JPH0568774B2 - - Google Patents
Info
- Publication number
- JPH0568774B2 JPH0568774B2 JP61178513A JP17851386A JPH0568774B2 JP H0568774 B2 JPH0568774 B2 JP H0568774B2 JP 61178513 A JP61178513 A JP 61178513A JP 17851386 A JP17851386 A JP 17851386A JP H0568774 B2 JPH0568774 B2 JP H0568774B2
- Authority
- JP
- Japan
- Prior art keywords
- objective lens
- photodetector
- optical information
- light
- detection device
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 238000001514 detection method Methods 0.000 claims description 24
- 230000003287 optical effect Effects 0.000 claims description 23
- 230000004075 alteration Effects 0.000 claims description 14
- 230000000694 effects Effects 0.000 claims description 2
- 230000002411 adverse Effects 0.000 claims 1
- 230000004907 flux Effects 0.000 claims 1
- 238000010586 diagram Methods 0.000 description 8
- 239000000758 substrate Substances 0.000 description 7
- 239000004065 semiconductor Substances 0.000 description 3
- 229910000808 amorphous metal alloy Inorganic materials 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 230000007246 mechanism Effects 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 229910052761 rare earth metal Inorganic materials 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 238000004544 sputter deposition Methods 0.000 description 2
- 239000010409 thin film Substances 0.000 description 2
- 229910052723 transition metal Inorganic materials 0.000 description 2
- 150000003624 transition metals Chemical class 0.000 description 2
- 238000007740 vapor deposition Methods 0.000 description 2
- 230000009471 action Effects 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 201000009310 astigmatism Diseases 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 230000007257 malfunction Effects 0.000 description 1
- 229910052706 scandium Inorganic materials 0.000 description 1
Landscapes
- Optical Head (AREA)
- Automatic Focus Adjustment (AREA)
- Optical Recording Or Reproduction (AREA)
Description
【発明の詳細な説明】
〈産業上の利用分野〉
本発明は光情報検出装置、特に円状または螺旋
状にガイドトラツクを設けた情報記録媒体を用い
て情報を記録再生するものにおいて、フオーカシ
ングエラー信号の品質の低下を防止した装置に関
するものである。DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an optical information detection device, particularly an optical information detection device that records and reproduces information using an information recording medium provided with a circular or spiral guide track. The present invention relates to a device that prevents deterioration in the quality of sing error signals.
〈従来の技術〉
従来、光情報検出装置として第２図に示すもの
があつた。同図において、１は半導体レーザ、２
はコリメーターレンズ、３はビームスプリツタ、
４は対物レンズ、５は基板、６は基板５上に設け
られた情報トラツク、６′はその両側に存在する
ガイドトラツク、７は基板５上に形成された情報
記録媒体、８は収束レンズ、９はシリンドリカル
レンズ、１０は光検出器で、ここでは田の字型に
分割された４分割光検出器である。<Prior Art> Conventionally, there has been an optical information detection device as shown in FIG. In the figure, 1 is a semiconductor laser, 2
is a collimator lens, 3 is a beam splitter,
4 is an objective lens, 5 is a substrate, 6 is an information track provided on the substrate 5, 6' is a guide track present on both sides thereof, 7 is an information recording medium formed on the substrate 5, 8 is a converging lens, 9 is a cylindrical lens, and 10 is a photodetector, which here is a four-part photodetector divided into a square shape.
次に、上記した構成の光情報検出装置の動作を
説明する。 Next, the operation of the optical information detection device having the above configuration will be explained.
半導体レーダ１より出射された光線は、コリメ
ーターレンズ２によつて平行光になされ、ビーム
スプリツタ３を通過して対物レンズ４に入射し、
情報記録媒体７上にスポツトを形成する。そし
て、この情報記録媒体７からの反射光は再び対物
レンズ４を通過し、ビームスプリツタ３で反射さ
れた後、収束レンズ８及びシリンドリカルレンズ
９を介することで非点収差を有する光線とされ、
シリンドリカルレンズ９の母線方向に対し45°傾
けた４分割光検出器１０に入射される。 The light beam emitted from the semiconductor radar 1 is made into parallel light by the collimator lens 2, passes through the beam splitter 3, and enters the objective lens 4.
