JPS60171643A - Focus deviation detecting device of optical disk head - Google Patents
Focus deviation detecting device of optical disk headInfo
- Publication number
- JPS60171643A JPS60171643A JP59027181A JP2718184A JPS60171643A JP S60171643 A JPS60171643 A JP S60171643A JP 59027181 A JP59027181 A JP 59027181A JP 2718184 A JP2718184 A JP 2718184A JP S60171643 A JPS60171643 A JP S60171643A
- Authority
- JP
- Japan
- Prior art keywords
- photodetector
- beam splitter
- optical disk
- disk head
- 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.)
- Granted
Links
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
-
- 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
- G11B7/12—Heads, e.g. forming of the optical beam spot or modulation of the optical beam
- G11B7/135—Means for guiding the beam from the source to the record carrier or from the record carrier to the detector
Landscapes
- Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Optical Head (AREA)
- Automatic Focus Adjustment (AREA)
- Optical Recording Or Reproduction (AREA)
Abstract
Description
【発明の詳細な説明】
〔発明の技術分野１
この発明は、光デイスクヘッドのフォーカスずれ検出装
置に関するものであり、とりわけ、デジタルオーディオ
ディスク、ビデオディスク等の光学的情報記録媒体から
非接触で情報を読出し、あるいは書込むための光デイス
クヘッドのフォーカスずれを検出する装置に関するもの
である。Detailed Description of the Invention [Technical Field of the Invention 1] The present invention relates to a defocus detection device for an optical disk head, and more particularly, to a device for detecting defocus of an optical disk head, and in particular, detects information from an optical information recording medium such as a digital audio disk or a video disk in a non-contact manner. The present invention relates to a device for detecting defocus of an optical disk head for reading or writing.
従来のこの種の装置を第１図について説明すると、発光
貯／からのレーザ出射光束−はビームスプリッタ３を通
過し、コリメートレンズψにより平行光束Ｓにされ、四
分の一波長板６を通って対物レンズ７により光ディスク
ｇの面上に微小な集光スポットタを形成する。この集光
スポット９からの反射光束は対物レンズ７に再入射し、
これから四分の一波長板６、コリメートレンズ≠を辿っ
て光路を逆戻りする。この逆戻りした反射光束１０ 。To explain a conventional device of this type with reference to FIG. A minute condensing spotter is formed on the surface of the optical disc g by the objective lens 7. The reflected light flux from this focused spot 9 enters the objective lens 7 again,
From there, the optical path is returned by following the quarter-wave plate 6 and the collimating lens ≠. This reflected light beam 10 is reflected back.
はビームスプリッタ３によって反射され９σ方向を変え
られる。？σ丈方向変えられた反射光束は光路途中に設
置されたノ・−フミラー／ｌによりΩつの光束に分けら
れる。ここでノ・−フミラー／ｌを透過した第１の光束
／Ｊａは点Ｐｚｉで集光し、ハーフミラ−／／で反射さ
れた第一の光束／、２ｂは点Ｐ、２に集光する。矢印Ｘ
は光ディスクｇのずれ方向を示す。is reflected by the beam splitter 3 and its direction is changed by 9σ. ? The reflected light beam whose direction has been changed is divided into Ω light beams by a nof mirror/l installed in the middle of the optical path. Here, the first light beam /Ja that has passed through the half mirror /l is condensed at a point Pzi, and the first light beam /2b reflected by the half mirror // is condensed at a point P,2. arrow x
indicates the direction of displacement of the optical disc g.
集光点Ｐｔの手前に第１の光検知器１３、集光点Ｐλの
後方には第２の光検知器／ダが配設されており、これら
の光検知器／ 、３ 、 ／ ｌｌ−は第４図（ａ）。A first photodetector 13 is provided in front of the focal point Pt, and a second photodetector/da is provided behind the focal point Pλ, and these photodetectors / , 3 , / ll- is shown in Figure 4(a).
（ｂ）にそれぞれ示すように、円形の内側有感領域１／
＋１．２ と外側有感領域ＴＩ 、 、■−に２分割さ
れている。As shown in (b), the circular inner sensitive area 1/
It is divided into two areas: +1.2 and outer sensitive area TI, , ■-.
第１の光検知器１３は、光ディスクざが対物レンズ７の
合焦点位置にあるとき、第３図（ａｌ Ｋ示すよ５１Ｃ
内側有感領域Ｉ／と外側有感領域ＩＩ ／に入射する光
スポットｉｓの光量が互いに等しくなるように、その位
置および内側有感領域Ｉ／の大きさが設定されている。The first photodetector 13 detects when the optical disc is at the focal point position of the objective lens 7, as shown in FIG.
