JPS6391834A - Optical head - Google Patents
Optical headInfo
- Publication number
- JPS6391834A JPS6391834A JP61236122A JP23612286A JPS6391834A JP S6391834 A JPS6391834 A JP S6391834A JP 61236122 A JP61236122 A JP 61236122A JP 23612286 A JP23612286 A JP 23612286A JP S6391834 A JPS6391834 A JP S6391834A
- Authority
- JP
- Japan
- Prior art keywords
- light beam
- wavelength
- light
- luminous flux
- incident
- 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 50
- 230000004907 flux Effects 0.000 claims abstract description 15
- 230000010287 polarization Effects 0.000 claims abstract description 5
- 239000004065 semiconductor Substances 0.000 claims description 13
- 238000001514 detection method Methods 0.000 claims description 5
- 238000002834 transmittance Methods 0.000 claims description 3
- 238000007493 shaping process Methods 0.000 abstract description 3
- 238000003475 lamination Methods 0.000 abstract 5
- 238000000926 separation method Methods 0.000 description 3
- 230000003595 spectral effect Effects 0.000 description 3
- 238000010586 diagram Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 230000013011 mating Effects 0.000 description 2
- 206010041662 Splinter Diseases 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
Landscapes
- Optical Head (AREA)
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は光ディスクプレーヤ等に用いられる光ヘッドに
関し、特に光ディスクに信号を記録し、記録された信号
の再生、消去を行なうのに好適な光ヘッドに関する。[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an optical head used in optical disc players, etc., and in particular to an optical head suitable for recording signals on an optical disc and reproducing and erasing the recorded signals. Regarding the head.
従来の、波長の異なる２つの半導体レーザを用いる光ヘ
ッドとしては、例えば特開昭５８−１３２２１４号公報
に記載のように、偏光ビームスプリッタ、４分の１波長
板、波長選択性を有するミラーなどで構成される光束合
成手段を用いていた。Conventional optical heads that use two semiconductor lasers with different wavelengths include polarizing beam splitters, quarter-wave plates, mirrors with wavelength selectivity, etc., as described in JP-A-58-132214, for example. A beam combining means consisting of the following was used.
上記した様に、従来技術では、偏光ビームスプリッタ、
４分の１波長板、波長選択を有するミラーなどで構成さ
れる光束合成手段を用いている為、部品数が多くなシ構
成が複雑となるという問題点があった。As mentioned above, in the conventional technology, polarizing beam splitter,
Since a beam combining means consisting of a quarter wavelength plate, a mirror with wavelength selection, etc. is used, there are problems in that the number of parts is large and the configuration is complicated.
そこで、本発明の目的は、上記した従来技術の問題点を
除去し、簡単な構成で波長の異なる２つの光束の合成が
行なえる光束合成手段を用いた光ヘッドを提供すること
にある。SUMMARY OF THE INVENTION An object of the present invention is to eliminate the problems of the prior art described above and to provide an optical head using a beam combining means that can combine two beams of different wavelengths with a simple configuration.
上記した目的を達成するために、本発明では、光ビーム
合成手段を、第１の波長の光束を入射する第１の入射面
と、第２の波長の光束を入射する第２の入射面と、波長
によシ透過率の異なる波長選択性を有し、前記第１及び
第２の入射面より入射された第１及び第２の波長の光束
をそれぞれ互いに相異なる側から入射して、一方を透過
し他方を反射することにより略同一な光軸に合成する反
射膜と、合成された光束の光軸を対物レンズの光軸方向
に向きを変える反射面と、該反射面にて反射された該光
束を前記対物レンズに向かって出射する第１の出射面と
、光ディスクで反射され対物レンズを介して該第１の出
射面よシ再び入射した光束を、反射して分離する偏光反
射面と、分離された該光束を検出手段に向かって出射す
る第２の出射面と、を有したプリズムで構成するように
したものである。In order to achieve the above-mentioned object, the present invention includes a light beam combining means having a first entrance surface into which a light beam of a first wavelength is incident, and a second entrance surface into which a light beam of a second wavelength is incident. , which has wavelength selectivity with different transmittance depending on the wavelength, and allows the light fluxes of the first and second wavelengths incident from the first and second incident surfaces to be incident from different sides, so that one A reflective film that transmits the light flux and reflects the other light beam to combine the light beams into substantially the same optical axis, a reflective surface that changes the direction of the optical axis of the combined light beam in the direction of the optical axis of the objective lens, and a first exit surface that emits the light beam toward the objective lens; and a polarization reflecting surface that reflects and separates the light beam that is reflected by the optical disk and enters the first exit surface again via the objective lens. and a second exit surface that emits the separated light beam toward the detection means.
