity values for forming pits of the same size for medium reflectance and medium sensitivity, and the storage circuit 8 outputs a power intensity value corresponding to an input signal. . The light beam drive circuit 9 drives the laser light source 9 so that the light beam power corresponds to the output of the memory circuit 8.
ここで記憶回路８はＲＯＭ等の記憶素子により構成され
るが、当該記憶回路８にあらかじめ記憶させる値は次の
様にして決定される。Here, the memory circuit 8 is constituted by a memory element such as a ROM, and the values to be stored in advance in the memory circuit 8 are determined as follows.
まず媒体１で反射した光はビームスプリッタによシ媒体
からの反射光のみを通過させるから媒体反射率に応じた
光量のみ光検出器５に入射され、このときの光検出器５
の出力信号は媒体反射率に比例した値を示す。媒体反射
率と記録情報による再生時の信号振幅は第３図に示した
ように媒体反射率の増加に従い再生時の信号振幅が減少
する。First, the light reflected by the medium 1 passes through the beam splitter, so that only the amount of light corresponding to the medium reflectance is incident on the photodetector 5.
The output signal of represents a value proportional to the medium reflectance. As shown in FIG. 3, the signal amplitude during reproduction due to medium reflectance and recorded information decreases as the medium reflectance increases.
これは媒体感度が媒体反射率の増加に対して減少する傾
向があるために、形成されるピットサイズが小さくなる
ことによるものである。従って媒体の反射率が変化して
も０．８〜１．０μｍのピットを形成できる様にするに
はあらかじめ媒体反射率と媒体感度の関係及び、媒体感
度と形成されるピットサイズを０．８〜１．０ｔｔｒｎ
とする記録パワーとの関係を求めておけば、媒体反射率
を測定することにより記録時の最適パワーの値を求める
ことができることになる。この時の媒体反射率と記録・
くワーとの関係は第２図に示すようになる。This is because the medium sensitivity tends to decrease as the medium reflectance increases, resulting in a smaller pit size. Therefore, in order to be able to form pits of 0.8 to 1.0 μm even if the reflectance of the medium changes, the relationship between the medium reflectance and the medium sensitivity, and the medium sensitivity and the pit size to be formed should be determined in advance by 0.8 μm. ~1.0ttrn
By determining the relationship between the recording power and the recording power, the optimum power value for recording can be determined by measuring the medium reflectance. Medium reflectance and recording at this time
Figure 2 shows the relationship between the
そこで、上記のようにして求めた媒体反射率に対する記
録パワーの設定値をＲＯＭ等の記憶素子にあらかじめ記
憶させておけば、媒体感度の変化に対しても常に安定し
たピットサイズを得ることができる。Therefore, if the setting value of the recording power for the medium reflectance determined as described above is stored in advance in a storage element such as a ROM, it is possible to always obtain a stable pit size even when the medium sensitivity changes. .
このようにして、常に安定したビットサイズが得られる
ので、媒体感度のバラツキによシ発生する、ピットサイ
ズの増大による分解能の低下やクロストークの増加及び
、ピットサイズが小さくなったために起こるす公比の減
少等が改善されると共に、ピットサイズのバラツキが少
なくなるので、分解能やクロストークを確保するために
大きくとっていたトラックピッチやピット間隔をせまく
することができることになり、記憶容量を増やすことが
できる。又、媒体感度に対する許容範囲を広げることが
できるので媒体の歩留まりも向上する。In this way, a stable bit size can be obtained at all times, which prevents resolution degradation and crosstalk caused by increased pit size due to variations in media sensitivity, as well as problems caused by smaller pit sizes. This improves the ratio reduction and reduces the variation in pit size, which means that the track pitch and pit spacing, which used to be large to ensure resolution and crosstalk, can be narrowed, increasing storage capacity. be able to. Furthermore, since the allowable range for medium sensitivity can be widened, the yield of the medium can also be improved.
本実施例では、ピットが形成された場合反射光量が増大
するような媒体にて説明したが、ピットの形成により反
射光量が減少するような媒体についても適用することが
できる。又、記憶回路部においてＲＯＭ等の記憶素子を
用いて説明したがマイクロプロセッサ等の処理装置によ
り Ａ／ｂコンバータ７の出力に応じた光ビーム駆動回
路９に対する設定値を出力させてもよい。Although this embodiment has been described using a medium in which the amount of reflected light increases when pits are formed, the present invention can also be applied to a medium in which the amount of reflected light decreases due to the formation of pits. Further, although the description has been made using a storage element such as a ROM in the storage circuit section, a processing device such as a microprocessor may output a setting value for the light beam drive circuit 9 according to the output of the A/b converter 7.
発明の詳細
な説明したように本発明は、媒体反射率と媒体感度に対
する同一サイズのピット形成の為のレーザーパワー強度
値をあらかじめ記憶させておき、光ディスクからの反射
光量に応じて媒体に対する最適パワー値を求めかつレー
ザー光源を駆動することにより、媒体感度のバラツキに
対しても安定なビットサイズが得られるため、’、ｙ
、分解能。DETAILED DESCRIPTION OF THE INVENTION As described above, in the present invention, laser power intensity values for forming pits of the same size for medium reflectance and medium sensitivity are stored in advance, and the optimum power for the medium is determined according to the amount of reflected light from the optical disk. By calculating the value and driving the laser light source, a stable bit size can be obtained even with variations in media sensitivity, so ', y
,resolution.
