JPH0512773B2 - - Google Patents
Info
- Publication number
- JPH0512773B2 JPH0512773B2 JP58070351A JP7035183A JPH0512773B2 JP H0512773 B2 JPH0512773 B2 JP H0512773B2 JP 58070351 A JP58070351 A JP 58070351A JP 7035183 A JP7035183 A JP 7035183A JP H0512773 B2 JPH0512773 B2 JP H0512773B2
- Authority
- JP
- Japan
- Prior art keywords
- prism
- angle
- collimator lens
- total reflection
- 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.)
- Expired - Lifetime
Links
- 230000003287 optical effect Effects 0.000 claims description 43
- 239000004065 semiconductor Substances 0.000 claims description 11
- 230000001105 regulatory effect Effects 0.000 claims description 2
- 238000006243 chemical reaction Methods 0.000 description 13
- NCGICGYLBXGBGN-UHFFFAOYSA-N 3-morpholin-4-yl-1-oxa-3-azonia-2-azanidacyclopent-3-en-5-imine;hydrochloride Chemical compound Cl.[N-]1OC(=N)C=[N+]1N1CCOCC1 NCGICGYLBXGBGN-UHFFFAOYSA-N 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
Classifications
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/12—Heads, e.g. forming of the optical beam spot or modulation of the optical beam
- G11B7/135—Means for guiding the beam from the source to the record carrier or from the record carrier to the detector
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/12—Heads, e.g. forming of the optical beam spot or modulation of the optical beam
- G11B7/22—Apparatus or processes for the manufacture of optical heads, e.g. assembly
Landscapes
- Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Optical Head (AREA)
Description
【発明の詳細な説明】
産業上の利用分野
本発明は、例えば円盤状記録媒体（以下光デイ
スクと称する。）に半導体レーザーからの光を集
光し情報を記録再生する光学式記録再生装置に用
いる光学ヘツドに関するものである。DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an optical recording and reproducing device that records and reproduces information by condensing light from a semiconductor laser onto, for example, a disk-shaped recording medium (hereinafter referred to as an optical disk). This relates to the optical head used.
従来例の構成とその問題点
高出力半導体レーザーの発光パターンは、楕円
ビームであり、この様な楕円ビームを集光しても
絞り性能が良くないことは、波動光学の教えると
ころである。従つて光学式記録再生装置の記録再
生特性を向上するためには、楕円ビームを平行な
円ビームに変換することが不可欠である。Conventional configuration and its problems The emission pattern of a high-power semiconductor laser is an elliptical beam, and wave optics teaches that even if such an elliptical beam is focused, the aperture performance is not good. Therefore, in order to improve the recording and reproducing characteristics of an optical recording and reproducing device, it is essential to convert an elliptical beam into a parallel circular beam.
従来、この様な光ビーム形状の変換は特開昭55
−108612号公報に見られるように凹凸シリンドリ
カルレンズが用いられていた。第１図は、その凹
凸シリンドリカルレンズを用いた光学系の断面図
である。第１図において、１は、半導体レーザ
ー、２は集光レンズ、３は、凹シリンドリカルレ
ンズ、４は凸シリンドリカルレンズ、５は、光学
ヘツド全体の筐筒である。 Conventionally, such a conversion of the light beam shape was proposed in Japanese Patent Application Laid-open No. 1983
As seen in Publication No.-108612, a concave-convex cylindrical lens was used. FIG. 1 is a sectional view of an optical system using the concave-convex cylindrical lens. In FIG. 1, 1 is a semiconductor laser, 2 is a condensing lens, 3 is a concave cylindrical lens, 4 is a convex cylindrical lens, and 5 is a housing for the entire optical head.
この様な凹凸シリンドリカルレンズを用いた光
学系では光軸方向の寸法が大きくなるといつた欠
点を有していた。 An optical system using such a concave-convex cylindrical lens has the disadvantage that the dimension in the optical axis direction becomes large.
