JP2013037250A - Optical element, and optical system and optical device including the same - Google Patents
Optical element, and optical system and optical device including the same Download PDFInfo
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Abstract
Description
本発明は、光学レンズに関し、特に光学レンズの遮光性能に関するものである。 The present invention relates to an optical lens, and more particularly to the light shielding performance of an optical lens.
多くの光学装置には多種多様な効果を持つ光学素子が使用されている。例えばカメラなどに使用されている光学レンズは、入射した光を屈折させて集光・発散する効果を持つ。また、顕微鏡やプロジェクターに利用されるプリズムは、入射した光を透過・屈折させて光路を制御する効果を持つ。これらの光学素子には、入射した光に対して作用をもたらす光学面と、光に作用しない非光学面が有る。例えばレンズには入射した光を屈折させる屈折面に対し、レンズを機械的に保持するための保持面がある。前者は光学面であり、後者は非光学面である。 Many optical devices use optical elements having various effects. For example, optical lenses used in cameras and the like have an effect of refracting incident light to collect and diverge light. In addition, prisms used in microscopes and projectors have the effect of controlling the optical path by transmitting and refracting incident light. These optical elements have an optical surface that acts on incident light and a non-optical surface that does not act on light. For example, a lens has a holding surface for mechanically holding the lens against a refractive surface that refracts incident light. The former is an optical surface, and the latter is a non-optical surface.
従来、この非光学面には光に対して余分な作用をもたらさないように、遮光塗料を塗布することが一般的である。それは、光学系や光学装置内で反射・散乱した光が非光学面に当たり、迷光となって余分な作用をもたらすことを防ぐためである。例えば、特許文献１では光入出射面の一方の光学面に可視域の波長以下の微細凹凸構造体が形成された光学素子において、光学素子の外周部（非光学面）は光軸方向に沿って段差のある段付き形状より成る素子が開示されている。微細凹凸構造はスピンコート法を利用して形成されている。この素子では、外周部の段差によりコバ面に塗工液がほとんど付着することなく、鏡筒に高精度に保持することができることを特徴としている。また、特許文献２には花弁状透明アルミナ膜を利用した反射防止構造体の作製例が開示されている。本文献によると、酸化アルミの薄膜をゾルゲル法により塗布し、焼成後に１００℃の熱水中に０．５〜２．０時間浸漬処理することで得られる花弁状透明アルミナ膜を利用した構成が開示されている。このように、熱水に浸漬する処理を施すことで光学素子を作製する手法があることは知られている。 Conventionally, a light-shielding paint is generally applied to the non-optical surface so as not to have an extra effect on light. This is to prevent light reflected or scattered in the optical system or optical apparatus from hitting the non-optical surface and causing extra light as stray light. For example, in Patent Document 1, in an optical element in which a fine concavo-convex structure having a wavelength equal to or less than a visible wavelength is formed on one optical surface of the light incident / exit surface, the outer peripheral portion (non-optical surface) of the optical element is along the optical axis direction. An element having a stepped shape with a step is disclosed. The fine concavo-convex structure is formed using a spin coating method. This element is characterized in that the coating liquid hardly adheres to the edge surface due to a step in the outer peripheral portion and can be held in the lens barrel with high accuracy. Patent Document 2 discloses an example of manufacturing an antireflection structure using a petal-like transparent alumina film. According to this document, a configuration using a petal-like transparent alumina film obtained by applying a thin film of aluminum oxide by a sol-gel method and immersing it in hot water at 100 ° C. for 0.5 to 2.0 hours after firing. It is disclosed. As described above, it is known that there is a method of manufacturing an optical element by performing a process of immersing in hot water.
上述したように、特許文献１に開示された従来技術では、光学素子の取付け安定性を向上させるために、非光学面（保持面）に段差を設けることが開示されている。この段差を設けることにより特許文献１の光学素子は、取付け安定性の向上のみならず光学素子の重量が低減されるという効果も得られる。しかしながら、そのような段差を有する光学素子の保持面に遮光膜を形成した場合において、その段差の形状によっては遮光膜の剥がれや欠けが発生しやすくなるため、遮光性能が著しく劣化してしまうことが考えられる。また、そのような遮光膜は、熱水に浸漬すると膨潤・伸縮するため、上記と同様、段差の形状によっては剥がれや欠けが発生しやすくなるため、遮光性能が著しく劣化してしまうことが考えられる。 As described above, the prior art disclosed in Patent Document 1 discloses that a step is provided on the non-optical surface (holding surface) in order to improve the mounting stability of the optical element. By providing this level difference, the optical element disclosed in Patent Document 1 can not only improve the mounting stability but also reduce the weight of the optical element. However, when a light-shielding film is formed on the holding surface of an optical element having such a step, the light-shielding film is likely to be peeled off or chipped depending on the shape of the step, so that the light-shielding performance is significantly deteriorated. Can be considered. In addition, since such a light-shielding film swells and expands when immersed in hot water, similarly to the above, depending on the shape of the step, peeling or chipping is likely to occur, so that the light-shielding performance may be significantly deteriorated. It is done.
そこで、本発明の目的は、熱水処理を施す光学素子において、光学素子の重量を軽減しつつ、かつ非光学面の遮光性能の良い光学素子を提供することである。 SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an optical element having a good light-shielding performance on a non-optical surface while reducing the weight of the optical element in an optical element subjected to hydrothermal treatment.
