JPH0727659B2 - Light pickup - Google Patents
Light pickupInfo
- Publication number
- JPH0727659B2 JPH0727659B2 JP59118522A JP11852284A JPH0727659B2 JP H0727659 B2 JPH0727659 B2 JP H0727659B2 JP 59118522 A JP59118522 A JP 59118522A JP 11852284 A JP11852284 A JP 11852284A JP H0727659 B2 JPH0727659 B2 JP H0727659B2
- Authority
- JP
- Japan
- Prior art keywords
- light
- optical
- waveguide
- optical pickup
- photodetector
- 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
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
- G11B7/12—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
-
- 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
Description
【発明の詳細な説明】 産業上の利用分野 本発明は、光ディスク装置の光ピックアップに関するも
のであり、特に１チップ集積化可能な小形軽量の光ピッ
クアップに関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical pickup for an optical disk device, and more particularly to a compact and lightweight optical pickup that can be integrated in one chip.
従来例の構成とその問題点 近年、コンパクトディスクやレーザディスク等の光ディ
スク装置が注目されている。信号を検出する光ピックア
ップは光ディスク装置の心臓部とも言える重要な構成要
素である。従来の光ピックアップの基本構造を第１図に
示す。同図において光源である半導体レーザ１から出射
した光２はレンズ３によって平行光となり、偏向ビーム
スプリッタ４と1/4波長板５を通過してレンズ６によっ
て集光され、光ディスク７のピット８のある信号面に入
射し反射される。信号面で反射された光９は再び同じレ
ンズ６、同じ1/4波長板５及び偏向ビームスプリッタ４
を通過するが、1/4波長板５を往復した光の位相はもと
の光の位相に比べて90゜の位置遅れを生じており、その
ため偏向ビームスプリッタ４により反射されて90゜向き
を変え、その後のレンズ10によって光検出器11上に集光
される。光検出器11では光の強弱が電気信号に変換され
て出力される。つまり、光ディスク７の信号面にピット
８があるかないかで光の反射率が異なるため、光ディス
クの信号を電気信号で検出できることになる。又、同図
には示していないが、これ以外にフォーカス制御とトラ
ック制御を行う機構も必要であることは言うまでもな
い。Configuration of Conventional Example and Problems Thereof In recent years, optical disc devices such as compact discs and laser discs have received attention. An optical pickup that detects a signal is an important component that can be said to be the heart of an optical disk device. The basic structure of a conventional optical pickup is shown in FIG. In the figure, the light 2 emitted from the semiconductor laser 1 which is the light source is collimated by the lens 3, passes through the deflecting beam splitter 4 and the 1/4 wavelength plate 5, is condensed by the lens 6, and the pit 8 of the optical disk 7 It is incident on a certain signal surface and reflected. The light 9 reflected by the signal surface is again the same lens 6, the same 1/4 wavelength plate 5 and the deflecting beam splitter 4.
However, the phase of the light that reciprocates through the 1/4 wavelength plate 5 has a position delay of 90 ° with respect to the phase of the original light. Therefore, the light is reflected by the deflection beam splitter 4 and is directed at 90 °. Then, the light is focused on the photodetector 11 by the lens 10 after that. The photodetector 11 converts the intensity of light into an electric signal and outputs the electric signal. That is, since the light reflectance differs depending on whether or not the signal surface of the optical disk 7 has the pits 8, the signal of the optical disk can be detected by an electric signal. Although not shown in the figure, it goes without saying that a mechanism for performing focus control and track control is also required in addition to this.
以上のように、第１図の従来の構成では光学系が複雑で
あり位置合せ精度が要求され、従って作製が難しく価格
も高い。As described above, in the conventional configuration shown in FIG. 1, the optical system is complicated and alignment accuracy is required. Therefore, the fabrication is difficult and the cost is high.
発明の目的 本発明はこのような従来の問題に鑑み、小形軽量で、光
学系が簡単，作製容易であり、信頼性の高い１チップ集
積化可能な光ビックアップを提供することを目的とす
る。SUMMARY OF THE INVENTION In view of such conventional problems, it is an object of the present invention to provide a small and lightweight optical system that has a simple and easy optical system and is highly reliable and can be integrated on one chip. .
