JP2635372B2 - Light head - Google Patents
Light headInfo
- Publication number
- JP2635372B2 JP2635372B2 JP63160090A JP16009088A JP2635372B2 JP 2635372 B2 JP2635372 B2 JP 2635372B2 JP 63160090 A JP63160090 A JP 63160090A JP 16009088 A JP16009088 A JP 16009088A JP 2635372 B2 JP2635372 B2 JP 2635372B2
- Authority
- JP
- Japan
- Prior art keywords
- light
- optical
- light beam
- reflecting surface
- reflecting
- 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 - Fee Related
Links
Landscapes
- Optical Head (AREA)
Description
【発明の詳細な説明】 産業上の利用分野 本発明はビデオディスク等のようにディスク上に記録
された情報を光学的に読み取る光学的再生装置、あるい
はディスクに情報を光学的に記録，再生もしくは消去す
る装置に用いられる光ヘッドに関するものである。Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical reproducing apparatus for optically reading information recorded on a disk, such as a video disk, or to optically recording, reproducing, or reproducing information on a disk. The present invention relates to an optical head used for an erasing device.
従来の技術 近年、光学的記録再生装置は音響，映像分野からコン
ピュータ外部記憶媒体に利用されるようになってきた。
まず、従来の光学的記録再生装置の一例について説明す
る。2. Description of the Related Art In recent years, an optical recording / reproducing apparatus has been used as an external storage medium in a computer from the fields of audio and video.
First, an example of a conventional optical recording / reproducing apparatus will be described.
第８図は従来の光学的記録再生装置の光学系を示すも
のであり、１は半導体レーザ、２は半導体レーザから出
射された光を平行光にするコリメートレンズ、３はビー
ム整形をして光量損を抑制する整形プリズム、４はディ
スクから反射して戻ってきた光束をフォトダイオードへ
導くための偏光ビームスプリッタ、５は偏光ビームプリ
ッタと組合せてディスク面で反射した光が半導体レーザ
に戻って生じるバックトークを防止する４分の１波長
板、６はディスク上で約１μｍのビームスポットを形成
する対物レンズである。FIG. 8 shows an optical system of a conventional optical recording / reproducing apparatus, wherein 1 is a semiconductor laser, 2 is a collimating lens for converting light emitted from the semiconductor laser into parallel light, and 3 is a beam shaping and light quantity. A shaping prism for suppressing the loss, a polarizing beam splitter 4 for guiding the light flux returned from the disk and returning to the photodiode, and a back light 5 generated in combination with the polarizing beam splitter to return the light reflected from the disk surface to the semiconductor laser A quarter-wave plate 6 for preventing talk is an objective lens for forming a beam spot of about 1 μm on the disk.
以上のように構成された光学的記録再生装置におい
て、半導体レーザ１から出射された光ビームは第９図に
示すように遠視野像は回折現象によって決まるビームの
拡がりをもち、接合面に垂直方向の拡がり角θ⊥の方
が、接合面に平行方向の拡がり角θ に比べ約２倍ない
し３倍大きくなる。 In the optical recording / reproducing apparatus configured as described above,
The light beam emitted from the semiconductor laser 1 is shown in FIG.
As shown, the far-field image is
Spread, spread angle θ perpendicular to the joint surface⊥Who
Is the divergence angle θ in the direction parallel to the joining surface Not about twice as much as
3 times larger.
このビームの光量損失を少なくして平行光にするよう
に、コリメートレンズ２を用いる。また、記録再生装置
などの記録も行なう光ディスク光学系では、光源から記
録面までの光量損が重要な問題となる。また対物レンズ
６に入射する光の強度分布が等方的でないと、ディスク
上でビームスポットが円形に絞れない。したがってビー
ムを整形する整形プリズム３と組合せて光量損を抑制す
る。The collimating lens 2 is used to reduce the light quantity loss of the beam and make it parallel light. Further, in an optical disk optical system that also performs recording such as a recording / reproducing apparatus, loss of light amount from a light source to a recording surface is an important problem. If the intensity distribution of the light incident on the objective lens 6 is not isotropic, the beam spot on the disk cannot be narrowed down to a circle. Therefore, the light amount loss is suppressed in combination with the shaping prism 3 for shaping the beam.
この整形されたビームを対物レンズに入射させる。こ
のとき式（１）で表現されるガウシアンの強度分布を持
つ入射ビームは、第８図のごとく対物レンズで集光され
て、スポット像を形成する。The shaped beam is incident on the objective lens. At this time, the incident beam having the Gaussian intensity distribution expressed by the equation (1) is condensed by the objective lens as shown in FIG. 8 to form a spot image.
