JPH05241095A - Method for compensating spherical aberration of optical disk and optical head using the same - Google Patents
Method for compensating spherical aberration of optical disk and optical head using the sameInfo
- Publication number
- JPH05241095A JPH05241095A JP4044750A JP4475092A JPH05241095A JP H05241095 A JPH05241095 A JP H05241095A JP 4044750 A JP4044750 A JP 4044750A JP 4475092 A JP4475092 A JP 4475092A JP H05241095 A JPH05241095 A JP H05241095A
- Authority
- JP
- Japan
- Prior art keywords
- thickness
- spherical aberration
- optical disk
- optical
- cover glass
- 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
Landscapes
- Automatic Focus Adjustment (AREA)
- Optical Head (AREA)
- Lenses (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は光学的に情報を記録ある
いは再生を行ういわゆるコンパクトディスク(ＣＤ)やビ
デオディスク(ＶＤ)などの光ディスク装置に用いられる
光ディスクの球面収差の補正方法とそれを用いた光ヘッ
ドに関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for correcting spherical aberration of an optical disk used in an optical disk device such as a so-called compact disk (CD) or video disk (VD) which optically records or reproduces information and uses it. It is related to the optical head.
【０００２】[0002]
【従来の技術】光ディスク装置では、レーザー等の光源
から発散する光束を、情報記録媒体(以下これを単に光
ディスクという)に集光して、情報の記録及び、読み出
しを行う。そのときには、回折限界程度の集光性能を有
する高性能な光学系が必要である。2. Description of the Related Art In an optical disk device, a light flux diverging from a light source such as a laser is focused on an information recording medium (hereinafter, simply referred to as an optical disk) to record and read information. In that case, a high-performance optical system having a condensing performance that is about the diffraction limit is required.
【０００３】最近は、光ディスクの高密度化が開発にお
ける重要な課題の一つである。高密度化を実現するため
にはレーザー等の光源からの光束をより小さなスポット
に集光する必要があり、その実現のために多くの方法が
検討されている。その中で、開口数の大きなレンズを用
いて、従来よりも小さなスポット径に集光する方法があ
る。しかしレンズの開口数が大きくなると、光ディスク
のそりや傾きに対してコマ収差が発生しやすくなる。こ
の場合には光ディスクのカバーガラスの厚みが薄い方が
コマ収差の発生を少なくできるという点で有利である。Recently, increasing the density of optical disks has become one of the important issues in development. In order to realize a high density, it is necessary to focus the light flux from a light source such as a laser into a smaller spot, and many methods have been studied for realizing it. Among them, there is a method of using a lens having a large numerical aperture to collect light to a spot diameter smaller than the conventional one. However, when the numerical aperture of the lens increases, coma tends to occur due to the warp or tilt of the optical disc. In this case, it is advantageous that the cover glass of the optical disc has a small thickness because the occurrence of coma can be reduced.
【０００４】[0004]
【発明が解決しようとする課題】現在、ＣＤプレーヤー
などの光ディスクのカバーガラスの厚みは1.2mmである
が、高密度記録用に光ディスクのカバーガラス厚を1.2m
mよりも薄くした場合を考える。このとき、1.2mmのカバ
ーガラス厚みに対応した光ヘッドで、高密度記録用の薄
いカバーガラスの光ディスクを使った場合には、負の球
面収差が発生し十分な集光性能が得られない。逆に、薄
いカバーガラスの光ディスクに対応した光ヘッドで、カ
バーガラス厚みが1.2mmの光ディスクを使った場合に
は、正の球面収差が発生し、やはり十分な集光性能を得
ることが出来ない。つまり、これまでに提案されてきた
ような光ヘッド用の集光光学系では光ディスクカバーガ
ラス厚みを変えると光ディスクの互換性が損なわれてし
まうことになる。At present, the thickness of the cover glass of an optical disk such as a CD player is 1.2 mm, but the cover glass of the optical disk has a thickness of 1.2 m for high density recording.
Consider the case where it is thinner than m. At this time, when an optical head corresponding to a cover glass thickness of 1.2 mm and a thin cover glass optical disk for high density recording are used, negative spherical aberration occurs and sufficient condensing performance cannot be obtained. On the other hand, when an optical head with a cover glass thickness of 1.2 mm is used with an optical head compatible with a thin cover glass optical disk, positive spherical aberration occurs and it is not possible to obtain sufficient focusing performance. . In other words, in the condensing optical system for optical heads that has been proposed so far, if the thickness of the optical disc cover glass is changed, the compatibility of optical discs will be impaired.