クロストークの変動を抑さえることができる効果がある
。This has the effect of suppressing crosstalk fluctuations.
第１図は本発明の情報記録可成装置の一実施例を示すブ
ロック図、第２図は媒体反射率と記録・くワーを示す図
、第３図は記録パワーを一定としたときの媒体反射率と
信号振幅の関係を示す図、第４図は記録パワーと信号振
幅との関係を示す図、第５図は形成されたピットを表わ
す図である。
主要部分の符号の説明
１・・・記録媒体 ２・・・対物レンズ３・・
・ビームスプリッタ ４・・・レーザー光源５・・・光
検出器 ７・・・〜勺コン・く−タ８・・・記
憶回路
９・・・光ビーム駆動回路Fig. 1 is a block diagram showing an embodiment of the information recording device of the present invention, Fig. 2 is a diagram showing the medium reflectance and the recording head, and Fig. 3 is a diagram showing the medium when the recording power is constant. FIG. 4 is a diagram showing the relationship between reflectance and signal amplitude, FIG. 4 is a diagram showing the relationship between recording power and signal amplitude, and FIG. 5 is a diagram showing formed pits. Explanation of symbols of main parts 1... Recording medium 2... Objective lens 3...
・Beam splitter 4...Laser light source 5...Photodetector 7...~Content converter 8...Memory circuit 9...Light beam drive circuit
Claims (1)
る光ビームの光量を制御する光学式情報記録再生装置の
光量制御装置であつて、前記記録媒体の記録面を経た光
を受光しその光量に応じた出力を発生する光検出器と、
あらかじめ設定された値を記憶しておきその記憶値の中
から前記光検出器の出力に応じた値の出力を発生する記
憶回路とを備え、前記記憶回路の出力に応じて前記光源
の出射光量を制御することを特徴とする光量制御装置。A light amount control device for an optical information recording/reproducing device that controls the amount of light beam emitted from a light source toward a recording surface of a disk-shaped recording medium, the device receiving light that has passed through the recording surface of the recording medium and controlling the amount of light. a photodetector that generates an output according to the
and a storage circuit that stores preset values and generates an output of a value corresponding to the output of the photodetector from among the stored values, and adjusts the amount of light emitted from the light source according to the output of the storage circuit. A light amount control device characterized by controlling.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60025953A JPS61184742A (en) | 1985-02-13 | 1985-02-13 | Light quantity controller of optical information recording and reproducing device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60025953A JPS61184742A (en) | 1985-02-13 | 1985-02-13 | Light quantity controller of optical information recording and reproducing device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS61184742A true JPS61184742A (en) | 1986-08-18 |
Family
ID=12180120
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP60025953A Pending JPS61184742A (en) | 1985-02-13 | 1985-02-13 | Light quantity controller of optical information recording and reproducing device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS61184742A (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0482027A (en) * | 1990-07-24 | 1992-03-16 | Kenwood Corp | Laser driving circuit for optical disk recording and reproducing device |
| JPH04258820A (en) * | 1991-02-13 | 1992-09-14 | Olympus Optical Co Ltd | Optical recording and reproducing device |
| US5231625A (en) * | 1990-09-27 | 1993-07-27 | International Business Machines Corporation | Optical disk drive wherein a preset reading laser power is used to generate a desired white laser power |
| US5264692A (en) * | 1989-12-09 | 1993-11-23 | Robert Bosch Gmbh | Circuit arrangement for the operation of a light source for the optical scanning of recording media |
| JPH06215376A (en) * | 1993-01-14 | 1994-08-05 | Nec Corp | Optical disk device |
| JPH0750028A (en) * | 1992-12-25 | 1995-02-21 | Victor Co Of Japan Ltd | Optical disk device |
-
1985
- 1985-02-13 JP JP60025953A patent/JPS61184742A/en active Pending
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5264692A (en) * | 1989-12-09 | 1993-11-23 | Robert Bosch Gmbh | Circuit arrangement for the operation of a light source for the optical scanning of recording media |
| JPH0482027A (en) * | 1990-07-24 | 1992-03-16 | Kenwood Corp | Laser driving circuit for optical disk recording and reproducing device |
| JP2763663B2 (en) * | 1990-07-24 | 1998-06-11 | 株式会社ケンウッド | Laser drive circuit for optical disk recording / reproducing device |
| US5231625A (en) * | 1990-09-27 | 1993-07-27 | International Business Machines Corporation | Optical disk drive wherein a preset reading laser power is used to generate a desired white laser power |
| JPH04258820A (en) * | 1991-02-13 | 1992-09-14 | Olympus Optical Co Ltd | Optical recording and reproducing device |
| JPH0750028A (en) * | 1992-12-25 | 1995-02-21 | Victor Co Of Japan Ltd | Optical disk device |
| JPH06215376A (en) * | 1993-01-14 | 1994-08-05 | Nec Corp | Optical disk device |
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