JPS59128510A - Beam pattern shaping device of polarized light beam splitter - Google Patents
Beam pattern shaping device of polarized light beam splitterInfo
- Publication number
- JPS59128510A JPS59128510A JP58003735A JP373583A JPS59128510A JP S59128510 A JPS59128510 A JP S59128510A JP 58003735 A JP58003735 A JP 58003735A JP 373583 A JP373583 A JP 373583A JP S59128510 A JPS59128510 A JP S59128510A
- Authority
- JP
- Japan
- Prior art keywords
- polarizing film
- pattern
- prism
- angle
- beam splitter
- 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
Classifications
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/28—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 for polarising
- G02B27/283—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 for polarising used for beam splitting or combining
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Optical Head (AREA)
Abstract
Description
【発明の詳細な説明】
本発明はビーム・パターン整形機能を備えた偏光ビーム
・スプリッタ、特に半導体レーザを光源とする光学式ビ
デオ・ディスク或はオーディオ・ディスク・プレーヤ月
光ビックアップのビーム・パターン整形装置に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a polarizing beam splitter with a beam pattern shaping function, particularly for beam pattern shaping of an optical video disc or audio disc player Gekko Startup using a semiconductor laser as a light source. Regarding equipment.
光学式のビデオ又はオーディオ・ディスク・プレーヤに
使用する元ピック・アップは周知の如く第１図の如き基
本構成金とるが一般的である。As is well known, a pickup used in an optical video or audio disc player generally has a basic configuration as shown in FIG.
即ち、半導体レーザ１を発したレーザ・ビーム＝！ｌ：
：！！にリメータ・レンズ２及びビーム・パターン整形
プリズム３全通して真円とした上で偏光膜４を直角プリ
ズム５，５でサンドイッチした偏光ビーム・スプリッタ
６で例えばＰ偏光成分のみのビームとなしこれを１／４
波長板７を介して円偏光とする。この真円のパターンを
有するビーム全フォーカシングΦレンズ８ｆ、用いてデ
ィスク９表面に刻んだピットに照射し所定の変調を受け
た反射光を再び前記１／４波長板７を通すことによって
８偏光に変換した上で前記偏光膜４で完全に反射させフ
ォト・ダイオード等のセンサ１０によって前記ディスク
９のビット・パターンに対応した信号に変換するもので
ある。That is, the laser beam emitted from the semiconductor laser 1 =! l:
:! ! The remeter lens 2 and the beam pattern shaping prism 3 are completely circular, and a polarizing beam splitter 6 in which a polarizing film 4 is sandwiched between right angle prisms 5 is used to convert the beam into a beam containing only the P-polarized component, for example. 1/4
It becomes circularly polarized light through a wavelength plate 7. Using this full-beam focusing Φ lens 8f having a perfect circular pattern, the reflected light is irradiated onto pits carved on the surface of the disk 9, and the reflected light, which has undergone a predetermined modulation, is passed through the quarter-wave plate 7 again to be converted into 8-polarized light. After the signal is converted, it is completely reflected by the polarizing film 4 and converted into a signal corresponding to the bit pattern of the disk 9 by a sensor 10 such as a photo diode.
しかしながら上述の構成は単に原理を示すものに過ぎず
現実には部品点数、調整箇所を削減する為光学部品の一
体化が行なわれていることはいうまでもない。However, the above-mentioned configuration merely shows the principle, and it goes without saying that in reality, optical components are integrated in order to reduce the number of parts and adjustment locations.
第２図はその一例を示す図であるが半導体レーザ１を出
たレーザ・ビームを４辺形のビーム・パターン整形プリ
ズム３で真円に整形しこれをその一面に付着した偏光膜
４で特定偏光状態とじ１７４波長板７及びフォーカシン
グ・レンゲ８を介してディスク９表面に照射しその反射
光を前記偏光膜４表面で反射しセンサ１０に導くもので
ある。本例に示す光ピツクアップは前記４辺形のプリズ
ム３で整形したビーム・パターンに前記センサ１０に導
びくまでの間そのパターンを極力変形しないよう工夫す
ると共に光学系の調整を容易にする為もあって極めて複
雑な形状となり従って高価となるのみならず前記レーザ
発振器１へのもどり光によってひき起こされるバック・
トークの影響が少なくないという問題がある。FIG. 2 shows an example of this. The laser beam emitted from the semiconductor laser 1 is shaped into a perfect circle by a quadrilateral beam pattern shaping prism 3, and this is identified by a polarizing film 4 attached to one surface of the laser beam. The light is irradiated onto the surface of the disk 9 via the polarization state adjusting 174 wavelength plate 7 and the focusing lens 8, and the reflected light is reflected by the surface of the polarizing film 4 and guided to the sensor 10. The optical pickup shown in this example is designed so that the beam pattern shaped by the quadrilateral prism 3 is not deformed as much as possible until it is guided to the sensor 10, and also to facilitate adjustment of the optical system. This results in an extremely complicated shape, which not only makes it expensive, but also reduces back-up caused by the light returning to the laser oscillator 1.