本発明の一側面としての光学素子は、熱水浸漬処理が施される光学素子において、光学研磨された光学面と、前記光学面の外周に設けられた算術平均粗さが５μｍ以上に粗面加工された非光学面と、前記非光学面に成膜された遮光膜と、を有し、前記非光学面は、前記光学素子の光軸に直交する成分が主で前記光軸に平行な方向に離間した２つの第１の面と、前記２つの第１の面の間に設けられ前記光軸に平行な成分が主の第２の面と、前記２つの第１の面と前記第２の面とを繋ぐ曲面とからなる段部を有し、前記曲面は、１．０ｍｍ以上の曲率半径を有することを特徴とする。 An optical element according to one aspect of the present invention is an optical element that is subjected to a hot water immersion treatment, and an optically polished optical surface and an arithmetic average roughness provided on an outer periphery of the optical surface is a rough surface that is 5 μm or more. A processed non-optical surface and a light-shielding film formed on the non-optical surface, wherein the non-optical surface is mainly composed of a component orthogonal to the optical axis of the optical element and parallel to the optical axis. Two first surfaces that are spaced apart in the direction, and a component that is provided between the two first surfaces and that is parallel to the optical axis has a main second surface, the two first surfaces, and the first And a curved surface connecting the two surfaces, the curved surface having a radius of curvature of 1.0 mm or more.
本発明によれば、熱水処理を施す光学素子において、光学素子の重量を軽減しつつ、かつ非光学面の遮光性能の良い光学素子を提供することができる。 ADVANTAGE OF THE INVENTION According to this invention, in the optical element which performs a hot water process, the optical element with the favorable light-shielding performance of a non-optical surface can be provided, reducing the weight of an optical element.
以下に、本発明の好ましい実施の形態を、添付の図面に基づいて詳細に説明する。ここでは簡単のために使用波長域として可視域として説明する。 Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Here, for the sake of simplicity, the description will be made assuming that the visible wavelength range is used.
図１は、本発明の実施形態にかかわる光学素子の略断面図である。ここで、１０１は光学ガラスからなる光学素子、１０２は光軸、１０３、１０４は光学面、１０５、１０６、１０７は非光学面である。なお、非光学面において、１０５は光軸１０２に直交する成分が主の第１非光学面、１０６は光軸１０２に平行な成分が主の第２非光学面、１０７は非光学面１０５、１０６を繋ぐ曲面である。 FIG. 1 is a schematic cross-sectional view of an optical element according to an embodiment of the present invention. Here, 101 is an optical element made of optical glass, 102 is an optical axis, 103 and 104 are optical surfaces, and 105, 106 and 107 are non-optical surfaces. In the non-optical surface, 105 is a main first non-optical surface whose component is orthogonal to the optical axis 102, 106 is a main second non-optical surface whose component is parallel to the optical axis 102, 107 is a non-optical surface 105, 106 is a curved surface connecting 106.
光学素子１０１は回転対称系の光学レンズである。光学面１０３は光学研磨された第１光学面であり、光軸１０２に直交する平面に接している。光学面１０４は光学研磨された第２光学面であり、第１光学面１０３と光軸方向において離間し、光軸１０２に直交する平面に接している。光学面１０３、１０４を透過した光は光学素子１０１を構成する光学ガラスの屈折率に準じた屈折を示し、光路を曲げる作用を有する。また、非光学面１０５、１０６、１０７は、第１光学面１０３及び第２光学面１０４の外周に設けられている。ここで、本実施例では、光学素子１０１の基材としてＯＨＡＲＡ社製Ｓ−ＬＡＨ５５を利用した。該光学素子１０１の径はφ３５ｍｍ、第１光学面１０３の曲率半径は７８ｍｍ、第２光学面１０４の曲率半径は１６ｍｍである。また、第１非光学面１０５（第１の面）、第２非光学面１０６（第２の面）、曲面１０７は光に対して作用を与えない非光学面であり、光学素子１０１の光軸方向に沿って段部を形成している。第１非光学面１０５は光学素子１０１の光軸１０２に直交する２つの平面を有し、第２非光学面１０６は光学素子１０１の光軸１０２と平行な２つの平面を有する。ここでは説明のために光軸方向に平行・直交としているが、本発明はその要旨内で変更が可能である。例えば第１非光学面１０５は光軸１０２と厳密に直交である必要はなく、直交成分が主で有ればよい。直交成分が主というのは、第１非光学面１０５の光軸１０２の直交方向への正射影の長さが、非光学面１０５の長さの８５％以上であることを指す。第２非光学面１０６に関しても同様で、平行成分が主でかつ光軸１０２への正射影の長さが非光学面１０６の長さの８５％以上であれば良い。このような非光学面１０５、１０６は、装置への組み込み、保持に利用されることが一般的である。本発明では、非光学面１０５、１０６、１０７に入射した光が作用をもたらすことを防ぐために、遮光処理が施されていることを特徴としている。具体的には、非光学面１０５、１０６、１０７は算術平均粗さＲａが５μｍ以上の粗面加工された粗面であることを特徴としている。算術平均粗さＲａとは、粗さ曲線からその平均線の方向に基準長さだけ抜き取り、この抜き取り部分の平均線から測定曲線までの偏差の絶対値を合計し、平均した値である。また、非光学面１０５、１０６、１０７は可視域の光を主に吸収する遮光膜が２〜３０μｍの厚みで成膜されている。これにより、非光学面１０５、１０６、１０７に入射する光は粗面にて散乱し、かつ遮光膜によって吸収されるため、遮光効率は非常に高くなる。 The optical element 101 is a rotationally symmetric optical lens. The optical surface 103 is an optically polished first optical surface and is in contact with a plane orthogonal to the optical axis 102. The optical surface 104 is a second optical surface that has been optically polished, is separated from the first optical surface 103 in the optical axis direction, and is in contact with a plane orthogonal to the optical axis 102. The light transmitted through the optical surfaces 103 and 104 is refracted according to the refractive index of the optical glass constituting the optical element 101 and has an action of bending the optical path. Further, the non-optical surfaces 105, 106, and 107 are provided on the outer circumferences of the first optical surface 103 and the second optical surface 104. In this example, S-LAH55 manufactured by OHARA was used as the base material of the optical element 101. The diameter of the optical element 101 is 35 mm, the radius of curvature of the first optical surface 103 is 78 mm, and the radius of curvature of the second optical surface 104 is 16 mm. Further, the first non-optical surface 105 (first surface), the second non-optical surface 106 (second surface), and the curved surface 107 are non-optical surfaces that do not act on light, and the light of the optical element 101 A step portion is formed along the axial direction. The first non-optical surface 105 has two planes orthogonal to the optical