本発明による光ヘッドに用いる前記したプリズムは、そ
れ一つでもって、半導体レーザ光の楕円状強度分布を補
正するための光束整形プリズム、互いに波長の異なる２
つの光束を略同一な光軸に合成するための波長分離フィ
ルタ、合成された２つの光束の光軸を対物レンズの元軸
方向に向きを変えるミラー、光ディスクからの反射光を
半導体レーザと対物レンズとを結ぶ光路中から分離する
ための偏光ビームスプリッタ、の各機能をすべて有して
いるために、光ヘッドの構成は従来に比較して簡単にな
る。The above-described prism used in the optical head according to the present invention is a beam shaping prism for correcting the elliptical intensity distribution of semiconductor laser light, and two prisms having different wavelengths.
A wavelength separation filter that combines two light beams into almost the same optical axis, a mirror that changes the direction of the optical axis of the two combined light beams toward the original axis of the objective lens, and a semiconductor laser and objective lens that direct the reflected light from the optical disk. Since the optical head has all the functions of a polarizing beam splitter for separating the beam from the optical path connecting the optical head, the configuration of the optical head is simpler than that of the conventional one.
以下、本発明の一実施例を第１図から第４図によシ説明
する。An embodiment of the present invention will be described below with reference to FIGS. 1 to 4.
第１図は本発明の一実施例としての光ヘッドを示す斜視
図、第２図は第１図における光ディスク上の光スポット
の状態を示す説明図、第６図は第１図におけるプリズム
の平面図、第４図は第３図（Ｄ ）ＩＪ スムにおける
反射膜の分光特性を示すグラフ、である。FIG. 1 is a perspective view showing an optical head as an embodiment of the present invention, FIG. 2 is an explanatory diagram showing the state of the optical spot on the optical disk in FIG. 1, and FIG. 6 is a plane view of the prism in FIG. 1. Figure 4 is a graph showing the spectral characteristics of the reflective film in Figure 3 (D) IJ Sum.
半導体レーザ１は波長λ１のレーザ光を発し、このレー
ザ光はコリメータレンズ６によシ略平行な光束５に変換
され、プリズム８の入射面８ａに入射して屈折し、張り
合せ面８０に入射する。一方、半導体レーザ２は波長λ
２のレーザ光を発し、このレーザ光はコリメータレンズ
４によυ略平行な光束６に変換され、円筒レンズ７を透
過してプリズム８の入射面８ｂに入射して屈折し張シ合
せ面８Ｃに入射する。The semiconductor laser 1 emits a laser beam with a wavelength λ1, which is converted into a substantially parallel beam 5 by the collimator lens 6, enters the incident surface 8a of the prism 8, is refracted, and enters the bonding surface 80. do. On the other hand, the semiconductor laser 2 has a wavelength λ
This laser beam is converted into a substantially parallel light beam 6 by the collimator lens 4, passes through the cylindrical lens 7, enters the entrance surface 8b of the prism 8, is refracted, and is refracted at the joining surface 8C. incident on .