The position and the size of the inner sensitive area I/ are set so that the amount of light of the light spot is incident on the inner sensitive area I/ and the outer sensitive area II/ is equal to each other.
従って有感領域１．、Ｈ，の出力差（ＩＩ／Ｔ／）は合
焦点時には零となる。一方、光ディスクｇが合焦点位置
より遠ざかると第１の光束／、２ａの集光点Ｐ／は第１
の光検知器７．７に近づき、第７の光検知器／３面上の
光スポット／Ｓは第３図（ｂ）に示すように小さくなり
、有感領域Ｉ／への入射光量が大きくなり、その出力差
（■／Ｔ／）は負となる。逆に光ディスクｇが合焦点位
置より近づくと、第３図（ｃ）に示すように光スポット
／Ｓは大きくなり、光検知器出力差（ＩＩ／ Ｔ／）は
正となる。したがって横軸に光ディスクｇの合焦点位置
からのずれＸ（遠ざかる方向を正）を、縦軸に光検知器
出力差（ＩＩ／−Ｉ／）をとると第７図に示すような特
性曲線が得られる。特性曲線が第９図のような形になる
ことは実験と理論の両面から確認されている。このよう
に第１の光検知器／３だけから得られる特性は合焦点付
近の検出感度が非線形で、ゼロクロス（Ｘ軸と交わる点
）がコケ所ある等の理由から、これのみではフォーカス
ずれ検出信号としては不適である。第一の光検出器“ｌ
ｑは以上の点を補うものであり、第７の光検出器１３と
同様に光ディスクｇが合焦点位置にあるとき、第Ｓ図（
ａ、）のように内側有感領域■Ｊ、外側有感領域ｆｉｓ
に入射する光スポットｌ乙の光量が等しくなるよう第２
の光検知器／弘の位置、領域Ｉａの大きさが設定されて
いる。従って合焦点時の有感領域Ｉ ｎ ＋ １１２の
出力差（ｔ ５−１１ ｓ、）は零になるが、光ディス
クｇが合°焦点位置より遠ざかると第一の光束／２ｂの
集光点Ｐ２は第一の光検知器／４’より遠ざかり第一の
光検知器７７面上の光スポット／６は第５図（ｂ） Ｋ
示すように大きくなり、その出力差（Ｉｘ−Ｈλ）は負
となる。また逆に光ディスクｇが合焦点位置より近づく
と第５図（ｃ）に示すように光スポラ）／Ａは小さくな
り、光検知器出力差（Ｔａ−１１ｘ）は正となる。した
がって横軸に光ディスクにの合焦点位置からのずれＸ（
遠ざかる方向を正）を、縦軸に光検知器出力差（ｒｐ−
１［ｚ）をとると第６図に示すような特性曲線が得られ
る。この特性は第Ｖ図の特性を原点のまわりに／ｇσ回
転させた形になっている。したがって、第７図のよ５に
光検知器／、３．／’Ｉに接続した減Ｘ器／りの出力を
加算器／ｇで加算すれば第Ｖ図の特性曲線と第６図の特
性曲線を〃口え合わせた第５図に示すような特性曲線を
得ることができる。このようにして得られた特性は合焦
点付近の検出感度が線形であり、ゼロクロスが一ケ所で
あるためフォーカスずれ検出信号として最適なものにな
る。Therefore, sensitive area 1. , H, the output difference (II/T/) becomes zero at the time of focus. On the other hand, when the optical disc g moves away from the focal point position, the first light beam /, the focal point P/ of 2a becomes the first
The light spot /S on the seventh photodetector/3 surface becomes smaller as shown in Fig. 3(b), and the amount of light incident on the sensitive area I/ increases. Therefore, the output difference (■/T/) is negative. Conversely, when the optical disc g approaches the focal point position, the optical spot /S becomes larger and the photodetector output difference (II/T/) becomes positive, as shown in FIG. 3(c). Therefore, if we take the deviation X of the optical disc g from the focused position (positive in the direction of moving away) on the horizontal axis and the photodetector output difference (II/-I/) on the vertical axis, we get a characteristic curve as shown in Figure 7. can get. It has been confirmed both experimentally and theoretically that the characteristic curve takes the form shown in Figure 9. In this way, the characteristics obtained only from the first photodetector/3 are that the detection sensitivity near the in-focus point is non-linear, and the zero cross (the point where it intersects with the Not suitable as a signal. The first photodetector “l
q supplements the above points, and when the optical disc g is at the focused position like the seventh photodetector 13,
a,), the inner sensitive area ■J, the outer sensitive area fis
The second light spot is set so that the amount of light incident on the light spot
The position of the photodetector/hiro and the size of area Ia are set. Therefore, the output difference (t 5 - 11 s,) of the sensitive area I n + 112 at the focused point becomes zero, but when the optical disc g moves away from the focused point, the focal point P2 of the first beam /2b is the light spot /6 on the surface of the first photodetector 77 which moves away from the first photodetector /4' is shown in Fig. 5(b) K