axis 102 of the optical element 101, and the second non-optical surface 106 has two planes parallel to the optical axis 102 of the optical element 101. Here, for the sake of explanation, it is assumed to be parallel / orthogonal to the optical axis direction, but the present invention can be modified within the gist thereof. For example, the first non-optical surface 105 does not need to be strictly orthogonal to the optical axis 102, and only needs to have an orthogonal component. The fact that the orthogonal component is dominant indicates that the length of the orthogonal projection of the first non-optical surface 105 in the orthogonal direction of the optical axis 102 is 85% or more of the length of the non-optical surface 105. The same applies to the second non-optical surface 106 as long as the parallel component is main and the length of the orthogonal projection onto the optical axis 102 is 85% or more of the length of the non-optical surface 106. Such non-optical surfaces 105 and 106 are generally used for incorporation and holding in an apparatus. The present invention is characterized in that a light shielding process is performed in order to prevent the light incident on the non-optical surfaces 105, 106, and 107 from having an effect. Specifically, the non-optical surfaces 105, 106, and 107 are characterized by being roughened surfaces having an arithmetic average roughness Ra of 5 μm or more. The arithmetic average roughness Ra is a value obtained by extracting a reference length from the roughness curve in the direction of the average line, and summing up absolute values of deviations from the average line of the extracted portion to the measurement curve. In addition, the non-optical surfaces 105, 106, and 107 are formed with a light shielding film having a thickness of 2 to 30 μm that mainly absorbs light in the visible range. Thereby, the light incident on the non-optical surfaces 105, 106, and 107 is scattered on the rough surface and absorbed by the light shielding film, so that the light shielding efficiency is very high.
本発明に関わるような光学素子１０１は、光学系や光学装置に使用されることが多い。それらの使用用途においては、光学レンズの重量や体積等は非常に大きな影響を及ぼす。特に光学系内で可動するズーム群、フォーカス群、防振群等の可動群はメカの追従性や即応性にも影響するため、そこに使用される光学レンズはできるだけ重量や体積を削ることが望ましい。重量を削るためには、非光学面である１０５、１０６の部分を段付き形状にすることが最も効果的である。そのため、本実施例の光学素子１０１は、光軸に平行した非光学面が２面、光軸に直交した非光学面が２面存在し、光軸方向に沿って段差を形成することで、非光学面の余分な体積を除去していることを特徴としている。 The optical element 101 according to the present invention is often used in an optical system or an optical apparatus. In these usages, the weight and volume of the optical lens have a very large effect. In particular, movable groups such as the zoom group, focus group, and anti-vibration group that move within the optical system also affect the follow-up and responsiveness of the mechanism, so the optical lens used there can reduce the weight and volume as much as possible. desirable. In order to reduce the weight, it is most effective to make the portions 105 and 106 which are non-optical surfaces into stepped shapes. Therefore, the optical element 101 of the present embodiment has two non-optical surfaces parallel to the optical axis and two non-optical surfaces orthogonal to the optical axis, and forms a step along the optical axis direction. It is characterized in that an extra volume of the non-optical surface is removed.
また、本発明では７０度以上の熱水に１０分以上浸漬する処理を施すことを特徴としている。そして、非光学面１０５、１０６を繋ぐ曲面１０７のうち、少なくとも１つは１．０ｍｍ以上の曲率半径を持つ曲面からなることを特徴としている。光学素子１０１に熱水浸漬処理を施すことは、例えばアルミニウムを主成分とする水和酸化物であるベーマイトを利用した薄膜を作製するのに用いられる。ベーマイトを得るには、まず真空成膜法や液相法（ゾルゲル法など）に代表される手法により、アルミニウム（または酸化アルミニウム）の薄膜を形成する。その薄膜を７０度以上の熱水に浸漬することにより、その表面を部分的に溶解または析出させる。そのようにすることで、アルミニウム（または酸化アルミニウム）の表層は平均ピッチ２０〜２００ｎｍ以下で配列したベーマイトからなる微細凹凸構造層となる。このような可視光の波長以下で配列した微細凹凸構造層は、可視光領域では低屈折率の薄膜と同様の振る舞いを示すため、反射防止膜などに利用することができる。 Moreover, in this invention, the process immersed in the hot water of 70 degree | times or more is performed for 10 minutes or more, It is characterized by the above-mentioned. Of the curved surfaces 107 connecting the non-optical surfaces 105 and 106, at least one of them is characterized by a curved surface having a curvature radius of 1.0 mm or more. Applying the hot water immersion treatment to the optical element 101 is used, for example, to produce a thin film using boehmite which is a hydrated oxide mainly composed of aluminum. In order to obtain boehmite, an aluminum (or aluminum oxide) thin film is first formed by a technique typified by a vacuum film formation method or a liquid phase method (sol-gel method or the like). The surface is partially dissolved or deposited by immersing the thin film in hot water of 70 degrees or more. By doing so, the surface layer of aluminum (or aluminum oxide) becomes a fine concavo-convex structure layer made of boehmite arranged at an average pitch of 20 to 200 nm or less. Such fine concavo-convex structure layers arranged below the wavelength of visible light exhibit the same behavior as a thin film having a low refractive index in the visible light region, and thus can be used as an antireflection film.