そこで、プリズムを用いて光ビーム形状変換行
なう光学ヘツドを提唱した。第２図は、そのプリ
ズムを用いた光学ヘツドの構成図である。第２図
において、１は半導体レーザー、２は集光レン
ズ、６は、楕円ビームを円ビームに変換するとと
もに入射主光線CR１の光路を出射主光線CR３の
光路へ直交変換する機能を持つプリズムである。
Ｐ，Ｑ，Ｒ，Ｚはア各々プリズム６の頂点を示
す。また、稜線QRで代表される面は、全反射面
として機能している。 Therefore, we proposed an optical head that uses a prism to transform the shape of a light beam. FIG. 2 is a block diagram of an optical head using the prism. In Fig. 2, 1 is a semiconductor laser, 2 is a condensing lens, and 6 is a prism that has the function of converting an elliptical beam into a circular beam and orthogonally converting the optical path of the incident chief ray CR1 to the optical path of the outgoing chief ray CR3. be.
P, Q, R, and Z each indicate the apex of the prism 6. Furthermore, the surface represented by the ridgeline QR functions as a total reflection surface.
ここで、プリズム６のビーム形状変換率は、断
面AAに於けるビーム径I1と断面BBにおけるビー
ム径I2の比で表わすことができる。 Here, the beam shape conversion rate of the prism 6 can be expressed as the ratio of the beam diameter I 1 at the cross section AA to the beam diameter I 2 at the cross section BB.
この比I2／I1は、稜線PQで代表される入射面にお
ける屈折から導ることができる。すなわち、入射
角をθ1、屈折角θ2とすれば、
I2／I1＝Cosθ2／Cosθ1
しかるに、屈折角θ2は、プリズム材料の屈折率
をｎとすれば、スネルの法則から一義的に、
θ2＝Sin-1（１／ｎSinθ1）で決定される。 This ratio I 2 /I 1 can be derived from the refraction at the plane of incidence represented by the ridgeline PQ. That is, if the angle of incidence is θ 1 and the angle of refraction is θ 2 , then I 2 /I 1 =Cosθ 2 /Cosθ 1 However, if the refractive index of the prism material is n, then the angle of refraction θ 2 is calculated from Snell's law. Uniquely, θ 2 =Sin −1 (1/nSin θ 1 ) is determined.
従つて、プリズム６のビーム形状変換率は、入
射主光線CR１と稜線PQで代表される入射面の法
線のなす角θ1すなわち、CR１とPQのなす角で決
定されることがわかる。 Therefore, it can be seen that the beam shape conversion rate of the prism 6 is determined by the angle θ 1 between the incident chief ray CR1 and the normal to the plane of incidence represented by the ridgeline PQ, that is, the angle between CR1 and PQ.
また、入射主光線CR１と、出射主光線CR３の
なす角（偏角）によつて、プリズム６の光路変換
機能が示されるが、これは、第２図から明らかの
様に、まず、屈折主光線CR２と、辺QRで代表さ
れる全反射面となす角度と、その全反射面で反射
された光線と、辺RZで代表される面となす角度
とで決定される。 Furthermore, the optical path conversion function of the prism 6 is indicated by the angle (declination) between the incident principal ray CR1 and the outgoing principal ray CR3. It is determined by the angle between the light ray CR2 and the total reflection surface represented by the side QR, the light ray reflected by the total reflection surface, and the angle between the light ray CR2 and the surface represented by the side RZ.
以上述べたことから、プリズム６のビーム形状
変換機能と、光路変換機能は、角θ1、角θ3、角θ4
によつて決定付けられることが分かる。 From the above, the beam shape conversion function and optical path conversion function of the prism 6 are determined by the angle θ 1 , angle θ 3 , and angle θ 4
It can be seen that it is determined by
つまり、第２図に示した、光ビーム形状及び光
路変換プリズム６を用いた光学系においては、プ
リズム６の単体加工時における角θ3、角θ3の角度
精度と、組立時の角θ1の角度精度が重要となる。 In other words , in the optical system using the light beam shape and optical path changing prism 6 shown in FIG. The angular accuracy is important.
一方、別途考えたプリズムにおいては、入射光
軸CR１と全反射面とのなす角をθ4に等しくなる
設定をすれば、入射光軸CR１と出射光軸CR３と
の直交性及び所望のビーム径比I2／I1が得られる角
θ1を与えるような角θ3、θ4が形成されている。 On the other hand, in a separately considered prism, if the angle between the incident optical axis CR1 and the total reflection surface is set equal to θ 4 , the orthogonality between the incident optical axis CR1 and the output optical axis CR3 and the desired beam diameter can be achieved. The angles θ 3 and θ 4 are formed to provide the angle θ 1 from which the ratio I 2 /I 1 is obtained.
従つて、入射光軸CR１と全反射面がθ4に等し
い角度をなす事が、本プリズムを用いる光学ヘツ
ドにおいて第１の要目となる。 Therefore, the first important point in an optical head using this prism is that the incident optical axis CR1 and the total reflection surface form an angle equal to θ4 .
しかしながら、従来例においては、その手段は
明示されていなかつた。 However, in the conventional example, the means for doing so was not clearly specified.
発明の目的
本発明は上記の点を考慮し、プリズムの光ビー
ム形状変換及び光路変換機能の精度を確実なもの
とすることを目的とする。Purpose of the Invention The present invention takes the above points into consideration and aims to ensure the accuracy of the light beam shape conversion and optical path conversion functions of the prism.
発明の構成
本発明は、半導体レーザーとコリメータレンズ
とを有し、このコリメータレンズにより平行楕円
ビームに変換された入射光を、この入射光と直交
する平行円ビームに変換するよう構成された全反
射面を持つたプリズムを設け、前記コリメータレ
ンズの光軸と前記プリズムの全反射面のなす角度
を規制する位置決め部を前記コリメータレンズお
よび前記プリズムを収納した筐体に設け、プリズ
ムの光ビーム形状変換機能と光路変換機能の精度
を確実なものとした光学ヘツドである。Structure of the Invention The present invention has a semiconductor laser and a collimator lens, and is configured to convert incident light, which has been converted into a parallel elliptical beam by the collimator lens, into a parallel circular beam orthogonal to the incident light. A prism having a surface is provided, a positioning portion for regulating the angle formed between the optical axis of the collimator lens and the total reflection surface of the prism is provided in a housing housing the collimator lens and the prism, and the light beam shape of the prism is converted. This is an optical head that ensures the accuracy of its functions and optical path conversion function.
実施例の説明
次に本発明の一実施例を第３図、第４図を用い
て説明する。第３図は、本発明の一実施例におけ
る光学ヘツドの平面図、第４図は同正面図であ
る。７は、半導体レーザー１及びコリメータレン
ズ２を収納した鏡筒２ａの光軸の位置決め用段部
である。８は、プリズム６の全反射面の位置決め
用段部である。この位置決め段部７，８は各々、
LL、SSで代表される位置決め面のなす角をプリ
ズム６の頂角θ4と等しくするよう形成されてい
る。DESCRIPTION OF EMBODIMENTS Next, an embodiment of the present invention will be described with reference to FIGS. 3 and 4. FIG. 3 is a plan view of an optical head according to an embodiment of the present invention, and FIG. 4 is a front view thereof. Reference numeral 7 denotes a stepped portion for positioning the optical axis of the lens barrel 2a that accommodates the semiconductor laser 1 and the collimator lens 2. 8 is a step portion for positioning the total reflection surface of the prism 6. The positioning step portions 7 and 8 are each
It is formed so that the angle formed by the positioning surfaces represented by LL and SS is equal to the apex angle θ 4 of the prism 6.
従つてプリズム６の全反射面を段部８押し当て
て固着し、半導体レーザー１及び鏡筒２ａを段部
７に押し当てて固着すれば、プリズム６への入射
光軸と、プリズム６の全反射面のなす角は、角θ4
に規定される。従つて、プリズム６の角θ3、θ4と
から、プリズム６の入射面への入射角θ1が正しく
設定され、プリズム６のビーム形状変換機能は、
所定の変換率を満足し、さらに、入射光軸と出射
光軸の直交性も満足される。 Therefore, if the total reflection surface of the prism 6 is pressed against the stepped portion 8 and fixed, and the semiconductor laser 1 and lens barrel 2a are pressed against the stepped portion 7 and fixed, the optical axis of incidence on the prism 6 and the entire surface of the prism 6 will be The angle formed by the reflective surface is angle θ 4
stipulated in Therefore, from the angles θ 3 and θ 4 of the prism 6, the angle of incidence θ 1 to the incident surface of the prism 6 is set correctly, and the beam shape conversion function of the prism 6 is as follows.
A predetermined conversion rate is satisfied, and the orthogonality between the incident optical axis and the output optical axis is also satisfied.
ここで、全反射面すなわち、稜QRで代表され
る面を位置決め面として用いるのは、稜PQで代
表される入射面あるいは稜RZで代表される出射
面を、位置決め面に用いると、開口制限を行なう
ことになり、プリズム６の大型化をまねく。 Here, the reason why the total reflection surface, that is, the surface represented by the edge QR is used as the positioning surface is because if the entrance surface represented by the edge PQ or the exit surface represented by the edge RZ is used as the positioning surface, the aperture restriction This results in an increase in the size of the prism 6.
また、コリメータレンズ２あるいは、プリズム
６の出射面に続いて配置される光学系等の形状及
び配置に制限を与える。また稜PZで代表される
面は、プリズム６の精度に何ら関与しない面であ
るため、この面を位置決め面に用いることは、で
きないからである。 Further, restrictions are placed on the shape and arrangement of the collimator lens 2 or the optical system disposed subsequent to the exit surface of the prism 6. Further, since the surface represented by the edge PZ has no influence on the accuracy of the prism 6, this surface cannot be used as a positioning surface.
次に、本発明の他の実施例を第５図、第６図を
用いて説明する。第５図は、本発明の他の実施例
の平面図、第６図はその正面部分断面図である。
図中の８は光学系の筐体に設けた段部であり本実
施例の場合は、プリズム６の取り付け面より低い
段部として形成されている。９は、その中心軸
が、プリズム６の全反射面と角θ4をなすよう形成
されている位置決め穴であり、コリメータレンズ
２を収納したレンズ鏡筒２ａ及び半導体レーザー
１を同軸的に係合する。 Next, another embodiment of the present invention will be described using FIGS. 5 and 6. FIG. 5 is a plan view of another embodiment of the present invention, and FIG. 6 is a front partial sectional view thereof.
Reference numeral 8 in the figure is a stepped portion provided in the housing of the optical system, and in the case of this embodiment, it is formed as a stepped portion lower than the mounting surface of the prism 6. 9 is a positioning hole formed so that its central axis forms an angle θ 4 with the total reflection surface of the prism 6, and the lens barrel 2a housing the collimator lens 2 and the semiconductor laser 1 are coaxially engaged. do.
この実施例における、プリズム６の全反射面の
位置決めは、段部８に、位置決め板を置きその位
置決め板に全反射面を押し当て位置決め後は、位
置決め板を取りはらうことにより行なわれる。 In this embodiment, the positioning of the total reflection surface of the prism 6 is carried out by placing a positioning plate on the stepped portion 8, pressing the total reflection surface against the positioning plate, and after positioning, removing the positioning plate.
この様な構成とすると、全反射面は、空気と直
接接触することになるので特別な反射防止膜を形
成しなくとも、良好な反射特性が得られる。 With such a configuration, the total reflection surface comes into direct contact with air, so that good reflection characteristics can be obtained without forming a special antireflection film.
発明の効果
以上のように本発明の光学ヘツドは、半導体レ
ーザーとコリメータレンズを有し、このコリメー
タレンズにより平行楕円ビームに変換された入射
光を前記入射光と直交する平行円ビームに変換す
るよう構成された全反射面を備えたプリズムを有
すると共にコリメータレンズの光軸と前記プリズ
ムの全反射面のなす角度を規制する位置決め部を
筐体に設けたことにより、プリズムの入射面、出
射面の開口及びプリズムの入射側、出射側の光学
系の形状、配置に何ら制限を与えることなく、前
記プリズムのビーム形状変換機能及び光路変換機
能が所定の値を満足することを可能にしたもの
で、その工業的価値は大きい。Effects of the Invention As described above, the optical head of the present invention has a semiconductor laser and a collimator lens, and the collimator lens converts incident light into a parallel elliptical beam into a parallel circular beam orthogonal to the incident light. By having a prism with a structured total reflection surface and providing a positioning part in the housing that regulates the angle between the optical axis of the collimator lens and the total reflection surface of the prism, the entrance surface and the exit surface of the prism are It is possible for the beam shape conversion function and optical path conversion function of the prism to satisfy predetermined values without imposing any restrictions on the shape and arrangement of the optical system on the entrance side and output side of the aperture and the prism, Its industrial value is great.
第１図は、従来例における光学ヘツドの断側面
図、第２図は、本発明の光学ヘツドに用いられる
プリズムの平面図、第３図は、本発明の一実施例
における光学ヘツドの断平面図、第４図は、同正
面図、第５図は、本発明の他の実施例における光
学ヘツドの断平面図、第６図は、同断正面図であ
る。
１……半導体レーザー、２……コリメータレン
ズ、６……プリズム、７，８……位置決め段部、
９……位置決め穴。
FIG. 1 is a sectional side view of an optical head in a conventional example, FIG. 2 is a plan view of a prism used in an optical head of the present invention, and FIG. 3 is a sectional plane of an optical head in an embodiment of the present invention. 4 is a front view of the same, FIG. 5 is a sectional plan view of an optical head according to another embodiment of the present invention, and FIG. 6 is a sectional front view of the same. 1... Semiconductor laser, 2... Collimator lens, 6... Prism, 7, 8... Positioning step section,
9...Positioning hole.
Claims (1)
このコリメータレンズにより平行楕円ビームに変
換された入射光を、この入射光と直交する平行円
ビームに変換するよう構成された全反射面を備え
たプリズムを設け、前記コリメータレンズの光軸
と前記プリズムの全反射面のなす角度を規制する
位置決め部を前記コリメータレンズおよび前記プ
リズムを収納した筐体に設けた光学ヘツド。1 Has a semiconductor laser and a collimator lens,
A prism is provided with a total reflection surface configured to convert the incident light converted into a parallel elliptical beam by the collimator lens into a parallel circular beam orthogonal to the incident light, and the optical axis of the collimator lens and the prism An optical head, wherein a positioning portion for regulating the angle formed by the total reflection surface of the optical head is provided in a housing housing the collimator lens and the prism.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58070351A JPS59195347A (en) | 1983-04-20 | 1983-04-20 | Optical head |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58070351A JPS59195347A (en) | 1983-04-20 | 1983-04-20 | Optical head |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS59195347A JPS59195347A (en) | 1984-11-06 |
| JPH0512773B2 true JPH0512773B2 (en) | 1993-02-18 |
Family
ID=13428917
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP58070351A Granted JPS59195347A (en) | 1983-04-20 | 1983-04-20 | Optical head |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS59195347A (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4759616A (en) * | 1985-08-26 | 1988-07-26 | Eastman Kodak Company | Method and apparatus for anamorphically shaping and deflecting electromagnetic beams |
| DE69127324T2 (en) * | 1990-06-29 | 1998-01-15 | Toshiba Kawasaki Kk | Optical head |
| EP1964220A1 (en) * | 2005-12-23 | 2008-09-03 | Carl Zeiss Laser Optics GmbH | Optical system and method for shaping a profile of a laser beam |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5511601B2 (en) * | 1975-05-19 | 1980-03-26 | ||
| JPS57100632A (en) * | 1980-12-12 | 1982-06-22 | Matsushita Electric Ind Co Ltd | Optical system reproducer |
| JPS57104915A (en) * | 1980-12-22 | 1982-06-30 | Ricoh Co Ltd | Laser recorder |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6114012Y2 (en) * | 1978-06-12 | 1986-05-01 |
-
1983
- 1983-04-20 JP JP58070351A patent/JPS59195347A/en active Granted
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5511601B2 (en) * | 1975-05-19 | 1980-03-26 | ||
| JPS57100632A (en) * | 1980-12-12 | 1982-06-22 | Matsushita Electric Ind Co Ltd | Optical system reproducer |
| JPS57104915A (en) * | 1980-12-22 | 1982-06-30 | Ricoh Co Ltd | Laser recorder |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS59195347A (en) | 1984-11-06 |
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