発明の構成 本発明の光ピックアップは、基板上に設けられた光導波
路と、基板上もしくは光導波路上に設けられた少なくと
も１組の集光グレーティングカップラと、光源と、光検
出器から構成されたものであり、小形軽量の１チップ集
積化可能な信頼性の高い光ピックアップを構成可能とす
るものである。The optical pickup of the present invention comprises an optical waveguide provided on a substrate, at least one set of condenser grating couplers provided on the substrate or on the optical waveguide, a light source, and a photodetector. Therefore, it is possible to configure a compact, lightweight, and highly reliable optical pickup that can be integrated on one chip.
実施例の説明 第２図は本発明の１実施例の光ピックアップの基板側の
構成を示す平面図であり、第３図は本発明の１実施例の
光ピックアップの全体構成を示す断面図である。第２
図，第３図を用いて本発明の１実施例の光ピックアップ
の構成を説明する。同図において表面にSiO212′を有す
るSiO2/Siを基板12とし、その基板12上にSi3N4光導波路
13,Si基板12内に光検出器17,18、光導波路13上にフレネ
ル導波路レンズ16,集光グレーティングカップラ14,15が
形成されており、光導波路13の端面に光源である半導体
レーザ１が設けられている。半導体レーザ１により励振
された導波光22は導波路レンズ16により平行光となり、
導波光出力用の集光グレーティングカップラ14により外
部に光23として出力され、光ディスク７のピット８のあ
る信号面に集光される。信号面で反射された光24は、反
射光入力用の集光グレーティングカップラ15に入力し、
導波光25となり、フォーカス制御用と信号検出用を兼ね
た２分割の光検出器17に結合される。なお、この光検出
器は、２分割以上であってもよいのは言うまでもない。
１組の集光グレーティングカップラ14,15の間に設けた
光吸収手段21は、集光グレーティングカップラ14により
外部に出力されなかった１部の導波光を吸収するための
ものであり、この吸収手段21を設けることにより、信号
光でない導波光の光検出器17へ与える影響を防ぎSN比を
向上させることができる。Description of Embodiments FIG. 2 is a plan view showing the structure of a substrate side of an optical pickup of one embodiment of the present invention, and FIG. 3 is a sectional view showing the overall structure of the optical pickup of one embodiment of the present invention. is there. Second
The configuration of the optical pickup according to the first embodiment of the present invention will be described with reference to FIGS. In the figure, SiO 2 / Si having SiO 2 12 ′ on the surface is used as a substrate 12, and a Si 3 N 4 optical waveguide is formed on the substrate 12.
13, photodetectors 17 and 18 are formed in the Si substrate 12, a Fresnel waveguide lens 16 and condensing grating couplers 14 and 15 are formed on the optical waveguide 13, and a semiconductor laser 1 as a light source is formed on the end face of the optical waveguide 13. Is provided. The guided light 22 excited by the semiconductor laser 1 becomes parallel light by the waveguide lens 16,
Light 23 is output to the outside by the light-collecting grating coupler 14 for outputting guided light, and is condensed on the signal surface of the optical disk 7 having the pits 8. The light 24 reflected by the signal surface is input to the condenser grating coupler 15 for inputting reflected light,
It becomes the guided light 25, and is coupled to the two-divided photodetector 17 for both focus control and signal detection. Needless to say, this photodetector may be divided into two or more.
The light absorbing means 21 provided between the pair of condensing grating couplers 14 and 15 is for absorbing a part of the guided light which is not output to the outside by the condensing grating coupler 14, and this absorbing means By providing 21, it is possible to prevent the influence of the guided light which is not the signal light on the photodetector 17 and to improve the SN ratio.
