JPH01211330A - Optical head - Google Patents
Optical headInfo
- Publication number
- JPH01211330A JPH01211330A JP63038092A JP3809288A JPH01211330A JP H01211330 A JPH01211330 A JP H01211330A JP 63038092 A JP63038092 A JP 63038092A JP 3809288 A JP3809288 A JP 3809288A JP H01211330 A JPH01211330 A JP H01211330A
- Authority
- JP
- Japan
- Prior art keywords
- light
- reflecting mirror
- optical head
- rays
- optical
- 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 33
- 239000004065 semiconductor Substances 0.000 claims description 7
- 238000007493 shaping process Methods 0.000 abstract description 8
- 230000002093 peripheral effect Effects 0.000 abstract 1
- 238000010586 diagram Methods 0.000 description 3
- 230000010287 polarization Effects 0.000 description 3
- 201000009310 astigmatism Diseases 0.000 description 2
- 230000002542 deteriorative effect Effects 0.000 description 1
- 230000000694 effects Effects 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、画像ファイル、文書ファイル及びコンピュー
タ用の外部メモリー装置等に用いられ、半導体レーザの
光ビームを利用して、情報を記録再生す。る光学式記録
及再生装置の光学ヘッドに関するものである。DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is used for image files, document files, external memory devices for computers, etc., and records and reproduces information using a light beam of a semiconductor laser. This invention relates to an optical head for an optical recording and reproducing device.
従来の技術
近年、コンピュータ用の外部メモリー装置として、高密
度大容量として光メモリー装置の開発が期待されている
が、原理的には、半導体レーザから放射される光ビーム
を、対物レンズによ多情報記録媒体上に集光させ、情報
記録膜に凹部を設ける等して情報を記録し、再生時には
情報記録面の平坦部と凹部とで光量変化が生じることを
利用して、情報信号を取り出すものである。2. Description of the Related Art In recent years, high-density, large-capacity optical memory devices have been expected to be developed as external memory devices for computers. Information is recorded by condensing light onto an information recording medium, creating recesses in the information recording film, etc., and extracting information signals by taking advantage of the change in light intensity between the flat and recessed areas of the information recording surface during playback. It is something.
従来の光記録再生装置について第2図を用いて説明する
。1は半導体レーザであシ、この半導体レーザ1から放
射される光ビームは、発散かつ楕円ビームとなっている
。従ってこの発散ビームをコリメートレンズ2により平
行ビームに変換している。またこの平行ビームは楕円ビ
ームとなっているため整形プリズム3によシ円ビームに
修正された後、偏光ビームスプリッタ−4と四分の一波
長板6を透過して、46°平面反射ミラー6で情報記録
媒体の方へ直角に曲げられる。直角に曲げられた光ビー
ムは対物レンズ7に入射し、情報記録媒体上に集光され
る。この時、対物レンズ7に入射される光ビームを対物
レンズγの有効径より大きくして入射させれば、対物レ
ンズ7により絞られたビームは1回折効果によシエアリ
ーディスク分布を示し、ビーム径は小さく絞られる。ま
だ絞られたビームがラジアル方向1周方向とで均一なビ
ーム径としようとすると、対物レンズ7に入射される平
行ビーム径は円ビームとし、ラジアル方向と周方向とで
強度分布を均一にすることが必要である。情報記録媒体
上にビーム径が円ビームとなり、かつ小さく絞ることが
できれば、レーザ光のエネルギーが集束され、記録膜に
凹部を設けることができる。また情報記録媒体上に照射
された光ビームは、反射され、再び対物レンズ7に入射
し、平行ビームとなる。この平行ビームは再び四分の一
波長板5に入射され、偏光面が90回転され、偏光ビー
ムスプリッタ−4によシ反射全光量が反射され、偏光ビ
ームスプリッタ−8の方へ入射される。偏光ビームスプ
リッタ−8でP偏光とS偏光の光ビームに分離され、反
射されたS偏光のビームは凸レンズ9によシ集光され、
2分割フォトティチクター10に結像され、トラッキン
グエラー信号が検出される。一方透過されたP偏光のビ
ームは、凸レンズ11によシ集光され、シリンドルカル
レンズ12によシ非点収差が発生され、4分割フォトデ
ィテクター13に結像され、フォーカスエラー信号が検
出される。これらのフォーカスエラー信号、トラッキン
グエラー信号によシ、情報記録媒体に面振れや、偏芯が
ある程度あっても、フォーカス方向に±1μm程度の焦
点梁度内に、トラッキング方向にも±0.1μm程度の
位置決め制御を、レンズ駆動用コイルにより対物レンズ
7を駆動させることにより達成している。A conventional optical recording/reproducing device will be explained using FIG. 2. 1 is a semiconductor laser, and the light beam emitted from this semiconductor laser 1 is a diverging and elliptical beam. Therefore, this diverging beam is converted into a parallel beam by the collimating lens 2. Since this parallel beam is an elliptical beam, it is modified into a circular beam by a shaping prism 3, and then transmitted through a polarizing beam splitter 4 and a quarter-wave plate 6, and then passed through a 46° flat reflecting mirror 6. It is bent at right angles towards the information recording medium. The light beam bent at right angles