張シ合せ面８ｃの一部には、波長によシ透過率の異なる
波長選択性を有する反射ｉ８ｄが形成されてお９、その
分光特性は第４因に示す通りである。すなわち、波長的
８００ｎｍを境にしてそれ以上の波長では入射光は透過
し、それ以下の波長では入射光は反射する。ここで、半
導体レーザ１の波長λ１として約８３０ｎｍ、半導体レ
ーザ２の波長λ２として約７８０ｎｍとすると、光束５
は張）合せ面８ｃを透過し、光束６は張シ合せ面８ｃで
反射する。このとき、光束５．光束６の張り合せ面８Ｃ
への入射角はほぼ等しく、入射する位置もほぼ等しいた
めに光束５と光束６は略同一な光軸に合成される。A reflection i8d having wavelength selectivity with different transmittance depending on the wavelength is formed in a part of the tensioned joint surface 8c, and its spectral characteristics are as shown in the fourth factor. That is, the incident light is transmitted at wavelengths beyond 800 nm, and the incident light is reflected at wavelengths below 800 nm. Here, assuming that the wavelength λ1 of the semiconductor laser 1 is approximately 830 nm and the wavelength λ2 of the semiconductor laser 2 is approximately 780 nm, the luminous flux 5
The light beam 6 passes through the mating surface 8c and is reflected by the mating surface 8c. At this time, the luminous flux 5. Bonding surface 8C of luminous flux 6
Since the angles of incidence on the light beams are approximately the same and the positions of incidence are also approximately the same, the light beams 5 and 6 are combined onto substantially the same optical axis.
この２つの光束は反射面８ｅで反射され、張シ合せ面８
ｃに入射する。この部分には反射膜８ｄが形成されてお
らず、２つの光束は透過し、更に、偏光反射面８ｆを透
過して出射面８ｇから出射される。その後、４分の１波
長板９を透過して、対物レンズ１０によ）、モータ（図
示せず）により回転する光ディスク１１上に焦点を結ぶ
。These two light beams are reflected by the reflecting surface 8e, and the tensioning surface 8
incident on c. The reflective film 8d is not formed in this portion, and the two light beams are transmitted therethrough, further transmitted through the polarized light reflective surface 8f, and then emitted from the output surface 8g. Thereafter, the light passes through a quarter-wave plate 9 and is focused by an objective lens 10 onto an optical disk 11 which is rotated by a motor (not shown).
光ディスク１１によシ反射した光束は対物レンズ１０に
より再び略平行な光束にに換され、４分の１波長板９を
透過して偏光反射面８ｆで反射され、出射１ｓｈから出
射して検出レンズ１６によシ検出器１７上に集光される
。検出器１７からは元ディスク１１に記録された情報信
号、フォーカシング誤差信号、トラッキング誤差信号な
どが恢出される。しかし上記し７を信号の検出方法は本
発明の重置には関係ないために詳細な説明は省略する。The light beam reflected by the optical disk 11 is converted into a substantially parallel light beam again by the objective lens 10, passes through the quarter-wave plate 9, is reflected by the polarization reflecting surface 8f, and is emitted from the output 1sh to the detection lens. 16, the light is focused onto a detector 17. The detector 17 outputs information signals recorded on the original disk 11, focusing error signals, tracking error signals, and the like. However, since the signal detection method described in 7 above is not relevant to the present invention, a detailed explanation thereof will be omitted.
ところで、元ディスク１１上には第２図に示すように光
束５．６によ）２つのスポット１２．１３がそれぞれ結
ばれる。光束５はほぼ円形のスポット１２に結ばれるが
、光束６は円筒レンズ７の作用により元ディスク１１の
トラックＴｌａ方向（Ｘ方向）に長い長円形のスポット
１６に結ばれる。By the way, as shown in FIG. 2, two spots 12 and 13 are formed on the original disk 11 by the light beam 5.6. The light beam 5 is focused on a substantially circular spot 12, while the light beam 6 is focused on an oval spot 16 that is elongated in the track Tla direction (X direction) of the original disk 11 due to the action of the cylindrical lens 7.
ここで、元ディスク１１にはたとえばＳ（１，Ｔｅ、
Ｓｅ等を主成分とする記録膜が蒸着されている。Here, the original disk 11 has, for example, S(1, Te,
A recording film containing Se or the like as a main component is deposited.
半導体レーザ１の光出力を高出力にすると、この記録膜
は円形スポット１２によシ急熱・急冷されて、結晶状態
が結晶からアモルファス（非晶質）に変化する。半導体
レーザ２の光出力を高出力にすると、この記録膜は長円
形スポット１３により徐熱・徐冷されて結晶状態がアモ
ルファスから結晶に変化する。第２図の黒点１４．１５
はアモルファス状態であ）、記録された信号を示してい
る。When the optical output of the semiconductor laser 1 is made high, the recording film is rapidly heated and cooled by the circular spot 12, and its crystalline state changes from crystal to amorphous. When the optical output of the semiconductor laser 2 is made high, the recording film is gradually heated and cooled by the oval spot 13, and its crystalline state changes from amorphous to crystalline. Black dot 14.15 in Figure 2
is in an amorphous state) and shows the recorded signal.