なお、１組の集光グレーティングカップラ14,15をそれ
ぞれの光軸を傾けたオフアキシス形に配置しても同様の
効果が得られる。反射光入力用のグレーティングカップ
ラ15の焦点上の片側に設けた光遮へい手段19は、光検出
器17と組合わせてフォーカス制御に用いるものである。
光ディスク７の位置が集光グレーティングカップラの焦
点からずれると、導波光25の焦点の位置もずれ、光遮へ
い手段19で導波光25の１部が遮へいされる。光ディスク
が近いときは光検出器171に結合される導波光が減少
し、遠いときは光検出器172に結合される導波光が減少
する。従って、光検出器171と172の出力信号の差を検出
することによってフォーカス制御を行うことができる。
反射光入力用の集光グレーティングカップラ15と光検出
器17の間に設けた光路変換手段20は別の少なくとも２分
割の光検出器18と組合わせてトラック制御を行うための
ものである。本実施例ではこの光路変換手段20として光
導波路13上に周期が徐々に変化するチャープグレーティ
ングを形成し、信号光である導波光の１部を光検出器18
の方向に偏向させた。光ディスク７への入射光23が正常
なトラッキングを行なっておれば光検出器181と182に入
射する光の強度は同じであるが、トラックずれが生じる
と光検出器181と182に入射する光の強度が変わり、光検
出器181と182の出力信号の差を検出することによってト
ラック制御を行うことができる。The same effect can be obtained by arranging a set of condensing grating couplers 14 and 15 in an off-axis type with their optical axes inclined. The light shielding means 19 provided on one side of the focal point of the reflected light input grating coupler 15 is used in combination with the photodetector 17 for focus control.
When the position of the optical disk 7 deviates from the focal point of the condensing grating coupler, the focal point position of the guided light 25 also deviates, and a part of the guided light 25 is shielded by the light shielding means 19. The guided light coupled to the photodetector 17 1 decreases when the optical disk is near, and the guided light coupled to the photodetector 17 2 decreases when the optical disk is far. Therefore, focus control can be performed by detecting the difference between the output signals of the photodetectors 17 1 and 17 2 .
The optical path changing means 20 provided between the condensing grating coupler 15 for inputting reflected light and the photodetector 17 is for performing track control in combination with another photodetector 18 divided into at least two. In this embodiment, a chirp grating having a gradually changing period is formed on the optical waveguide 13 as the optical path changing means 20, and a part of the guided light which is the signal light is detected by the photodetector 18.
Deflected in the direction of. If the incident light 23 on the optical disk 7 is normally tracked, the intensity of the light incident on the photodetectors 18 1 and 18 2 is the same, but if a track shift occurs, the photodetectors 18 1 and 18 2 will be detected. Track intensity can be controlled by changing the intensity of incident light and detecting the difference between the output signals of the photo detectors 18 1 and 18 2 .
本実施例では、集光グレーティングカップラ14,15及び
導波路レンズ16,光路変換手段20を光導波路13上に形成
したが、基板12上もしくは光導波路13中に形成してもよ
い。光導波路13中に形成する場合は、導波路の屈折率を
変化させればよいわけであり、イオンドープングや、又
カルコゲナイドを光導波路13に用いた場合は電子ビーム
や光を用いて作製が可能である。集光グレーティングカ
ップラ14,15は、断面を鋸歯状にし、歯の深さを最適化
すれば100％に近い高効率の光の入出力が可能であり、
グレーティングの周期，形状を変化させることにより、
任意の位置に設計通り集光させることができる。本実施
例では導波路レンズ16を設けたが、導波路レンズ16をな
くして導波光出力用のグレーティングカップラ14に導波
路レンズ16の役割を兼ねさせてもよい。以上説明してき
たのは、SiO2/Si基板を用いた光ピックアップである
が、SiO2/Siに代えてGaAs基板を用いた実施例では、光
源１を基板12上もしくは光導波路13に完全集積化し、Si
O2/Si基板の光ピックアップと同様の効果が確認でき
た。本実施例の光ピックアップはサイズが1cm×0.5cmで
厚さ300μm,重さ約5gであり、従来の光学ヘッドの重さ
約20gと比べると重量比で約1/4となった。さらに、完全
１チップ化を実現したGaAs基板光学ヘッドは重さが約1g
と超軽量になった。In this embodiment, the condensing grating couplers 14 and 15, the waveguide lens 16, and the optical path changing means 20 are formed on the optical waveguide 13, but they may be formed on the substrate 12 or in the optical waveguide 13. When it is formed in the optical waveguide 13, it is sufficient to change the refractive index of the waveguide.When ion doping or chalcogenide is used in the optical waveguide 13, it can be produced by using an electron beam or light. It is possible. The condensing grating couplers 14 and 15 have a saw-tooth cross section and can optimize the tooth depth to input and output highly efficient light close to 100%.
By changing the grating period and shape,
The light can be condensed at an arbitrary position as designed. Although the waveguide lens 16 is provided in the present embodiment, the waveguide lens 16 may be omitted and the grating coupler 14 for outputting the guided light may also serve as the waveguide lens 16. Although the optical pickup using the SiO 2 / Si substrate has been described above, in the embodiment using the GaAs substrate instead of SiO 2 / Si, the light source 1 is completely integrated on the substrate 12 or the optical waveguide 13. And Si
The same effect as the optical pickup of the O 2 / Si substrate was confirmed. The optical pickup of this embodiment has a size of 1 cm × 0.5 cm, a thickness of 300 μm, and a weight of about 5 g, which is about 1/4 of the weight of the conventional optical head, which is about 20 g. In addition, the GaAs substrate optical head, which has been completely integrated into one chip, weighs about 1 g.
And became super lightweight.
発明の効果 以上のように、本発明の光ピックアップの構成として、
基板上に光導波路と、基板上もしくは光導波路上に１組
の集光グレーティングカップラを形成し、さらに光源と
光検出器を設けたものであり、本発明の構成によると１
チップ集積化が可能であり、このため従来の光ピックア
ップとは比較にならないほど小形軽量で光学系が簡単，
作製容易であり、信頼性が高い光ピックアップが実現で
きるものである。As described above, as the configuration of the optical pickup of the present invention,
An optical waveguide and a set of condenser grating couplers are formed on the substrate or on the optical waveguide, and a light source and a photodetector are further provided.
Chip integration is possible, and as a result, the optical system is so compact and lightweight that it cannot be compared with conventional optical pickups.
An optical pickup that is easy to manufacture and highly reliable can be realized.
第１図は従来の光ピックアップの基本構成図、第２図は
本発明の１実施例の光ピックアップの平面図、第３図は
本発明の１実施例のディスクおよび第２図Ａ−Ａ′線の
光ピックアップ部の断面図である。 １……光源、12……基板、13……光導波路、14……導波
光出力用集光グレーティングカップラ、15……反射光入
力用集光グレーティングカップラ、16……導波路レン
ズ、17……信号検出用，フォーカス制御用光検出器、18
……トラック制御用光検出器、19……光遮へい手段、20
……光路変換手段、21……光吸収手段。FIG. 1 is a basic configuration diagram of a conventional optical pickup, FIG. 2 is a plan view of an optical pickup according to one embodiment of the present invention, and FIG. 3 is a disc according to one embodiment of the present invention and FIGS. It is sectional drawing of the optical pickup part of a line. 1 ... Light source, 12 ... Substrate, 13 ... Optical waveguide, 14 ... Collective grating coupler for output of guided light, 15 ... Collective grating coupler for input of reflected light, 16 ... Waveguide lens, 17 ... Photodetector for signal detection and focus control, 18
...... Track control light detector, 19 ...... Light shielding means, 20
...... Optical path changing means, 21 …… Light absorbing means.
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 昭58−169107（ＪＰ，Ａ) 特開 昭59−79441（ＪＰ，Ａ) 特開 昭58−130448（ＪＰ，Ａ) 特開 昭60−129938（ＪＰ，Ａ) ─────────────────────────────────────────────────── --- Continuation of the front page (56) Reference JP-A-58-169107 (JP, A) JP-A-59-79441 (JP, A) JP-A-58-130448 (JP, A) JP-A-60- 129938 (JP, A)
Claims (6)
上又は上記光導波路上に設けられた導波光出力用と反射
光入力用の少なくとも１組の集光グレーティングカップ
ラと、上記導波光を発する光源と、上記反射光を検出す
る光検出器と、上記反射光入力用の集光グレーティング
カップラと上記光検出器の間に設けられた導波形フォー
カス制御信号検出手段及び導波形トラック制御信号検出
手段から構成されたことを特徴とする光ピックアップ。1. An optical waveguide provided on a substrate, at least one condensing grating coupler for outputting guided light and inputting reflected light, which is provided on the substrate or on the optical waveguide, and the guided light. A light source that emits light, a photodetector that detects the reflected light, a focusing grating coupler for inputting the reflected light, and waveguide-type focus control signal detection means and waveguide-type track control signal provided between the photodetector. An optical pickup comprising a detection means.
射光入力用集光グレーティングカップラの焦点上のどち
らか一方側に設けた光遮へい手段であることを特徴とす
る特許請求の範囲第１項記載の光ピックアップ。2. The waveguide type focus control signal detecting means is a light shielding means provided on one side of the focal point of the reflected light input condenser grating coupler. The optical pickup described.
