JPH0424768B2 - - Google Patents
Info
- Publication number
- JPH0424768B2 JPH0424768B2 JP57227315A JP22731582A JPH0424768B2 JP H0424768 B2 JPH0424768 B2 JP H0424768B2 JP 57227315 A JP57227315 A JP 57227315A JP 22731582 A JP22731582 A JP 22731582A JP H0424768 B2 JPH0424768 B2 JP H0424768B2
- Authority
- JP
- Japan
- Prior art keywords
- light
- photodetector
- beam splitter
- lens
- focusing means
- 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
- 230000003287 optical effect Effects 0.000 claims description 19
- 238000001514 detection method Methods 0.000 claims description 11
- 238000000926 separation method Methods 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
- G11B7/0908—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 focusing only
Description
【発明の詳細な説明】
この発明は光学的な信号記録材例えばビデオデ
イスク等の再生装置に於て、焦点位置の検出を行
うピツクアツプ装置に関するものである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pickup device for detecting a focal position in a reproducing device for optical signal recording materials such as video disks.
従来のこの種の装置としては特開昭57−
105831.特開昭57−105832.特開昭57−108811.特開
昭57−127933が提案されている。 As a conventional device of this kind, Japanese Patent Application Laid-Open No. 1987-
105831. JP-A-57-105832. JP-A-57-108811. JP-A-57-127933 have been proposed.
しかしながら特開昭57−105831.特開昭57−
105832に於ては光偏向手段としてプリズムを用い
ているので、光分離手段通過後に光検出器上に集
束させるための例えばレンズのような光検出器集
束手段を必要としたために、構成部品数の増加に
よるコストアツプ、名手段の調整手数の増加、位
置精度の向上等の問題があつた。 However, JP-A-57-105831.
Since the 105832 uses a prism as the light deflection means, it requires a photodetector focusing means such as a lens to focus the light onto the photodetector after passing through the light separation means, which reduces the number of components. Problems such as an increase in cost, an increase in the number of steps required for adjustment of the known means, and an improvement in positional accuracy have arisen.
又特開昭57−108811及び特開昭57−127933に於
ては記録材の反射光の通路中にその通路の片側を
通る反射光を遮断若しくは減光させるナイフエツ
ジ、マスク等を配するために、光検出器に到達し
ない光量が損失となるので、光検出器の動作に必
要な光量とするために光源を強くしなければなら
ず、その寿命、信頼性が劣り、更に光通路中のナ
イフエツジ、マスク以外で生じる損失によつて機
能が減退する等の欠点がある。 Further, in JP-A-57-108811 and JP-A-57-127933, a knife edge, mask, etc. is provided in the path of the reflected light of the recording material to block or attenuate the reflected light passing through one side of the path. Since the amount of light that does not reach the photodetector becomes a loss, the light source must be made stronger to provide the amount of light necessary for the operation of the photodetector, which reduces its lifespan and reliability, and furthermore, the knife edge in the optical path However, there are drawbacks such as reduced functionality due to losses occurring in areas other than the mask.
本発明は特開昭57−105831.同57−105832に於
ける光偏向手段と、光検出器集束手段を、光軸を
ずらして一体化したレンズ系で兼ねさせることに
よつて、前述の欠点を除去することを目的とする
ものである。 The present invention solves the above-mentioned drawbacks by integrating the optical axis of the optical deflection means and the photodetector focusing means in JP-A-57-105831. The purpose is to remove the
本発明の実施例を第１図乃至第８図に就いて説
明すれば、光源１から出た光はレンズ２で平行光
線となり、ビームスプリツタ３を通り、対物レン
ズ４でデイスク５上に集束され、デイスク５で反
射され、対物レンズ４を通つてビームスプリツタ
３で入射光と分離され、光軸をずらした２個のレ
ンズ６ａ，６ｂからなるレンズ系６を通つて、前
記光軸のずれた方向を含んで４分割された光検出
器７に到達する。 An embodiment of the present invention will be described with reference to FIGS. 1 to 8. Light emitted from a light source 1 is converted into parallel rays by a lens 2, passes through a beam splitter 3, and is focused onto a disk 5 by an objective lens 4. The light is reflected by the disk 5, passes through the objective lens 4, is separated from the incident light by the beam splitter 3, and passes through the lens system 6 consisting of two lenses 6a and 6b whose optical axes are shifted. The light reaches the photodetector 7, which is divided into four parts including the shifted direction.
即ち、レンズ系６は第２図ｂに示すようにレン
ズ中心面を平面とする２個の凸レンズ６ａ，６ｂ
の平面部分を互いにずらせて貼り合せ、２本のず
れた光軸９，１０を有するように形成したもの
で、これに反射光８が入るものである。 That is, the lens system 6 includes two convex lenses 6a and 6b whose center plane is a plane, as shown in FIG. 2b.
