JPS63144432A - Optical head device - Google Patents
Optical head deviceInfo
- Publication number
- JPS63144432A JPS63144432A JP61290874A JP29087486A JPS63144432A JP S63144432 A JPS63144432 A JP S63144432A JP 61290874 A JP61290874 A JP 61290874A JP 29087486 A JP29087486 A JP 29087486A JP S63144432 A JPS63144432 A JP S63144432A
- Authority
- JP
- Japan
- Prior art keywords
- thin film
- film waveguide
- light
- photodetector
- head 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.)
- Pending
Links
- 230000003287 optical effect Effects 0.000 title claims abstract description 34
- 239000010409 thin film Substances 0.000 claims abstract description 28
- 238000000926 separation method Methods 0.000 claims 1
- 238000000034 method Methods 0.000 abstract description 8
- 239000000758 substrate Substances 0.000 abstract description 7
- 230000000593 degrading effect Effects 0.000 abstract 1
- 238000001514 detection method Methods 0.000 description 7
- 238000010586 diagram Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 239000004065 semiconductor Substances 0.000 description 4
- 230000004075 alteration Effects 0.000 description 3
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 3
- 229910052681 coesite Inorganic materials 0.000 description 2
- 230000008878 coupling Effects 0.000 description 2
- 238000010168 coupling process Methods 0.000 description 2
- 238000005859 coupling reaction Methods 0.000 description 2
- 229910052906 cristobalite Inorganic materials 0.000 description 2
- 230000002542 deteriorative effect Effects 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 229910052682 stishovite Inorganic materials 0.000 description 2
- 229910052905 tridymite Inorganic materials 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 235000012239 silicon dioxide Nutrition 0.000 description 1
Landscapes
- Optical Integrated Circuits (AREA)
- Optical Head (AREA)
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は光により情報の記録、再生を行なう光記録に用
いる光ヘッド装置に関する。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an optical head device used for optical recording that records and reproduces information using light.
光ディスクなどの光記録に用いられる従来の光ヘッド装
置は第５図に示すような構成であり、レーザの出射光を
微小スポットとして記録媒体上に集光する光学系と、記
録媒体での反射光からスポットの位置エラー信号と情報
信号を得る検出系とからなっている。A conventional optical head device used for optical recording of optical discs and the like has a configuration as shown in Figure 5, which includes an optical system that focuses the emitted laser light onto the recording medium as a minute spot, and a system that collects the reflected light from the recording medium. It consists of a detection system that obtains a spot position error signal and an information signal from the spot.
第５図は従来の光ヘッド装置の一構成例を示すブロック
図である。同図において、半導体レーザ１の出射光はコ
リメートレンズ２．ビームスプリッタ３．集光レンズ４
を介して記録媒体５上に微小スポットとして集光される
。このスポットからの反射光はビームスプリッタ３によ
ってレーザ出射光から分離され、一部はトラックエラー
検出器７に、他の一部はビームスプリッタ３．収束レン
ズ１２．ナイフェツジ１３を介してフォーカスエラー検
出器８に収束される。FIG. 5 is a block diagram showing an example of the configuration of a conventional optical head device. In the figure, light emitted from a semiconductor laser 1 is transmitted through a collimating lens 2. Beam splitter 3. Condensing lens 4
The light is focused as a minute spot on the recording medium 5 through the light beam. The reflected light from this spot is separated from the laser emitted light by the beam splitter 3, and part of it is sent to the track error detector 7, and the other part is sent to the beam splitter 3. Converging lens 12. It is focused on the focus error detector 8 via the knife 13.
トラックエラーは２分割型の光検出器によるプッシュプ
ル法によって検出され、フォーカスエラーはナイフェツ
ジ法によって検出される。また情報信号はトラックエラ
ー検出器の和信号から得られる。Track errors are detected by a push-pull method using a two-part photodetector, and focus errors are detected by a Knifezi method. The information signal is also obtained from the sum signal of the track error detector.
上述した従来の光ヘッドはレンズやプリズムなどの個別
部品を組合わせて構成されるので、形状も大きく重量も
重い。したがって、光デイスク装置全体の小型化や情報
検索時のアクセス時間の低減が十分に実現できなかった
。The conventional optical head described above is constructed by combining individual parts such as lenses and prisms, so it is large in size and heavy in weight. Therefore, it has not been possible to sufficiently reduce the size of the entire optical disk device or reduce the access time during information retrieval.
光ヘッド装置を小型化する方法として第６図に示すよう
な導波路素子を用いる方法が提案されている。第６図は
第５図における検出系の一例を示す斜視図で、薄膜導波
路９の端面に半導体レーザ１の出射光を結合し、集光型
のグレーティング結合器１０により集光ビームを記録媒
体に照射する。As a method for downsizing an optical head device, a method using a waveguide element as shown in FIG. 6 has been proposed. FIG. 6 is a perspective view showing an example of the detection system in FIG. 5, in which the emitted light of the semiconductor laser 1 is coupled to the end face of the thin film waveguide 9, and the condensed beam is directed to the recording medium by the condensing grating coupler 10. irradiate.
この記録媒体からの反射光はグレーティング結合器１０
により再び薄膜導波路９に導かれ、さらに分波器１４に
よって分離されて端面出射光が光検出器１５で受光され
る。The reflected light from this recording medium is transmitted to a grating coupler 10.
The light is again guided to the thin film waveguide 9, further separated by a demultiplexer 14, and end-emitted light is received by a photodetector 15.
この構成により光ヘッド装置を小型化することが可能と
なるが、レーザ出射光を端面において薄膜導波路９と結
合するのは１μｍオーダの精度が必要となり、その製作
が難しい。また、グレーティング結合器１０により出射
光を１μｍ程度のスポットに集光するためには、グレー
ティングの形成精度が０．０１μｍで数ｍｍ２以上の面
積にわたり必要となるので、さらに製造が難しいという
欠点がある。Although this configuration makes it possible to downsize the optical head device, coupling the laser emitted light to the thin film waveguide 9 at the end face requires precision on the order of 1 μm, which is difficult to manufacture. In addition, in order to condense the emitted light into a spot of about 1 μm using the grating coupler 10, the grating must be formed with an accuracy of 0.01 μm over an area of several mm2 or more, which has the disadvantage of making it even more difficult to manufacture. .
本発明の光ヘッド装置は、レーザ光源の出射光を微小ス
ポットとして記録媒体上に集光する第１の光学系と、前
記記録媒体からの反射光を分離する第２の光学系を有す
る光ヘッド装置において、前記分゛離された反射光の一
部を薄膜導波路中へ集光ビームとして導くグレーティン
グ結合器および導波光をビーム光軸で２分割する分割器
を備える薄膜導波素子と、前記薄膜導波路の端面におい
て前記導波光を受光する２分割型の第１の光検出器と、
前記グレーティング結合器を透過した前記記録媒体から
の反射光を受光する２分割型の第２の光検出器とを備え
、前記第１．第２の光検出器は前記薄膜導波素子上に集
積されてもよい。An optical head device of the present invention includes a first optical system that focuses emitted light from a laser light source onto a recording medium as a minute spot, and a second optical system that separates reflected light from the recording medium. In the apparatus, the thin film waveguide element includes a grating coupler that guides a part of the separated reflected light into the thin film waveguide as a condensed beam, and a splitter that splits the guided light into two along the beam optical axis; a two-part first photodetector that receives the guided light at an end face of a thin film waveguide;
a two-segment type second photodetector that receives reflected light from the recording medium that has passed through the grating coupler; A second photodetector may be integrated onto the thin film waveguide element.
光ヘッド装置において、高い利用効率や低収差を求めら
れるのは、レーザ光源からの出射光を記録媒体上に集光
する第１の光学系である。これは微小スポットと集光す
るためである。一方、反射光を検出する第２の光学系は
温度変動などによる特性の変化が少なければ収差に対す
る許容量は大きい、したがって本発明においては、従来
の光ヘッド装置で光学系の半分以上を占めている第２の
光学系を薄膜素子化することにより、光ヘッド装置の特
性を劣化させることなく小型化を実現している６
〔実施例〕
次に本発明について第１図〜第４図を参照して説明する
。In an optical head device, a first optical system that focuses emitted light from a laser light source onto a recording medium is required to have high utilization efficiency and low aberration. This is because the light is focused on a minute spot. On the other hand, the second optical system that detects the reflected light has a large tolerance for aberrations if there are few changes in characteristics due to temperature fluctuations, etc. Therefore, in the present invention, the second optical system that detects the reflected light has a large tolerance for aberrations. By converting the second optical system into a thin film element, the optical head device can be miniaturized without deteriorating its characteristics.6 [Example] Next, regarding the present invention, refer to Figs. 1 to 4. and explain.