As shown, the output difference (Ix-Hλ) becomes negative. Conversely, when the optical disk g approaches the focal point position, the optical spoiler (/A) becomes smaller and the photodetector output difference (Ta-11x) becomes positive, as shown in FIG. 5(c). Therefore, the horizontal axis shows the deviation X (
The direction of moving away is positive), and the vertical axis is the photodetector output difference (rp-
1 [z), a characteristic curve as shown in FIG. 6 is obtained. This characteristic is obtained by rotating the characteristic in Figure V by /gσ around the origin. Therefore, as shown in FIG. 7, the photodetector/3. By adding the outputs of the subtractor /' connected to /'I using the adder /g, a characteristic curve as shown in Figure 5 is obtained by combining the characteristic curve in Figure V and the characteristic curve in Figure 6. can be obtained. The characteristics thus obtained are linear in detection sensitivity near the in-focus point, and have a zero cross at only one location, making it optimal as a defocus detection signal.
このフォーカスずれ検出信号は対物レンズ７または光学
系全体を元軸方向に駆動する機構（図示せず）を制御す
るため罠用いられる。より詳細には、検出信号が常に零
になるよつＩＣ対物レンズ７または光学系全体を駆動す
るための機構（例えばボイスコイル）へ帰還されるので
ある。This defocus detection signal is used as a trap to control a mechanism (not shown) that drives the objective lens 7 or the entire optical system in the direction of the original axis. More specifically, the detection signal, which is always zero, is fed back to the IC objective lens 7 or a mechanism (for example, a voice coil) for driving the entire optical system.
しかし、以上の構成になる従来装置は、第１゜第一の光
検知器／３，１％の位置をそれぞれ独立して３軸調整し
なければならず、調整が複雑で調整コストが高くなると
いう欠点を有していた。また、ハーフミラ−／／、光検
知器１３．／フカ各別に配置されてるため、経年変化等
圧よるこれら要素の変位の影響をもたらすおそれがあり
、信頼性が低いという欠点も有していた。However, in the conventional device with the above configuration, the positions of 1st, 1st photodetector, and 3,1% must be adjusted independently on three axes, which makes the adjustment complicated and increases the adjustment cost. It had the following drawback. Also, half mirror //, photodetector 13. / Since each hook is placed separately, there is a risk of displacement of these elements due to aging and isobaric changes, which also has the disadvantage of low reliability.
この発明は、上記のような従来のものの欠点を除去する
ことを目的とするもので、従来のビームスプリッタに加
えて、反射光束を２つの光束に分離する一定の第一のビ
ームスプリッタを設け、第一のビームスプリッタと第１
．第一の光検知器を一体化することにより、ＩＡ整が簡
単で１整コストが安く、かつ、経年変化等に対する信頼
性の高い光デイスクヘッドのフォーカスずれ検出装ホを
提供する。The present invention aims to eliminate the above-mentioned drawbacks of the conventional one, and includes, in addition to the conventional beam splitter, a certain first beam splitter that separates the reflected beam into two beams, a first beam splitter and a first beam splitter;
．． To provide a defocus detection device for an optical disk head that is easy to perform IA adjustment, has a low cost for one adjustment, and has high reliability against aging and the like by integrating a first photodetector.
第９図は、この発明の第一の実施例を示し、第１図と同
一符号は同一または相当部分を示−１，図において、／
りは第一のビームスプリッタをなす筒状のハーフプリズ
ムで反射光束１０は反射面／９ａで反射される第１の光
束／２ａとそのまま透過する第２の光束／２ｂとに分離
される。まず、第１の光束／２ｆｌはハーフプリズムｌ
？外方の集光点Ｐｔに向かって進み光路ヱ、合焦点時の
集光点Ｐｌ より手前ＶＣ置かれた第１の光検知器／Ｊ
Ｋ入射する。第１の光検知器１３の当て面はハーフプリ
ズム１９の１つの外面／？ｂと一致するようになってお
り、かつ、外面ｌデｂＫ接着などにより固定されている
。また反射面／？ａで反射された第一の光束１２ｂはハ
ーフプリズム／ｆ中を進み、ハーフプリズム／？内の集
光点ＰＪＩＣ集光し。FIG. 9 shows a first embodiment of the present invention, in which the same reference numerals as in FIG. 1 indicate the same or corresponding parts.