２つの光スポラ）１２．１３を第２図に示すように同一
トラック上に配置し、光ディスク１１の回転方向を矢印
１８とすると、すでに記録された信号１４をスポット１
６により消去しながら、スポット１２によシ新たに信号
１５を記録することができる。If two optical spoilers (12 and 13) are arranged on the same track as shown in FIG.
A new signal 15 can be recorded in the spot 12 while erasing the signal 15 in the spot 12.
第５図は本発明の他の実施例を示す斜視図である。FIG. 5 is a perspective view showing another embodiment of the present invention.
第５図の実施例において、円筒レンズ７を用いないこと
以外は第１図の実施例と同一である。この様に円筒レン
ズ７を用いない場合は、光スポット１２．１３はともに
円形となる。The embodiment shown in FIG. 5 is the same as the embodiment shown in FIG. 1 except that the cylindrical lens 7 is not used. In this way, when the cylindrical lens 7 is not used, the light spots 12 and 13 are both circular.
その結果、例えば、第６図に示すように２つの光スポッ
ト１２．１３を同一トラック上に配置することによシ、
光スポット１３で信号を記録すると同時に光スポット１
２で信号を再生することができる。また第７図に示すよ
うに２つの光スポット＋２．ｉを隣接トラック上に配置
することにより、２つのトラックに同時に信号を記録し
、また同時に再生したシ、一方のスポットで記録し、他
方のスポットで再生することもできる。As a result, for example, by arranging two light spots 12, 13 on the same track as shown in FIG.
At the same time as recording a signal with optical spot 13, optical spot 1
2 can reproduce the signal. In addition, as shown in FIG. 7, two light spots +2. By arranging the signals on adjacent tracks, it is possible to record signals on two tracks at the same time and to reproduce them at the same time, recording on one spot and reproducing on the other spot.
本発明による光ヘッドにおいては、半導体レーザの楕円
状強度分布を補正するための光束整形プリズム、互いに
波長の異なる２つの光束を略同一な光軸に合成するため
の波長分離フィルタ、合成された２つの光束の光軸を対
物レンズの光軸方向に向きを変えるミラー、光ディスク
からの反射光を分離するための偏光ビームスプリンタ、
の谷機能をすべて有する、プリズムを用いているので、
光ヘッドの構成を簡略化することができる。The optical head according to the present invention includes a beam shaping prism for correcting the elliptical intensity distribution of a semiconductor laser, a wavelength separation filter for combining two beams having different wavelengths onto substantially the same optical axis, and a wavelength separation filter for combining two beams having different wavelengths onto substantially the same optical axis. A mirror that changes the direction of the optical axis of two light beams in the direction of the optical axis of the objective lens, a polarizing beam splinter that separates the reflected light from the optical disk,
Since it uses a prism that has all the valley functions of
The configuration of the optical head can be simplified.
第１図は本発明の一実施例を示す斜視図、第２図は第１
図における元ディスク上の光スポットの状態を示す説明
図、第３図は第１図におけるプリズムの平面図、第４図
は第５図のプリズムにおける反射膜の分光特性を示すグ
ラフ、第５図は本発明の他の実施例を示す斜視図、第６
図及び第７図はそれぞれ第５図における光ディスク上の
光スポットの状態を示す説明図、である。
１．２・・・半導体レーザ、７・・・円筒レンズ、８・
・・プリズム、１０・・・対物レンズ、１１・・・光デ
ィスク。FIG. 1 is a perspective view showing one embodiment of the present invention, and FIG. 2 is a perspective view showing one embodiment of the present invention.
3 is a plan view of the prism in FIG. 1, FIG. 4 is a graph showing the spectral characteristics of the reflective film in the prism in FIG. 5, and FIG. 6 is a perspective view showing another embodiment of the present invention.
7 and 7 are explanatory diagrams showing the state of the light spot on the optical disk in FIG. 5, respectively. 1.2... Semiconductor laser, 7... Cylindrical lens, 8...