このような熱水浸漬処理を施すと、非光学面１０５、１０６、１０７に施された遮光膜は膨潤・伸縮のために光学ガラスから剥がれやすくなる。一度剥がれてしまうと、剥がれた部分の遮光性能は著しく劣化してしまい、好ましくない。このような剥がれは非光学面１０５、１０６のような平面部よりも曲面１０７のような曲面部の方で起こりやすい。それは、曲面部には均一に遮光膜が成膜されにくく、平面部に比べて膜厚のムラが出やすいからである。このムラは熱収縮の際に応力が集中する部分となるため、膜が剥がれやすくなってしまう。また、このようなムラは凸面よりも凹面のほうが大きくなるため、凹面のほうが応力集中と剥がれは発生しやすい。 When such hot water immersion treatment is performed, the light-shielding film applied to the non-optical surfaces 105, 106, and 107 is easily peeled off from the optical glass due to swelling and expansion / contraction. Once peeled off, the light-shielding performance of the peeled portion is significantly deteriorated, which is not preferable. Such peeling is more likely to occur on the curved surface portion such as the curved surface 107 than on the flat surface portions such as the non-optical surfaces 105 and 106. This is because it is difficult to form a light-shielding film uniformly on the curved surface portion, and unevenness in film thickness is likely to occur compared to the flat surface portion. Since this unevenness is a portion where stress is concentrated during thermal contraction, the film is easily peeled off. Further, since such unevenness is larger on the concave surface than on the convex surface, stress concentration and peeling are more likely to occur on the concave surface.
それに対し、曲面１０７の曲率半径を１．０ｍｍ以上にすると、遮光膜と光学ガラスの接触面積が広がり、かつ成膜の膜厚ムラが出にくい。つまり、曲率半径を１．０ｍｍ以上とすることで、その面を緩やかな曲面とみなすことができる。そのため、熱水への浸漬処理を施しても膜の熱収縮の応力集中が発生しづらく、遮光膜の剥がれを抑制することができる。また、曲面１０７上に塗膜を形成する場合、凸型の曲面よりも凹型の曲面の方が塗膜の応力が集中しやすい。そのため、上記条件は凸面よりも凹面に施すほうが応力集中を緩和させることができるため、より効果が大きい。 On the other hand, when the curvature radius of the curved surface 107 is set to 1.0 mm or more, the contact area between the light shielding film and the optical glass is widened, and the film thickness unevenness of the film formation hardly occurs. That is, when the curvature radius is 1.0 mm or more, the surface can be regarded as a gentle curved surface. Therefore, even if the immersion treatment in hot water is performed, it is difficult for stress concentration due to thermal contraction of the film to occur, and peeling of the light shielding film can be suppressed. Further, when the coating film is formed on the curved surface 107, the stress of the coating film is more likely to be concentrated on the concave curved surface than on the convex curved surface. For this reason, the above conditions can be more effective because the stress concentration can be relaxed when applied to the concave surface than the convex surface.
また、このような剥がれは基材内部の欠陥を起点として発生しやすい。特に非光学面は粗面加工しているため、その加工の際にマイクロクラックが残存しやすい。マイクロクラックとはガラス内部に残存する微細な破片であり、その上に成膜された遮光膜に応力が集中すると、その部分が欠落・崩落して大きな空隙となりやすい。この空隙は基材と遮光膜が剥がれたような状況に見え、遮光性能の著しい劣化を招いてしまう。このようなマイクロクラックは、基材の硬さによって発生しやすさが異なる。特に、本発明ではヌープ硬度が６００Ｎ/ｍｍ２以上の光学ガラスだと、マイクロクラックが発生しやすく剥がれが発生しやすいことを見出した。そこで、ヌープ硬度が６００Ｎ／ｍｍ２以上の光学ガラスを利用した光学素子に対して本発明を適用することで、より大きな効果が期待できる。このヌープ硬度は、６５０Ｎ／ｍｍ２以上だとより効果が大きく、７００Ｎ／ｍｍ２以上だと特に効果が大きい。上述したように、本実施例では光学ガラスとしてＳ−ＬＡＨ５５（Ｓ−ＬＡＨ５５は株式会社ＯＨＡＲＡの商品名）を利用しており、このガラスのヌープ硬度は７５０Ｎ／ｍｍ２であり、本発明の要件を満たしている。そのため、本発明の効果により遮光性能を向上させることができる。 Also, such peeling is likely to occur starting from defects inside the substrate. In particular, since the non-optical surface is roughened, microcracks are likely to remain during the processing. A microcrack is a fine fragment remaining inside glass, and when stress is concentrated on a light-shielding film formed thereon, the portion is easily lost or collapsed to form a large gap. This gap looks like a situation where the substrate and the light-shielding film are peeled off, causing a significant deterioration of the light-shielding performance. Such microcracks are easily generated depending on the hardness of the substrate. In particular, in the present invention, it has been found that when the optical glass has a Knoop hardness of 600 N / mm 2 or more, microcracks are likely to occur and peeling is likely to occur. Therefore, by applying the present invention to an optical element using optical glass having Knoop hardness of 600 N / mm 2 or more, a greater effect can be expected. The Knoop hardness is greater and more effective when they 650 N / mm 2 or more, especially large effect when it 700 N / mm 2 or more. As described above, in this example, S-LAH55 (S-LAH55 is a trade name of OHARA Co., Ltd.) is used as an optical glass, and the Knoop hardness of this glass is 750 N / mm 2 , and the requirements of the present invention Meet. Therefore, the light shielding performance can be improved by the effect of the present invention.
また、本発明では図１において光軸に対して直交する方向の距離をＨとしたときに、光学面１０３の光軸からの最大距離をＨ２、光学面１０４の光軸からの最大距離をＨ１と定義する。そして、曲面１０７の光軸からの最大距離をＨｉとしたとき、以下の条件式を満たす曲面の曲率半径を１．０ｍｍ以上とすることを特徴としている。 Further, in the present invention, when the distance in the direction orthogonal to the optical axis in FIG. 1 is H, the maximum distance from the optical axis of the optical surface 103 is H2, and the maximum distance from the optical axis of the optical surface 104 is H1. It is defined as When the maximum distance from the optical axis of the curved surface 107 is Hi, the curvature radius of the curved surface satisfying the following conditional expression is set to 1.0 mm or more.
Ｈ１＋０．２＊（Ｈ２−Ｈ１） ＜ Ｈｉ ＜ Ｈ１＋０．７＊（Ｈ２−Ｈ１） （１）
上記（１）式を満たす曲面１０７は、光学面１０３側から見たときに、虚像が複数に見えやすくなる。これを模式的に表したのが図２である。
H1 + 0.2 * (H2-H1) <Hi <H1 + 0.7 * (H2-H1) (1)
When the curved surface 107 satisfying the expression (1) is viewed from the optical surface 103 side, a plurality of virtual images are likely to be seen. This is schematically shown in FIG.
図２において、２０１は光学ガラスからなる光学素子で、上述の光学素子１０１と同じものである。Ｃは光学素子２０１の断面図で、２０２、２１４は光軸、２０３、２０４は光学面、２０５、２０６、２０７は光学素子２０１の非光学面を結ぶ曲面である。Ｔは光学素子２０１を光学面２０３側から見た上面図で、２０９は光学面２０３の端部、２１０は曲面２０５、２０６の像、２１１は光学面２０４の端部、２１２は曲面２０６の虚像、２１３は曲面２０５の虚像である。ここでは簡単のため上面図Ｔでは光学面２０３での屈折を無視した構成で記載している。実際は屈折の影響によりそれぞれの像は断面図Ｃの半径より内側に像を結ぶ。ここで、曲面２０５、２０６の曲率半径は１．２ｍｍであり、曲面２０７の曲率半径は０．２ｍｍである。曲面２０５、２０６は、非光学面において、光学素子２０１の光軸と直交する方向に平行で光軸方向に離間した２つの第１の面２１５と、該２つの第１の面の間に設けられ光学素子２０１の光軸方向に平行な第２の面２１６を繋ぐ曲面である。この曲面２０５、２０６は上記した（１）式を満たす範囲にあるが、曲面２０７は（１）式を満たす範囲にない。したがって、曲面２０５〜２０７のうち曲率半径を１．０ｍｍ以上とすべき面は、曲面２０５、２０６のみでよい。なお本発明は、曲面２０７の曲率半径を１．０ｍｍ以上とすることを妨げるものではなく、曲面２０７の曲率半径を１．０ｍｍ以上としてもよい。光学素子２０１を光学面２０３側から見た場合、曲面２０５、２０６は像２１０のように見える。また、曲面２０５、２０６は、光学面２０４で反射した像２１２、２１３も上面図Ｔでは確認できる。このように、曲面によっては直接見える像と光学面２０４などで反射した像など、複数の像が見える曲面が有る。一方、曲面２０７は上面図では直接像も反射像も見えることはない。 In FIG. 2, 201 is an optical element made of optical glass, which is the same as the optical element 101 described above. C is a cross-sectional view of the optical element 201, 202 and 214 are optical axes, 203 and 204 are optical surfaces, and 205, 206, and 207 are curved surfaces connecting non-optical surfaces of the optical element 201. T is a top view of the optical element 201 viewed from the optical surface 203 side, 209 is an end of the optical surface 203, 210 is an image of the curved surfaces 205 and 206, 211 is an end of the optical surface 204, and 212 is a virtual image of the curved surface 206. Reference numeral 213 denotes a virtual image of the curved surface 205. Here, for the sake of simplicity, the top view T is shown in a configuration ignoring refraction at the optical surface 203. Actually, each image forms an image inside the radius of the sectional view C due to the influence of refraction. Here, the curvature radii of the curved surfaces 205 and 206 are 1.2 mm, and the curvature radius of the curved surface 207 is 0.2 mm. The curved surfaces 205 and 206 are non-optical surfaces provided between two first surfaces 215 that are parallel to the direction orthogonal to the optical axis of the optical element 201 and spaced apart in the optical axis direction. This is a curved surface connecting the second surfaces 216 parallel to the optical axis direction of the optical element 201. The curved surfaces 205 and 206 are in a range satisfying the above-described expression (1), but the curved surface 207 is not in a range satisfying the expression (1). Therefore, the curved surfaces 205 and 207 need only have curved surfaces 205 and 206 that have a radius of curvature of 1.0 mm or more. Note that the present invention does not prevent the curvature radius of the curved surface 207 from being 1.0 mm or more, and the curvature radius of the curved surface 207 may be 1.0 mm or more. When the optical element 201 is viewed from the optical surface 203 side, the curved surfaces 205 and 206 look like an image 210. In addition, the curved surfaces 205 and 206 can also be confirmed in the top view T by the images 212 and 213 reflected by the optical surface 204. As described above, depending on the curved surface, there are curved surfaces in which a plurality of images can be seen, such as an image directly visible and an image reflected by the optical surface 204 or the like. On the other hand, the curved surface 207 shows neither a direct image nor a reflected image in the top view.
このように、（１）式を満たす範囲にある曲面２０５、２０６は光学面２０３から見たときに２つの像が視認されてしまう。そのため、このような曲面２０５、２０６の遮光性能が劣化すると、視認性も高くなってしまうため好ましくない。そこで本発明を適用すると、熱水浸漬処理を施しても遮光性能に優れた光学素子２０１を提供することができる。 Thus, when the curved surfaces 205 and 206 in the range satisfying the expression (1) are viewed from the optical surface 203, two images are visually recognized. Therefore, if the light shielding performance of the curved surfaces 205 and 206 is deteriorated, the visibility is also increased, which is not preferable. Therefore, when the present invention is applied, it is possible to provide the optical element 201 having excellent light shielding performance even when the hot water immersion treatment is performed.
また、本発明はその要旨の中で種々のレンズ形状に応用することができる。例えば光学素子２０１のようなメニスカスレンズ、光学面が両面とも凹面の両凹レンズや平面と凹面を利用した平凹レンズなどがあげられる。ただし、本発明をより有効に活用するには、レンズ形状はメニスカスレンズであることが望ましい。特に、光学素子２０１のように凸のパワーよりも凹のパワーのほうが強い負のメニスカスレンズであることが望ましい。ほかのレンズ形状に比べ、負のメニスカスレンズは虚像の視認性、及び曲面２０５、２０６への光の入射効率は高くなりやすい。そのため、負のメニスカスレンズに本発明を適用すると、非常に高い効果が期待できる。 In addition, the present invention can be applied to various lens shapes within the gist thereof. For example, a meniscus lens such as the optical element 201, a biconcave lens in which both optical surfaces are concave, and a plano-concave lens using a flat surface and a concave surface are exemplified. However, in order to utilize the present invention more effectively, the lens shape is preferably a meniscus lens. In particular, a negative meniscus lens having a stronger concave power than a convex power like the optical element 201 is desirable. Compared to other lens shapes, a negative meniscus lens tends to have high visibility of a virtual image and efficiency of light incident on the curved surfaces 205 and 206. Therefore, when the present invention is applied to a negative meniscus lens, a very high effect can be expected.
このような光学素子２０１は、多くの光学装置で使用することができる。例えば、図３には、本実施例の光学素子２０１を用いた光学装置の例としてデジタルカメラを示している。なお、本発明の光学装置はこれに限定されず、例えばビデオカメラやプロジェクターであってもよい。 Such an optical element 201 can be used in many optical devices. For example, FIG. 3 shows a digital camera as an example of an optical apparatus using the optical element 201 of this embodiment. The optical device of the present invention is not limited to this, and may be a video camera or a projector, for example.
３００はカメラ本体、３０１は本実施例の光学素子２０１を一部用いた撮像光学系である。３０２はカメラ本体３００に内蔵され、撮像光学系３０１によって形成された被写体像を受光するＣＣＤセンサやＣＭＯＳセンサ等の固体撮像素子（光電変換素子）である。３０３は撮像素子３０２によって光電変換された被写体像に対応する情報を記録するメモリ、３０４は液晶ディスプレイパネル等によって構成され、固体撮像素子３０２上に形成された被写体像を観察するための表示素子である。 Reference numeral 300 denotes a camera body, and 301 denotes an imaging optical system using a part of the optical element 201 of this embodiment. Reference numeral 302 denotes a solid-state imaging device (photoelectric conversion device) such as a CCD sensor or a CMOS sensor that receives a subject image formed by the imaging optical system 301 and is built in the camera body 300. Reference numeral 303 denotes a memory that records information corresponding to the subject image photoelectrically converted by the image sensor 302, and 304 denotes a display element that includes a liquid crystal display panel or the like and that is used to observe the subject image formed on the solid-state image sensor 302. is there.
このようなデジタルカメラ３００の撮像光学系３０１では、固体撮像素子３０２によって反射した光が撮像光学系３０１に戻り、各光学素子によってさらに反射された光が固体撮像素子３０２に戻って写りこんでしまうという課題が有る。これは光学素子の光学面だけでなく非光学面にも起きる課題で有り、これを抑制するには出来るだけ非光学面の遮光性能を向上させる必要がある。そこで、撮像光学系３０１に本発明の光学素子２０１を使用することで、熱水への浸漬処理を施す光学素子においても、迷光による映りこみや散乱を十分に抑えた撮像光学系３０１を提供することが出来る。 In such an imaging optical system 301 of the digital camera 300, the light reflected by the solid-state imaging element 302 returns to the imaging optical system 301, and the light further reflected by each optical element returns to the solid-state imaging element 302 and is reflected. There is a problem. This is a problem that occurs not only on the optical surface of the optical element but also on the non-optical surface. To suppress this, it is necessary to improve the light-shielding performance of the non-optical surface as much as possible. Therefore, by using the optical element 201 of the present invention for the imaging optical system 301, an imaging optical system 301 that sufficiently suppresses reflection and scattering due to stray light is provided even in an optical element that is immersed in hot water. I can do it.
なお、本実施例の光学素子２０１は、上述したようなデジタルカメラ３００の撮像光学系３０１だけでなく、液晶プロジェクターの照明光学系及び投射光学系等にも使用することができる。それにより、不要な反射を抑えて迷光の発生を抑制した光学系を有する光学装置を提供することができる。 The optical element 201 of this embodiment can be used not only for the imaging optical system 301 of the digital camera 300 as described above but also for the illumination optical system and the projection optical system of a liquid crystal projector. Accordingly, it is possible to provide an optical device having an optical system in which unnecessary reflection is suppressed and generation of stray light is suppressed.
また、このような光学素子２０１は、段差が形成されることにより光学レンズとして体積を小さくすることができるため、重量を軽くすることができる。そのため、撮像光学系３０１の中でも可動群に好適に利用することができる。例えば、ピントを合わせるためのフォーカス群や焦点距離を変更するためのズーム群といった光軸方向に移動可能な可動群、手ぶれ防止のための防振群といった光軸と直交する方向に移動可能な可動群等に好適に適用できる。このような場所に光学素子２０１を利用すると、遮光性能が優れかつ可動時にメカ部品の負荷の小さい撮像光学系３０１を得ることができる。
（比較例）
本発明に対する比較例を図４に示す。ここでＣは比較例における光学素子４０１の断面図で、４０２、４１４は光軸、４０３、４０４は光学面、４０５、４０６、４０７は光学素子４０１の非光学面を結ぶ曲面である。Ｔは光学素子４０１を光学面４０３側から見た上面図で、４０９は光学面４０３の端部、４１０は曲面４０５、４０６の実像、４１１は光学面４０４の端部、４１２は曲面４０６の虚像、４１３は曲面４０５の虚像である。ここで、光学素子４０１は基材としてＳ−ＬＡＨ５５（Ｓ−ＬＡＨ５５は株式会社ＯＨＡＲＡの商品名）を用いた。また曲面４０５、４０６、４０７の曲率半径は０．１ｍｍであり、ほぼ曲面形状を示していない（緩やかな曲面をなしていない）。
In addition, such an optical element 201 can be reduced in weight because an optical lens can be reduced in volume by forming a step. Therefore, the imaging optical system 301 can be suitably used for the movable group. For example, a movable group that can move in the optical axis direction, such as a focus group for focusing and a zoom group for changing the focal length, and a movable group that can move in a direction perpendicular to the optical axis, such as a vibration-proof group for preventing camera shake. It can be suitably applied to groups. When the optical element 201 is used in such a place, it is possible to obtain an imaging optical system 301 that has excellent light shielding performance and a small mechanical component load when it is movable.
(Comparative example)
A comparative example for the present invention is shown in FIG. Here, C is a sectional view of the optical element 401 in the comparative example, 402 and 414 are optical axes, 403 and 404 are optical surfaces, and 405, 406 and 407 are curved surfaces connecting non-optical surfaces of the optical element 401. T is a top view of the optical element 401 viewed from the optical surface 403 side, 409 is an end of the optical surface 403, 410 is a real image of the curved surfaces 405 and 406, 411 is an end of the optical surface 404, and 412 is a virtual image of the curved surface 406. Reference numeral 413 denotes a virtual image of the curved surface 405. Here, S-LAH55 (S-LAH55 is a trade name of OHARA Co., Ltd.) was used for the optical element 401 as a base material. In addition, the curvature radii of the curved surfaces 405, 406, and 407 are 0.1 mm, and the curved surfaces 405, 406, and 407 have almost no curved surface shape (no gentle curved surface).
このような光学素子２０１の非光学面に遮光膜を成膜し、熱水への浸漬処理を与えると、その曲面４０５、４０６、４０７を起点にして剥がれが発生しやすい。特に基材のヌープ硬度が高いため、剥がれは非常に発生しやすい。特に凹面である４０５は非常に剥がれやすく、視認性も高い。それを光学面４０３側からみると、実像４１０、虚像４１２、４１３のように剥がれた部分が非常に見えやすくなる。これは著しい遮光性能の劣化であり、非常に好ましくない。 When a light-shielding film is formed on the non-optical surface of the optical element 201 and subjected to immersion treatment in hot water, peeling is likely to occur starting from the curved surfaces 405, 406, and 407. In particular, because the Knoop hardness of the substrate is high, peeling is very likely to occur. In particular, the concave surface 405 is very easy to peel off and has high visibility. When viewed from the optical surface 403 side, the peeled portions such as the real image 410 and the virtual images 412, 413 are very easily seen. This is a significant deterioration of the light shielding performance, which is very undesirable.
以上、本発明の好ましい実施形態について説明したが、本発明はこれらの実施形態に限定されず、その要旨の範囲内で種々の変形及び変更が可能である。 As mentioned above, although preferable embodiment of this invention was described, this invention is not limited to these embodiment, A various deformation | transformation and change are possible within the range of the summary.
本発明の光学素子は、ビデオカメラ、コンパクトカメラあるいは一眼レフカメラ、プロジェクターなどの光学装置に好適に利用できる。 The optical element of the present invention can be suitably used for an optical apparatus such as a video camera, a compact camera, a single-lens reflex camera, or a projector.
１０１、２０１ 光学素子
１０３、１０４、２０３、２０４ 光学面
１０５〜１０７、２０５〜２０７、２１５、２１６ 非光学面
３００ カメラ本体
３０１ 撮像光学系
101, 201 Optical elements 103, 104, 203, 204 Optical surfaces 105-107, 205-207, 215, 216 Non-optical surfaces 300 Camera body 301 Imaging optical system
Claims (10)
光学研磨された光学面と、
前記光学面の外周に設けられた算術平均粗さが５μｍ以上に粗面加工された非光学面と、
前記非光学面に成膜された遮光膜と、
を有し、
前記非光学面は、前記光学素子の光軸に直交する成分が主で前記光軸に平行な方向に離間した２つの第１の面と、前記２つの第１の面の間に設けられ前記光軸に平行な成分が主の第２の面と、前記２つの第１の面と前記第２の面とを繋ぐ曲面とからなる段部を有し、
前記曲面は、１．０ｍｍ以上の曲率半径を有することを特徴とする光学素子。 In the optical element subjected to hot water immersion treatment,
An optically polished optical surface;
A non-optical surface roughened to an arithmetic average roughness of 5 μm or more provided on the outer periphery of the optical surface;
A light-shielding film formed on the non-optical surface;
Have
The non-optical surface is provided between two first surfaces that are mainly components perpendicular to the optical axis of the optical element and are separated in a direction parallel to the optical axis, and the two first surfaces. A component parallel to the optical axis has a step portion consisting of a main second surface, and a curved surface connecting the two first surfaces and the second surface,
The optical element, wherein the curved surface has a radius of curvature of 1.0 mm or more.
前記光学素子の光軸と直交する方向の距離をＨとしたときに、各光学面の光軸と直交する方向の最大距離をＨ１、Ｈ２（ただしＨ１＜Ｈ２）、前記曲面の光軸と直交する方向の最大距離をＨｉとすると、
前記Ｈｉは、以下の条件式を満たすことを特徴とする請求項１に記載の光学素子。
Ｈ１＋０．２＊（Ｈ２−Ｈ１） ＜ Ｈｉ ＜ Ｈ１＋０．７＊（Ｈ２−Ｈ１） The optical surface includes two optical surfaces spaced apart in the optical axis direction,
When the distance in the direction orthogonal to the optical axis of the optical element is H, the maximum distance in the direction orthogonal to the optical axis of each optical surface is H1, H2 (where H1 <H2), and orthogonal to the optical axis of the curved surface. If the maximum distance in the direction to do is Hi,
The optical element according to claim 1, wherein the Hi satisfies the following conditional expression.
H1 + 0.2 * (H2-H1) <Hi <H1 + 0.7 * (H2-H1)
アルミニウム又は酸化アルミニウムを主成分とするベーマイトが平均ピッチ２０〜２００ｎｍ以下で配列している微細凹凸構造層を形成していることを特徴とする請求項１から４のいずれか１項に記載の光学素子。 At least one of the optical surfaces of the optical element,
The optical system according to any one of claims 1 to 4, wherein a fine concavo-convex structure layer in which boehmite mainly composed of aluminum or aluminum oxide is arranged at an average pitch of 20 to 200 nm or less is formed. element.
前記熱水浸漬処理は前記光学素子を７０度以上の熱水に１０分以上浸漬させる処理であることを特徴とする請求項１から６のいずれか１項に記載の光学素子。 The light shielding film has a thickness of 2 to 30 μm,
The optical element according to any one of claims 1 to 6, wherein the hot water immersion treatment is a process of immersing the optical element in hot water of 70 degrees or more for 10 minutes or more.
該可動群は、請求項１から７のいずれか１項に記載の光学素子から構成されることを特徴とする光学系。 Having a movable group movable in the direction of the optical axis or in the direction perpendicular to the optical axis,
The optical system, wherein the movable group includes the optical element according to any one of claims 1 to 7.
An optical apparatus comprising the optical system according to claim 8.
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| JP2011174432A JP2013037250A (en) | 2011-08-10 | 2011-08-10 | Optical element, and optical system and optical device including the same |
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| Application Number | Priority Date | Filing Date | Title |
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| JP2011174432A JP2013037250A (en) | 2011-08-10 | 2011-08-10 | Optical element, and optical system and optical device including the same |
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| JP2013037250A true JP2013037250A (en) | 2013-02-21 |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2016121503A1 (en) * | 2015-01-29 | 2016-08-04 | コニカミノルタ株式会社 | Display member and head-up display device |
| JP2018141822A (en) * | 2017-02-27 | 2018-09-13 | キヤノン株式会社 | Optical element, manufacturing method thereof, and optical device |
| EP3407098A1 (en) * | 2017-05-25 | 2018-11-28 | Canon Kabushiki Kaisha | Optical element and optical device |
-
2011
- 2011-08-10 JP JP2011174432A patent/JP2013037250A/en not_active Withdrawn
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2016121503A1 (en) * | 2015-01-29 | 2016-08-04 | コニカミノルタ株式会社 | Display member and head-up display device |
| JP2018141822A (en) * | 2017-02-27 | 2018-09-13 | キヤノン株式会社 | Optical element, manufacturing method thereof, and optical device |
| EP3407098A1 (en) * | 2017-05-25 | 2018-11-28 | Canon Kabushiki Kaisha | Optical element and optical device |
| CN108931828A (en) * | 2017-05-25 | 2018-12-04 | 佳能株式会社 | Optical element and optical device |
| JP2018200341A (en) * | 2017-05-25 | 2018-12-20 | キヤノン株式会社 | Optical element and optical apparatus |
| US10436944B2 (en) | 2017-05-25 | 2019-10-08 | Canon Kabushiki Kaisha | Optical element and optical device |
| CN108931828B (en) * | 2017-05-25 | 2020-11-13 | 佳能株式会社 | Optical element and optical device |
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