JPH04310639A - Optical head and its manufacture - Google Patents
Optical head and its manufactureInfo
- Publication number
- JPH04310639A JPH04310639A JP3075384A JP7538491A JPH04310639A JP H04310639 A JPH04310639 A JP H04310639A JP 3075384 A JP3075384 A JP 3075384A JP 7538491 A JP7538491 A JP 7538491A JP H04310639 A JPH04310639 A JP H04310639A
- Authority
- JP
- Japan
- Prior art keywords
- light
- optical
- optical head
- propagation path
- head according
- 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 145
- 238000004519 manufacturing process Methods 0.000 title claims description 5
- 239000000758 substrate Substances 0.000 claims abstract description 16
- 230000000644 propagated effect Effects 0.000 claims abstract description 12
- 230000001902 propagating effect Effects 0.000 claims description 24
- 238000013459 approach Methods 0.000 claims description 2
- 230000007423 decrease Effects 0.000 claims 1
- 230000005540 biological transmission Effects 0.000 description 4
- 238000000034 method Methods 0.000 description 3
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- 229910052737 gold Inorganic materials 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 239000004065 semiconductor Substances 0.000 description 2
- 229910052709 silver Inorganic materials 0.000 description 2
- 238000003848 UV Light-Curing Methods 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- 201000009310 astigmatism Diseases 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005323 electroforming Methods 0.000 description 1
- 238000010894 electron beam technology Methods 0.000 description 1
- 238000000609 electron-beam lithography Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 230000015654 memory Effects 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 229920003229 poly(methyl methacrylate) Polymers 0.000 description 1
- 239000004926 polymethyl methacrylate Substances 0.000 description 1
- 239000010453 quartz Substances 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
Landscapes
- Optical Head (AREA)
- Optical Couplings Of Light Guides (AREA)
- Diffracting Gratings Or Hologram Optical Elements (AREA)
Abstract
Description
【０００１】0001
【産業上の利用分野】本発明は、光学的記録装置の、フ
ォーカス制御機構のない安価な光学ヘッドに関するもの
である。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inexpensive optical head without a focus control mechanism for an optical recording device.
【０００２】0002
【従来の技術】光ディスク、光カードメモリ等の光学的
記録媒体の信号を読み出す重要構成部品として光学ヘッ
ドがある。特に、再生専用の光カードシステムに用いる
光学ヘッドは、安価でコンパクトなことが要求され、フ
ォーカス制御機構のない構造のものが提案されている。2. Description of the Related Art An optical head is an important component for reading signals from optical recording media such as optical discs and optical card memories. In particular, optical heads used in read-only optical card systems are required to be inexpensive and compact, and optical heads without a focus control mechanism have been proposed.
【０００３】光カード再生専用の従来の光学ヘッドとし
ては、図９に示すものがあった（Ｊ．Ｄｒｅｘｌｅｒ、
公開特許公報昭６１−５０１１５）。光源１であるＬＥ
Ｄから出力された光は、コリメータレンズ１７によって
平行光になり、シリンドリカルレンズ１８によって一方
向のみ集光され、ビームスプリッタ１９を通過して、光
記録媒体７である光カード上のピット列に線状に照明さ
れる。ピット列によって反射された光は、ビームスプリ
ッタ１９によって向きを変え、集光レンズ２０によって
光検出器アレイ６であるＣＣＤ上に集光され、ピット列
の信号が読み出しされるものである。[0003] As a conventional optical head exclusively used for reproducing optical cards, there is one shown in FIG. 9 (J. Drexler,
Published Patent Publication No. 61-50115). LE which is light source 1
The light output from D is turned into parallel light by the collimator lens 17, focused in only one direction by the cylindrical lens 18, passes through the beam splitter 19, and forms a line on the pit row on the optical card, which is the optical recording medium 7. illuminated in a manner. The light reflected by the pit row is changed direction by a beam splitter 19, focused by a condensing lens 20 onto a CCD which is a photodetector array 6, and the signal of the pit row is read out.
【０００４】0004
【発明が解決しようとする課題】しかしながら、図９に
示した従来の光学ヘッドでは、光学系が複雑で、各光学
部品の位置合わせ精度が要求され、従って組み立てが難
しく、小形軽量化、低価格化が困難であるという課題が
あった。[Problems to be Solved by the Invention] However, the conventional optical head shown in FIG. 9 has a complicated optical system and requires precision alignment of each optical component, making it difficult to assemble, making it compact, lightweight, and inexpensive. The problem was that it was difficult to
【０００５】本発明は、上記従来の光学ヘッドの課題に
鑑みてなされたもので、各光学部品の位置合わせが容易
で小形軽量、低価格化可能な光学ヘッドを提供すること
を目的とするものである。The present invention has been made in view of the above-mentioned problems with the conventional optical head, and it is an object of the present invention to provide an optical head that allows easy alignment of each optical component, is small, lightweight, and can be made at a low cost. It is.