第１図は本発明の光ヘッド装置の一実施例を示すブロッ
ク図である。同図において、半導体レーザ１の出射光は
コリメートレンズ２．ビームスプリッタ３．集光レンズ
４を介して記録媒体５上に集光する。記録媒体５からの
反射光はビームスプリッタ３で分離され薄膜導波素子６
に導かれる。FIG. 1 is a block diagram showing an embodiment of an optical head device of the present invention. In the figure, light emitted from a semiconductor laser 1 is transmitted through a collimating lens 2. Beam splitter 3. The light is focused onto the recording medium 5 via the focusing lens 4. The reflected light from the recording medium 5 is separated by a beam splitter 3 and sent to a thin film waveguide element 6.
guided by.
この薄膜導波素子６は例えば第２図に示す構造を有して
いる。第２図は第１図における検出系の一例を示す斜視
図で、グレーティング結合器１０により入射光の一部は
薄膜導波路９に集光性のビームとして導かれる。この導
波光は分割器１１によって光軸から２つに分割され、薄
膜導波路９端面にある２分割型のフォーカスエラー検出
器８に導かれる。このような構成にすれば、ナイフェツ
ジ法によるフォーカスエラー検出が可能となる。また、
分割した他方のビームからもエラー検出が可能である。This thin film waveguide element 6 has a structure shown in FIG. 2, for example. FIG. 2 is a perspective view showing an example of the detection system shown in FIG. 1, in which a portion of the incident light is guided by the grating coupler 10 to the thin film waveguide 9 as a condensing beam. This guided light is split into two from the optical axis by a splitter 11 and guided to a two-split type focus error detector 8 on the end face of the thin film waveguide 9. With such a configuration, it becomes possible to detect focus errors using the Knifezi method. Also,
Error detection is also possible from the other divided beam.
薄膜導波素子６を形成している基板に透明なガラス基板
等を用いればグレーティング結合冊１０への入射光の一
部はそのまま透過するので、ビームが透過する位置にト
ラックエラー検出器７を設けることにより、プッシュプ
ル法によるトラックエラーの検出が可能となる。If a transparent glass substrate or the like is used as the substrate forming the thin film waveguide element 6, a part of the light incident on the grating coupling book 10 will pass through as is, so the track error detector 7 is provided at the position where the beam passes through. This makes it possible to detect tracking errors using the push-pull method.
上記の薄膜導波素子６に用いる分割器１１はグレーティ
ングやリブ構造等により容易に形成できる。The divider 11 used in the thin film waveguide element 6 described above can be easily formed using a grating, a rib structure, or the like.
第３図は第１図における検出系の他の例を示す斜視図で
ある。同図に示すようにトラックエラー検出器７および
フォーカスエラー検出器８を薄膜導波路９上に集積して
もよい、ｒＩＡえば、Ｓｉ基板上にＳ ｉ ０２のバッ
ファ層を介してガラスなどで薄膜導波路やグレーティン
グ素子を形成すれば、Ｓｉ基板上に光検出器を形成する
ことは容易である。フォーカスエラー検出器８の位置で
はＳｉＯ２バッファ層を除去しておけば、導波光はその
まま基板に形成された光検出器に結合する。また、トラ
ックエラー検出器７の位置ではＳｉＯ□バッファ層を残
しておけば、導波光は光検出器に結合せずに、薄膜導波
路に結合しなかったグレーティングへの入射光のみが光
検出器へ入射することになる６
第４図は本発明の他の実施例を示すブロック図で、第１
図で示したコリメートレンズ２を無くした簡単な構成と
なっているが、第１図に示した一実施例と同等の効果が
得られる。FIG. 3 is a perspective view showing another example of the detection system in FIG. 1. As shown in the figure, a track error detector 7 and a focus error detector 8 may be integrated on a thin film waveguide 9. For example, in rIA, a thin film made of glass or the like is placed on a Si substrate with a buffer layer of Si02 interposed therebetween. Once a waveguide and a grating element are formed, it is easy to form a photodetector on a Si substrate. If the SiO2 buffer layer is removed at the position of the focus error detector 8, the guided light will be directly coupled to the photodetector formed on the substrate. Furthermore, if the SiO□ buffer layer is left at the position of the track error detector 7, the guided light will not be coupled to the photodetector, and only the incident light to the grating that has not been coupled to the thin film waveguide will be coupled to the photodetector. Figure 4 is a block diagram showing another embodiment of the present invention.
Although the structure is simple without the collimating lens 2 shown in the figure, the same effect as the embodiment shown in FIG. 1 can be obtained.