The problem is that the influence of talk is considerable.
本発明は上述の如き従来の光ピツクアップの問題に鑑み
てなされたものであって、ビーム・パターン整形プリズ
ムのビーム入射面に偏光膜全付着すると共に該面に於け
る入射角を前記プリズムからの出射ビーム・パターンが
実質的に真円となるようにした偏光ビーム・スプリクタ
ノヒーム・パターン整形装置全提供することを目的とす
る。The present invention has been made in view of the problems of conventional optical pickup as described above, and includes a polarizing film completely attached to the beam incidence surface of a beam pattern shaping prism, and the incident angle on the surface is changed from that of the prism. It is an object of the present invention to provide a polarizing beam splitter beam pattern shaping device in which an emitted beam pattern becomes a substantially perfect circle.
以下本発明を理論とこれを応用した実施例とによって詳
細に説明する。Hereinafter, the present invention will be explained in detail based on theory and examples to which the theory is applied.
先ず偏光ビーム・スプリッタに必須の偏光膜の性格につ
いて説明する。First, the characteristics of the polarizing film essential for a polarizing beam splitter will be explained.
偏光膜は周知の如く例えば５ｉＯ３ｔ ’Ｌ ｉＯ２の
様な低い屈折率と高い屈折率と金有する誘電体薄膜全交
互に十数乃至数十層積層したもので構成するがその透過
或は反射特性は波長及び入射角に大きく依存する。第３
図（ａ）及び（ｂ）は夫々５ｉ０２及びＴｉ０２ｅ交互
に３０層積層した偏光膜に於いて入射角４５°と６０°
との場合の反射率Ｔの波長依存性を示した図であるが、
本図から明らかな如く偏光膜面に対する入射角が大なる
場合は波長λの変動に対してＰ偏光の透過率は鈍感であ
りしかもＳ偏光成分の反射率は極めて犬であるに反し入
射角が小さくなると波長変動に敏感とな９Ｐ偏光成分と
Ｓ偏光成分との分離が困難となる傾向にあることが理解
されよう。As is well known, a polarizing film is composed of dielectric thin films having low refractive index, high refractive index, and gold, such as 5iO3t'L iO2, which are alternately laminated in dozens or dozens of layers, but their transmission or reflection characteristics are It is highly dependent on wavelength and angle of incidence. Third
Figures (a) and (b) show incident angles of 45° and 60° for polarizing films in which 30 layers of 5i02 and Ti02e are alternately laminated.
It is a diagram showing the wavelength dependence of the reflectance T in the case of
As is clear from this figure, when the angle of incidence with respect to the polarizing film surface is large, the transmittance of P-polarized light is insensitive to fluctuations in wavelength λ, and the reflectance of S-polarized light is extremely small. It will be understood that as the wavelength becomes smaller, it tends to become difficult to separate the 9P polarization component and the S polarization component, which are sensitive to wavelength fluctuations.
このことは偏光ビーム骨スゲリッタ、特に発振波長のバ
ラツキの大なる半導体レーザを用いるビーム・スプリッ
タに於いてレーザ・ビームを小さな入射角で偏光膜に入
射せしめるならばもどり光を増大しバック・トークが問
題となる機械のパーセンテイジを高める可能性があるこ
と金示すものである。This means that in a polarized beam bone sgelitter, especially in a beam splitter that uses a semiconductor laser with a large variation in oscillation wavelength, if the laser beam is made incident on the polarizing film at a small angle of incidence, the return light will increase and back talk will occur. This indicates that there is a potential to increase the percentage of machines in question.