手段であることを特徴とする特許請求の範囲第１項記載
の光ピックアップ。3. The optical pickup according to claim 1, wherein the waveguide type track control signal means is an optical path changing means.
に、光吸収手段を設けたことを特徴とする特許請求の範
囲第１項記載の光ピックアップ。4. An optical pickup according to claim 1, wherein a light absorbing means is provided between the pair of condenser grating couplers.
アキシスに配置したことを特徴とする特許請求の範囲第
１光記載の光ピックアップ。5. The optical pickup according to claim 1, wherein a set of condenser grating couplers is arranged off-axis.
であることを特徴とする特許請求の範囲第３項記載の光
ピックアップ。6. The optical pickup according to claim 3, wherein the optical path changing means is a chirped grating.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59118522A JPH0727659B2 (en) | 1984-06-08 | 1984-06-08 | Light pickup |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59118522A JPH0727659B2 (en) | 1984-06-08 | 1984-06-08 | Light pickup |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS60263350A JPS60263350A (en) | 1985-12-26 |
| JPH0727659B2 true JPH0727659B2 (en) | 1995-03-29 |
Family
ID=14738695
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP59118522A Expired - Lifetime JPH0727659B2 (en) | 1984-06-08 | 1984-06-08 | Light pickup |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0727659B2 (en) |
Families Citing this family (17)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0658744B2 (en) * | 1984-09-14 | 1994-08-03 | オムロン株式会社 | Optical information processing device |
| JPH0658743B2 (en) * | 1984-09-14 | 1994-08-03 | オムロン株式会社 | Optical information processing device |
| JPS6171428A (en) * | 1984-09-14 | 1986-04-12 | Omron Tateisi Electronics Co | Optical information processor |
| JPH0619846B2 (en) * | 1984-09-14 | 1994-03-16 | オムロン株式会社 | Optical information processing device |
| JPH0630164B2 (en) * | 1985-12-16 | 1994-04-20 | キヤノン株式会社 | Optical head device |
| JPS62256240A (en) * | 1986-04-26 | 1987-11-07 | Furukawa Electric Co Ltd:The | Thin film waveguide type optical pickup |
| JPS632128A (en) * | 1986-06-20 | 1988-01-07 | Matsushita Electric Ind Co Ltd | Optical pickup |
| JPH0834011B2 (en) * | 1987-04-20 | 1996-03-29 | 富士写真フイルム株式会社 | Pickup for optical recording media |
| DE3852307T2 (en) * | 1987-12-29 | 1995-06-01 | Matsushita Electric Ind Co Ltd | OPTICAL HEAD. |
| JP2728502B2 (en) * | 1989-06-05 | 1998-03-18 | 株式会社日立製作所 | Optical integrated circuit and optical device |
| JP2714033B2 (en) * | 1988-09-19 | 1998-02-16 | 三洋電機株式会社 | Optical pickup |
| WO1991000596A1 (en) * | 1989-06-30 | 1991-01-10 | Matsushita Electric Industrial Co., Ltd. | Optical disk device |
| JP2753337B2 (en) * | 1989-07-26 | 1998-05-20 | パイオニア株式会社 | Optical information reader |
| JPH04219640A (en) * | 1990-07-16 | 1992-08-10 | Matsushita Electric Ind Co Ltd | Optical head and its manufacture |
| US5390157A (en) * | 1992-07-15 | 1995-02-14 | Eastman Kodak Company | Waveguide optical pick-up head using mach-zehnder interferometer wavefront sensor apparatus and method |
| KR100480786B1 (en) * | 2002-09-02 | 2005-04-07 | 삼성전자주식회사 | Integrated type optical head with coupler |
| JP2011107384A (en) * | 2009-11-17 | 2011-06-02 | Nec Corp | Method for manufacturing optical coupling device |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS543380B2 (en) * | 1974-10-21 | 1979-02-22 | ||
| JPS58169107A (en) * | 1982-03-30 | 1983-10-05 | Toshiba Corp | Input and output device for optical information |
| JPH0743843B2 (en) * | 1982-10-29 | 1995-05-15 | オムロン株式会社 | Optical reader |
-
1984
- 1984-06-08 JP JP59118522A patent/JPH0727659B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPS60263350A (en) | 1985-12-26 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EXPY | Cancellation because of completion of term |