A spot is formed on the information recording medium 7. Then, the reflected light from the information recording medium 7 passes through the objective lens 4 again, is reflected by the beam splitter 3, and then passes through the converging lens 8 and the cylindrical lens 9 to become a light beam having astigmatism.
The light is incident on a four-split photodetector 10 tilted at 45 degrees with respect to the generatrix direction of the cylindrical lens 9.
ここで、例えばガラス等の光透過性材料からな
る基板５上には、高密度記録再生を行うためにあ
らかじめ円状又は螺旋状に溝状のトラツク６，
６′が形成されている。さらにその上に、例えば
希土類と遷移金属とのアモルフアス合金薄膜等か
らなる情報記録媒体７が蒸着、スパツタリング等
によつて被覆されている。 Here, on the substrate 5 made of a light-transmitting material such as glass, there are in advance circular or spiral groove-shaped tracks 6,
6' is formed. Furthermore, an information recording medium 7 made of, for example, an amorphous alloy thin film of a rare earth element and a transition metal is coated thereon by vapor deposition, sputtering, or the like.
次に、このような光情報検出装置における焦点
検出の原理について説明する。第３図は従来の光
情報検出装置の焦点検出の原理を示す図である。
４分割光検出器１０の４つの受光部１０ａ，１０
ｂ，１０ｃ，１０ｄでの受光量をそれぞれSa，
Sb，Sc，Sdとする。合焦時には光検出器１０上
のビームスポツトは、同図ａ，ｂに示すように円
形となる為４つの受光部で検出される受光量Sa，
Sb，Sc，Sdは等しく、よつて（Sa＋Sc）−（Sb＋
Sd）は０である。次に対物レンズ４が情報記録
媒体７に向けて相対的に近づくと、光検出器１０
上のビームスポツトは同図ｃ，ｄに示すようにシ
リンドリカルレンズ１０の母線と平行方向b0を長
軸とする楕円となり、（Sa＋Sc）−（Sb＋Sd）は
負になる。対物レンズ４が情報記録媒体７から相
対的に遠ざかると、光検出器１０上のビームスポ
ツトは、同図ｅ，ｆに示すように、シリンドリカ
ルレンズ９の母線と直角方向a0を長軸とする楕円
となり、（Sa＋Sc）−（Sb＋Sd）は正になる。 Next, the principle of focus detection in such an optical information detection device will be explained. FIG. 3 is a diagram showing the principle of focus detection in a conventional optical information detection device.
Four light receiving sections 10a, 10 of the 4-split photodetector 10
The amount of light received at b, 10c, and 10d is Sa,
Sb, Sc, Sd. When in focus, the beam spot on the photodetector 10 becomes circular as shown in Figures a and b, so the amount of light received by the four light receiving sections Sa,
Sb, Sc, and Sd are equal, so (Sa+Sc)−(Sb+
Sd) is 0. Next, when the objective lens 4 approaches the information recording medium 7, the photodetector 10
The upper beam spot is an ellipse whose major axis is in the direction b0 parallel to the generatrix of the cylindrical lens 10, as shown in c and d of the figure, and (Sa+Sc)-(Sb+Sd) is negative. When the objective lens 4 moves relatively away from the information recording medium 7, the beam spot on the photodetector 10 has its long axis in the direction a0 perpendicular to the generatrix of the cylindrical lens 9, as shown in e and f of the figure. It becomes an ellipse, and (Sa + Sc) - (Sb + Sd) is positive.
以上の様にフオーカシングエラー信号としては
（Sa＋Sc）−（Sb＋Sd）を演算した結果を用いれ
ばよい。 As described above, the result of calculating (Sa+Sc)-(Sb+Sd) may be used as the focusing error signal.