A cylindrical half prism forming a first beam splitter separates the reflected light beam 10 into a first light beam /2a that is reflected by a reflecting surface /9a and a second light beam /2b that is transmitted unchanged. First, the first luminous flux/2fl is the half prism l
? The optical path 〇 proceeds toward the outer focal point Pt, and the first photodetector /J is placed in front of the focal point Pl when the focal point is focused.
K is incident. The contact surface of the first photodetector 13 is one outer surface of the half prism 19/? b, and is fixed by adhesive or the like on the outer surface l de b k. Also a reflective surface/? The first light beam 12b reflected by a travels through the half prism/f, and passes through the half prism/? Focus the light inside PJIC.
合焦点時の集光点ＰＪより後方ＶＣ［かれた第２の光検
知器／ＦＫ入射する。第一の光検知器／Ｆは第１の光検
知器１３同様、当て面がハーフプリズムｌデの他の外面
／９ｃと一致して固定されている。従って、あらかじめ
決められた精度でハーフプリズムｌデを形成し、光検知
器／、３．／’Ｉをそれぞれ適当な精度で外面／９ｂ、
／９ｃに固定すれば、光検知器の調整は光検知器／Ｊ、
／’Ｉとハーフプリズム／？が一体化されたものを３軸
調整するだけで足りる。VC enters the second photodetector/FK behind the condensing point PJ at the time of focusing. Like the first photodetector 13, the first photodetector /F is fixed so that its contact surface coincides with the other outer surface /9c of the half prism lde. Therefore, a half prism is formed with a predetermined precision, and a photodetector is formed.3. /'I respectively with appropriate precision on the outer surface /9b,
If fixed at /9c, the adjustment of the photodetector is as follows: photodetector /J,
/'I and Half Prism/? It is sufficient to adjust the 3-axis integrated device.
以上のように、従来のものと比較して調整箇所が著しく
少なくなり、調整が容易となって調整コストが安くなる
。また、ハーフプリズム／９、光検知器／、？、／Ｇ１
が一体化されているので、これらを各別に配置した従来
のものよりも経年変化等による素子の不所望な変位の影
響が少なく、信頼性も向上する。As described above, compared to the conventional system, the number of adjustment points is significantly reduced, the adjustment becomes easier, and the adjustment cost is reduced. Also, half prism/9, photodetector/? ,/G1
Since these are integrated, the influence of undesired displacement of the elements due to aging etc. is reduced compared to the conventional structure in which these are arranged separately, and reliability is improved.
なお、上記におけるフォーカスずれ検出信号は、第７図
と同一の演算回路により得られることはいうまでもない
。It goes without saying that the focus shift detection signal described above is obtained by the same arithmetic circuit as in FIG. 7.
上記第一の実施例ではハーフプリズム／デの二つの外面
／ ？ｂ 、／ ９ｄＫ第１ 、第一の光検知器／、ｌ
、 ／Ｇ’を固定したが、漉；の実施例として第１Ｏ
図、第１／図に示すような形状のハ〜フプリズムコθ、
すなわちλつの反射面２０ａ、２０ｂをもつものを用い
ればλつの光検知器をハーフプリズム、２０の同一外面
に配設することができる。・・したがって、第１／図に
示すようなパターンをもつｖ分割光検知器、２１を１個
用いれば７つの光検知器、２／をハーフプリズムの一つ
の外面に固定するだけでよく、一層の調整の簡略化が達
成される。In the first embodiment above, the two outer surfaces of the half prism/de/? b,/9dK 1st, 1st photodetector/,l
, /G' are fixed, but as an example of filtration, the first O
A half prism θ having a shape as shown in Fig. 1/Fig.
That is, by using one having λ reflecting surfaces 20a and 20b, λ photodetectors can be arranged on the same outer surface of the half prism 20. ...Therefore, if one V-split photodetector 21 having a pattern as shown in Fig. 1/ is used, seven photodetectors, 2/, need only be fixed to one outer surface of the half prism, making it even more convenient. simplification of the adjustment is achieved.