上述の問題全解決する為には半導体レーザを発したレー
ザ・ビームを大入射角（７０°近傍が最良である）で偏
光膜に入射するよう設計すればよい。しかも好都合なこ
とに半導体レーザのビーム・パターンは既ね長軸対短軸
の比が２：１にも及ぶ楕円形状であるので、このパター
ンをビーム入射面に偏光膜全付着したプリズムで実質的
に真円となるようにすることは容易である。In order to solve all of the above problems, the laser beam emitted from the semiconductor laser should be designed to be incident on the polarizing film at a large angle of incidence (near 70° is best). Moreover, conveniently, the beam pattern of a semiconductor laser is already an ellipse with a ratio of major axis to minor axis of 2:1, so this pattern can be effectively converted into a prism with a polarizing film fully attached to the beam incidence surface. It is easy to make it a perfect circle.
第４図はその一実施例を示す図である。FIG. 4 is a diagram showing an example thereof.
即ち、はソ平行四辺形のプリズム３を屈折率ｎ＝１．５
１ のガラスで形成しその一面に偏光膜４を付着し該
面に対しレーザ・ビームを入射角７１°で入射するよう
に構成すると長軸対短軸比２．４：１ のパターンを
有するレーザ・ビームははソ真円となりその形状を維持
したままディスク９０ビツトヲ照射する。而してその反
射光は前記偏光膜４の背面で完全に反射しレーザ発振器
１への戻り光は事実上無視し得るものとなる。That is, the refractive index of the parallelogram prism 3 is n=1.5.
1, a polarizing film 4 is attached to one surface of the glass, and the laser beam is made incident on the surface at an incident angle of 71°, resulting in a laser having a pattern with a long axis to short axis ratio of 2.4:1. - The beam becomes a perfect circle and irradiates 90 bits of the disk while maintaining that shape. The reflected light is completely reflected on the back surface of the polarizing film 4, and the light returning to the laser oscillator 1 can be virtually ignored.
しかしながら前記偏光膜背面での反射角は約３９°とな
る為ビーム・パターンにや＼変形してセンサ１０に入射
するが、この程度のパターン変形はセンサ側に於ける信
号の電気的処理で充分補正可能である。又、上述の電気
的補正が不都合であるならばレンズ、絞り或はプリズム
等で光学的に補正することも格別の困難はない。However, since the reflection angle on the back surface of the polarizing film is about 39°, the beam pattern is slightly deformed and enters the sensor 10, but this degree of pattern deformation can be easily achieved by electrical processing of the signal on the sensor side. Can be corrected. Furthermore, if the above-mentioned electrical correction is inconvenient, it is not particularly difficult to perform optical correction using a lens, diaphragm, prism, or the like.
本発明は以上説明した如く構成するので比較的単純な形
状のプリズムで半導体レーザのビーム・パターンを整形
すると共にそのプリズムを出射するビームの偏光状態全
入射ビームの波長の大きなバラツキに対してもはソ完全
に偏らせることが可能となるから光学式のビデオ又はオ
ーディオ・ディスク番プレーヤの光ピツクアップ或は各
種の光学計測器２元通信用アイソレータ等の特性を向イ
弓ストヲ低下させる上で著しい効果を発揮する。Since the present invention is constructed as described above, it is possible to shape the beam pattern of a semiconductor laser using a prism of a relatively simple shape, and also to compensate for large variations in the wavelength of all incident beams in the polarization state of the beam emitted from the prism. Since it is possible to completely bias the beam, it has a remarkable effect on reducing the bow deflection characteristics of optical pickups of optical video or audio disk players or isolators for two-way communication of various optical measuring instruments. demonstrate.
同、前記プリズムの形状は第４図に示した実施例に限定
される必要はなく、レーザ発振器。Similarly, the shape of the prism is not limited to the embodiment shown in FIG. 4, and the shape of the prism is not limited to the embodiment shown in FIG.
ディスク及びセンサの位置によって変形するものである
ことはいうまでもあるまい。Needless to say, the shape changes depending on the position of the disk and sensor.
第１図は偏光ビーム・スプリッタを使用した光ピツクア
ップの基本構成金示す原理図、第２図は従来のビーム・
パターン、整形機能を有する偏光ビーム・スプリッタの
一例金示す図、第３図（ａｌ及び（ｂｌは夫々入射角の
大小による偏光膜の機能の差を示す図、第４図は本発明
に係る偏光ビーム・スプリッタを用いた光ピツクアップ
の一実施例を示す図である。
１・・・・・・レーザ発振器、 ３・・・・・・ビーム
・パターン整形用プリズム、 ４・・・・・・偏光膜、
７・・・両波長板、 １０・川・・センサ
特許出願人 東洋通信機株式会社Figure 1 is a principle diagram showing the basic configuration of optical pickup using a polarizing beam splitter, and Figure 2 is a diagram showing the basic configuration of an optical pickup using a polarizing beam splitter.
An example of a polarizing beam splitter with a pattern and shaping function is shown in Figure 3 (al and (bl are diagrams showing the difference in the function of a polarizing film depending on the magnitude of the incident angle, respectively), and Figure 4 is a diagram showing a polarizing beam splitter according to the present invention. It is a diagram showing an example of optical pickup using a beam splitter. 1... Laser oscillator, 3... Beam pattern shaping prism, 4... Polarized light. film,
7...Double wave plate, 10...Sensor patent applicant Toyo Tsushinki Co., Ltd.
Claims (1)
光ビーム−スプリッタに於いで、前記プリズムのビーム
入射面に偏光膜を付着すると共に該面に対するビームの
入射角を前記プリズムを出射するビームのパターンが実
質的に真円になるよう位置せしめたこと？％徴とする偏
光ビーム・スプリッタのビーム−パターン整形装置。 Ｃ）前記偏光膜面に対するビーム入射角θヲ４５゜〈θ
〈９０°に設定することによって入射ビームの波長変動
に対する特定の偏光成分の透過率及び反射率の変動を微
少ならしめたことを特徴とする特許請求の範囲１記載の
偏光ビーム・スプリッタのビーム・パターン整形装置。(1) In a polarizing beam splitter equipped with a prism for beam pattern shaping, a polarizing film is attached to the beam incidence surface of the prism, and the incident angle of the beam with respect to the surface is adjusted so that the pattern of the beam exiting the prism is adjusted. Did you position it so that it was essentially a perfect circle? Beam-pattern shaping device for polarizing beam splitter with % characteristics. C) Beam incident angle θ with respect to the polarizing film surface 45°〈θ
<The beam splitter of the polarizing beam splitter according to claim 1, characterized in that by setting the angle to 90°, variations in the transmittance and reflectance of a specific polarized light component with respect to wavelength variations of the incident beam are minimized. Pattern shaping device.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58003735A JPS59128510A (en) | 1983-01-12 | 1983-01-12 | Beam pattern shaping device of polarized light beam splitter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58003735A JPS59128510A (en) | 1983-01-12 | 1983-01-12 | Beam pattern shaping device of polarized light beam splitter |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS59128510A true JPS59128510A (en) | 1984-07-24 |
Family
ID=11565492
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP58003735A Pending JPS59128510A (en) | 1983-01-12 | 1983-01-12 | Beam pattern shaping device of polarized light beam splitter |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS59128510A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS59188852A (en) * | 1983-04-12 | 1984-10-26 | Hitachi Ltd | Polarized beam splitter |
| JPS6278743A (en) * | 1986-09-04 | 1987-04-11 | Hitachi Ltd | Optical head |
| JPS6316437A (en) * | 1986-07-08 | 1988-01-23 | Nec Home Electronics Ltd | Optical head |
| JPH0291830A (en) * | 1988-09-28 | 1990-03-30 | Mitsubishi Electric Corp | Optical head device |
-
1983
- 1983-01-12 JP JP58003735A patent/JPS59128510A/en active Pending
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS59188852A (en) * | 1983-04-12 | 1984-10-26 | Hitachi Ltd | Polarized beam splitter |
| JPH0533466B2 (en) * | 1983-04-12 | 1993-05-19 | Hitachi Ltd | |
| JPS6316437A (en) * | 1986-07-08 | 1988-01-23 | Nec Home Electronics Ltd | Optical head |
| JPS6278743A (en) * | 1986-09-04 | 1987-04-11 | Hitachi Ltd | Optical head |
| JPH0534735B2 (en) * | 1986-09-04 | 1993-05-24 | Hitachi Ltd | |
| JPH0291830A (en) * | 1988-09-28 | 1990-03-30 | Mitsubishi Electric Corp | Optical head device |
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