Ｉ（ｐ）＝exp（−２ρ2/w2） ……（１） 対物レンズが無収差の回折限界レンズとすれば、像面で
のスポット半径woは次式で表わされる。I (p) = exp (−2ρ 2 / w 2 ) (1) If the objective lens is a diffraction-limited lens having no aberration, the spot radius w o on the image plane is expressed by the following equation.
wo＝Ｋ＊ λ/NA ……（２） K:レンズの開口形状や入射ビームの断面の強度分布など
で決まる定数 NA:対物レンズの開口数 発明が解決しようとする課題 しかしながら上記のような構成では、次のような問題
点を有している。 wo = K * λ / NA (2) K: constant determined by the aperture shape of the lens and the intensity distribution of the cross section of the incident beam NA: numerical aperture of the objective lens Problems to be solved by the Invention However, as described above. The configuration has the following problems.
光源たとえば半導体レーザから出射されたビームを平
行光に変換した後、楕円ビームの断面形状を円形に整形
するためのプリズムとビームをディスク側に進む方向を
変える全反射ミラーを有し、光ヘッドの小型化・薄型化
に対して大きな弊害となっていた。After converting a beam emitted from a light source such as a semiconductor laser into parallel light, the prism includes a prism for shaping the cross-sectional shape of the elliptical beam into a circular shape and a total reflection mirror for changing the direction in which the beam advances to the disk side. This has been a major harm to miniaturization and thinning.
本発明は上記問題点に鑑み、小型・軽量・薄型にでき
る光学的記録再生装置用の光ヘッドを提供することを目
的とするものである。An object of the present invention is to provide an optical head for an optical recording / reproducing apparatus which can be reduced in size, weight and thickness in view of the above problems.
課題を解決するための手段 上記課題を解決するために、本発明の光ヘッドは、入
射した光ビームを所定の傾斜角に設定した反射面を順次
階段状に形成した光学素子の反射面上で一方向で２以上
に分割して反射させるようにし、かつ各々の反射面の高
さあるいは隣接する反射面間の距離をことならせること
により、光ビームの断面形状の長軸方向と短軸方向の変
換比を変え、かつ光ビームの光強度分布を補正するよう
にしたものである。Means for Solving the Problems In order to solve the above problems, an optical head of the present invention is provided on a reflecting surface of an optical element in which a reflecting surface in which an incident light beam is set at a predetermined inclination angle is sequentially formed in a step shape. The light beam is divided into two or more in one direction and reflected, and the height of each reflecting surface or the distance between adjacent reflecting surfaces is varied, so that the cross-sectional shape of the light beam in the major axis direction and the minor axis direction Is changed, and the light intensity distribution of the light beam is corrected.
作用 本発明は、上記した構成によって、楕円等の光ビーム
の長軸方向と短軸方向の長さを整形し、かつ光強度分布
を理想的に交換して光量損を抑制する整形プリズムを廃
止でき、従来複雑な構成を持たざるを得なかった光ヘッ
ド構成を簡単にすることができ、小型・軽量・薄型化で
きる。Function The present invention eliminates the shaping prism that shapes the length of the long axis direction and the short axis direction of a light beam such as an ellipse and suppresses the light amount loss by ideally exchanging the light intensity distribution by the above-described configuration. It is possible to simplify the optical head configuration, which had to have a complicated configuration in the past, and to reduce the size, weight, and thickness.
実 施 例 以下、本発明の一実施例の光学的記録再生装置用の光
ヘッドについて、図面を参照しながら説明する。Embodiment Hereinafter, an optical head for an optical recording / reproducing apparatus according to an embodiment of the present invention will be described with reference to the drawings.
第１図から第６図は本発明を説明するための参考図を
示すものである。第１図において１は半導体レーザ、２
はコリメートレンズ、10は光ビームの断面形状変換用の
光学素子、６は対物レンズである。1 to 6 show reference diagrams for explaining the present invention. In FIG. 1, 1 is a semiconductor laser, 2
Is a collimating lens, 10 is an optical element for converting the cross-sectional shape of the light beam, and 6 is an objective lens.
この光学素子10は、端面に、反射面として、入射ピー
ムをＹ方向で２以上に分割して反射する階段状の反射面
を形成して、半導体レーザ１からの光ビームをＹ方向の
断面の長さを長くするようにして反射させるようにして
いる。This optical element 10 has a stepped reflecting surface which is formed by dividing an incident beam into two or more in the Y direction and reflects the light beam from the semiconductor laser 1 as a reflecting surface on an end face, and allows the light beam from the semiconductor laser 1 to have a cross section in the Y direction. The length is made longer to reflect.