第１コ図は第三の実施例を示し、一端に四分の一波長板
２．２を接合した第二のビームスプリッタ２３を用いれ
ば光学系の一層のコンパクト化がはかれる。この場合、
反射光束ｉｏは反射面Ｊ３ａから外部の集光点Ｐ／に向
かって進み四分の一波長板２．２を通過して第１の光検
知器１３に入射する。ここで四分の一波長板２．２の外
面２３ｂはハーフミラ−コーティングが施されており、
第１の光検知器／、？ｌｌＣ入射した光束の半分は外面
λ３ｂで反射される。この反射光束は四分の一波長板λ
コを再び通過し、ビームスプリッタ２３中を進む。Figure 1 shows a third embodiment, in which the optical system can be made even more compact by using a second beam splitter 23 having a quarter-wave plate 2.2 attached to one end. in this case,
The reflected light flux io advances from the reflective surface J3a toward the external focal point P/, passes through the quarter-wave plate 2.2, and enters the first photodetector 13. Here, the outer surface 23b of the quarter-wave plate 2.2 is coated with a half mirror coating.
First photodetector/? Half of the luminous flux incident on llC is reflected by the outer surface λ3b. This reflected light flux is reflected by a quarter-wave plate λ
The beam passes through the beam splitter 23 again and proceeds through the beam splitter 23.
この光は四分の一波長板２コをコ度通過しているため直
線偏光の偏光方向が９ダ回転し、ビームスプリンタコ３
の反射面２３ａでは反射されずに透過して内部の集光点
Ｐａで集光し、第二の光検知器ｌｐＫ！する。光検知器
／３．／＃の当て面はそれぞれ外面、２３ｂおよびこれ
に対向する外面２３ｃ゛と一致してる。Since this light passes through two quarter-wave plates, the polarization direction of the linearly polarized light is rotated by 9 degrees, and the beam splitter plate rotates by 9 degrees.
The light is transmitted through the reflecting surface 23a without being reflected, and is focused at an internal focusing point Pa, and the light is transmitted to the second photodetector lpK! do. Photodetector/3. The contact surfaces of /# coincide with the outer surface 23b and the opposing outer surface 23c, respectively.
この実施例のものは、調整の簡略化・高信頼性に加えて
光学系のコンパクト化の効果も期待できる。In addition to simplifying adjustment and high reliability, this embodiment can also be expected to have the effect of making the optical system more compact.
第１．？図は第四の実施例を示し、第二のビームスプリ
ッタ２グの７つの外面、ｌ≠ｂの半分はミラーコーティ
ング、２ｊが施され、残余の部分に第１の光検知器コロ
を配設し、外面２ｅｂに対向する外面２１１ｃに第２の
光検知器２７で配置してなり、第１ダ図（ａ） 、 （
ｂ） Ｋ示すような有声領域を有している。かくして反
射光束１０は一部半内部が光検知器２６に入射し、残り
半円部はミラーコーティング２Ｓで反射されて第２のビ
ームスプリッタ、２弘中を進行し、第二の光検知器Ｊ？
［入射する。1st. ? The figure shows a fourth embodiment, in which the seven outer surfaces of the second beam splitter 2g, half of which l≠b are coated with mirrors and 2j, and the remaining part is provided with a first photodetector roller. A second photodetector 27 is arranged on the outer surface 211c opposite to the outer surface 2eb, as shown in FIG.
b) It has a voiced area as shown in K. Thus, part of the reflected light beam 10 enters the photodetector 26, and the remaining semicircular portion is reflected by the mirror coating 2S and travels through the second beam splitter, 2S, and the second photodetector J?
[Inject.
この実施例の場合も第三の実施例と同様の効果が期待で
きる。こらに、以上の各実施例では円形または半円形の
有感領域をもつλつの二分割光検知器または７つの１分
割光検知器を用いたが、第五の実施例として第ｉｓ図に
示すような２つの３分割光検知器−ｇ、コ９またはこの
２つからなる１つの６分割の短冊型の光検知器を用いて
もよい。In the case of this embodiment as well, the same effects as in the third embodiment can be expected. In each of the above embodiments, λ two-segment photodetectors or seven one-segment photodetectors each having a circular or semicircular sensitive area were used, but the fifth embodiment is shown in FIG. It is also possible to use two 3-split photodetectors such as G and G9, or one 6-split strip-shaped photodetector made of these two.
／７は減算器、／ざは加算器で、この場合のフォーカス
ずれ検出信号Ｅｆは
Ｅｆ ＝ （ｉ コ＋ ｍ、＋＋ｎ、） −（Ｉ／ ＋
ｌＩコ ＋■コ）となる。この光検知器２１．１９の分
割線方向をトラッキングに伴って光検知器面上の光スポ
ットが動く方向（図中ｒ方向）と平行になるように設定
すれば、トラッキングに伴うフォーカスずれ検出エラー
を生じさせない利点を有する。/7 is a subtracter, /za is an adder, and the focus shift detection signal Ef in this case is Ef = (i + m, ++n,) - (I / +
It becomes lIko +■ko). If the dividing line direction of the photodetector 21.19 is set to be parallel to the direction in which the light spot on the photodetector surface moves with tracking (direction r in the figure), the focus shift detection error due to tracking can be avoided. It has the advantage of not causing
以上の説明によって明らかＫしたようＫ、この発明は、
特性のよいフォーカスずれ検出が簡単な調整で行なうこ
とができ、調整コストが安く装置全体が安価にできると
いう優れた効果を有している。また、光学部品を一体化
してるため、経年変化等による素子の変位の影響も極小
となり、信頼性が向上するという効果も有している。As is clear from the above explanation, this invention is
It has the excellent effect that defocus detection with good characteristics can be performed by simple adjustment, and that the adjustment cost is low and the entire device can be made inexpensive. Furthermore, since the optical components are integrated, the effect of element displacement due to aging etc. is minimized, which also has the effect of improving reliability.
第７図〜第を図は従来装置を示し、第１図は光学配置側
面図、第一図（ａ） 、 （ｂ）はそれぞれ光検知器の
平面図、第３図（ａ） 、 ｆｂ） 、 （ｃ）は第１
の光検知器の動作説明平面図、第弘図は第１の光検知器
の特性線図、第５図（ａ） 、 （ｂ） 、 （Ｃ）は
第二の光検知器の動作説明平面図、第６図は第二の光検
知器の特性線図、第７図は光検知器の結線図、第に図は
第７図による特性線図である。
第デ図〜第１左図はこの発明の実施例を示し、第り図は
第一の実施例の光学配置側面図、第７０図および第１／
図は第二の実施例の一部側断面図および一部正面図、第
１−図は第三の実施例の光学配置側面図、第７３図は第
四の実施例の一部側断面図、第１ダ図（ａ） 、 （ｂ
）はそれぞれ第１３図におげろ光検知器の平面図、第１
ｊ−図は第五の実施［ｕＪの光検知器とその結線図であ
る。
／・・発光源、コ・・出射光束、３・・第１のビームス
プリッタ、ダ・・コリメートレンズ、５・・平行光束、
６・・四分の一波長板、７・・対物レンズ、ざφ・光デ
ィスク、？・拳集光スポット、ｉｏ−・反射光束、ｌコ
ａ、／２ｂ・・第八第一の光束、／３．／≠ｅ＋＋第１
．第コの光検知器、／？・・減算器、１ｇ・・加算器、
ｔ９．−〇・ｅハーフプリズム（第一のビームスプリッ
タ）、−２７−−光検知！、ココ、コ弘−・第一のビー
ムスプリッタ、２よ・・ミラーコーティング、２６゜２
７＃・第１１第２の光検出器、ユ１ｇ、２デ・・第１．
第一の梯検知器。
なお、各図中、同一符号は同−又は相当部分を示す。
ｖ）５図
６
第１２図
）ｊｆ）１３図
幣１４図
殆１５図Figures 7 to 7 show the conventional device, Figure 1 is a side view of the optical arrangement, Figures 1 (a) and (b) are plan views of the photodetector, and Figures 3 (a) and fb). , (c) is the first
Figure 5 is a plan view explaining the operation of the photodetector, Figure 5 is a characteristic diagram of the first photodetector, and Figures 5 (a), (b), and (C) are plane views explaining the operation of the second photodetector. 6 is a characteristic line diagram of the second photodetector, FIG. 7 is a connection diagram of the photodetector, and the third figure is a characteristic line diagram according to FIG. 7. Figures D to 1st left figure show an embodiment of the present invention, and Figure 2 is a side view of the optical arrangement of the first embodiment, Figure 70, and Figure 1/1.
The figures are a partial side sectional view and a partial front view of the second embodiment, Figure 1-1 is a side view of the optical arrangement of the third embodiment, and Figure 73 is a partial side sectional view of the fourth embodiment. , Figure 1 (a), (b
) are the plan view of the Gero photodetector and the first
Figure J is the fifth implementation [uJ's photodetector and its wiring diagram. /... Light emitting source, Co... Outgoing light flux, 3... First beam splitter, Da... Collimating lens, 5... Parallel light flux,
6. Quarter wavelength plate, 7. Objective lens, φ optical disk, ?・Fist focused spot, io-・Reflected light beam, l core a, /2b・・Eighth first light beam, /3. /≠e++1st
．． No. 1 photodetector, /? ...Subtractor, 1g...Adder,
t9. -〇・e half prism (first beam splitter), -27--Light detection! , Coco, Kohiro - First beam splitter, 2... Mirror coating, 26°2
7#・11th second photodetector, U1g, 2de・1st.
First ladder detector. In each figure, the same reference numerals indicate the same or corresponding parts. v) 5 Figures 6 Figures 12) jf) 13 Figures 14 Figures Almost 15 Figures
Claims (1)
せる対物レンズと、前記光デイスク上の集光スポットか
らの前記対物レンズを経た反射光束と前記出射光束を分
離するビームスプリッタと、分離された前記反射光束を
２分した第１．第２の光束のそれぞれの集光点に対して
光軸方向にそれぞれ前方、後方に配置された少な（とも
２つの有感領域をもつ第１．第２の光検知器を備えた光
デイスクヘッドのフォーカスずれ検出装置において、第
１の前記ビームスプリッタと、前記反射光束を前記第１
．第一の光束に分離し前記第１．第２の光束の前記集光
点がそれぞれ外部と内部に位置する第一のビームスグリ
ツタと、この第一のビームスプリッタの外面に一体に装
着された前記第１゜第２の光検出器を備えてなることを
特徴とする光デイスクヘッドのフォーカスずれ検出装置
。 （Ｕ） 第２のビームスプリッタがハーフプリズムであ
る特許請求の範囲第１項記載の光デイスクヘッドのフォ
ーカスずれ検出装置。 （３）反射光束を第１．第２の光束に分離する第１の反
射面と前記第λの光束を前記第１の光束に平行な方向に
反射する第２の反射面が形成された第２のビームスプリ
ッタと、この第２のビームスプリッタの７つの外面に装
着され互いに一体の第１、第一の光検出器を備えた豹許
請求の範囲第１項記載の光デイスクヘッドのフォーカス
ずれ検出装置。 （φ）外面にハーフミラ−コーティングを施した四分の
一波長板が一端面に装着された第２のビームスプリッタ
と、前記外面に装着された第１の光検知器と、前記第一
のビームスプリッタの前記一端面に対向する端面に装着
された第一の光検知器を備えた特許請求の範囲第１項記
載の光デイスクヘッドのフォーカスずれ検出装置。 （５）一端面の半分にミラーコーティングが施された第
一のビームスプリッタと、前記一端面の残余のや分に装
着された第１の光検知器と、前記第λのビームスプリン
タの前記一端面に対向する端面に装着された第一の光検
知器を備えた特許請求の範囲第１項記載の光デイスクヘ
ッドのフォーカスずれ検出装置。 （６）有感領域が矩形状に、７分割されてなる第ハ第コ
の光検知器を備えた特許請求の範囲第１項記載の光デイ
スクヘッドのフォーカスずれ検出装置。 （７）第１．第一の光検知器が互いに一体に形成された
特許請求の範囲第６項記依の光ティスフヘッドのフォー
カスずれ検出装置。[Scope of Claims] (1) An objective lens that focuses an emitted light beam from a light source onto an optical disk, and a reflected light beam that passes through the objective lens from a condensed spot on the optical disk and separates the output light beam. and a first beam splitter that divides the separated reflected light beam into two. An optical disk head equipped with a first and a second photodetector each having two sensitive areas arranged in front and behind the optical axis direction with respect to each condensing point of the second light beam. In the defocus detection device, the first beam splitter and the reflected light beam are connected to the first beam splitter.