【０００６】[0006]
【課題を解決するための手段】本発明は、ジグザグ状に
光が伝搬する光伝搬路を設けた基板と、第１及び第２の
光集光手段と、光源と、光検出器とから構成され、上記
光伝搬路の厚さ及び幅は伝搬光波長の１０倍以上であっ
て、上記光源からの光を上記光伝搬路に導き、上記伝搬
光を上記第１の光集光手段で集光して光記録媒体に出力
し、上記光記録媒体からの反射光を、上記第２の光集光
手段に入力し、上記光検出器に導く光学ヘッドを提供す
るものである。[Means for Solving the Problems] The present invention comprises a substrate provided with an optical propagation path through which light propagates in a zigzag pattern, first and second light condensing means, a light source, and a photodetector. The thickness and width of the light propagation path are at least 10 times the wavelength of the propagating light, and the light from the light source is guided to the light propagation path, and the propagating light is collected by the first light focusing means. The present invention provides an optical head that outputs light to an optical recording medium, inputs reflected light from the optical recording medium to the second light condensing means, and guides it to the photodetector.
【０００７】[0007]
【作用】本発明は、従来光学ヘッドにおいて自由空間中
にとっていた光学系の光路を、境界面の反射を利用して
ジグザグ状に光が伝搬する光伝搬路中にとることにより
、光学部品を１つの基板（伝搬路）上または基板（伝搬
路）中に設置することが可能になり、従って、本発明の
光学ヘッドは光学的位置合わせが容易になり、小形軽量
化、低価格化が実現できる。[Operation] The present invention replaces the optical path of the optical system in free space in the conventional optical head with an optical propagation path in which light propagates in a zigzag pattern using reflection from the boundary surface. Therefore, the optical head of the present invention can be installed on or in a single substrate (propagation path), making optical alignment easier and realizing smaller size, lighter weight, and lower cost. .
【０００８】[0008]
【実施例】図１、図２は、本発明の第１の実施例の光学
ヘッドの基本構成と、光の伝搬、集光の様子を示す、そ
れぞれ平面図、側面図である。本発明の第１の実施例の
光学ヘッドについて、図１、図２を用いて詳細に説明す
る。DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 1 and 2 are a plan view and a side view, respectively, showing the basic structure of an optical head according to a first embodiment of the present invention, and how light is propagated and focused. An optical head according to a first embodiment of the present invention will be explained in detail using FIGS. 1 and 2.
【０００９】同図において、基板２として、例えば厚さ
（Ｚ方向サイズ）１ｍｍ、幅（Ｘ方向サイズ）４ｍｍ、
長さ（Ｙ方向サイズ）７．５ｍｍのガラスを用い、この
基板２自体が、表面と裏面の反射を利用しジグザグ状に
光が伝搬する光伝搬路１３となっている。基板２として
は、使用波長に対して透明であれば良い。特に石英等の
ガラス基板は、温度的にも安定である。光伝搬路１３の
裏面上に設けた光源である、例えば波長０．７８μｍの
半導体レーザ１から、光軸の角度がＺ軸から例えば３０
゜斜め方向に出射された光は、伝搬光８となり、光伝搬
路１３の表面に設けた、例えばＡｇやＡｌ、Ａｕ等の金
属層または誘電体の多層膜である反射層１１ａで反射さ
れ、反射層１１ｂを有する、光伝搬路１３裏面上に設け
た、例えば焦点距離２．３ｍｍ、口径１ｍｍのコリメー
タ手段である反射形コリメータレンズ３に入射し、光軸
の角度はそのまま（例えば３０゜）で反射・コリメート
される。例えば幅１ｍｍのコリメートされた光は、反射
層１１ａで反射されジグザグ状に伝搬し、同じく光伝搬
路１３裏面上に設けた第１の集光手段である、例えば口
径１ｍｍ、焦点距離５ｍｍの反射形シリンドリカル対物
レンズ４により、Ｙ方向のみ集光されて斜め方向に出力
され、光記録媒体７である光カード上への出射光９とな
り、ピット列に線状に照明されるようになっている。光
記録媒体７のピット列によって反射された光１０は、光
伝搬路１３中を通過し、光伝搬路１３裏面上に設けた、
例えば口径１ｍｍ、焦点距離４ｍｍの第２の集光手段で
ある反射形集光レンズ５に入射して、例えば３０°の光
軸をもって反射集光され、ジグザグ状に伝搬して、光伝
搬路１３裏面上に設けた、例えばＣＣＤの光検出器アレ
イ６に入射し、ピット列の情報が検出されるようになっ
ている。In the figure, the substrate 2 has, for example, a thickness (Z direction size) of 1 mm, a width (X direction size) of 4 mm,
Glass having a length (size in the Y direction) of 7.5 mm is used, and the substrate 2 itself serves as a light propagation path 13 in which light propagates in a zigzag pattern using reflections on the front and back surfaces. The substrate 2 only needs to be transparent to the wavelength used. In particular, glass substrates such as quartz are stable in terms of temperature. From a semiconductor laser 1 with a wavelength of 0.78 μm, for example, which is a light source provided on the back surface of the optical propagation path 13, the angle of the optical axis is, for example, 30 μm from the Z axis.
゜The light emitted in the oblique direction becomes the propagating light 8 and is reflected by the reflective layer 11a, which is a multilayer film of a metal layer or dielectric, such as Ag, Al, Au, etc., provided on the surface of the optical propagation path 13, The light enters a reflective collimator lens 3, which is a collimator means with a focal length of 2.3 mm and an aperture of 1 mm, which is provided on the back surface of the light propagation path 13 and has a reflective layer 11b, and the angle of the optical axis remains unchanged (for example, 30 degrees). reflected and collimated. For example, collimated light with a width of 1 mm is reflected by the reflective layer 11a and propagates in a zigzag pattern, and is reflected by a first condensing means provided on the back surface of the light propagation path 13, for example, with a diameter of 1 mm and a focal length of 5 mm. A shaped cylindrical objective lens 4 focuses the light only in the Y direction and outputs it in an oblique direction, and the light 9 is emitted onto an optical card, which is an optical recording medium 7, and the pit row is illuminated in a linear manner. . The light 10 reflected by the pit row of the optical recording medium 7 passes through the light propagation path 13, and passes through a light propagation path 13 provided on the back surface of the light propagation path 13.
For example, the light enters a reflective condensing lens 5, which is a second condensing means, with an aperture of 1 mm and a focal length of 4 mm, is reflected and condensed with an optical axis of, for example, 30°, propagates in a zigzag pattern, and is transmitted through a light propagation path 13. The light enters a photodetector array 6, such as a CCD, provided on the back surface, and information on the pit row is detected.
【００１０】反射形コリメータレンズ３と反射形シリン
ドリカル対物レンズ４、及び反射形集光レンズ５は、例
えば溝の最大深さ０．２８μｍの複数のグレーティング
ゾーンと反射層から構成された反射形の回折光学素子で
ある。このような回折光学素子を用いることにより、膜
厚がせいぜい１μｍ以下とでき、さらに光伝搬路１３に
集積化可能であるため、大幅に小形軽量化、安定化され
る。The reflective collimator lens 3, the reflective cylindrical objective lens 4, and the reflective condensing lens 5 are, for example, reflective diffraction lenses composed of a plurality of grating zones with a maximum depth of 0.28 μm and a reflective layer. It is an optical element. By using such a diffractive optical element, the film thickness can be reduced to 1 μm or less at most, and furthermore, it can be integrated into the optical propagation path 13, resulting in significant reduction in size, weight, and stability.
【００１１】光源１と光検出器６、光学素子３、４、５
はすべて光伝搬路１３の裏面（光カード７のない方）に
配置することにより、光カード７のある表面は、反射層
１１だけとなり、フラットにすることができる。また、
光カード７が基板２表面に接触しても、構成部品は裏面
にあるため、損傷の心配がほとんどなく耐環境性が向上
する。[0011] Light source 1, photodetector 6, optical elements 3, 4, 5
By arranging them all on the back side of the optical propagation path 13 (the side without the optical card 7), the surface on which the optical card 7 is located is only the reflective layer 11, and can be made flat. Also,
Even if the optical card 7 comes into contact with the surface of the board 2, since the components are on the back side, there is little fear of damage and environmental resistance is improved.
【００１２】なお、本実施例の反射形コリメータレンズ
の各グレーティングゾーンは、伝搬光８の光軸方向であ
るＹ軸方向に長軸をもつ同じ離心率の楕円形状で、外周
になるにつれて周期が小さくなる。この楕円形パターン
の中心位置は、外周部にいくにしたがって、楕円形の長
軸方向のうち伝搬光の進行方向とは逆向き（−Ｙ方向）
に、徐々にずれている。このような形状のコリメータレ
ンズとすることにより、斜め入射の影響で通常生じるコ
マ収差と非点収差をなくし、良好にコリメートすること
ができる。[0012] Each grating zone of the reflective collimator lens of this embodiment has an elliptical shape with the same eccentricity with the long axis in the Y-axis direction, which is the optical axis direction of the propagating light 8, and the period increases toward the outer periphery. becomes smaller. The center position of this elliptical pattern is located in the direction opposite to the traveling direction of the propagating light (-Y direction) in the long axis direction of the ellipse as it goes to the outer periphery.
It is gradually shifting. By using a collimator lens having such a shape, it is possible to eliminate comatic aberration and astigmatism that normally occur due to the influence of oblique incidence, and to achieve good collimation.
【００１３】反射形シリンドリカル対物レンズ４のグレ
ーティングゾーンは、直線状であり、グレーティングゾ
ーンの周期は、伝搬光の進行方向（Ｙ方向）に従って、
徐々に小さくなる構造を有している。The grating zone of the reflective cylindrical objective lens 4 is linear, and the period of the grating zone is set according to the traveling direction (Y direction) of the propagating light.
It has a structure that gradually becomes smaller.
【００１４】また、反射形集光レンズ５は、伝搬光の進
行方向（Ｙ方向）に対して、グレーティングゾーンの周
期は徐々に大きくなり、各グレーティングゾーンは弓な
りの曲線グレーティングから構成されたものである。こ
れらの回折光学素子３、４、５は高効率となるように断
面を鋸歯状化した。原盤の光学素子３、４、５は、別の
基板上に例えば、ＰＭＭＡ、ＣＭＳ等の電子ビームレジ
ストをコーティングし、作製する素子の膜厚に応じて照
射量を制御する電子ビーム描画法を行ない、現像処理を
してレジストの膜厚を変化させることにより形成出来る
。このように形成した光学素子（原盤）から、例えばニ
ッケル電鋳法により光学素子３、４、５を同時に含む金
形を作製し、例えばＵＶ硬化樹脂を用いて、光伝搬路１
３上に原盤と同一レンズ３、４、５を複製する。この方
法によれば、一度に３つの回折光学素子３、４、５を位
置精度よく光伝搬路１３上に同一特性で容易に形成可能
であり、同時に低価格化の効果がある。反射層１１ｂは
、複製の後、例えばＡｇやＡｌ、Ａｕ等の金属層をその
上に堆積した。Further, in the reflective condensing lens 5, the period of the grating zone gradually increases with respect to the traveling direction (Y direction) of the propagating light, and each grating zone is composed of an arched curved grating. be. These diffractive optical elements 3, 4, and 5 have sawtooth cross sections to achieve high efficiency. The master optical elements 3, 4, and 5 are produced by coating another substrate with an electron beam resist such as PMMA or CMS, and performing an electron beam lithography method that controls the amount of irradiation depending on the film thickness of the element to be fabricated. It can be formed by changing the film thickness of the resist through development treatment. From the optical element (master) formed in this way, a mold containing the optical elements 3, 4, and 5 at the same time is produced by, for example, a nickel electroforming method, and the light propagation path 1 is formed using, for example, a UV curing resin.
3, duplicate the same lenses 3, 4, and 5 as on the original. According to this method, three diffractive optical elements 3, 4, and 5 can be easily formed at once on the optical propagation path 13 with good positional accuracy and have the same characteristics, and at the same time, there is an effect of reducing costs. After the reflective layer 11b is replicated, a metal layer such as Ag, Al, Au, etc. is deposited thereon.
【００１５】本発明の光学ヘッドでは、光伝搬路１３は
幅、厚さとも例えば数ｍｍであり、これは、光学素子３
、４、５の大きさに基づいて決まり（ほぼ同じオーダ）
、ジグザグに光を光線として伝搬させるという幾何光学
的な取扱いができる。ちなみに、従来から、光伝搬路の
厚さがほぼ波長サイズである光集積回路が研究開発され
ていた。光伝搬路の厚さ、もしくはその幅が波長サイズ
となる領域では、光は波としての特徴を顕著に出すよう
になり、光伝搬路はむしろ光導波路となり、ジグザグに
光は伝搬するというよりも、山形の強度分布をもった波
動として、伝搬するようになる。このような光導波路の
素子では、波動光学的な取扱が必要であり、光の入射・
出射効率が悪いとか、光導波路を伝搬する光の情報量は
１次元であるといった欠点が出てくる。In the optical head of the present invention, the light propagation path 13 has a width and a thickness of several mm, for example, and this is because the optical element 3
, 4, and 5 (almost the same order)
, it can be treated as a geometrical optic by propagating light as a ray in a zigzag pattern. Incidentally, optical integrated circuits in which the thickness of the optical propagation path is approximately the same as the wavelength have been researched and developed. In a region where the thickness or width of the optical propagation path is the same as the wavelength, light begins to exhibit distinct characteristics as a wave, and the optical propagation path becomes more of an optical waveguide, rather than propagating in a zigzag pattern. , it begins to propagate as a wave with a chevron-shaped intensity distribution. Such optical waveguide elements require wave-optical handling, and light incidence and
Disadvantages include poor output efficiency and the one-dimensional information content of light propagating through the optical waveguide.
【００１６】本発明の光学ヘッドは、このような従来の
光集積型デバイスの欠点を克服した構造を有している。
すなわち、本発明者は、光伝搬路の厚さ、及びその幅が
、波長の十倍程度厚ければ、光導波路ではなくて、光線
として表わせる光伝搬路となることを見いだした。特に
、光伝搬路の厚さが、波長の１００倍程度以上では、完
全に光伝搬路となる。従って、本発明の光学ヘッドの光
伝搬路の厚さは、光の波長の１０倍以上であれば良く、
波長の１００倍以上であればさらに取扱は簡単になる。The optical head of the present invention has a structure that overcomes the drawbacks of such conventional optical integrated devices. That is, the present inventor has discovered that if the thickness and width of the optical propagation path are about ten times as thick as the wavelength, the optical propagation path can be expressed as a light beam rather than an optical waveguide. In particular, when the thickness of the optical propagation path is about 100 times or more the wavelength, it becomes a complete optical propagation path. Therefore, the thickness of the optical propagation path of the optical head of the present invention may be at least 10 times the wavelength of the light.
If the wavelength is 100 times or more, handling becomes easier.
【００１７】図３、図４は、それぞれ本発明の第２の実
施例の光学ヘッドの基本構成と、光の伝搬、集光の様子
を示す平面図、側面図である。本発明の第２の実施例の
光学ヘッドは、第１の実施例の光学ヘッドとほぼ同じで
あるが、次に述べる点で異なっている。即ち、異なる点
は、反射形コリメータレンズ３と反射形シリンドリカル
対物レンズ４を、第１の光集光手段としての反射形コリ
メータ対物レンズ１２の１つで置き換えたことである。
このレンズ１２は１つで、半導体レーザ１から出射され
た伝搬光８を、コリメートし、同時にＹ軸方向のみ集光
し、出射光９として光カード７へ線状に集光するレンズ
である。この反射形コリメータ対物レンズ１２は、伝搬
光の進行方向（Ｙ方向）に対して、グレーティングゾー
ンの周期は徐々に小さくなり、各グレーティングゾーン
は表面に反射層を有する弓なりの曲線グレーティングか
ら構成されたものであり、反射形集光レンズ５と弓なり
の曲率、方向は違うがパターン形状はよく似ている回折
光学素子である。FIGS. 3 and 4 are a plan view and a side view, respectively, showing the basic structure of an optical head according to a second embodiment of the present invention, and how light is propagated and focused. The optical head according to the second embodiment of the present invention is almost the same as the optical head according to the first embodiment, but differs in the following points. That is, the difference is that the reflective collimator lens 3 and the reflective cylindrical objective lens 4 are replaced with one of the reflective collimator objective lenses 12 as the first light focusing means. This lens 12 is a single lens that collimates the propagating light 8 emitted from the semiconductor laser 1, condenses the light only in the Y-axis direction, and condenses the light linearly onto the optical card 7 as the emitted light 9. In this reflective collimator objective lens 12, the period of the grating zone becomes gradually smaller with respect to the traveling direction (Y direction) of the propagating light, and each grating zone is composed of an arched curved grating having a reflective layer on the surface. It is a diffractive optical element whose pattern shape is very similar to that of the reflective condensing lens 5, although its arch curvature and direction are different.
【００１８】この反射形コリメータ対物レンズ１２を用
いることにより、構成は一層簡単になる。ただ、レンズ
１２の設計作製がやや難しくなり、さらに光源１と反射
形コリメータ対物レンズ１２の組立時の位置合わせ精度
が一層要求される。By using this reflective collimator objective lens 12, the construction becomes even simpler. However, the design and fabrication of the lens 12 becomes somewhat difficult, and moreover, higher alignment accuracy is required when assembling the light source 1 and the reflective collimator objective lens 12.
【００１９】図５は、本発明の第３の実施例の光学ヘッ
ドの基本構成の平面図、図６は本発明の第３の実施例の
光学ヘッドの基本構成と、光の伝搬、集光の様子を示す
側面図である。本発明の第３の実施例の光学ヘッドの、
第１の実施例の光学ヘッドと違う点は、シリンドリカル
対物レンズ１４および集光レンズ１５を透過形の回折光
学素子にし、光学素子３、１４、１５をすべて光伝搬路
１３の表側に配置したことである。本実施例の構成によ
れば、シリンドリカル対物レンズ１４と集光レンズ１５
は透過形のため、光カード７に近く配置できるため、ワ
ーキングディスタンスを短くすることができ、実際に必
要なレンズサイズを基板２の厚さに対応するぶんだけ小
さくでき、レンズ設計が容易になる。ただ、透過形の回
折光学素子は最適レンズ膜厚が反射形の回折光学素子に
比べて数倍から５、６倍大きくなるため、作製が難しく
なる。なお、レンズ１４、１５の一方を透過形に、もう
一方を反射形にした構成も可能である。FIG. 5 is a plan view of the basic configuration of an optical head according to a third embodiment of the present invention, and FIG. 6 is a plan view of the basic configuration of an optical head according to a third embodiment of the present invention, and light propagation and focusing. FIG. The optical head according to the third embodiment of the present invention,
The difference from the optical head of the first embodiment is that the cylindrical objective lens 14 and the condenser lens 15 are transmissive diffractive optical elements, and the optical elements 3, 14, and 15 are all arranged on the front side of the light propagation path 13. It is. According to the configuration of this embodiment, the cylindrical objective lens 14 and the condensing lens 15
Since it is a transmission type, it can be placed close to the optical card 7, so the working distance can be shortened, and the actually required lens size can be made smaller to correspond to the thickness of the substrate 2, making lens design easier. . However, since the optimum lens film thickness of a transmission type diffractive optical element is several to five or six times larger than that of a reflection type diffraction optical element, it is difficult to manufacture it. Note that a configuration in which one of the lenses 14 and 15 is a transmissive type and the other is a reflective type is also possible.
【００２０】図７は、本発明の第４の実施例の光学ヘッ
ドの基本構成の平面図、図８は本発明の第４の実施例の
光学ヘッドの基本構成と、光の伝搬、集光の様子を示す
側面図である。本発明の第４の実施例の光学ヘッドと第
３の実施例の光学ヘッドと違う点は、反射形コリメータ
レンズ３と透過形シリンドリカル対物レンズ１４を、第
１の光集光手段としての透過形コリメータ対物レンズ１
６で置き換えたことである。このレンズ１６は、伝搬光
の光軸方向に短軸を有する楕円形の複数のグレーティン
グゾーンからなり、この楕円形の中心位置は、レンズ１
６の外周部にいくにしたがって、伝搬光の進行方向とは
逆向きに、徐々にずれている構成をもつ。従って、本実
施例の光学ヘッドは光学部品の構成要素が減り、その結
果、光学ヘッドのサイズが減少し、総合的な光利用効率
が上昇するという長所を有する。ただ、透過形コリメー
タ対物レンズ１６の設計、作製は難しくなる。FIG. 7 is a plan view of the basic configuration of an optical head according to a fourth embodiment of the present invention, and FIG. 8 is a plan view of the basic configuration of an optical head according to a fourth embodiment of the present invention, and how light propagates and focuses FIG. The difference between the optical head of the fourth embodiment of the present invention and the optical head of the third embodiment is that the reflective collimator lens 3 and the transmissive cylindrical objective lens 14 are used as a transmissive type as the first light condensing means. Collimator objective lens 1
6. This lens 16 is composed of a plurality of elliptical grating zones having short axes in the direction of the optical axis of the propagating light, and the center position of this ellipse is located at the center of the lens 1.
6 has a configuration in which it gradually deviates from the traveling direction of the propagating light as it approaches the outer periphery. Therefore, the optical head of this embodiment has the advantage that the number of optical components is reduced, and as a result, the size of the optical head is reduced and the overall light utilization efficiency is increased. However, designing and manufacturing the transmission type collimator objective lens 16 becomes difficult.
【００２１】以上説明した本発明の光学ヘッドでは、基
板が光伝搬路となっていたが、これに限らず、基板上に
光伝搬路を設けた構造でも良い。[0021] In the optical head of the present invention described above, the substrate serves as the optical propagation path, but the present invention is not limited to this, and a structure in which the optical propagation path is provided on the substrate may also be used.
【００２２】また、本発明に用いられるレンズは、上記
実施例に用いたコリメータレンズ、対物レンズ、集光レ
ンズ等に限られないことはいうまでもない。It goes without saying that the lenses used in the present invention are not limited to the collimator lenses, objective lenses, condensing lenses, etc. used in the above embodiments.
【００２３】また、光検出器及び／又は光源は、光伝搬
路中に設けてもよい。[0023] Furthermore, a photodetector and/or a light source may be provided in the optical propagation path.
【００２４】[0024]
【発明の効果】以上のように本発明は、ジグザグ状に光
が伝搬する、厚さ及び幅がその伝搬光波長の１０倍以上
である光伝搬路が設けられた基板と、光を発生する光源
と、その光源からの光を光伝搬路に導き、伝搬光を集光
して光記録媒体に出力する第１の光集光手段と、光記録
媒体からの反射光を、光検出器に導く第２の光集光手段
とを備えているので、光学ヘッド各光学部品の位置合わ
せが容易で小形軽量化可能な光学ヘッドが実現可能であ
るという効果を有する。As described above, the present invention provides a substrate provided with an optical propagation path through which light propagates in a zigzag pattern and whose thickness and width are at least 10 times the wavelength of the propagating light, and a substrate that generates light. a light source, a first light focusing means that guides light from the light source to an optical propagation path, collects the propagated light and outputs it to an optical recording medium, and directs reflected light from the optical recording medium to a photodetector. Since the optical head is provided with a second light condensing means for guiding the light, it is possible to easily align each optical component of the optical head and to realize an optical head that can be made smaller and lighter.
【図１】本発明の第１の実施例の光学ヘッドの基本構成
と、光の伝搬、集光の様子を示す平面図である。FIG. 1 is a plan view showing the basic configuration of an optical head according to a first embodiment of the present invention, and how light is propagated and focused.
【図２】本発明の第１の実施例の光学ヘッドの基本構成
と、光の伝搬、集光の様子を示す側面図である。FIG. 2 is a side view showing the basic configuration of the optical head according to the first embodiment of the present invention, and how light is propagated and focused.
【図３】本発明の第２の実施例の光学ヘッドの基本構成
と、光の伝搬、集光の様子を示す平面図である。FIG. 3 is a plan view showing the basic configuration of an optical head according to a second embodiment of the present invention, and how light is propagated and focused.
【図４】本発明の第２の実施例の光学ヘッドの基本構成
と、光の伝搬、集光の様子を示す側面図である。FIG. 4 is a side view showing the basic configuration of an optical head according to a second embodiment of the present invention, and how light is propagated and focused.
【図５】本発明の第３の実施例の光学ヘッドの基本構成
を示す平面図である。FIG. 5 is a plan view showing the basic configuration of an optical head according to a third embodiment of the present invention.
【図６】本発明の第３の実施例の光学ヘッドの基本構成
と、光の伝搬、集光の様子を示す側面図である。FIG. 6 is a side view showing the basic configuration of an optical head according to a third embodiment of the present invention, and how light is propagated and focused.
【図７】本発明の第４の実施例の光学ヘッドの基本構成
を示す平面図である。FIG. 7 is a plan view showing the basic configuration of an optical head according to a fourth embodiment of the present invention.
【図８】本発明の第４の実施例の光学ヘッドの基本構成
と、光の伝搬、集光の様子を示す側面図である。FIG. 8 is a side view showing the basic configuration of an optical head according to a fourth embodiment of the present invention, and how light is propagated and focused.
【図９】従来の光学ヘッドの斜視図である。FIG. 9 is a perspective view of a conventional optical head.
１ 光源
２ 基板
３ 反射形コリメータレンズ（コリメータ手段）
４ 反射形シリンドリカル対物レンズ（第１の光
集光手段）
５ 反射形集光レンズ（第２の光集光手段）６
光検出器アレイ（光検出器）７ 光記録媒
体
８ 伝搬光
９ 出射光
１０ 反射光
１１ 反射層
１２ 反射形コリメータ対物レンズ（第１の光集光手
段）
１３ 光伝搬路
１４ 透過形シリンドリカル対物レンズ（第１の光集
光手段）
１５ 透過形集光レンズ（第２の光集光手段）１６
透過形コリメータ対物レンズ（第１の光集光手段）1 Light source 2 Substrate 3 Reflective collimator lens (collimator means)
4 Reflective cylindrical objective lens (first light focusing means) 5 Reflective focusing lens (second light focusing means) 6
Photodetector array (photodetector) 7 Optical recording medium 8 Propagating light 9 Outgoing light 10 Reflected light 11 Reflective layer 12 Reflective collimator objective lens (first light focusing means) 13 Light propagation path 14 Transmissive cylindrical objective lens (First light condensing means) 15 Transmissive condensing lens (second light condensing means) 16
Transmission type collimator objective lens (first light focusing means)
Claims (10)
幅がその伝搬光波長の１０倍以上である光伝搬路が設け
られた基板と、光を発生する光源と、その光源からの光
を前記光伝搬路に導き、前記伝搬光を集光して光記録媒
体に出力する第１の光集光手段と、前記光記録媒体から
の反射光を、光検出器に導く第２の光集光手段とを備え
たことをことを特徴とする光学ヘッド。1. A substrate provided with an optical propagation path in which light propagates in a zigzag pattern and whose thickness and width are 10 times or more the wavelength of the propagating light, a light source that generates light, and light from the light source. a first light condenser that guides the propagated light to the optical propagation path, condenses the propagated light, and outputs it to an optical recording medium; and a second light condenser that guides the reflected light from the optical recording medium to a photodetector. An optical head comprising: a light condensing means.
波長の１００倍以上であることを特徴とする請求項１の
光学ヘッド。2. The optical head according to claim 1, wherein the thickness and width of the optical propagation path are 100 times or more the wavelength of the propagating light.
表面、または裏面に反射層が設けられていることを特徴
とする請求項１の光学ヘッド。3. The optical head according to claim 1, wherein the substrate is used as a light propagation path, and a reflective layer is provided on the front or back surface of the light propagation path.
手段は、複数のグレーティングゾーンからなる回折光学
素子であり、そのグレーティングゾーンのパターン形状
は弓なりの曲線であり、その回折光学素子は前記光伝搬
路上もしくは光伝搬路中に設けられていることを特徴と
する請求項１の光学ヘッド。4. At least the first or second light focusing means is a diffractive optical element consisting of a plurality of grating zones, the pattern shape of the grating zone is an arched curve, and the diffractive optical element is configured to The optical head according to claim 1, wherein the optical head is provided on a propagation path or in a light propagation path.
も１つは、前記光伝搬路上もしくは光伝搬路中に設けて
いることを特徴とする請求項１の光学ヘッド。5. The optical head according to claim 1, wherein at least one of a photodetector and a light source is provided on or in the light propagation path.
前記光検出器は、前記光伝搬路の裏面側（光記録媒体の
ない方）に設けられていることを特徴とする請求項３の
光学ヘッド。6. The first and second light condensing means, the light source, and the photodetector are provided on the back side of the light propagation path (the side without the optical recording medium). The optical head according to claim 3.
れ、前記光源からの伝搬光は、前記コリメータ手段でコ
リメートされた後、前記第１の光集光手段に導かれるも
のであって、そのコリメート手段は、複数のグレーティ
ングゾーンと、前記グレーティングゾーン上に設けられ
た反射層からなり、前記グレーティングゾーンのパター
ン形状は、前記伝搬光の光軸方向に長軸を有する楕円形
であり、前記楕円形の中心位置は、前記グレーティング
ゾーンの外周部にいくにしたがって、前記伝搬光の進行
方向とは逆向きに、徐々にずれていることを特徴とする
請求項１の光学ヘッド。7. A collimator means is provided on a light propagation path, and the propagating light from the light source is collimated by the collimator means and then guided to the first light condensing means, the collimator The means includes a plurality of grating zones and a reflective layer provided on the grating zones, and the pattern shape of the grating zones is an ellipse having a long axis in the optical axis direction of the propagating light, and the elliptical shape 2. The optical head according to claim 1, wherein the center position of the grating zone gradually shifts in a direction opposite to the traveling direction of the propagating light as it approaches the outer periphery of the grating zone.
グレーティングゾーンからなり、前記グレーティングゾ
ーンの周期は、前記伝搬光の進行方向に従って、徐々に
小さくなることを特徴とする請求項７の光学ヘッド。8. The first light condensing means includes a plurality of linear grating zones, and the period of the grating zones gradually decreases in accordance with the traveling direction of the propagating light. 7 optical head.
軸方向に短軸を有する楕円形の複数のグレーティングゾ
ーンからなり、前記楕円形の中心位置は、前記グレーテ
ィングゾーンの外周部にいくにしたがって、前記楕円形
の長軸方向のうち伝搬光の進行方向とは逆向きに、徐々
にずれていることを特徴とする請求項１に記載の光学ヘ
ッド。9. The first light focusing means includes a plurality of elliptical grating zones having short axes in the optical axis direction of the propagating light, and the center position of the ellipse is located at the outer periphery of the grating zone. 2. The optical head according to claim 1, wherein the long axis of the ellipse gradually deviates in a direction opposite to the traveling direction of the propagating light.
集光手段を同時に含む金型を作製し、その金形を用いて
、前記第１と第２の光集光手段を同時に複製することを
特徴とする請求項４に記載の光学ヘッドの製造方法。10. A mold that simultaneously includes at least a first light condensing means and a second light condensing means is produced, and the mold is used to simultaneously condense the first and second light condensing means. 5. The method of manufacturing an optical head according to claim 4, further comprising duplicating the optical head.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3075384A JPH04310639A (en) | 1991-04-08 | 1991-04-08 | Optical head and its manufacture |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3075384A JPH04310639A (en) | 1991-04-08 | 1991-04-08 | Optical head and its manufacture |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH04310639A true JPH04310639A (en) | 1992-11-02 |
Family
ID=13574647
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3075384A Pending JPH04310639A (en) | 1991-04-08 | 1991-04-08 | Optical head and its manufacture |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH04310639A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH06259800A (en) * | 1993-03-05 | 1994-09-16 | Matsushita Electric Ind Co Ltd | Optical device |
| JP2004103792A (en) * | 2002-09-09 | 2004-04-02 | Ricoh Co Ltd | Compound optical device and method of manufacturing the same |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS62146444A (en) * | 1985-12-17 | 1987-06-30 | インタ−ナショナル ビジネス マシ−ンズ コ−ポレ−ション | Reading/writing head |
| JPS63259844A (en) * | 1987-04-16 | 1988-10-26 | Kuraray Co Ltd | Optical head |
| JPH01311429A (en) * | 1988-01-27 | 1989-12-15 | Hitachi Ltd | Optical information reader |
| JPH0276138A (en) * | 1988-09-12 | 1990-03-15 | Hitachi Ltd | Light pickup |
| JPH02191916A (en) * | 1988-09-19 | 1990-07-27 | Hitachi Ltd | Optical head and optical information processor |
-
1991
- 1991-04-08 JP JP3075384A patent/JPH04310639A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS62146444A (en) * | 1985-12-17 | 1987-06-30 | インタ−ナショナル ビジネス マシ−ンズ コ−ポレ−ション | Reading/writing head |
| JPS63259844A (en) * | 1987-04-16 | 1988-10-26 | Kuraray Co Ltd | Optical head |
| JPH01311429A (en) * | 1988-01-27 | 1989-12-15 | Hitachi Ltd | Optical information reader |
| JPH0276138A (en) * | 1988-09-12 | 1990-03-15 | Hitachi Ltd | Light pickup |
| JPH02191916A (en) * | 1988-09-19 | 1990-07-27 | Hitachi Ltd | Optical head and optical information processor |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH06259800A (en) * | 1993-03-05 | 1994-09-16 | Matsushita Electric Ind Co Ltd | Optical device |
| JP2004103792A (en) * | 2002-09-09 | 2004-04-02 | Ricoh Co Ltd | Compound optical device and method of manufacturing the same |
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