The planar portions of the two are offset from each other and pasted together to form two optical axes 9 and 10 that are offset from each other, into which the reflected light 8 enters.
従つてビームスプリツタ３で分離された反射光
８は２分割されたレンズ６ａ，６ｂによつて、光
検出器７がレンズ６ａ，６ｂの光軸９，１０のず
れた方向を含んで４つの検出素子７ａ，７ｂ，７
ｃ，７ｄに分かれているので、光軸９，１０のず
れた距離だけ離れた点、即ちレンズ６ｂの集光点
１１ａ、レンズ６ａの集光点１１ｂで検出素子上
に集光する。 Therefore, the reflected light 8 separated by the beam splitter 3 is divided into two by the lenses 6a and 6b, and the photodetector 7 is divided into four directions including the shifted directions of the optical axes 9 and 10 of the lenses 6a and 6b. Detection elements 7a, 7b, 7
c and 7d, the light is focused on the detection element at a point separated by a distance shifted by the optical axes 9 and 10, that is, at a focusing point 11a of the lens 6b and a focusing point 11b of the lens 6a.
第４図に於て検出素子７ａ，７ｂ，７ｃ，７ｄ
の出力をそれぞれVa，Vb，Vc，Vdとすると、デ
イスク５上に集光しているときには光検出器７上
でも集光するので、第４図ｂの状態となり、（Va
＋Vd）−（Vb＋Vc）＝０となるが、第４図ａのよ
うにデイスク５が集束点より離れていると
（Va＋Vd）−（Vb＋Vc）＞０
第４図ｃのようにデイスク５が集光点よりも近
づいていると
（Va＋Vd）−（Vb＋Vc）＜０
となり、（Va＋Vd）−（Vb＋Vc）の値の変化は第
５図の状態となるので、焦点の検出が可能とな
る。 In Fig. 4, detection elements 7a, 7b, 7c, 7d
Assuming that the outputs of are V a , V b , V c , and V d , respectively, when the light is focused on the disk 5, it is also focused on the photodetector 7, resulting in the state shown in Fig. 4b, and (V a
+V d ) - (V b + V c ) = 0, but if the disk 5 is far from the focal point as shown in Figure 4 a, (V a + V d ) - (V b + V c ) > 0. As shown in Figure c, when the disk 5 is closer than the focal point, (V a + V d ) - (V b + V c ) < 0, and the value of (V a + V d ) - (V b + V c ) Since the change becomes the state shown in FIG. 5, the focus can be detected.
又第６図の矢印Ａの方向にトラツク方向がある
ようにすると、（Va＋Vb）−（Vc＋Vd）をトラツ
キングエラ信号とすることができる。 If the tracking direction is set in the direction of arrow A in FIG. 6, then (V a +V b )-(V c +V d ) can be used as the tracking error signal.
更に本発明は上記実施例のレンズ６ａ，６ｂを
凸レンズとする他に、第７図に示すように凹レン
ズで形成し、ビームスプリツタ３をレンズ２の間
に置いてもさしつかえはない。 Furthermore, in the present invention, instead of using the lenses 6a and 6b of the above embodiment as convex lenses, they may be formed as concave lenses as shown in FIG. 7, and the beam splitter 3 may be placed between the lenses 2.
又第８図に示すように光検出器７に検出素子７
ｅ，７ｆを設けて３ビーム方式のトラツキング検
出を行つてもよい。 Furthermore, as shown in FIG.
e and 7f may be provided to perform three-beam tracking detection.
更にレンズ６ａ，６ｄをグレーテイングレン
ズ、ホログラフイーレンズとしてもよいものであ
る。 Furthermore, the lenses 6a and 6d may be used as grating lenses or holographic lenses.
叙上のように本発明は光軸をずらして一体化し
たレンズ系によつて光偏向と、光検出器集束を行
なわせたので、光量損失が生ずることなく、光源
の照度を高める必要がないので、その寿命、信頼
性が向上するばかりでなく、光偏向と集束が同時
に行なわれるので、部品数の減少、組立調整手数
の低減が行なわれ、しかもフオーカス時に光検出
器上に反射光の集束点が位置するように構成され
ているので、スキヤン時等フオーカスサーボをか
けたままトラツクを横切る場合に、トラツクエラ
によるデフオーカスが生じにくい等の利点を有す
るものである。 As mentioned above, in the present invention, the optical axis is shifted and the integrated lens system is used to deflect light and focus the photodetector, so there is no loss of light quantity and there is no need to increase the illuminance of the light source. This not only improves its lifespan and reliability, but also reduces the number of parts and the number of assembly and adjustment steps because light deflection and focusing are performed at the same time.Furthermore, the reflected light is focused on the photodetector during focusing. Since the structure is such that the point is located, it has the advantage that defocus due to track error is less likely to occur when crossing a track with focus servo applied, such as during scanning.
第１図は本発明の一実施例、第２図ａ，ｂは光
軸をずらした光偏向手段のレンズの正面図および
斜視図、第３図は光検出器の検出面、第４図ａ〜
ｃは焦点位置検出の原理図、第５図はその出力を
示し、第６図はトラツキング検出の原理図で、第
７図は本発明の他の実施例、第８図は３ビーム方
式のトラツキング検出に用いる光検出器を示す。
１……光源、２……レンズ、３……ビームスプ
リツタ、４……レンズ、５……デイスク、６ａ，
６ｂ……光軸のずれたレンズ、７……光検出器。
Figure 1 shows an embodiment of the present invention, Figures 2a and b are front and perspective views of the lens of the optical deflection means with the optical axis shifted, Figure 3 is the detection surface of the photodetector, Figure 4a ~
c shows the principle of focal position detection, Fig. 5 shows its output, Fig. 6 shows the principle of tracking detection, Fig. 7 shows another embodiment of the present invention, and Fig. 8 shows three-beam tracking. The photodetector used for detection is shown. 1... Light source, 2... Lens, 3... Beam splitter, 4... Lens, 5... Disk, 6a,
6b... Lens with shifted optical axis, 7... Photodetector.
Claims (1)
束手段により集束し、前記信号記録材からの反射
光を入射光と直交する方向に分離するビームスプ
リツタにより取り出し、ビームスプリツタで分離
される光を集光手段を介して光検出器に導いて焦
点を検出する光学的ピツクアツプ装置における焦
点検出装置において、ビームスプリツタで分離さ
れる光を光検出器に導く集光手段として、単一の
凸レンズ又は凸レンズと凹レンズからなる集光素
子であり、前記単一の凸レンズ又は凹レンズはビ
ームスプリツタと光検出器との間に配置され、そ
の単一の凸レンズ又は凹レンズの光軸を含む平面
で二分割し、その光軸を含む平面を光軸と直交す
る方向にずらした構成の二つの光軸を有してお
り、前記光検出器は、前記レンズ系の二つの光軸
に対応する結像点を検出する４分割された単一の
検出素子からなることを特徴とする光学的ピツク
アツプ装置における焦点検出装置。1. The light from the light source is focused on the recording surface of the signal recording material by a light focusing means, and the reflected light from the signal recording material is extracted by a beam splitter that separates it in a direction orthogonal to the incident light, and the light is separated by the beam splitter. In a focus detection device in an optical pickup device, which guides the light that is separated by the beam splitter to the photodetector through a focusing means to detect the focus, a single light focusing means is used as the focusing means to guide the light separated by the beam splitter to the photodetector. A condensing element consisting of one convex lens or a convex lens and a concave lens, the single convex lens or concave lens being disposed between a beam splitter and a photodetector, and a plane including the optical axis of the single convex lens or concave lens. It has two optical axes configured such that the plane containing the optical axis is shifted in a direction perpendicular to the optical axis, and the photodetector corresponds to the two optical axes of the lens system. 1. A focus detection device for an optical pickup device, characterized in that it consists of a single detection element divided into four parts for detecting an image-forming point.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP22731582A JPS59121634A (en) | 1982-12-28 | 1982-12-28 | Focus detecting device in optical pickup device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP22731582A JPS59121634A (en) | 1982-12-28 | 1982-12-28 | Focus detecting device in optical pickup device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS59121634A JPS59121634A (en) | 1984-07-13 |
| JPH0424768B2 true JPH0424768B2 (en) | 1992-04-28 |
Family
ID=16858871
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP22731582A Granted JPS59121634A (en) | 1982-12-28 | 1982-12-28 | Focus detecting device in optical pickup device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS59121634A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2638778B2 (en) * | 1986-03-18 | 1997-08-06 | 日本電気株式会社 | Optical head device |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5683849A (en) * | 1979-12-11 | 1981-07-08 | Matsushita Electric Ind Co Ltd | Optical information reader |
-
1982
- 1982-12-28 JP JP22731582A patent/JPS59121634A/en active Granted
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5683849A (en) * | 1979-12-11 | 1981-07-08 | Matsushita Electric Ind Co Ltd | Optical information reader |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS59121634A (en) | 1984-07-13 |
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