enters the objective lens 7 and is focused onto the information recording medium. At this time, if the light beam incident on the objective lens 7 is made larger than the effective diameter of the objective lens γ, the beam focused by the objective lens 7 exhibits a shearly disk distribution due to the single diffraction effect, and the beam The diameter is narrowed down. If we try to make the still narrowed beam a uniform beam diameter in the radial direction and one circumference direction, the diameter of the parallel beam incident on the objective lens 7 will be a circular beam, and the intensity distribution will be made uniform in the radial direction and the circumferential direction. It is necessary. If the beam diameter becomes a circular beam on the information recording medium and can be converged to a small size, the energy of the laser beam will be focused and a recessed portion can be provided in the recording film. Further, the light beam irradiated onto the information recording medium is reflected and enters the objective lens 7 again to become a parallel beam. This parallel beam is again incident on the quarter-wave plate 5, the plane of polarization is rotated by 90 degrees, and the total amount of reflected light is reflected by the polarizing beam splitter 4, and is incident on the polarizing beam splitter 8. A polarizing beam splitter 8 separates the light beam into P-polarized light and S-polarized light beam, and the reflected S-polarized light beam is focused by a convex lens 9.
An image is formed on the two-split phototicketor 10, and a tracking error signal is detected. On the other hand, the transmitted P-polarized beam is focused by the convex lens 11, astigmatism is generated by the cylindrical lens 12, and imaged by the 4-split photodetector 13, where a focus error signal is detected. Ru. Due to these focus error signals and tracking error signals, even if the information recording medium has surface runout or eccentricity to some extent, the focal beam angle is within ±1 μm in the focus direction and ±0.1 μm in the tracking direction. This positioning control is achieved by driving the objective lens 7 with a lens drive coil.
発明が解決しようとする課題
光記録再生装置及び消去可能型光記録装置の開発動向と
しては、コンピュータ用外部メモリー装置代替市場ねら
いということで、小型大容量化。Problems to be Solved by the Invention The trend in the development of optical recording and reproducing devices and erasable optical recording devices is toward smaller size and larger capacity, with the aim of replacing external memory devices for computers.
高速アクセス化が検討されている。小型薄型化に対して
も、磁気記録用磁気ヘッドに比較して光記録用ヘッドは
はるかに大きく厚い。また高速アクセス化に対しても、
固定磁気ディスタ装置と比べて一部近く遅い。その原因
も第2図の光学ヘッドが磁気ヘッドよシニ桁近く重たい
ところにある。High-speed access is being considered. Even when it comes to miniaturization and thinning, optical recording heads are much larger and thicker than magnetic recording heads. Also, for high-speed access,
Some parts are almost slower than fixed magnetic disk devices. The reason for this is that the optical head shown in Figure 2 is nearly an order of magnitude heavier than the magnetic head.
従って光記録再生装置がコンピュータ用外部メモリー装
置代替商品となるには、この光学ヘッドの小型薄型、軽
量化が最大の課題である。Therefore, in order for an optical recording/reproducing device to become a substitute product for external memory devices for computers, the biggest challenge is to make the optical head smaller, thinner, and lighter.
課題を解決するための手段
前記課題を解決するため本発明は従来の平行光の光軸を
直角方向に変換させる46°平面反射ミラー6のかわシ
に表面が円筒面状の反射ミラーを配置するものである。Means for Solving the Problems In order to solve the above problems, the present invention arranges a reflection mirror with a cylindrical surface on the edge of the 46° flat reflection mirror 6 that converts the optical axis of the conventional parallel light to the right angle direction. It is something.