... Prism, 10... Objective lens, 11... Optical disk.
Claims (1)
、第２の波長の光束を出射する第２の半導体レーザと、
前記第１及び第２の波長の光束を略同一な光軸に合成す
るための光ビーム合成手段と、該光ビーム合成手段から
出射した第１及び第２の波長の光束を光ディスク上に焦
点を結ばせるための対物レンズと、該光ディスクにより
反射した第１及び第２の波長の光束のうち、少なくとも
一方の光束を前記対物レンズを介し前記光ビーム合成手
段において反射された後、検出する検出手段と、を少な
くとも備えた光ヘッドにおいて、前記光ビーム合成手段
は、前記第１の波長の光束を入射する第１の入射面と、
前記第２の波長の光束を入射する第２の入射面と、波長
により透過率の異なる波長選択性を有し、前記第１及び
第２の入射面より入射された第１及び第２の波長の光束
をそれぞれ互いに相違なる側から入射して、一方を透過
し他方を反射することにより略同一な光軸に合成する反
射膜と、合成された光束の光軸を前記対物レンズの光軸
方向に向きを変える反射面と、該反射面にて反射された
該光束を前記対物レンズに向かって出射する第１の出射
面と、前記光ディスクで反射され対物レンズを介して該
第１の出射面より再び入射した光束を、反射して分離す
る偏光反射面と、分離された該光束を前記検出手段に向
かって出射する第２の出射面と、を有したプリズムから
成ることを特徴とする光ヘッド。1. A first semiconductor laser that emits a luminous flux of a first wavelength; a second semiconductor laser that emits a luminous flux of a second wavelength;
a light beam combining means for combining the light beams of the first and second wavelengths onto substantially the same optical axis, and focusing the light beams of the first and second wavelengths emitted from the light beam combining means onto an optical disk. an objective lens for combining the light beams, and a detection means for detecting at least one of the light beams of the first and second wavelengths reflected by the optical disk after being reflected by the light beam combining means through the objective lens. In an optical head comprising at least the following, the light beam combining means includes a first entrance surface into which the light beam of the first wavelength is incident;
a second entrance surface into which the light beam of the second wavelength is incident; and a first and second wavelengths which have wavelength selectivity with different transmittance depending on the wavelength, and which are incident on the first and second entrance surfaces. A reflective film that allows the light beams to enter from different sides and combine them into substantially the same optical axis by transmitting one and reflecting the other, and directing the optical axis of the combined light beam in the optical axis direction of the objective lens. a first exit surface that emits the light beam reflected by the reflection surface toward the objective lens; and a first exit surface that emits the light beam reflected by the optical disk and passes through the objective lens. A light characterized by comprising a prism having a polarization reflecting surface that reflects and separates the light beam that has entered the light beam again, and a second exit surface that emits the separated light beam toward the detection means. head.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61236122A JPS6391834A (en) | 1986-10-06 | 1986-10-06 | Optical head |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61236122A JPS6391834A (en) | 1986-10-06 | 1986-10-06 | Optical head |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS6391834A true JPS6391834A (en) | 1988-04-22 |
Family
ID=16996074
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP61236122A Pending JPS6391834A (en) | 1986-10-06 | 1986-10-06 | Optical head |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6391834A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0411335A (en) * | 1990-04-27 | 1992-01-16 | Victor Co Of Japan Ltd | Optical disk device |
| KR100323936B1 (en) * | 1996-10-30 | 2002-02-09 | 니시무로 타이죠 | Optical head and optical components thereof and manufacturing method thereof and optical disk apparatus |
-
1986
- 1986-10-06 JP JP61236122A patent/JPS6391834A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0411335A (en) * | 1990-04-27 | 1992-01-16 | Victor Co Of Japan Ltd | Optical disk device |
| KR100323936B1 (en) * | 1996-10-30 | 2002-02-09 | 니시무로 타이죠 | Optical head and optical components thereof and manufacturing method thereof and optical disk apparatus |
| KR100354950B1 (en) * | 1996-10-30 | 2002-10-11 | 가부시끼가이샤 도시바 | Optical head and optical components thereof and manufacturing method thereof and optical disk apparatus |
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