以上説明したように本発明は、薄膜導波路中にグレーテ
ィング結合器と分割器を設け、２種類の光検出器を備え
ることにより、特性の劣化を招くこと無く光へ・・ｌド
装置を小型化することが可能となる効果がある。As explained above, the present invention provides a grating coupler and a divider in a thin film waveguide, and is equipped with two types of photodetectors, thereby making it possible to reduce the size of the optical device without deteriorating the characteristics. This has the effect of making it possible to
第１図、第４図は本発明の光ヘッド装置の一実施例、ｅ
の実施例を示すブロック図、第２図、第３図は第１図に
おける検出系の一例、池の例を示す斜視図、第５図は従
来の光ヘッド装置の一楕成例を示すブロック図、第６図
は第５図における検出系の一例を示す斜視図である。
１・・・半導体レーザ、２・・・コリメートレンズ、３
ビームスプリツタ、４・・・集光レンズ、５・・・記録
媒体、６・・・薄膜導波素子、７・・・トラックエラー
検出器、８・・・フォーカスエラー検出器、９・・・薄
膜導波路、１０・・・グレーティング結合器、１１・・
・分割器、１２・・・収束レンズ、１３・・・ナイフェ
ツジ、１４・・・分波器、１５・・・光検出器。
第２区
第５図FIGS. 1 and 4 show an embodiment of the optical head device of the present invention, e
FIGS. 2 and 3 are a block diagram showing an example of the detection system in FIG. 1, and a perspective view showing an example of a pond. FIG. 6 is a perspective view showing an example of the detection system in FIG. 5. 1... Semiconductor laser, 2... Collimator lens, 3
Beam splitter, 4... Condensing lens, 5... Recording medium, 6... Thin film waveguide element, 7... Track error detector, 8... Focus error detector, 9... Thin film waveguide, 10... grating coupler, 11...
- Divider, 12... Converging lens, 13... Knife lens, 14... Demultiplexer, 15... Photodetector. 2nd Ward Figure 5
Claims (2)
体上に集光する第１の光学系と、前記記録媒体からの反
射光を分離する第２の光学系を有する光ヘッド装置にお
いて、前記分離された反射光の一部を薄膜導波路中へ集
光ビームとして導くグレーティング結合器および導波光
をビーム光軸で２分割する分割器を備える薄膜導波素子
と、前記薄膜導波路の端面において前記導波光を受光す
る２分割型の第１の光検出器と、前記グレーティング結
合器を透過した前記記録媒体からの反射光を受光する２
分割型の第２の光検出器とを備えることを特徴とする光
ヘッド装置。(1) In an optical head device having a first optical system that focuses emitted light from a laser light source onto a recording medium as a minute spot, and a second optical system that separates reflected light from the recording medium, the separation a thin film waveguide element comprising a grating coupler that guides a part of the reflected light into the thin film waveguide as a condensed beam, and a splitter that divides the guided light into two along the beam optical axis; a two-part first photodetector that receives guided light; and a second photodetector that receives reflected light from the recording medium that has passed through the grating coupler.
An optical head device comprising: a split-type second photodetector.
おいて、第１の光検出器と第２の光検出器とが薄膜導波
素子上に集積されなる光ヘッド装置。(2) An optical head device according to claim (1), in which the first photodetector and the second photodetector are integrated on a thin film waveguide element.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61290874A JPS63144432A (en) | 1986-12-05 | 1986-12-05 | Optical head device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61290874A JPS63144432A (en) | 1986-12-05 | 1986-12-05 | Optical head device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS63144432A true JPS63144432A (en) | 1988-06-16 |
Family
ID=17761619
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP61290874A Pending JPS63144432A (en) | 1986-12-05 | 1986-12-05 | Optical head device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS63144432A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH02247834A (en) * | 1989-03-20 | 1990-10-03 | Hitachi Ltd | Optical head and optical information processing device |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS61233439A (en) * | 1985-04-08 | 1986-10-17 | Canon Inc | Optical pickup device |
-
1986
- 1986-12-05 JP JP61290874A patent/JPS63144432A/en active Pending
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS61233439A (en) * | 1985-04-08 | 1986-10-17 | Canon Inc | Optical pickup device |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH02247834A (en) * | 1989-03-20 | 1990-10-03 | Hitachi Ltd | Optical head and optical information processing device |
| JP2749107B2 (en) * | 1989-03-20 | 1998-05-13 | 株式会社日立製作所 | Light head |
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