作用
前記した様に、46°平面反射ミラーのかわシに表面が
円筒面状の反射ミラーを配置しているので、この反射ミ
ラーに楕円平行光を入射させると、光軸が垂直方向に変
換され、情報記録媒体方向に照射させられるとともに1
反射面が円筒面状になっていることによシ短軸方向が拡
がシ、対物レンズに入射する光量分布をラジアル方向を
周方向とでほぼ均一にでき、従って対物レンズによシ絞
られるビームは均一な円ビームでかつ小さく絞ることが
可能となる。従って対物レンズで絞られるビームの特性
を劣化させずに、整形プリズムと46°平面反射ミラー
を兼ねそなえた機能をもたせることができる。Function As mentioned above, a reflecting mirror with a cylindrical surface is placed on the edge of the 46° flat reflecting mirror, so when elliptical parallel light is incident on this reflecting mirror, the optical axis is converted to the vertical direction. , is irradiated in the direction of the information recording medium, and 1
Since the reflecting surface is cylindrical, the light is expanded in the short axis direction, making the distribution of light incident on the objective lens almost uniform in both the radial and circumferential directions, and therefore narrowed down by the objective lens. The beam becomes a uniform circular beam and can be narrowed down to a small size. Therefore, it is possible to provide the function of both a shaping prism and a 46° flat reflection mirror without deteriorating the characteristics of the beam focused by the objective lens.
実施例
本発明による実施例について、第1図を使って説明する
。第1図は本発明による光記録再生装置用光学ヘッドの
構成図を示す。記録再生の原理は従来例と全く同じであ
シ、構成要素部品の一部。Embodiment An embodiment of the present invention will be described with reference to FIG. FIG. 1 shows a configuration diagram of an optical head for an optical recording/reproducing apparatus according to the present invention. The principle of recording and playback is exactly the same as the conventional example, and only some of the component parts are used.
すなわち、従来の46°平面反射ミラー6を1表面が円
筒面状となった反射ミラー14に入れかわっただけであ
る。That is, the conventional 46° flat reflecting mirror 6 is simply replaced with a reflecting mirror 14 having one surface having a cylindrical shape.
半導体レーザ1を、水平方向に長短方向がくる様に配置
させると、半導体レーザ1から放射された楕円発散光は
コリメートレンズ2によシ平行光に変換され、偏光ビー
ムスプリッタ−4,四分の一波長板6を透過し、反射ミ
ラー14の円筒状面に入射される。するとここで光軸が
垂直方向になると同時に、楕円平行ビームの矩形方法が
発散ビ−ムとなシ、はぼ円ビームになる。そしてここに
対物レンズ7を配置しているので情報記録媒体上にビー
ムスポットが結ばれる。照射された光ビームは再び情報
記録媒体で反射され、四分の一波長板5を透過し、偏光
ビームスプリッタ−4で反射全光量が反射され、偏光ビ
ームスプリッタ−8でP偏光とS偏光の光ビームに分離
され、反射されたS偏光のビームは凸レンズ9によシ集
光され。When the semiconductor laser 1 is arranged so that the long and short directions are in the horizontal direction, the elliptically diverging light emitted from the semiconductor laser 1 is converted into parallel light by the collimating lens 2, and then the polarizing beam splitter 4 and the quarter The light passes through the one-wavelength plate 6 and is incident on the cylindrical surface of the reflecting mirror 14 . Then, at this point, the optical axis becomes vertical, and at the same time the rectangular shape of the elliptical parallel beam changes to a diverging beam and becomes an almost circular beam. Since the objective lens 7 is placed here, a beam spot is focused on the information recording medium. The irradiated light beam is again reflected by the information recording medium, transmitted through the quarter-wave plate 5, the total amount of reflected light is reflected by the polarization beam splitter 4, and the polarization beam splitter 8 separates the P-polarized light and the S-polarized light. The S-polarized beam, which is separated into light beams and reflected, is focused by a convex lens 9.
2分割フォトディテクター10に結像され、トラッキン
グエラー信号が検出される。一方透過されたP偏光の光
ビームは凸レンズ11によシ集光され、シリンドルカル
レンズ12によシ非点収差が発生され、4分割フォトデ
ィテクター13に結像され、フォカスエラー信号が検出
される。An image is formed on the two-segment photodetector 10, and a tracking error signal is detected. On the other hand, the transmitted P-polarized light beam is focused by a convex lens 11, astigmatism is generated by a cylindrical lens 12, and an image is formed on a 4-split photodetector 13, where a focus error signal is detected. Ru.
発明の効果
以上の様に、本発明によυ、はとんど構成をかえず、簡
易的な方法で、従来の楕円ビームを円ビームに整形する
整形プリズムを削減できるばかりでなく、楕円ビームの
平行光で光学素子を透過させることが可能なため、薄い
光学素子で構成でき。As described above, the present invention not only makes it possible to reduce the number of conventional shaping prisms used to shape an elliptical beam into a circular beam, but also to reduce the need for a shaping prism for shaping a conventional elliptical beam into a circular beam without changing the configuration. It is possible to transmit parallel light through the optical element, so it can be constructed with a thin optical element.
薄型、小型、軽量化の光学ヘッドを達成でき、安価でか
つ薄型軽量化のものを提供できるものである。It is possible to achieve a thin, compact, and lightweight optical head, and to provide an inexpensive, thin, and lightweight optical head.
第1図は本発明の一実施例における光学ヘッドの構成図
、第2図は従来の光記録再生用光学ヘッドの構成図を示
す。
1・・・・・・半導体レーザ、2・川・・コリメートレ
ンズ。
4・・・・・・偏光ビームスプリッタ−16・・・・・
・四分の一波長板、7・・・・・・対物レンズ、8・山
・・偏光ビームスプリッタ−19・山・・凸レンズ、1
0・・・・・・2分割フォトディテクター、11・山・
・凸レンズ、12・・・・・・シリンドルカルレンズ、
13・川・・4分割フォトディテクター、14・川・・
反射ミラー。
代理人の氏名 弁理士 中 尾 敏 男 ほか1名区
−へFIG. 1 is a block diagram of an optical head according to an embodiment of the present invention, and FIG. 2 is a block diagram of a conventional optical recording/reproducing optical head. 1... Semiconductor laser, 2... Collimating lens. 4...Polarizing beam splitter-16...
・Quarter wavelength plate, 7...Objective lens, 8・Mountain...Polarizing beam splitter-19・Mountain...Convex lens, 1
0...2-split photodetector, 11・Mountain・
・Convex lens, 12... Cylindrical lens,
13. River... 4-split photodetector, 14. River...
reflective mirror. Name of agent: Patent attorney Toshio Nakao and 1 other person
Claims (2)
平行光に変換するコリメートレンズと、平行光の光軸を
直角方向に変換させるミラーと、記録媒体に光ビームを
集光させる対物レンズを備え、前記ミラーとして表面が
円筒面状の反射ミラーを使用した光学ヘッド。(1) A semiconductor laser that emits elliptically diverging light, a collimating lens that converts the diverging light into parallel light, a mirror that converts the optical axis of the parallel light to a right angle direction, and an objective lens that focuses the light beam on the recording medium. An optical head comprising: a reflecting mirror having a cylindrical surface as the mirror.
を直角に変換させる部分に入射させる構成とした特許請
求の範囲第1項記載の光学ヘッド。(2) The optical head according to claim 1, wherein the elliptical parallel beam is made incident on a portion of the cylindrical reflecting mirror that converts the optical axis to a right angle.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP63038092A JPH01211330A (en) | 1988-02-19 | 1988-02-19 | Optical head |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP63038092A JPH01211330A (en) | 1988-02-19 | 1988-02-19 | Optical head |
Publications (1)
Publication Number | Publication Date |
---|---|
JPH01211330A true JPH01211330A (en) | 1989-08-24 |
Family
ID=12515829
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP63038092A Pending JPH01211330A (en) | 1988-02-19 | 1988-02-19 | Optical head |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH01211330A (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN100412969C (en) * | 2005-03-25 | 2008-08-20 | 鸿富锦精密工业(深圳)有限公司 | Optical system and optical recording/reproducing device using the same |
-
1988
- 1988-02-19 JP JP63038092A patent/JPH01211330A/en active Pending
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN100412969C (en) * | 2005-03-25 | 2008-08-20 | 鸿富锦精密工业(深圳)有限公司 | Optical system and optical recording/reproducing device using the same |
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