第２図は光ビームの断面形状変換用の光学素子10のビ
ーム断面形状を変える動作を示す。FIG. 2 shows the operation of changing the beam cross-sectional shape of the optical element 10 for changing the cross-sectional shape of a light beam.
第２図に示すように入射した光ビームの断面形状の長
軸方向（Ｘ方向）あるいは短軸方向（Ｙ方向）の長さを 変換比η＝（a cosθ＋ｂ）/b で拡大することができる。As shown in FIG. 2, the length of the cross-sectional shape of the incident light beam in the major axis direction (X direction) or the minor axis direction (Y direction) can be increased by the conversion ratio η = (a cos θ + b) / b. .
以上のように参考図の第１図によれば、光源から発光
された光ビームを所定の角度に設定した反射面を順次階
段状に形成した光学素子10に、一定方向から入射させ、
その素子面上で反射させることにより、光ビーム断面形
状の長軸方向と短軸方向の変換比を変えることができ
る。According to FIG. 1 of the reference diagram as described above, the light beam emitted from the light source is made to enter the optical element 10 in which a reflecting surface set at a predetermined angle is sequentially formed in a stepwise manner, from a certain direction,
By reflecting the light beam on the element surface, the conversion ratio between the major axis direction and the minor axis direction of the light beam cross-sectional shape can be changed.
第３図に他の参考図による光ビームの断面形状を変換
する光学素子10を示す。この光学素子10は、端面を所定
角度にした薄いプレート11を多数積み重ねて、端面を階
段状にし、その端面に対する入射ビームを分割して反射
することにより反射された光ビームの断面形状の長軸方
向と短軸方向の変換比率を自由に設定できる。FIG. 3 shows an optical element 10 for changing the cross-sectional shape of a light beam according to another reference drawing. This optical element 10 is formed by stacking a large number of thin plates 11 each having an end face at a predetermined angle, making the end face stepwise, dividing an incident beam to the end face and reflecting the divided beam, and the major axis of the cross-sectional shape of the reflected light beam. The conversion ratio between the direction and the minor axis direction can be set freely.
第４図に他の参考図による光ビームの断面形状を変換
する光学素子10を示す。FIG. 4 shows an optical element 10 for changing the cross-sectional shape of a light beam according to another reference drawing.
この参考図では、端面に所定の角度で反射面を設けた
薄いプレート11を各々蝶番12で結合して積重ね、相互に
摺動可能に構成して自由にプレート間の重ね合せ位置を
変える機構13を設けることにより、自由に光ビーム形状
の変換率を設定できる。In this reference diagram, a thin plate 11 provided with a reflecting surface at a predetermined angle on an end face is connected by a hinge 12 and stacked, and is configured to be slidable with each other to freely change a superposition position between the plates. Is provided, the conversion rate of the light beam shape can be set freely.
また第５図に示すように、端面に所定の角度を設けた
薄いプレート11を積み重ね、棒状のレバー14,15で、積
み重ねたプレート11両端面を傾けることによって、光ビ
ームの長軸と短軸の長さを所望の比に変換することがで
きる。Also, as shown in FIG. 5, thin plates 11 having a predetermined angle on their end surfaces are stacked, and both ends of the stacked plates 11 are tilted by rod-shaped levers 14 and 15 so that the long axis and the short axis of the light beam are changed. Can be converted to a desired ratio.
第６図に他の参考図による光ビームの断面形状を変換
する光学素子10を示す。この光学素子10は、一枚のプレ
ートにＶ型の溝16を平行に形成し、このプレートを任意
の角度に設定して光ビームを入射させることにより、光
ビーム断面形状を変換できる。FIG. 6 shows an optical element 10 for changing the cross-sectional shape of a light beam according to another reference drawing. In this optical element 10, a V-shaped groove 16 is formed in a single plate in parallel, and the plate is set at an arbitrary angle so that a light beam is incident thereon, whereby the light beam cross-sectional shape can be converted.
第７図に本発明の実施例を示す。これは、各々一定の
反射角度を持つ反射面の高さあるいは反射面と反射面の
距離をそれぞれ変えることにより、入射ビームの断面に
おける光強度分布を一方向のみ自由に変えることができ
る。たとえば第７図に示すようにガウシアン分布で入射
した光ビームを方形波に変えて反射させることができ
る。これによりビームを一方向ではあるが、見かけ上で
NAを大きくすることができ、第１図に示す対物レンズ６
を通過後、ビームスポットを小さく絞ることができる。FIG. 7 shows an embodiment of the present invention. This means that the light intensity distribution in the cross section of the incident beam can be freely changed in only one direction by changing the height of the reflecting surface having a constant reflecting angle or the distance between the reflecting surfaces. For example, as shown in FIG. 7, a light beam having a Gaussian distribution can be changed into a square wave and reflected. This allows the beam to be in one direction, but apparently
The NA can be increased, and the objective lens 6 shown in FIG.