【０００５】光ディスクのカバーガラス厚みが薄くなっ
た場合に、発生する球面収差を補正する方法として、平
行平板の媒体を対物レンズと光ディスクの間に挿入する
ことによって、対物レンズから像点までの光路長を規定
の値に保つことは可能である。この位置に収差の補正を
目的とした平行平板を挿入する収差の補正方法は特開昭
62−66433号に開示されている。As a method of correcting the spherical aberration that occurs when the cover glass of the optical disc becomes thin, a parallel plate medium is inserted between the objective lens and the optical disc to determine the optical path from the objective lens to the image point. It is possible to keep the length at a specified value. A method of correcting an aberration by inserting a parallel plate at this position for the purpose of correcting the aberration is disclosed in Japanese Patent Laid-Open No.
No. 62-66433.
【０００６】しかし、光ディスクの動作中には、対物レ
ンズは最適なフォーカス及びトラッキングを得るために
動いており、また光ディスクも高速で回転しているた
め、対物レンズと光ディスクの間に前記のような平行平
板の媒体を挿入するのは困難であり、対物レンズと光デ
ィスクの間に平行平板の媒体を挿入することにより、十
分な作動距離を確保できなくなるなどの理由から、対物
レンズと光ディスクの間に平行平板の媒体を挿入する収
差補正法は有効な方法であるとは言い難い。また、光デ
ィスクの厚みに応じて複数のヘッドを用意するのも解決
策の一つではあるが、装置が複雑になってしまう。However, during the operation of the optical disc, the objective lens is moving for obtaining the optimum focus and tracking, and the optical disc is also rotating at a high speed. It is difficult to insert a parallel plate medium, and because inserting a parallel plate medium between the objective lens and the optical disc makes it impossible to secure a sufficient working distance. It is hard to say that the aberration correction method of inserting a parallel plate medium is an effective method. Further, preparing a plurality of heads according to the thickness of the optical disk is one of the solutions, but the apparatus becomes complicated.
【０００７】本発明は上記の点に鑑み、光ディスクの厚
みの変化によって発生する球面収差を良好に除去できる
球面収差の補正方法を提供し、その球面収差の補正方法
を用いて、異なったカバーガラス厚みの光ディスクの記
録再生が可能な光ヘッドを提供することを目的とする。In view of the above points, the present invention provides a spherical aberration correction method capable of satisfactorily removing the spherical aberration caused by a change in the thickness of an optical disc, and using the spherical aberration correction method, different cover glasses are provided. It is an object of the present invention to provide an optical head capable of recording / reproducing a thick optical disc.
【０００８】[0008]
【発明が解決しようとする課題】本発明の光ヘッドの球
面収差の補正方法は、光源から発散する光束を光ディス
クに集光する集光光学系と、前記光源と集光光学系の間
に平行平板の媒体(以下、補正板という)が挿入された構
成の光学系において、前記光ディスクのカバーガラスの
厚みが変化することにより発生する収差を、前記補正板
の厚みを調整して補正することを特徴とし、この球面収
差方法を用いた光ヘッドで構成される。SUMMARY OF THE INVENTION A method of correcting spherical aberration of an optical head according to the present invention comprises a condensing optical system for condensing a light beam diverging from a light source onto an optical disc, and a parallel optical system between the light source and the condensing optical system. In an optical system having a configuration in which a flat medium (hereinafter referred to as a correction plate) is inserted, it is possible to correct an aberration caused by a change in the thickness of the cover glass of the optical disc by adjusting the thickness of the correction plate. It is characterized by an optical head using this spherical aberration method.
【０００９】[0009]
【作用】本発明によれば、光ディスクのカバーガラス厚
みが薄くなると負の球面収差が発生するが、この場合に
は、補正板の厚みを厚くすることによって発生する正の
球面収差を得て、これが光ディスクのカバーガラス厚み
が薄くなったことによって生ずる前記負の球面収差を打
ち消すように出来る。逆に、光ディスクのカバーガラス
厚みが厚くなった場合には、正の球面収差が発生する
が、この場合には、補正板の厚みを薄くすることによっ
て発生する負の球面収差を得て、これが光ディスク厚み
が厚くなったことにより発生した正の球面収差を打ち消
すように出来る。このようにすることで、光ディスクの
カバーガラスの厚みの変化によって発生する光ディスク
の球面収差を補正することが可能となる。According to the present invention, negative spherical aberration occurs when the thickness of the cover glass of the optical disc becomes thin. In this case, positive spherical aberration produced by increasing the thickness of the correction plate is obtained, This can cancel the negative spherical aberration caused by the thin cover glass of the optical disc. On the contrary, when the cover glass thickness of the optical disk becomes thick, positive spherical aberration occurs, but in this case, the negative spherical aberration generated by making the thickness of the correction plate thin is obtained, and this It is possible to cancel the positive spherical aberration generated due to the increased thickness of the optical disc. By doing so, it becomes possible to correct the spherical aberration of the optical disc caused by the change in the thickness of the cover glass of the optical disc.
【００１０】また、上記光ディスクの球面収差の補正方
法を用いた光ヘッドは異なったカバーガラス厚みの光デ
ィスクの記録再生が可能である。Further, the optical head using the method of correcting the spherical aberration of the optical disc described above can record and reproduce optical discs having different cover glass thicknesses.
【００１１】[0011]
【実施例】以下に本発明の補正方法を用いた光ディスク
用集光光学系の一実施例を図１に示し、その数値例を下
記に示し、数値例中、Ｒkは光源側より順に第ｋ番目の
面の頂点曲率半径、ｄkは光源側より順に第ｋ番目の面
間隔、ｎkは光源側より順に第ｋ番目の屈折率、ｆは全
系の焦点距離、ＮＡは光ディスク側の開口数、λは光源
の波長である。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a condensing optical system for an optical disk using the correction method of the present invention is shown below in FIG. 1, and numerical examples thereof are shown below, where R k is the first from the light source side. The vertex curvature radius of the k-th surface, d k is the k-th surface spacing in order from the light source side, n k is the k-th refractive index in order from the light source side, f is the focal length of the entire system, and NA is the optical disk side. The numerical aperture, λ, is the wavelength of the light source.
【００１２】本実施例による非球面係数は、第ｋ面の非
球面上の任意の点から前記非球面の頂点における接平面
までの距離をＸk、前記任意の点から光軸までの距離を
ｈ、第ｋ面の頂点近傍での円錐定数をＣk、第ｋ面での
４次、６次、８次、10次の非球面定数をＤk，Ｅk，
Ｆk，Ｇkとしたときに前記非球面の形状が、As for the aspherical surface coefficient according to this embodiment, the distance from an arbitrary point on the aspherical surface of the k-th surface to the tangent plane at the apex of the aspherical surface is X k , and the distance from the arbitrary point to the optical axis is h, the conical constant near the apex of the k-th surface is C k , the fourth-order, sixth-order, eighth-order, and tenth-order aspherical constants on the k -th surface are D k , E k ,
The shape of the aspherical surface when F k and G k are
【００１３】[0013]
【数１】 [Equation 1]
【００１４】にて表わされる非球面であるとする。It is assumed that the surface is an aspherical surface.
【００１５】なお屈折率は波長780nmにおける値であ
る。図１に光ディスク４のカバーガラス厚みが1.20mmの
場合の構成図を示し、第２面Ｒ2と第３図Ｒ3が補正板
１、第４面Ｒ4と第５面Ｒ5がコリメートレンズ２、第６
面Ｒ6と第７面Ｒ7が対物レンズ３、第８面Ｒ8と第９面
Ｒ9が光ディスク４のカバーガラスである。The refractive index is a value at a wavelength of 780 nm. FIG. 1 shows a configuration diagram when the cover glass thickness of the optical disk 4 is 1.20 mm. The second surface R 2 and FIG. 3 R 3 are the correction plate 1, and the fourth surface R 4 and the fifth surface R 5 are collimating lenses. 2, sixth
The surface R 6 and the seventh surface R 7 are the objective lens 3, and the eighth surface R 8 and the ninth surface R 9 are the cover glass of the optical disc 4.
【００１６】実施例の数値 ｆ ＝ ２.４０３ ＮＡ＝ ０.４５ λ ＝ ７８０nm Ｒ1 ＝ ０.０００ ｄ1 ＝ １.０００００ ｎ1 ＝ １.０００００ Ｒ2 ＝ ０.０００ ｄ2 ＝ 可変 ｎ2 ＝ １.５５０００ Ｒ3 ＝ ０.０００ ｄ3 ＝ ３.３５３７０ ｎ3 ＝ １.０００００ Ｒ4 ＝６０.１５７ ｄ4 ＝ ２.０００００ ｎ4 ＝ １.６７３１４ Ｒ5 ＝−４.２７２ ｄ5 ＝ １.０００００ ｎ5 ＝ １.０００００ Ｒ6 ＝ ２.７０１ ｄ6 ＝ ２.０００００ ｎ6 ＝ １.６７３１４ Ｒ7 ＝−５.６１６ ｄ7 ＝ 可変 ｎ7 ＝ １.０００００ Ｒ8 ＝ ０.０００ ｄ8 ＝ 可変 ｎ8 ＝ １.５５０００ Ｒ9 ＝ ０.０００ 第４面非球面係数 Ｃ4 ＝ ９.５８０５２７× 1 Ｄ4 ＝ ２.５０６５９７×~4 Ｅ4 ＝ ５.３９７８７２×~5 Ｆ4 ＝ ８.５４２８８３×~6 Ｇ4 ＝ ６.２７４９９４×~7 第５面非球面係数 Ｃ5 ＝−９.５７５１８６×~1 Ｄ5 ＝−３.３３３３４９×~4 Ｅ5 ＝ ４.０６９０４７×~5 Ｆ5 ＝ ４.９８７５６０×~6 Ｇ5 ＝ ４.０５６６０８×~7 第６面非球面係数 Ｃ6 ＝−１.２０４６０３ Ｄ6 ＝−１.４３０６６０×~3 Ｅ6 ＝−１.７６６４４９×~3 Ｆ6 ＝−８.２４７３６７×~5 Ｇ6 ＝−１.６４６６１０×~4 第７面非球面係数 Ｃ7 ＝ ８.９４２１８８ Ｄ7 ＝ ２.７７６２９１×~3 Ｅ7 ＝ ３.００２２７６×~3 Ｆ7 ＝ ８.５２０１００×~4 Ｇ7 ＝ ０.０ 可変間隔 ｄ2 ＝ ０.１３ ｄ7 ＝ １.４５０６５ ｄ8 ＝ １.２０ ｄ2 ＝ ０.４５ ｄ7 ＝ １.５２０１９ ｄ8 ＝ １.００ ｄ2 ＝ ０.９０ ｄ7 ＝ １.５７４０９ ｄ8 ＝ ０.８０ ｄ2 ＝ １.８０ ｄ7 ＝ １.５７６８６ ｄ8 ＝ ０.６０ 上記実施例中の光ディスクのカバーガラス厚が1.20mmの
場合の構成図を図１に示すが、その収差図を図２に示
し、この収差図において、Ｓはサジタル面での非点収
差、Ｍはメリジオナル面での非点収差を示し、以下の各
図３，４，６でも同じである。図３，図４はそれぞれ、
光ディスクのカバーガラス厚が1.00mm、0.80mmの場合の
各収差図であり、図５，図６は光ディスクのカバーガラ
ス厚が0.60mmの場合の構成図と収差図であり、図５に例
示のとおり図１と比較して分るとおり補正板１の厚みは
光ディスク４のカバーガラスの厚みに応じて球面収差を
補正する厚さになっている。Numerical value of the embodiment f = 2.403 NA = 0.45 λ = 780 nm R 1 = 0.000 d 1 = 1.0000 n 1 = 1.0000 R 2 = 0.000 d 2 = Variable n 2 = 1.55000 R 3 = 0.000 d 3 = 3.35370 n 3 = 1.00000 R 4 = 60.157 d 4 = 2.00000 n 4 = 1.67314 R 5 = -4.272 d 5 = 1.00000 n 5 = 1.00000 R 6 = 2.701 d 6 = 2.00000 n 6 = 1.67314 R 7 = -5.616 d 7 = variable n 7 = 1.00000 R 8 = 0.000 d 8 = variable n 8 = 1.55000 R 9 = 0.000 4th surface aspherical surface coefficient C 4 = 9.5580527 × 1 D 4 = 2.550697 × ~ 4 E 4 = 5.39772 × ~ 5 F 4 = 8.542883 × ~ 6 G 4 = 6.274994 × ~ 7 Fifth surface aspherical coefficient C 5 = -9.575186 × ~ 1 D 5 = -3.333349 × ~ 4 E 5 = 4.069047 × ~ 5 F 5 = 4.987560 × ~ 6 G 5 = 4.056608 × ~ 7 Sixth Surface aspherical coefficients C 6 = -1.204603 D 6 = -1.430660 × ~ 3 E 6 = -1.766449 × ~ 3 F 6 = -8.247367 × ~ 5 G 6 = -1.646610 × ~ 4 7th surface aspherical surface coefficient C 7 = 8.942188 D 7 = 2.777291 × ~ 3 E 7 = 3.02276 × ~ 3 F 7 = 8.520100 × ~ 4 G 7 = 0.0 Variable interval d 2 = 0.13 d 7 = 1.45065 d 8 = 1.20 d 2 = 0.45 d 7 = 1.52019 d 8 = 1.00 d 2 = 0.90 d 7 = 1.57409 d 8 = 0.0. 80 d 2 = 1.80 d 7 = 1.57686 d 8 = 0.60 FIG configuration diagram in the case of the cover glass thickness of an optical disk in the above embodiment is 1.20mm The aberration diagram is shown in FIG. 2. In this aberration diagram, S is astigmatism on the sagittal surface, M is astigmatism on the meridional surface, and in each of FIGS. Is the same. 3 and 4 respectively,
FIGS. 5 and 6 are aberration diagrams when the cover glass thickness of the optical disc is 1.00 mm and 0.80 mm, and FIGS. 5 and 6 are configuration diagrams and aberration diagrams when the cover glass thickness of the optical disc is 0.60 mm. As can be seen from comparison with FIG. 1, the thickness of the correction plate 1 is such that spherical aberration is corrected according to the thickness of the cover glass of the optical disc 4.
【００１７】上記、図２ないし図４及び図６から明らか
なように、光ディスクの厚みが、1.2mmから0.6mmへと変
化しても球面収差が良好に除去されていることがわか
る。As can be seen from FIGS. 2 to 4 and 6, the spherical aberration is well removed even when the thickness of the optical disk changes from 1.2 mm to 0.6 mm.
【００１８】なお、本実施例ではコリメートレンズ２と
対物レンズ３を組み合わせた集光光学系を用いたが、コ
リメートレンズと対物レンズが一体となってレンズ系を
構成し、単玉でレーザーからの発散光を受け取り光ディ
スクに集光するいわゆる一体型ピックアップや、レーザ
ー光の集光手段としてミラーなどの反射光学系を用いた
場合においても同様の効果が得られることは言うまでも
ない。In this embodiment, the condensing optical system in which the collimating lens 2 and the objective lens 3 are combined is used. However, the collimating lens and the objective lens are integrated to form a lens system, and a single lens is used to emit a laser beam. It goes without saying that the same effect can be obtained when a so-called integrated pickup that receives divergent light and focuses it on an optical disk, or when a reflection optical system such as a mirror is used as a means for focusing laser light.
【００１９】また図７，図８は補正板の他の構成例であ
り、図７において、１Ａは可動片であり、１Ｂは固定片
である。可動片１Ａと、固定片１Ｂは頂角が等しい三角
柱又は台形柱の形状であり、可動片１Ａを矢印の方向に
移動させることで任意の厚さの補正板を形成することが
でき、これによって任意の厚さの光ディスクに対応した
球面収差の補正が行える。また、図８は厚みがステップ
状に変化したステップ部１Ｃを有する形状の補正板であ
る。このような簡単な形状であっても数種の光ディスク
のカバーガラス厚に対応した球面収差の補正が可能であ
る。7 and 8 show another example of the structure of the correction plate. In FIG. 7, 1A is a movable piece and 1B is a fixed piece. The movable piece 1A and the fixed piece 1B are in the shape of a triangular prism or a trapezoidal pillar having the same apex angle, and by moving the movable piece 1A in the direction of the arrow, a correction plate having an arbitrary thickness can be formed. It is possible to correct spherical aberration corresponding to an optical disc having an arbitrary thickness. Further, FIG. 8 shows a correction plate having a shape having a step portion 1C whose thickness is changed stepwise. Even with such a simple shape, it is possible to correct spherical aberration corresponding to the cover glass thickness of several types of optical disks.
【００２０】図９は、本発明による球面収差の補正方法
を用いた光ヘッドの構成図を示し、光源５からの光束は
図７に例示した補正板１を通過後、ハーフミラー６によ
って反射され、コリメートレンズ２、及び対物レンズ３
により、光ディスク４に集光される。光ディスク４から
の反射光は対物レンズ３，コリメートレンズ２を経て、
ハーフミラー６を透過し、受光素子７に至り、この受光
素子７により光ディスク４上の情報が読み出される。図
９中で、実線は光ディスク４のカバーガラス厚みが厚い
場合であり、破線は、光ディスク４のカバーガラス厚み
の薄い場合を示す。光ディスクのカバーガラスの厚みが
薄くなった場合には、補正板１の厚みが最適となるよう
に補正板１を矢印方向に移動し、その厚みを調整し、光
源５の位置及び受光素子７の位置も最適となるように移
動すれば良い。このような構成の光ヘッドを用いること
により、光ディスクのカバーガラスの厚さが変化しても
情報の記録再生が正確に行なえる。FIG. 9 is a block diagram of an optical head using the spherical aberration correcting method according to the present invention. The light beam from the light source 5 is reflected by the half mirror 6 after passing through the correction plate 1 illustrated in FIG. , Collimator lens 2, and objective lens 3
Thus, the light is focused on the optical disc 4. The reflected light from the optical disc 4 passes through the objective lens 3 and the collimator lens 2,
After passing through the half mirror 6, it reaches the light receiving element 7, and the information on the optical disk 4 is read by the light receiving element 7. In FIG. 9, the solid line shows the case where the cover glass thickness of the optical disc 4 is thick, and the broken line shows the case where the cover glass thickness of the optical disc 4 is thin. When the cover glass of the optical disk becomes thin, the correction plate 1 is moved in the direction of the arrow so that the thickness of the correction plate 1 becomes optimum, and the thickness is adjusted to adjust the position of the light source 5 and the light receiving element 7. It may be moved so that the position is optimal. By using the optical head having such a structure, it is possible to accurately record and reproduce information even if the thickness of the cover glass of the optical disc changes.
【００２１】[0021]
【発明の効果】以上説明したように本発明によれば、光
ディスクのカバーガラス厚みが変化したときに発生する
球面収差を補正板によって、補正することが出来る。ま
た、補正板の挿入位置を光源と集光光学系の間に設定す
ることは、対物レンズ側に変更を加えることがないの
で、対物レンズのアクチュエータなどに負担をかけるこ
ともない上に、コリメートレンズは固定されたものであ
ることから、挿入し易く、加工の上でも有利である。こ
の、球面収差の補正方法を用いて光ヘッドをつくること
で、光ディスクのカバーガラス厚みの変化に対してコン
パチブルな光ディスク装置を実現することが可能とな
る。As described above, according to the present invention, the spherical aberration generated when the cover glass thickness of the optical disk changes can be corrected by the correction plate. In addition, setting the insertion position of the correction plate between the light source and the condensing optical system does not change the objective lens side, so that it does not burden the actuator of the objective lens and collimator. Since the lens is fixed, it can be easily inserted and is advantageous in processing. By making an optical head by using this spherical aberration correction method, it becomes possible to realize an optical disk device that is compatible with changes in the cover glass thickness of the optical disk.
【図１】本発明の一実施例に係る光ディスクのカバーガ
ラス厚みが1.20mmの場合の構成図である。FIG. 1 is a configuration diagram of an optical disc according to an embodiment of the present invention when a cover glass has a thickness of 1.20 mm.
【図２】図１の場合の収差図である。FIG. 2 is an aberration diagram in the case of FIG.
【図３】本発明の一実施例に係る光ディスクのカバーガ
ラス厚みが1.00mmの場合の収差図である。FIG. 3 is an aberration diagram in the case where the cover glass thickness of the optical disc according to the embodiment of the present invention is 1.00 mm.
【図４】本発明の一実施例に係る光ディスクのカバーガ
ラス厚みが0.80mmの場合の収差図である。FIG. 4 is an aberration diagram in the case where the cover glass thickness of the optical disc according to the embodiment of the present invention is 0.80 mm.
【図５】本発明の一実施例に係る光ディスクのカバーガ
ラス厚みが0.60mmの場合の構成図である。FIG. 5 is a configuration diagram of an optical disc according to an embodiment of the present invention when the cover glass thickness is 0.60 mm.
【図６】図５の場合の収差図である。FIG. 6 is an aberration diagram in the case of FIG.
【図７】本発明の補正板の他の構成例図である。FIG. 7 is a diagram showing another configuration example of the correction plate of the present invention.
【図８】本発明の補正板の他の構成例図である。FIG. 8 is a diagram showing another configuration example of the correction plate of the present invention.
【図９】本発明方法を実施した光ヘッドの構成図であ
る。FIG. 9 is a configuration diagram of an optical head that implements the method of the present invention.
１…補正板、 １Ａ…可動片、 １Ｂ…固定片、 １Ｃ
…ステップ部、 ２…コリメートレンズ、 ３…対物レ
ンズ、 ４…光ディスク、 ５…光源、 ６…ハーフミ
ラー、 ７…受光素子。1 ... Correction plate, 1A ... Movable piece, 1B ... Fixed piece, 1C
... step section, 2 ... collimator lens, 3 ... objective lens, 4 ... optical disk, 5 ... light source, 6 ... half mirror, 7 ... light receiving element.
Claims (2)
集光する集光光学系と、前記光源と集光光学系の間に平
行平板の媒体が挿入された構成の光学系において、前記
情報記録媒体のカバーガラスの厚みが変化することによ
り発生する球面収差を、前記平行平板の厚みを調整して
補正することを特徴とする光ディスクの球面収差の補正
方法。1. An optical system having a condensing optical system for condensing a light beam diverging from a light source onto an information recording medium, and an optical system having a parallel plate medium inserted between the light source and the condensing optical system. A method for correcting spherical aberration of an optical disk, which comprises correcting spherical aberration generated by changing the thickness of a cover glass of a recording medium by adjusting the thickness of the parallel plate.
補正方法を用いる平行平板と、情報記録媒体から反射あ
るいは透過した光を受光し、前記情報記録媒体上の情報
を読み出しするための情報読み出し手段と、前記平行平
板の厚み調整手段を有することを特徴とする光ヘッド。2. A parallel plate using the method for correcting spherical aberration of an optical disk according to claim 1, and information reading for receiving light reflected or transmitted from an information recording medium and reading information on the information recording medium. An optical head comprising means and means for adjusting the thickness of the parallel plate.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4044750A JPH05241095A (en) | 1992-03-02 | 1992-03-02 | Method for compensating spherical aberration of optical disk and optical head using the same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4044750A JPH05241095A (en) | 1992-03-02 | 1992-03-02 | Method for compensating spherical aberration of optical disk and optical head using the same |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH05241095A true JPH05241095A (en) | 1993-09-21 |
Family
ID=12700127
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP4044750A Pending JPH05241095A (en) | 1992-03-02 | 1992-03-02 | Method for compensating spherical aberration of optical disk and optical head using the same |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH05241095A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5737012A (en) * | 1994-12-01 | 1998-04-07 | Olympus Optical Co., Ltd. | Head mounted image display apparatus and image forming apparatus related thereto |
| US6229778B1 (en) | 1994-11-10 | 2001-05-08 | Olympus Optical Co., Ltd. | Information recording and/or reproducing apparatus for optical disks having various protective layer thicknesses |
| EP1511024A2 (en) * | 2003-08-27 | 2005-03-02 | Mitsumi Electric Co., Ltd. | Spherical aberration correction plate |
| US7821919B2 (en) | 2003-04-21 | 2010-10-26 | Nec Corporation | Data processing apparatus and data processing method |
-
1992
- 1992-03-02 JP JP4044750A patent/JPH05241095A/en active Pending
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6229778B1 (en) | 1994-11-10 | 2001-05-08 | Olympus Optical Co., Ltd. | Information recording and/or reproducing apparatus for optical disks having various protective layer thicknesses |
| US6356518B1 (en) | 1994-11-10 | 2002-03-12 | Olympus Optical Company, Ltd. | Information recording and/or reproducing apparatus for optical disks having various protective layer thicknesses |
| US6577583B2 (en) | 1994-11-10 | 2003-06-10 | Olympus Optical Co., Ltd. | Information recording and/or reproducing apparatus for optical disks having various protective layer thicknesses |
| US5737012A (en) * | 1994-12-01 | 1998-04-07 | Olympus Optical Co., Ltd. | Head mounted image display apparatus and image forming apparatus related thereto |
| US7821919B2 (en) | 2003-04-21 | 2010-10-26 | Nec Corporation | Data processing apparatus and data processing method |
| EP1511024A2 (en) * | 2003-08-27 | 2005-03-02 | Mitsumi Electric Co., Ltd. | Spherical aberration correction plate |
| EP1511024A3 (en) * | 2003-08-27 | 2006-08-02 | Mitsumi Electric Co., Ltd. | Spherical aberration correction plate |
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