．． The first beam is separated into the first beam. a first beam splitter in which the condensing points of the second beam are located on the outside and inside, respectively; and the first and second photodetectors integrally attached to the outer surface of the first beam splitter. What is claimed is: 1. A defocus detection device for an optical disk head, comprising: (U) The optical disk head focus shift detection device according to claim 1, wherein the second beam splitter is a half prism. (3) The reflected light flux is the first. a second beam splitter having a first reflecting surface that separates the beam into a second beam and a second reflecting surface that reflects the λ-th beam in a direction parallel to the first beam; 2. A defocus detecting device for an optical disk head according to claim 1, comprising first and second photodetectors that are integral with each other and are mounted on seven outer surfaces of a beam splitter. (φ) a second beam splitter having a quarter-wave plate with a half-mirror coating on the outer surface attached to one end surface, a first photodetector attached to the outer surface, and the first beam 2. The defocus detection device for an optical disk head according to claim 1, further comprising a first photodetector mounted on an end surface opposite to said one end surface of the splitter. (5) a first beam splitter having a mirror coating applied to half of one end surface; a first photodetector attached to the remaining half of the one end surface; The defocus detection device for an optical disk head according to claim 1, comprising a first photodetector mounted on an end face opposite to the end face. (6) The defocus detection device for an optical disk head according to claim 1, comprising a photodetector having a sensitive area divided into seven rectangular areas. (7) First. 7. A defocus detecting device for an optical tisf head according to claim 6, wherein the first photodetectors are integrally formed with each other.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59027181A JPH07107742B2 (en) | 1984-02-17 | 1984-02-17 | Optical disc head focus shift detector |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59027181A JPH07107742B2 (en) | 1984-02-17 | 1984-02-17 | Optical disc head focus shift detector |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS60171643A true JPS60171643A (en) | 1985-09-05 |
| JPH07107742B2 JPH07107742B2 (en) | 1995-11-15 |
Family
ID=12213904
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP59027181A Expired - Fee Related JPH07107742B2 (en) | 1984-02-17 | 1984-02-17 | Optical disc head focus shift detector |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH07107742B2 (en) |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS60217535A (en) * | 1984-04-11 | 1985-10-31 | Sony Corp | Focus detector |
| JPS61258339A (en) * | 1985-05-13 | 1986-11-15 | Matsushita Electric Ind Co Ltd | Optical recording and reproducing device |
| JPH0278025A (en) * | 1988-09-14 | 1990-03-19 | Copal Co Ltd | Optical pickup device |
| JPH0268318U (en) * | 1988-11-15 | 1990-05-23 | ||
| JPH03232121A (en) * | 1990-02-08 | 1991-10-16 | Pioneer Electron Corp | Position detector |
| JPH06349082A (en) * | 1993-03-30 | 1994-12-22 | Gold Star Co Ltd | Optical pickup device |
| JP2010127668A (en) * | 2008-11-26 | 2010-06-10 | Fuji Xerox Co Ltd | Light beam measuring device, focus adjuster, and image forming device |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5687241A (en) * | 1979-11-21 | 1981-07-15 | Thomson Csf | Nonnastigmatism optical device for sending and receiving interferable light* and optical recording and reading head having same device |
| JPS58128032A (en) * | 1982-01-27 | 1983-07-30 | Asahi Optical Co Ltd | Detection method of focusing position for optical type information reproducer |
-
1984
- 1984-02-17 JP JP59027181A patent/JPH07107742B2/en not_active Expired - Fee Related
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5687241A (en) * | 1979-11-21 | 1981-07-15 | Thomson Csf | Nonnastigmatism optical device for sending and receiving interferable light* and optical recording and reading head having same device |
| JPS58128032A (en) * | 1982-01-27 | 1983-07-30 | Asahi Optical Co Ltd | Detection method of focusing position for optical type information reproducer |
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS60217535A (en) * | 1984-04-11 | 1985-10-31 | Sony Corp | Focus detector |
| JPH0534732B2 (en) * | 1984-04-11 | 1993-05-24 | Sony Corp | |
| JPS61258339A (en) * | 1985-05-13 | 1986-11-15 | Matsushita Electric Ind Co Ltd | Optical recording and reproducing device |
| JPH051532B2 (en) * | 1985-05-13 | 1993-01-08 | Matsushita Electric Ind Co Ltd | |
| JPH0278025A (en) * | 1988-09-14 | 1990-03-19 | Copal Co Ltd | Optical pickup device |
| JPH0268318U (en) * | 1988-11-15 | 1990-05-23 | ||
| JPH03232121A (en) * | 1990-02-08 | 1991-10-16 | Pioneer Electron Corp | Position detector |
| JPH06349082A (en) * | 1993-03-30 | 1994-12-22 | Gold Star Co Ltd | Optical pickup device |
| JP2010127668A (en) * | 2008-11-26 | 2010-06-10 | Fuji Xerox Co Ltd | Light beam measuring device, focus adjuster, and image forming device |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH07107742B2 (en) | 1995-11-15 |
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| Date | Code | Title | Description |
|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |