JPS6327689B2 - - Google Patents
Info
- Publication number
- JPS6327689B2 JPS6327689B2 JP58062473A JP6247383A JPS6327689B2 JP S6327689 B2 JPS6327689 B2 JP S6327689B2 JP 58062473 A JP58062473 A JP 58062473A JP 6247383 A JP6247383 A JP 6247383A JP S6327689 B2 JPS6327689 B2 JP S6327689B2
- Authority
- JP
- Japan
- Prior art keywords
- light
- beam splitter
- light source
- condensing device
- spherical mirror
- 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
Links
- 230000004075 alteration Effects 0.000 claims description 15
- 238000010586 diagram Methods 0.000 description 5
- 230000003287 optical effect Effects 0.000 description 5
- 239000000470 constituent Substances 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000005357 flat glass Substances 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
Classifications
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B17/00—Systems with reflecting surfaces, with or without refracting elements
- G02B17/08—Catadioptric systems
- G02B17/0856—Catadioptric systems comprising a refractive element with a reflective surface, the reflection taking place inside the element, e.g. Mangin mirrors
- G02B17/086—Catadioptric systems comprising a refractive element with a reflective surface, the reflection taking place inside the element, e.g. Mangin mirrors wherein the system is made of a single block of optical material, e.g. solid catadioptric systems
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B17/00—Systems with reflecting surfaces, with or without refracting elements
- G02B17/008—Systems specially adapted to form image relays or chained systems
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B17/00—Systems with reflecting surfaces, with or without refracting elements
- G02B17/08—Catadioptric systems
Description
【発明の詳細な説明】
この発明は、光をミクロン程度に集光する集光
装置に関するものである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a condensing device that condenses light to about microns.
従来この種の装置として第１図に示すものが周
知である。図において、半導体レーザなどの点状
の発光中心を持つ光源１が設けられ、前記光源１
から出射光２が出され、前記出射光２を集光する
対物レンズ群３がさらに設けられ、それは構成レ
ンズ４ａ，４ｂ，４ｃと鏡筒５より構成されてい
る。前記レンズ群３により集光されて光スポツト
６が形成される。 A conventional device of this type is shown in FIG. 1 and is well known. In the figure, a light source 1 having a point-like emission center such as a semiconductor laser is provided, and the light source 1
An objective lens group 3 for condensing the output light 2 is further provided, and is composed of constituent lenses 4a, 4b, 4c and a lens barrel 5. The light is focused by the lens group 3 to form a light spot 6.
次に前記第１図の装置の機能ついて説明する。
このような装置は、ビデオデイスク、オーデイオ
デイスクなどの光学式情報記録再生装置によく用
いられる。一方、そのような応用装置では、光ス
ポツトをミクロン（μｍ）程度に集光する必要が
ある。そのため前記対物レンズ群３は、回折限界
近くまで光スポツトを集光できる程度に収差を少
なくする必要があり、そのために複数枚のレンズ
で構成されている。 Next, the functions of the apparatus shown in FIG. 1 will be explained.
Such devices are often used in optical information recording and reproducing devices such as video discs and audio discs. On the other hand, in such applied devices, it is necessary to condense a light spot to a size of about microns (μm). Therefore, the objective lens group 3 needs to reduce aberrations to such an extent that it can condense a light spot close to the diffraction limit, and for this purpose it is composed of a plurality of lenses.
光源１からの出射光には、対物レンズ群３に入
射し、この対物レンズ群の構成レンズ４ａ，４
ｂ，４ｃにより光スポツト６に集光される。なお
その際に、構成レンズ４ａ，４ｂ，４ｃで発生す
る収差を、対物レンズ群全体で見た場合、収差が
打ち消し合つて、小さくなるように各構成対物レ
ンズは設計されている。 The light emitted from the light source 1 enters the objective lens group 3, and the constituent lenses 4a, 4 of this objective lens group
b and 4c, the light is focused on a light spot 6. At this time, each component objective lens is designed so that when the aberrations generated in the component lenses 4a, 4b, and 4c are viewed in the entire objective lens group, the aberrations cancel each other out and become smaller.
従来の装置は、上記のように対物レンズの収差
を小さくするために複数枚の球面レンズを必要と
して、そのため研磨面の数も多くなり、結果とし
て対物レンズが非常に高価なものになる欠点があ
つた。 Conventional devices require multiple spherical lenses to reduce the aberrations of the objective lens as described above, which results in a large number of polished surfaces, which has the disadvantage of making the objective lens very expensive. It was hot.
本発明は上記のような従来装置の欠点を改善す
るためのもので、球面レンズを用いずに、球面反
射鏡とビームスプリツタおよび平行平板ガラスに
より集光系を形成し、研磨面を少なくすることに
より、集光装置を低価格にすることを目的として
いる。 The present invention is intended to improve the above-mentioned drawbacks of conventional devices. Instead of using a spherical lens, a condensing system is formed using a spherical reflector, a beam splitter, and a parallel flat glass, thereby reducing the need for polished surfaces. The purpose of this is to reduce the cost of the condensing device.
化下に、この発明の一実施例を第２図について
説明する。第２図において、出射光２と反射光束
８を分離するビームスプリツタ７が設けられ、光
源１はビームスプリツタの端面に置かれている。
球面ミラー９が設けられ、その曲率中心が光源１
の出射光と一致するように置かれ、ビームスプリ
ツタを同じ屈折率を持つた平凸レンズの曲面がミ
ラーになる形状をしている。球面ミラー９には反
射面１０が形成され、出射光２を光源１側へ反射
させる働きをする。ビームスプリツタ７よりも屈
折率の大きい平行平板１１がビームスプリツタの
側面に置かれている。 An embodiment of the present invention will now be described with reference to FIG. In FIG. 2, a beam splitter 7 is provided which separates the emitted light 2 and the reflected light beam 8, and the light source 1 is placed on the end face of the beam splitter.
A spherical mirror 9 is provided, the center of curvature of which is located at the light source 1.
The curved surface of a plano-convex lens with the same refractive index as the beam splitter serves as a mirror. A reflecting surface 10 is formed on the spherical mirror 9 and functions to reflect the emitted light 2 toward the light source 1 side. A parallel plate 11 having a larger refractive index than the beam splitter 7 is placed on the side surface of the beam splitter.
光源１からの出射光はミラー面１０で反射され
て、その反射光は光源１に向かう収束光となる。
この場合、第３図に示すように、球面ミラー１３
の曲率中心に置かれた点光源１２からの出射光
は、ミラー１３の接平面に直交するようにミラー
１３へ入射するので、再び元の光路を正確に戻
る。このため、反射光は全くの無収差で集光でき
ることになる。ところが、第３図のような構成で
は収束光は元の光源に再入射するので利用するこ
とができない。そこで第４図のように、反射球面
１５を持つたビームスプリツタ１４を置き、この
反射球面１５の曲率中心を点光源１２とすると、
ビームスプリツタ１４の端面に無収差光スポツト
６を得ることができる。しかし用途によつてはこ
れでもよいが、大気中に光スポツトを取出す用途
が多い。したがつて大気中に光スポツトを取出す
場合は、第５図のようにビームスプリツタを構成
する。 The light emitted from the light source 1 is reflected by the mirror surface 10, and the reflected light becomes convergent light directed toward the light source 1.
In this case, as shown in FIG.
The light emitted from the point light source 12 placed at the center of curvature enters the mirror 13 perpendicularly to the tangential plane of the mirror 13, so it accurately returns to the original optical path. Therefore, the reflected light can be focused without any aberration. However, in the configuration shown in FIG. 3, the convergent light re-enters the original light source and cannot be used. Therefore, as shown in FIG. 4, if a beam splitter 14 with a reflecting spherical surface 15 is placed and the center of curvature of this reflecting spherical surface 15 is taken as a point light source 12,
An aberration-free light spot 6 can be obtained at the end face of the beam splitter 14. However, although this may be acceptable depending on the application, there are many applications in which a light spot is extracted into the atmosphere. Therefore, when a light spot is taken out into the atmosphere, a beam splitter is constructed as shown in FIG.
しかしこの場合、ビームスプリツタ１４と大気
の屈折率の差により、収束光に収差が生じる。そ
こで、この収差補正のため第６図に示すように、
ビームスプリツタ１４よりも屈折率の大なる平行
平板１１を配置する。以下にこの収差補正の原理
を説明する。収束光が現在の媒体よりも屈折率の
小さな媒体に入射すると、第７ａ図に示すような
負の縦収差を生じる。一方、収束光が現在の媒体
よりも屈折率の大きな媒体に入射すると正の縦収
差を生じる。また入射する媒体の厚さが大になる
と、収差も大になる。したがつて第６図に示す平
行平板１１の厚さを適当に選ぶことにより収束系
の収差を軽減できる。第７ｂ図は本発明の設計例
であり、第７ａ図の平行平板１１のない場合に比
べて、収差が大きく改善されているのがわかる。
なお、計算にあたつてはd1＝１mm、d2＝8.3mm、
n1＝1.5、n2＝1.8、N.A.＝ｎ sinθ＝0.45の数値
を仮定した。 However, in this case, aberrations occur in the convergent light due to the difference in refractive index between the beam splitter 14 and the atmosphere. Therefore, in order to correct this aberration, as shown in Fig. 6,
A parallel plate 11 having a larger refractive index than the beam splitter 14 is arranged. The principle of this aberration correction will be explained below. If the convergent light is incident on a medium with a smaller refractive index than the current medium, negative longitudinal aberration will occur as shown in Figure 7a. On the other hand, if convergent light is incident on a medium with a larger refractive index than the current medium, positive longitudinal aberration will occur. Furthermore, as the thickness of the incident medium increases, aberrations also increase. Therefore, by appropriately selecting the thickness of the parallel plate 11 shown in FIG. 6, the aberrations of the focusing system can be reduced. FIG. 7b shows a design example of the present invention, and it can be seen that aberrations are greatly improved compared to the case without the parallel plate 11 in FIG. 7a.
In addition, when calculating, d 1 = 1 mm, d 2 = 8.3 mm,
The numerical values of n 1 = 1.5, n 2 = 1.8, NA = n sin θ = 0.45 were assumed.
なお上記第２図における実施例では、ビームス
プリツタ７と球面ミラー９を分離したが、第６図
に示すように一体化してもよい。 In the embodiment shown in FIG. 2, the beam splitter 7 and the spherical mirror 9 are separated, but they may be integrated as shown in FIG.
また第８図に示すように、ビームスプリツタと
して偏光ビームスプリツタ１７を用い。そのビー
ムスプリツタ膜１７と球面ミラー９の間に1/4波
長相板１８を挾み込んだ構成としてもよい。 Further, as shown in FIG. 8, a polarizing beam splitter 17 is used as a beam splitter. A configuration may also be adopted in which a quarter wavelength phase plate 18 is interposed between the beam splitter film 17 and the spherical mirror 9.
さらに第９図に示すようにビームスプリツタ１
９の光源側の端面を球面とし、かつその球面２０
と反射面１０の曲率中心を一致させ、その曲率中
心に光源１を置く構成としてもよい。この場合、
光源をビームスプリツタの端面より離すことがで
きる。 Furthermore, as shown in FIG.
The end surface of 9 on the light source side is a spherical surface, and the spherical surface 20
The center of curvature of the reflecting surface 10 may be made to coincide with the center of curvature, and the light source 1 may be placed at the center of the curvature. in this case,
The light source can be separated from the end face of the beam splitter.
第１０図には、本発明における集光装置の光学
式情報記録再生装置への応用例を示す。図におい
て、ビームスプリツタの側面上の平行平板１１の
外側にビデオデイスク２９が公知の態様で回転す
るように設けられ、その情報記録面３１が光スポ
ツト６に一致するような位置関係が選ばれる。こ
のデイスク２９はデイジタルオーデイオデイスク
その他の光学式情報記録担体であつてもよい。情
報記録面３１によつて反射された光がビームスプ
リツタ７を透過した反対側にはコリメートレンズ
４０が設けられ、それにより反射光が平光にされ
る。コリメートレンズ４０の次にプリズム４１が
設けられ、それを通る反射光は領域、、、
を持つ光検知器４２に入る。光検知器４２の領
域、、、は情報担体からの情報読取り
や、オートフオーカシング、オートトラツキング
などのアクチユエータのための信号を得るように
位置が選ばれる。その結果デイスク２９の情報記
録面３１の記録情報が光検知器４２で検知され
る。 FIG. 10 shows an example of application of the light condensing device of the present invention to an optical information recording/reproducing device. In the figure, a video disk 29 is rotatably provided outside the parallel plate 11 on the side surface of the beam splitter in a known manner, and the positional relationship is selected such that its information recording surface 31 coincides with the light spot 6. . This disk 29 may be a digital audio disk or other optical information storage carrier. A collimating lens 40 is provided on the opposite side from which the light reflected by the information recording surface 31 passes through the beam splitter 7, so that the reflected light is flattened. A prism 41 is provided next to the collimating lens 40, and the reflected light passing through it is reflected in the area...
enters a photodetector 42 with a The area of the photodetector 42 is selected in such a way as to obtain signals for reading information from an information carrier and for actuators such as autofocusing, autotracking, etc. As a result, the recorded information on the information recording surface 31 of the disk 29 is detected by the photodetector 42.
以上のように、本発明では、球面ミラーとビー
ムスプリツタと平行平板の組合わせで集光光学系
を構成したので、研磨の面到な球面が少なく、か
つ収差の少ない集光装置が安価に得られる効果が
ある。 As described above, in the present invention, since the condensing optical system is configured by a combination of a spherical mirror, a beam splitter, and a parallel plate, a condensing device with fewer polished spherical surfaces and less aberration can be produced at a low cost. There are benefits to be gained.
第１図は、従来の集光装置を示す図である。第
２図は、本発明の一実施例による集光装置を示す
図である。第３図ないし第６図は本発明の作用、
動作原理を説明する図である。第７図は、発明の
改善効果を示す図である。第８図ないし第９図
は、本発明の他の実施例を示す図である。第１０
図は、本発明の一応用例を示す図である。
図において、１は光源、７はビームスプリツ
タ、９は球面ミラー、１１は平行平板である。な
お、図中同一符号は、同一または相当部分を示
す。
FIG. 1 is a diagram showing a conventional light condensing device. FIG. 2 is a diagram showing a light condensing device according to an embodiment of the present invention. FIGS. 3 to 6 show the effects of the present invention,
It is a figure explaining an operating principle. FIG. 7 is a diagram showing the improvement effect of the invention. FIGS. 8 and 9 are diagrams showing other embodiments of the present invention. 10th
The figure is a diagram showing an example of application of the present invention. In the figure, 1 is a light source, 7 is a beam splitter, 9 is a spherical mirror, and 11 is a parallel plate. Note that the same reference numerals in the figures indicate the same or corresponding parts.
Claims (1)
１の透光媒体と、 前記凸球面上に形成され、凹面鏡として働く球
面ミラーと、 前記球面ミラーの曲率中心に置かれた光源と、 前記光源からの出射光が前記球面ミラーにより
反射されて収束光となつた第１の反射光を前記光
源に向かう方向と異なる方向へ第２の反射光とし
て分離するために、前記球面ミラーと前記光源と
の間で前記第１の透光媒体中に形成されたビーム
スプリツタ膜と、 前記第２の反射光を前記第１の透光媒体から第
２の屈折率を持つ第２の透光媒体中に取出す際に
生じる収差を補正するために、第３の屈折率を持
つ透光平行平板を備えたことを特徴とする集光装
置。 ２ 前記第１の透光媒体は複数の構成部分体を含
み、 前記ビームスプリツタ膜と前記球面ミラーとは
前記複数の構成部分体のうちの同一の部分体上に
形成されていることを特徴とする特許請求の範囲
第１項記載の集光装置。 ３ 前記第１の透光媒体は複数の構成部分体を含
み、 前記複数の構成部分体のうちの２つは前記ビー
ムスプリツタ膜を挾んで互いに接合されることに
よつて１つの直六面体を形成しており、 前記複数の構成部分体のうちのもう１つは平面
と凸球面を有する平凸レンズであり、前記球面ミ
ラーは前記平凸レンズの凸球面上に形成されてお
り、前記平凸レンズの平面は前記直六面体に接合
されていることを特徴とする特許請求の範囲第１
項記載の集光装置。 ４ 前記直六面体と前記平凸レンズとの間には1/
４波長板が挾まれていることを特徴とする特許請
求の範囲第３項記載の集光装置。 ５ 前記光源は前記第１の透光媒体の端面にして
いることを特徴とする特許請求の範囲第１項ない
し第４項のいずれかの項に記載された集光装置。 ６ 前記第１の透光媒体の前記光源側の端面は前
記光源を曲率中心とする凹球面を含んでいること
を特徴とする特許請求の範囲第１項ないし第４項
のいずれかの項に記載された集光装置。 ７ 前記ビームスプリツタ膜は偏光ビームスプリ
ツタ膜であることを特徴とる特許請求の範囲第１
項ないし第６項のいずれかの項に記載された集光
装置。 ８ 前記透光平行平板は複数の平行平板を含むこ
とを特徴とする特許請求の範囲第１項ないし第７
項のいずれかの項に記載された集光装置。[Claims] 1. A first light-transmitting medium having a convex spherical surface in part and having a first refractive index; a spherical mirror formed on the convex spherical surface and functioning as a concave mirror; a light source placed at the center of curvature; and a first reflected light, which is a convergent light produced by the emitted light from the light source being reflected by the spherical mirror, is separated into a second reflected light in a direction different from the direction toward the light source. a beam splitter film formed in the first transparent medium between the spherical mirror and the light source; and a beam splitter film formed in the first transparent medium between the spherical mirror and the light source; A light condensing device comprising a light-transmitting parallel flat plate having a third refractive index in order to correct aberrations that occur when the light is taken out into a second light-transmitting medium having a refractive index. 2. The first light-transmitting medium includes a plurality of component parts, and the beam splitter film and the spherical mirror are formed on the same part of the plurality of component parts. A light condensing device according to claim 1. 3. The first light-transmitting medium includes a plurality of component bodies, and two of the plurality of component bodies are joined to each other with the beam splitter film in between, thereby forming one rectangular hexahedron. another of the plurality of component parts is a plano-convex lens having a flat surface and a convex spherical surface, the spherical mirror is formed on the convex spherical surface of the plano-convex lens, and the spherical mirror is formed on the convex spherical surface of the plano-convex lens; Claim 1, characterized in that the plane is joined to the rectangular hexahedron.
The light condensing device described in Section 1. 4 There is a distance of 1/ between the rectangular hexahedron and the plano-convex lens.
4. A light condensing device according to claim 3, characterized in that a four-wavelength plate is sandwiched therebetween. 5. The light condensing device according to any one of claims 1 to 4, wherein the light source is provided at an end face of the first light-transmitting medium. 6. According to any one of claims 1 to 4, wherein the end surface of the first light-transmitting medium on the light source side includes a concave spherical surface having the light source as the center of curvature. Light concentrator as described. 7. Claim 1, wherein the beam splitter film is a polarizing beam splitter film.
The light condensing device described in any one of Items 6 to 6. 8. Claims 1 to 7, characterized in that the light-transmitting parallel flat plate includes a plurality of parallel flat plates.
A light condensing device described in any of the paragraphs.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58062473A JPS59187309A (en) | 1983-04-07 | 1983-04-07 | Light converging device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58062473A JPS59187309A (en) | 1983-04-07 | 1983-04-07 | Light converging device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS59187309A JPS59187309A (en) | 1984-10-24 |
| JPS6327689B2 true JPS6327689B2 (en) | 1988-06-03 |
Family
ID=13201190
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP58062473A Granted JPS59187309A (en) | 1983-04-07 | 1983-04-07 | Light converging device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS59187309A (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4896952A (en) * | 1988-04-22 | 1990-01-30 | International Business Machines Corporation | Thin film beamsplitter optical element for use in an image-forming lens system |
| US5089913A (en) * | 1990-07-11 | 1992-02-18 | International Business Machines Corporation | High resolution reduction catadioptric relay lens |
| US6831886B1 (en) | 1998-11-27 | 2004-12-14 | Minolta Co., Ltd. | Optical head and optical head device |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5768813A (en) * | 1980-10-17 | 1982-04-27 | Matsushita Electric Ind Co Ltd | Optical information reader |
-
1983
- 1983-04-07 JP JP58062473A patent/JPS59187309A/en active Granted
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5768813A (en) * | 1980-10-17 | 1982-04-27 | Matsushita Electric Ind Co Ltd | Optical information reader |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS59187309A (en) | 1984-10-24 |
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