〈発明が解決しようとする問題点〉
ここで、上記第３図ａ，ｂに示した合焦時にお
いて、トラツクずれのためにガイドトラツク６′
による回析で光検出器１０上に投影されるビーム
スポツトに生じる回析パターンの変化のために誤
つて発生するフオーカシングエラー信号（以下、
クロストロークと呼ぶ）がフオーカシングエラー
検出に及ぼす影響を検討する。まず、対物レンズ
４が収差を持たない理想的な場合を考える。第４
図に示すように、光検出器１０をＸ方向がトラツ
ク方向、Ｙ方向がトラツクに垂直な方向になるよ
うに配置し、情報トラツク６にビームスポツト１
１を照射して、その反射光を光検出器１０で受光
する。この時、第４図にそれぞれ示す情報トラツ
ク６とビームスポツト１１との位置関係｛第４図
ａ，ｂはビームスポツト１１が下にずれている状
態、第４図ｃ，ｄはずれがない状態、第４図ｅ，
ｆはビームスポツト１１が上にずれている状態を
それぞれ示す。｝に応じて、光検出器１０上に投
影される回析パターンが変化する。しかし、第４
図における回析パターンは、いずれもＹ軸につい
て対称なのでクロストークは発生しない。次に、
対物レンズ４が収差を持つ場合を考える。第５図
は、光検出器１０の配置方向及び情報トラツク６
とビームスポツト１１との位置関係を第４図と同
様に取つている。しかしながら、この場合には、
対物レンズ４の収差により光検出器１０上に投影
される回析パターンが乱されて、クロストークが
発生する。このため、合焦状態であるのにかかわ
らず、フオーカシングエラー信号は第５図ａ，
ｂ、第５図ｃ，ｄ、第５図ｅ，ｆでそれぞれ正、
０、負の値を取ることになり、フオーカシング制
御が不安定になる。<Problems to be Solved by the Invention> At the time of focusing shown in FIGS. 3a and 3b, the guide track 6'
A focusing error signal (hereinafter referred to as "focusing error signal") that is erroneously generated due to a change in the diffraction pattern that occurs in the beam spot projected onto the photodetector 10 due to diffraction caused by
We will examine the influence of crossstrokes (referred to as crossstrokes) on focusing error detection. First, consider an ideal case where the objective lens 4 has no aberration. Fourth
As shown in the figure, the photodetector 10 is arranged so that the X direction is the track direction and the Y direction is perpendicular to the track, and a beam spot 1 is placed on the information track 6.
1 and the reflected light is received by the photodetector 10. At this time, the positional relationship between the information track 6 and the beam spot 11 shown in FIG. 4 respectively {FIG. 4 a, b shows the state where the beam spot 11 is shifted downward, FIG. 4 c, d shows the state where there is no shift, Figure 4e,
f indicates a state in which the beam spot 11 is shifted upward. }, the diffraction pattern projected onto the photodetector 10 changes. However, the fourth
The diffraction patterns in the figure are all symmetrical about the Y axis, so crosstalk does not occur. next,
Consider a case where the objective lens 4 has aberration. FIG. 5 shows the arrangement direction of the photodetector 10 and the information track 6.
The positional relationship between the beam spot 11 and the beam spot 11 is the same as that shown in FIG. However, in this case,
The aberration of the objective lens 4 disturbs the diffraction pattern projected onto the photodetector 10, causing crosstalk. For this reason, regardless of the in-focus state, the focusing error signal in Fig. 5a,
b, Fig. 5 c, d, Fig. 5 e, f are correct, respectively.
0, a negative value will be taken, and focusing control will become unstable.
〈発明の目的〉
本発明は、対物レンズの収差が、光検出器に投
影されるガイドトラツクによる回析パターンに影
響をおよぼし、その結果としてフオーカシングエ
ラー信号の品質を低下させることのないエラー信
号検出系を備えた光情報検出装置を提供するもの
である。<Object of the Invention> The present invention aims to eliminate errors in which the aberrations of the objective lens do not affect the diffraction pattern due to the guide track projected onto the photodetector and, as a result, do not degrade the quality of the focusing error signal. The present invention provides an optical information detection device equipped with a signal detection system.
〈実施例〉
以下、本発明の実施例を図面を参照して説明す
る。<Example> Hereinafter, an example of the present invention will be described with reference to the drawings.
第１図に本発明に係る光情報検出装置の一実施
例の一部側断面図を示す。尚、この実施例におい
て光学系は第２図と同じものを用いる。 FIG. 1 shows a partial side sectional view of an embodiment of an optical information detection device according to the present invention. In this embodiment, the same optical system as in FIG. 2 is used.
同図で５は光デイスクの基板であつてガラス等
の光透過性材料からなる。該基板５には同心円状
又は螺旋状に溝状のトラツク６，６′（溝の深さ
は光源の波長λの1/8程度が適している。）が形成
され、さらにその上に、例えば希土類と遷移金属
とのアモルフアス合金薄膜等からなる情報記録媒
体７が蒸着、スパツタリング等の手法にて被覆さ
れている。４は第２図に示したものと同様の対物
レンズであり、１２はこの対物レンズ４をフオー
カス方向及びトラツキング方向に微小移動せしめ
る為の対物レンズ駆動装置である。この対物レン
ズ駆動装置１２の内部機構は第１図に示すよう
に、対物レンズ４を収納支持する対物レンズ鏡筒
１３を対物レンズ４の光軸方向に移動自在に具備
しており、この対物レンズ鏡筒１３はトラツキン
グ方向にのみ変位可能の一対のトラツキング方向
可動平行バネ１４，１４によつて中間支持体１５
に取付けられている。従つて対物レンズ４は、デ
イスク記録媒体７の半径方向に揺動可能に支持さ
れている。上記トラツキング方向可動平行バネ１
４の内側には、このバネの振動を吸収するための
ゴム状弾性体１６が接着されている。１７は上記
対物レンズ鏡筒１３の外周下部に外嵌された管状
のカウンタバランスウエートである。一方、対物
レンズ駆動装置１２の外郭を構成する固定支持体
１８は中空円筒状に形成され、その内側に固着さ
れたトラツキング用磁気回路１９は、トラツキン
グ用ヨークとトラツキング用マグネツトとで構成
され、両者の間でトラツキング用磁気空隙が形成
されている。このトラツキング用磁気空隙内に
は、この空隙を横切るように一端が対物レンズ鏡
筒１３に固着されたトラツキング駆動コイル２４
が挿入されている。上記のようなトラツキング用
磁気回路１９とトラツキング駆動用コイル２４
は、対物レンズ４の光軸を挾んで対称に一組設け
られている。従つて、上記トラツキング駆動用コ
イル２４への入力電流を変化させると、電磁作用
によりトラツキング駆動用コイル２４に外力が働
き、対物レンズ鏡筒１３及びこれに支持された対
物レンズ４をトラツキング方向に変位させる。一
方、２７はフオーカス用マグネツト、２６はフオ
ーカス用ヨークで、これらによりフオーカス磁気
回路２５が構成され、前記中間支持体１５の下端
に固定され、一端が磁気回路２５のフオーカス用
磁気空隙２９に挿入されたフオーカス駆動用コイ
ル３０とによりフオーカス方向の駆動手段が構成
されている。尚、３１，３１は、前記中間支持体
１５をフオーカス方向にのみ往復運動自在に支持
するフオーカス方向可動平行バネ、３２はゴム状
弾性体である。 In the figure, reference numeral 5 denotes a substrate of the optical disk, which is made of a light-transmitting material such as glass. Concentrically or spirally grooved tracks 6, 6' (the depth of the grooves is suitably about 1/8 of the wavelength λ of the light source) are formed on the substrate 5, and furthermore, for example, An information recording medium 7 made of an amorphous alloy thin film of a rare earth element and a transition metal is coated by a method such as vapor deposition or sputtering. 4 is an objective lens similar to that shown in FIG. 2, and 12 is an objective lens driving device for moving the objective lens 4 minutely in the focusing direction and the tracking direction. As shown in FIG. 1, the internal mechanism of the objective lens driving device 12 includes an objective lens barrel 13 that accommodates and supports the objective lens 4 and is movable in the optical axis direction of the objective lens 4. The lens barrel 13 is supported by an intermediate support 15 by a pair of tracking direction movable parallel springs 14, 14 which can be displaced only in the tracking direction.
installed on. Therefore, the objective lens 4 is supported so as to be swingable in the radial direction of the disk recording medium 7. The above tracking direction movable parallel spring 1
A rubber-like elastic body 16 is bonded to the inside of the spring 4 to absorb the vibrations of the spring. Reference numeral 17 denotes a tubular counterbalance weight fitted around the lower part of the outer periphery of the objective lens barrel 13. On the other hand, the fixed support 18 constituting the outer shell of the objective lens driving device 12 is formed into a hollow cylindrical shape, and the tracking magnetic circuit 19 fixed to the inside thereof is composed of a tracking yoke and a tracking magnet. A tracking magnetic gap is formed between the two. Within this magnetic gap for tracking, a tracking drive coil 24 whose one end is fixed to the objective lens barrel 13 so as to cross this gap.
has been inserted. Tracking magnetic circuit 19 and tracking drive coil 24 as described above
are provided symmetrically with respect to the optical axis of the objective lens 4. Therefore, when the input current to the tracking drive coil 24 is changed, an external force acts on the tracking drive coil 24 due to electromagnetic action, displacing the objective lens barrel 13 and the objective lens 4 supported therein in the tracking direction. let On the other hand, 27 is a focus magnet, and 26 is a focus yoke, which constitute a focus magnetic circuit 25, which is fixed to the lower end of the intermediate support 15, and one end is inserted into the focus magnetic gap 29 of the magnetic circuit 25. The focus drive coil 30 constitutes a focus direction drive means. Note that reference numerals 31 and 31 are focus direction movable parallel springs that support the intermediate support body 15 so that it can reciprocate only in the focus direction, and 32 is a rubber-like elastic body.
ここで、対物レンズ４は対物レンズ鏡筒１３に
対して回動可能な対物レンズホルダ３３に保持さ
れて対物レンズ鏡筒１３に取り付けられている。
そして光情報検出装置に以上の対物レンズ駆動装
置１２を組み込んだ後に、対物レンズ４を対物レ
ンズ鏡筒１３に対して対物レンズホルダ３３とと
もに回転せしめ、対物レンズ４の収差が第２図に
示す４分割光検出器１０上に投影される回析パタ
ーンに及ぼす影響が小さくなる位置、具体的には
対物レンズ４の収差による４分割光検出器１０の
受光量の減少が後述する第６図に示すようにＹ軸
について対称になる位置に対物レンズ４を設置固
定する。この固定は対物レンズホルダ３３と対物
レンズ鏡筒１３間の隙間３４に接着剤を充填すれ
ばよい。このように対物レンズ４の位置決めを行
なえば、対物レンズ４が収差を持つ場合であつて
も、情報トラツク６とビームスポツト１１との位
置関係のずれによつて回析パターンに変化が生じ
クロストークが発生することが無い。この様子を
第６図に示す。第６図ａ，ｂがビームスポツト１
１が情報トラツク６の下にずれている状態、第６
図ｃ，ｄはずれが無い状態、第６図ｅ，ｆはビー
ムスポツト１１が情報トラツク６の上にずれてい
る状態を示す。同図に示す様に対物レンズ４の収
差による受光量の減少がＹ軸について対称になる
ように対物レンズ４の回転による位置調整がなさ
れている為、前記した光検出器１０の４つの受光
部で検出される受光量による（Sa＋Sc）−（Sb＋
Sd）は０となり情報トラツク６とビームスポツ
ト１１との位置関係のずれによつてクロストーク
が生ぜずフオーカシング制御が不安定になること
が無い。第７図は情報トラツク６を横断した時の
フオーカシングエラー検出の特性図である。第７
図ａは従来の光情報検出装置の特性図で、情報ト
ラツク６をビームスポツト１１が横断する時にク
ロストークが発生しており、特に焦点近傍のクロ
ストークにより誤動作が生じている。第７図ｂは
本発明による光情報検出装置の特性図であり、焦
点近傍では、ほとんどクロストークは発生してい
ないので、安定したフオーカシング制御ができ
る。 Here, the objective lens 4 is attached to the objective lens barrel 13 while being held by an objective lens holder 33 that is rotatable relative to the objective lens barrel 13 .
After incorporating the objective lens driving device 12 into the optical information detection device, the objective lens 4 is rotated together with the objective lens holder 33 relative to the objective lens barrel 13, and the aberration of the objective lens 4 is adjusted to 4 as shown in FIG. The position where the influence on the diffraction pattern projected onto the split photodetector 10 is reduced, specifically, the decrease in the amount of light received by the 4-split photodetector 10 due to the aberration of the objective lens 4 is shown in FIG. 6, which will be described later. The objective lens 4 is installed and fixed at a position symmetrical about the Y axis. This fixation can be achieved by filling the gap 34 between the objective lens holder 33 and the objective lens barrel 13 with adhesive. If the objective lens 4 is positioned in this way, even if the objective lens 4 has aberrations, the diffraction pattern will change due to a shift in the positional relationship between the information track 6 and the beam spot 11, resulting in crosstalk. never occurs. This situation is shown in FIG. Figure 6 a and b are beam spot 1
1 is shifted below the information track 6, the 6th
Figures c and d show a state in which there is no deviation, and Figures 6e and f show a state in which the beam spot 11 is shifted above the information track 6. As shown in the figure, since the position of the objective lens 4 is adjusted by rotating so that the reduction in the amount of light received due to the aberration of the objective lens 4 is symmetrical about the Y axis, the four light receiving parts of the photodetector 10 described above are adjusted. (Sa + Sc) - (Sb +
Sd) becomes 0, and crosstalk does not occur due to a deviation in the positional relationship between the information track 6 and the beam spot 11, and the focusing control does not become unstable. FIG. 7 is a characteristic diagram of focusing error detection when the information track 6 is traversed. 7th
Figure a is a characteristic diagram of a conventional optical information detection device, in which crosstalk occurs when the beam spot 11 traverses the information track 6, and especially crosstalk near the focal point causes malfunctions. FIG. 7b is a characteristic diagram of the optical information detection device according to the present invention, and since almost no crosstalk occurs near the focal point, stable focusing control is possible.
以上の実施例においては対物レンズ４を対物レ
ンズ駆動装置１２に組み込んだ状態でその回転位
置調整を行なうものであつたが、対物レンズ４を
対物レンズ駆動装置１２に装着する前に、使用す
る対物レンズ４による像をスクリーン上に投影し
て、対物レンズ４の収差により発生する暗線の状
態を見て、その収差による暗線が情報トラツク６
と平行になるように対物レンズ４を対物レンズ駆
動装置１２に装着してもよい。この場合した対物
レンズ４の回転機構は必要ない。このように装着
することで対物レンズ４の収差による受光量の減
少が前述した４分割光検出器１０のＹ軸について
対称となり、対物レンズ４の持つ収差のために光
検出器１０上に投影される回析パターンの乱れに
よつて発生するクロストークを小さくすることが
できる。 In the embodiments described above, the rotational position of the objective lens 4 was adjusted after it was assembled into the objective lens drive device 12. However, before attaching the objective lens 4 to the objective lens drive device 12, Project the image from the lens 4 onto the screen to see the state of the dark line caused by the aberration of the objective lens 4.
The objective lens 4 may be attached to the objective lens driving device 12 so as to be parallel to the . In this case, the rotation mechanism for the objective lens 4 is not required. By mounting in this manner, the reduction in the amount of received light due to the aberration of the objective lens 4 becomes symmetrical about the Y axis of the 4-split photodetector 10, and the amount of light that is projected onto the photodetector 10 due to the aberration of the objective lens 4 becomes symmetrical. It is possible to reduce crosstalk caused by disturbances in the diffraction pattern.
ただし、この様な手法では対物レンズ４の収差
により発生する暗線の状態を見て対物レンズ４に
回転位置の目印を付けておく必要があり、手間が
かかり、生産性において若干難があり、更に対物
レンズ４を対物レンズ駆動装置１２に装着する際
に設置誤差が生じ易く、クロストークを完全に無
くすことが難しいので、第１図に示した実施例の
如く、対物レンズを対物レンズ駆動装置１２に装
着してから回転調整する方が安定した調整が実行
可能である。 However, with this method, it is necessary to mark the rotational position on the objective lens 4 by observing the state of the dark line caused by the aberration of the objective lens 4, which is time-consuming and somewhat difficult in terms of productivity. When attaching the objective lens 4 to the objective lens drive device 12, installation errors are likely to occur, and it is difficult to completely eliminate crosstalk. Therefore, as in the embodiment shown in FIG. It is more stable to adjust the rotation after attaching it to the camera.
〈発明の効果〉
以上説明したように、本発明によれば、対物レ
ンズの収差が光検出器上に投影される回析パター
ンに影響をおよぼし、フオーカシングエラー信号
の品質が低下して、フオーカシング制御が不安定
になることをほぼ完全になくした光情報検出装置
を実現することができる。<Effects of the Invention> As explained above, according to the present invention, the aberration of the objective lens affects the diffraction pattern projected onto the photodetector, and the quality of the focusing error signal deteriorates. It is possible to realize an optical information detection device that almost completely eliminates instability of focusing control.
第１図は本発明に係る光情報検出装置の一実施
例の一部側断面図、第２図は従来の光情報検出装
置の構成説明図、第３図は従来の光情報検出装置
の焦点検出の原理説明図、第４図乃至第６図はビ
ームスポツトと情報トラツクとの位置変化とそれ
による検出光の状態変化の説明図、第７図はフオ
ーカシングエラー検出の特性図を示す。
図中、１……半導体レーダ、２……コリメータ
ーレンズ、３……ビームスプリツタ、４……対物
レンズ、５……基板、６……情報トラツク、７…
…情報記録媒体、８……収束レンズ、９……シリ
ンドリカルレンズ、１０……４分割光検出器、１
３……対物レンズ鏡筒、３３……対物レンズホル
ダ。
FIG. 1 is a partial side cross-sectional view of an embodiment of an optical information detection device according to the present invention, FIG. 2 is an explanatory diagram of the configuration of a conventional optical information detection device, and FIG. 3 is a focal point of a conventional optical information detection device. FIGS. 4 to 6 are diagrams explaining the principle of detection. FIGS. 4 to 6 are diagrams explaining changes in the position of the beam spot and the information track and the resulting changes in the state of the detection light. FIG. 7 is a characteristic diagram of focusing error detection. In the figure, 1...Semiconductor radar, 2...Collimator lens, 3...Beam splitter, 4...Objective lens, 5...Substrate, 6...Information track, 7...
... Information recording medium, 8 ... Converging lens, 9 ... Cylindrical lens, 10 ... 4-split photodetector, 1
3...Objective lens barrel, 33...Objective lens holder.
Claims (1)
状にガイドトラツクが設けられた情報記録盤に集
光させるとともに該情報記録盤からの反射光束を
取り込む対物レンズと、前記反射光束を複数に分
割された受光部を有する光検出器に入射させる光
学系からなる光情報検出装置において、 前記対物レンズの収差が光検出器に投影される
回折パターン及ぼす悪影響を小さくするために前
記対物レンズを回転調整するための回転調整手段
を設けたことを特徴とする光情報検出装置。[Scope of Claims] 1. A light source, an objective lens that focuses the light beam from the light source onto an information recording disk provided with a circular or spiral guide track, and takes in the reflected light beam from the information recording disk; In an optical information detection device comprising an optical system that makes the reflected light flux incident on a photodetector having a light receiving section divided into a plurality of parts, in order to reduce the adverse effect that the aberration of the objective lens has on the diffraction pattern projected on the photodetector. An optical information detecting device characterized in that a rotation adjusting means for rotationally adjusting the objective lens is provided in the optical information detecting device.
Priority Applications (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61178513A JPS6334745A (en) | 1986-07-28 | 1986-07-28 | Optical information detector |
| EP87306575A EP0255305B1 (en) | 1986-07-28 | 1987-07-24 | Focusing error detecting device and method of manufacturing the same |
| CA000542944A CA1319194C (en) | 1986-07-28 | 1987-07-24 | Focusing error detector and optical data detecting device incorporating the focusing error detector |
| US07/078,773 US4812638A (en) | 1986-07-28 | 1987-07-28 | Focusing error detector and optical data detecting device incorporating the focusing error detector |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61178513A JPS6334745A (en) | 1986-07-28 | 1986-07-28 | Optical information detector |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6334745A JPS6334745A (en) | 1988-02-15 |
| JPH0568774B2 true JPH0568774B2 (en) | 1993-09-29 |
Family
ID=16049786
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP61178513A Granted JPS6334745A (en) | 1986-07-28 | 1986-07-28 | Optical information detector |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6334745A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0645903B2 (en) * | 1989-12-06 | 1994-06-15 | 新日本製鐵株式会社 | Steel plate for printed circuit board |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS60167131A (en) * | 1984-02-09 | 1985-08-30 | Mitsubishi Electric Corp | Optical mechanism of optical information recording and reproducing device |
-
1986
- 1986-07-28 JP JP61178513A patent/JPS6334745A/en active Granted
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS60167131A (en) * | 1984-02-09 | 1985-08-30 | Mitsubishi Electric Corp | Optical mechanism of optical information recording and reproducing device |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6334745A (en) | 1988-02-15 |
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