After passing through, the beam spot can be narrowed down.
発明の効果 以上にように本発明は、光ビーム断面形状を変換する
光学素子を光学的記録再生装置の光ヘッドに用いること
により、小型・軽量・薄型で波長変動による光軸ずれの
ない光ヘッドにすることができる。As described above, the present invention provides an optical head that is small, lightweight, and thin and has no optical axis shift due to wavelength fluctuation by using an optical element that converts a light beam cross-sectional shape for an optical head of an optical recording / reproducing apparatus. Can be
第１図〜第６図は本発明に関係する光ヘッドの側面図及
び拡大図、第７図は実施例の光ヘッドの側面図、第８図
は従来例の光ヘッドの斜視図、第９図はその対物レンズ
前後のビームを示す模式図である。 １……半導体レーザ、２……コリメートレンズ、３……
ビーム整形プリズム、４……偏光ビームスプリッタ、５
……４分の１波長板、６……対物レンズ、８……光学素
子。1 to 6 are side views and enlarged views of an optical head relating to the present invention, FIG. 7 is a side view of an optical head of an embodiment, FIG. 8 is a perspective view of a conventional optical head, and FIG. The figure is a schematic diagram showing beams before and after the objective lens. 1 ... Semiconductor laser, 2 ... Collimate lens, 3 ...
Beam shaping prism, 4 ... Polarizing beam splitter, 5
... Quarter-wave plate, 6 ... objective lens, 8: optical element.
Claims (1)
くは消去する光学的記録再生装置に用いられる光ヘッド
であって、 光ビームを出射する光源と、光源から出射された光を平
行光に変換するコリメートレンズと、情報媒体のディス
クに対してビームを絞る対物レンズと、前記コリメート
レンズと前記対物レンズとの間に、平行ビームを少なく
とも２つ以上に分割する略同一角度の反射面を持ち、各
々の反射面の高さまたは各々の隣接する反射面間の距離
を異ならせて、各々のビームを略平行に反射し、ビーム
径の垂直方向と平行方向での比率を変換し、かつ反射ビ
ームの断面での光強度分布を所望の光分布に変換する光
学素子を備えることを特徴とする光ヘッド。An optical head for use in an optical recording / reproducing apparatus for optically recording, reproducing, or erasing information on a disk, comprising: a light source for emitting a light beam; A collimating lens for conversion, an objective lens for converging a beam on a disc of an information medium, and a reflecting surface having substantially the same angle between the collimating lens and the objective lens for dividing a parallel beam into at least two or more beams. By making the height of each reflecting surface or the distance between each adjacent reflecting surface different, reflecting each beam substantially parallel, converting the ratio of the beam diameter in the vertical direction and the parallel direction, and reflecting An optical head comprising an optical element for converting a light intensity distribution in a beam cross section into a desired light distribution.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63160090A JP2635372B2 (en) | 1988-06-28 | 1988-06-28 | Light head |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63160090A JP2635372B2 (en) | 1988-06-28 | 1988-06-28 | Light head |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0210529A JPH0210529A (en) | 1990-01-16 |
| JP2635372B2 true JP2635372B2 (en) | 1997-07-30 |
Family
ID=15707643
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP63160090A Expired - Fee Related JP2635372B2 (en) | 1988-06-28 | 1988-06-28 | Light head |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2635372B2 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE69127324T2 (en) * | 1990-06-29 | 1998-01-15 | Toshiba Kawasaki Kk | Optical head |
| JP4093209B2 (en) * | 2004-07-12 | 2008-06-04 | ティアック株式会社 | Optical pickup device and optical disk device |
| US8384896B2 (en) * | 2009-10-01 | 2013-02-26 | Tornado Medical Systems, Inc. | Optical slicer for improving the spectral resolution of a dispersive spectrograph |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6313142A (en) * | 1986-07-03 | 1988-01-20 | Matsushita Electric Ind Co Ltd | Optical type recording and reproducing device |
| JP2866866B2 (en) * | 1988-03-31 | 1999-03-08 | 芝浦メカトロニクス株式会社 | Laser beam shaping device |
-
1988
- 1988-06-28 JP JP63160090A patent/JP2635372B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0210529A (en) | 1990-01-16 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |