JP2005201976A - Optical element and optical element array - Google Patents

Optical element and optical element array Download PDF

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JP2005201976A
JP2005201976A JP2004005803A JP2004005803A JP2005201976A JP 2005201976 A JP2005201976 A JP 2005201976A JP 2004005803 A JP2004005803 A JP 2004005803A JP 2004005803 A JP2004005803 A JP 2004005803A JP 2005201976 A JP2005201976 A JP 2005201976A
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optical element
flange portion
optical
thickness
molded
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Hiroyasu Muto
弘泰 武藤
Hiroaki Fujita
浩明 藤田
Yasuhiko Sato
保彦 佐藤
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Fujinon Corp
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    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B11/00—Pressing molten glass or performed glass reheated to equivalent low viscosity without blowing
    • C03B11/06—Construction of plunger or mould
    • C03B11/08—Construction of plunger or mould for making solid articles, e.g. lenses
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B2215/00—Press-moulding glass
    • C03B2215/40—Product characteristics
    • C03B2215/41—Profiled surfaces
    • C03B2215/414—Arrays of products, e.g. lenses
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B2215/00—Press-moulding glass
    • C03B2215/40—Product characteristics
    • C03B2215/46—Lenses, e.g. bi-convex
    • C03B2215/49—Complex forms not covered by groups C03B2215/47 or C03B2215/48
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B2215/00—Press-moulding glass
    • C03B2215/72—Barrel presses or equivalent, e.g. of the ring mould type

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Lenses (AREA)
  • Optical Head (AREA)

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical element and optical element array of glass forming of a high numerical aperture that can stop down a laser beam. <P>SOLUTION: The thickness of a flange section 3 adjacent to a convex optical function surface 2 obtained by glass forming is confined to less than 0.3 mm. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

本発明は、ガラス成形された超小型の光学素子及び光学素子アレイに関する。   The present invention relates to a glass molded ultra-compact optical element and an optical element array.

従来のガラス成形される光学素子は、加熱軟化されたガラス素材を成形型内に入れて加熱・加圧してプレス成形していた（特許文献１参照）。このようなプレス成形光学素子を、コンパクトディスク（ＣＤ）を読み取る際の光学系に用いた場合、レーザビームを小さなビームスポットとするために光学素子のＮＡ（開口数）を０．４５としていた（特許文献２参照）。ＮＡ（Numerical Aperture）は、光学系に収差がない場合の集光限界を表す。従来のＣＤには赤い光のレーザ光が用いられ、このレーザ波長は７８０ｎｍであり、このレーザ光を光学素子で絞り込んでいた。
特開平５−７０１５５号公報（第２頁、図１） 特開２００３−１１９０３８号公報（第６頁、図９及び図１０） Conventional optical elements to be glass-molded have been press-molded by placing a heat-softened glass material in a mold and heating and pressing (see Patent Document 1). When such a press-molding optical element is used in an optical system for reading a compact disc (CD), the NA (numerical aperture) of the optical element is set to 0.45 in order to make the laser beam a small beam spot ( Patent Document 2). NA (Numerical Aperture) represents the light collection limit when there is no aberration in the optical system. Conventional CDs use red laser light, the laser wavelength of which is 780 nm, and this laser light is narrowed down by an optical element.
JP-A-5-70155 (2nd page, FIG. 1) Japanese Unexamined Patent Publication No. 2003-119038 (6th page, FIG. 9 and FIG. 10)

従来の成形技術で成形された光学素子は、ＣＤを読み取るためのレーザ光の波長が７８０ｎｍ、ＮＡが０．４５程度までには対応できたが、より小さなビームスポットを実現するため光学素子によるさらなる光の絞り込みが必要となる場合には対応が困難であった。ＮＡは、焦点距離一定のときの開口瞳の大きさを示す値であり、ＮＡが大きいほどレーザ光が絞れ、高密度記録が可能となり、最近は、赤い光のレーザ光よりも短い波長の青紫色レーザ光（ブルーレーザ）を用い、ＮＡが０．６以上の光学素子を用いてディスクの記録を読み取るようになってきた。この場合、ＮＡが大きいため、光学素子と光ディスクとの距離が短く、スペースの確保が困難になってきている。そのような事情から、光学素子に形成される光学機能面となる凸部に隣接するフランジ部の厚みは、できるだけ薄い方が好ましい。   The optical element molded by the conventional molding technique can cope with the wavelength of the laser beam for reading the CD up to 780 nm and NA of about 0.45. However, in order to realize a smaller beam spot, the optical element is further improved. When it is necessary to narrow down the light, it was difficult to cope with it. NA is a value indicating the size of the aperture pupil when the focal length is constant, and the larger the NA, the narrower the laser beam and the higher the density recording possible. Recently, blue having a shorter wavelength than the red laser beam. The recording of a disk has been read using an optical element having a NA of 0.6 or more using a violet laser beam (blue laser). In this case, since the NA is large, the distance between the optical element and the optical disk is short, and it is difficult to secure a space. Under such circumstances, it is preferable that the thickness of the flange portion adjacent to the convex portion serving as the optical function surface formed in the optical element is as thin as possible.

そこで、本発明では、高開口数のガラス成形の光学素子と光学素子アレイであって、フランジ部の薄い形状のものを提供することを目的とする。   Therefore, an object of the present invention is to provide a high numerical aperture glass-molded optical element and an optical element array having a thin flange portion.

上述の目的を達成するため、本発明は、ガラス成形された凸状の光学機能面に隣接したフランジ部の厚みを０．３ｍｍ未満としたものである。また、本発明に係る光学素子のＮＡは０．６以上としたものである。さらに、フランジ部の薄い光学素子とするような型構造で成形を行なうと、凸部とフランジ部との境界面の転写性が悪い、あるいは型から取り出した時に割れてしまう等の不具合がある可能性があるので、そのような場合を考慮し、フランジ部の厚みが厚い状態でプレス成形を行ない、光学機能面と反対側を研磨面として、プレス成形後にこの研磨面を研磨してフランジ部の厚みを薄くしたものである。また、本発明に係る光学素子アレイは、ガラス素材をプレス成形して複数の凸状の光学機能面をフランジ部で連結してシート状にし、光学機能面に隣接したフランジ部の厚みを０．３ｍｍ未満としたものである。   In order to achieve the above-mentioned object, the present invention is such that the thickness of the flange portion adjacent to the convex optical functional surface formed with glass is less than 0.3 mm. The NA of the optical element according to the present invention is 0.6 or more. Furthermore, if molding is performed with a mold structure that uses an optical element with a thin flange portion, there is a possibility that the transferability of the boundary surface between the convex portion and the flange portion may be poor, or cracks may occur when removed from the mold. Therefore, in consideration of such a case, press molding is performed in a state where the flange portion is thick, and the polishing surface is polished after press molding with the opposite side of the optical function surface as the polished surface. The thickness is reduced. In the optical element array according to the present invention, a glass material is press-molded to connect a plurality of convex optical function surfaces with a flange portion into a sheet shape, and the thickness of the flange portion adjacent to the optical function surface is 0. It is less than 3 mm.

本発明によれば、曲率半径の小さな（曲率の大きな）光学機能面を有し、この光学機能面に隣接するフランジ部の厚みを０．３ｍｍ未満とすることで、光学素子と光ディスクとの距離を確保しつつ、短い波長のレーザ光（ブルーレーザ）を絞り込んで小さなビームスポットを実現することのできる光学素子を提供できる。また、ＮＡを０．６以上とした光学素子はブルーレーザ光を絞り込むのに適する。さらに、プレス成形後に光学機能面とは反対側の面を研磨してフランジ部を０．３ｍｍ未満とするので、従前のプレス成形手段で容易かつ迅速に成形可能である。また、ガラス素材をプレス成形して複数の凸状の光学機能面をフランジ部で連結してシート状にし、光学機能面に隣接したフランジ部の厚みを０．３ｍｍ未満としたものでは、大量生産が可能で、コストダウンを図れる。   According to the present invention, the optical functional surface having a small radius of curvature (large curvature) is provided, and the distance between the optical element and the optical disk is set by making the thickness of the flange portion adjacent to the optical functional surface less than 0.3 mm. It is possible to provide an optical element capable of realizing a small beam spot by narrowing down a short-wavelength laser beam (blue laser) while securing the above. An optical element with NA of 0.6 or more is suitable for narrowing down blue laser light. Furthermore, since the surface opposite to the optical function surface is polished after press molding to make the flange portion less than 0.3 mm, it can be easily and quickly molded by conventional press molding means. In addition, mass production is possible when a glass material is press-molded to connect a plurality of convex optical functional surfaces with a flange to form a sheet, and the thickness of the flange adjacent to the optical functional surface is less than 0.3 mm. It is possible to reduce costs.

以下に、本発明の実施形態について、図面を参照にして説明する。   Embodiments of the present invention will be described below with reference to the drawings.

図１は、本発明に係る光学素子１の断面図を示し、ガラス成形された凸状の光学機能面２に隣接したフランジ部３の厚みｔを０．３ｍｍ未満としてある。このフランジ部３の厚みｔは０．０５ｍｍ〜０．２ｍｍが好ましい。このような光学素子１を成形するには、図２に示すようなプレス成形用の成形型１００を用い、そのキャビティ１０１内にガラス素材を入れて加熱・加圧してプレス成形する。このような成形型１００でプレス成形された成形品は、図３に示すようにフランジ部３の厚みＴは最終製品の厚みｔよりも厚いものである。このプレス成形後の製品をラインＸに示す個所まで研磨し、図１に示すフランジ部３の厚みｔ（０．３ｍｍ未満）とする。したがって最終製品は、光学機能面２を備えた側をプレス成形面とし、この成形面とは反対側を平坦な研磨面としたものである。   FIG. 1 shows a cross-sectional view of an optical element 1 according to the present invention, in which the thickness t of a flange portion 3 adjacent to a glass-formed convex optical functional surface 2 is less than 0.3 mm. The thickness t of the flange portion 3 is preferably 0.05 mm to 0.2 mm. In order to mold such an optical element 1, a molding material 100 for press molding as shown in FIG. 2 is used, and a glass material is put in the cavity 101 and heated and pressed to perform press molding. In the molded product press-molded with such a mold 100, the thickness T of the flange portion 3 is thicker than the thickness t of the final product as shown in FIG. The product after the press molding is polished to the position indicated by line X to obtain the thickness t (less than 0.3 mm) of the flange portion 3 shown in FIG. Therefore, the final product has a side having the optical function surface 2 as a press-molded surface and a side opposite to the molded surface as a flat polished surface.

図４は、光学素子アレイのプレス成形装置を示す断面図であり、大きな平面型である上型１００Ａと、下型１００Ｂに中子１００Ｃを設け、キャビティ１０１にガラス素材を入れ、上型１００Ａと下型１００Ｂとを締結することによりガラス素材を加熱・プレスして成形する。中子１００Ｃに曲率の大きな凸状の光学機能面を形成するための凹部１Ａを形成してある。   FIG. 4 is a cross-sectional view showing an optical element array press molding apparatus, in which an upper mold 100A, which is a large flat mold, and a core 100C are provided in a lower mold 100B, a glass material is placed in a cavity 101, and an upper mold 100A A glass material is heated and pressed by fastening with the lower mold | type 100B, and it shape | molds. A concave portion 1A for forming a convex optical functional surface having a large curvature is formed in the core 100C.

図５は、図４のプレス成形装置で成形された光学素子アレイを示すものであり、複数の光学素子１が同時にプレス成形され、連結されたシート状になったものである。この図４のプレス成形装置で成形された直後は、フランジ部３の厚みｔは０．３ｍｍ以上であるため、この光学機能面２の反対側の平坦な面を研磨して０．３ｍｍ未満とする。この実施形態では、厚みが０．３ｍｍ未満のフランジ部３に隣接して凸状の光学機能面２よりも高さが高い外縁フランジ部３０が形成される。この外縁フランジ部３０は他の光学素子１との連結部でもある。この外縁フランジ部３０は、光学機能面２の高さよりも高い位置にあることにより、反対側の平坦面をラインＸまで研磨する時に、この外縁フランジ部３０の頂面が研磨台などに載置されることにより、光学機能面２を保護することとなる。このようにプレス成形された光学素子アレイはその外縁フランジ部３０の個所で切断し、他の光学素子と接合して用いられる。この１例としては、図６に示すように別の光学素子２０と光学素子１０と組合わせることにより、ＮＡの数値の高い光学素子を簡単に製造することができる。   FIG. 5 shows an optical element array molded by the press molding apparatus of FIG. 4, in which a plurality of optical elements 1 are simultaneously press-molded into a connected sheet shape. Immediately after being molded by the press molding apparatus of FIG. 4, since the thickness t of the flange portion 3 is 0.3 mm or more, the flat surface opposite to the optical functional surface 2 is polished to be less than 0.3 mm. To do. In this embodiment, an outer edge flange portion 30 having a height higher than that of the convex optical function surface 2 is formed adjacent to the flange portion 3 having a thickness of less than 0.3 mm. The outer edge flange portion 30 is also a connecting portion with another optical element 1. Since the outer edge flange portion 30 is located at a position higher than the height of the optical function surface 2, the top surface of the outer edge flange portion 30 is placed on a polishing table or the like when the opposite flat surface is polished to the line X. By doing so, the optical function surface 2 is protected. The optical element array thus press-molded is cut at a portion of the outer edge flange portion 30 and joined to other optical elements. As an example of this, by combining another optical element 20 and an optical element 10 as shown in FIG. 6, an optical element having a high numerical value of NA can be easily manufactured.

この発明の好適な実施形態を示す断面図。Sectional drawing which shows suitable embodiment of this invention. 図１の光学素子をプレス成形するための成形型の断面図。Sectional drawing of the shaping | molding die for press-molding the optical element of FIG. 図２の成形型で成形された直後の製品を示す断面図。Sectional drawing which shows the product immediately after shape | molding with the shaping | molding die of FIG. 光学素子アレイをプレス成形するためのプレス成形装置の１例を示す断面図。Sectional drawing which shows one example of the press molding apparatus for press-molding an optical element array. 図４の成形装置で成形された光学素子アレイの断面図。Sectional drawing of the optical element array shape | molded with the shaping | molding apparatus of FIG. 光学素子アレイから切取られた１単位の光学素子と他の光学素子とを接合したＮＡの数値の大きな光学素子の１例を示す断面図。Sectional drawing which shows an example of an optical element with a big numerical value of NA which joined the optical element of 1 unit cut out from the optical element array, and another optical element.

符号の説明Explanation of symbols

１，１０，２０ 光学素子
２ 凸状の光学機能面
３ 光学機能面に隣接したフランジ部 1, 10, 20 Optical element 2 Convex optical functional surface 3 Flange adjacent to optical functional surface

Claims (6)

ガラス成形された凸状の光学機能面に隣接したフランジ部の厚みが０．３ｍｍ未満であることを特徴とする光学素子。   An optical element characterized in that the thickness of a flange portion adjacent to a glass-formed convex optical functional surface is less than 0.3 mm. 前記凸状の光学機能面を備えた側をプレス成形面とし、この成形面とは反対側を研磨面としたことを特徴とする請求項１に記載の光学素子。   2. The optical element according to claim 1, wherein the side having the convex optical functional surface is a press-molded surface, and the side opposite to the molded surface is a polished surface. 前記フランジ部の厚みをプレス成形後では０．３ｍｍ以上の厚さとし、その後フランジ部を研磨して０．３ｍｍ未満としたことを特徴とする請求項２に記載の光学素子。   The optical element according to claim 2, wherein the thickness of the flange portion is 0.3 mm or more after press molding, and then the flange portion is polished to be less than 0.3 mm. ０．６以上の開口数（ＮＡ）を有することを特徴とする請求項１〜３のいずれか１項に記載の光学素子。   The optical element according to claim 1, having a numerical aperture (NA) of 0.6 or more. ガラス素材をプレス成形して複数の凸状の光学機能面をフランジ部で連結してシート状にし、光学機能面に隣接したフランジ部の厚みを０．３ｍｍ未満としたことを特徴とする光学素子アレイ。   An optical element characterized in that a glass material is press-molded to connect a plurality of convex optical functional surfaces at a flange portion into a sheet shape, and the thickness of the flange portion adjacent to the optical functional surface is less than 0.3 mm. array. 複数の光学素子を同時にプレス成形してシート状にしたときにフランジ部の厚みを０．３ｍｍ以上とし、その後に凸状の成形面とは反対側を研磨して光学機能面に隣接したフランジ部の厚みを０．３ｍｍ未満としたことを特徴とする請求項５に記載の光学素子アレイ。   When a plurality of optical elements are simultaneously press-molded into a sheet shape, the flange portion has a thickness of 0.3 mm or more, and then the flange portion adjacent to the optical functional surface is polished on the side opposite to the convex molding surface The optical element array according to claim 5, wherein the thickness of the optical element array is less than 0.3 mm.
JP2004005803A 2004-01-13 2004-01-13 Optical element and optical element array Pending JP2005201976A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109974583A (en) * 2019-04-11 2019-07-05 南京信息工程大学 A kind of non-contact optical element surface surface shape measurement device and method

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109974583A (en) * 2019-04-11 2019-07-05 南京信息工程大学 A kind of non-contact optical element surface surface shape measurement device and method
CN109974583B (en) * 2019-04-11 2024-03-26 南京信息工程大学 Non-contact optical element surface shape measuring device and method

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