JP2018169515A - Observation optical system and binoculars having the same - Google Patents
Observation optical system and binoculars having the same Download PDFInfo
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Abstract
Description
本発明は観察光学系に関し、特に観察光学系を構成する接眼光学系からの逆入射光ゴーストの視認性を低くし、物体像を良好に観察することができる双眼鏡、望遠鏡、撮像装置等に好適なものである。 The present invention relates to an observation optical system, and particularly suitable for binoculars, a telescope, an imaging device, etc. that can reduce the visibility of a back-incident light ghost from an eyepiece optical system constituting the observation optical system and can observe an object image satisfactorily. It is a thing.
双眼鏡や望遠鏡そして撮像装置等の光学機器の観察光学系には、ゴーストやフレアの発生を低減した、高品位かつ高性能な観察ができることが求められている。一般に、ゴーストやフレアの発生を低減するために、レンズ面には反射防止膜が構成されている。多くの反射防止膜は、ある範囲の波長領域でかつある入射角範囲において所望の反射防止性能が得られている。 Observation optical systems for optical instruments such as binoculars, telescopes, and imaging devices are required to be capable of high-quality and high-performance observation with reduced generation of ghosts and flares. In general, in order to reduce the occurrence of ghosts and flares, an antireflection film is formed on the lens surface. Many antireflection films have a desired antireflection performance in a certain wavelength range and in a certain incident angle range.
しかしながら入射角度の大きな斜入射光に対しては、必ずしも所望の反射防止性能が得られていない。そのため、例えば観察光学系を構成する接眼光学系では観察側から接眼光学系に大きな角度で入射した入射光線（逆入射光）が接眼レンズを構成するレンズ面に入り、多重反射を起こし観察側に戻り観察者の瞳に入射する。そうするとフレアやゴースト（以下、これらを逆入射光ゴーストという。）が発生してくる場合がある。 However, the desired antireflection performance is not necessarily obtained for obliquely incident light having a large incident angle. Therefore, for example, in an eyepiece optical system constituting an observation optical system, incident light (back-incident light) incident on the eyepiece optical system from the observation side at a large angle enters the lens surface constituting the eyepiece and causes multiple reflections on the observation side. Return to the observer's pupil. In this case, flare and ghost (hereinafter referred to as back-incident light ghost) may occur.
従来から、このような逆入射光ゴーストを低減するようにした観察光学系が提案されている（特許文献１乃至３）。特許文献１では可視域の波長よりも小さいナノサイズのくさび状の構造物をレンズ面に並べたＳＷＣ（Subwavelength Structure Coating）などの斜入射特性が優れた膜を利用して逆入射光ゴーストを低減している。特に、特許文献１ではＳＷＣの構成や配置場所を適切に設定することで瞳側（観察側）からの逆入射光ゴーストを効果的に防止している。 Conventionally, an observation optical system that reduces such a back-incident light ghost has been proposed (Patent Documents 1 to 3). Patent Document 1 uses a film with excellent oblique incidence characteristics such as SWC (Subwavelength Structure Coating) in which nano-sized wedge-shaped structures smaller than the wavelength in the visible range are arranged on the lens surface to reduce back-incident light ghosts. doing. In particular, Patent Document 1 effectively prevents back-incident light ghosts from the pupil side (observation side) by appropriately setting the configuration and location of the SWC.
特許文献２、３では、逆入射光の光路を物理的に遮蔽することによって、逆入射光ゴーストを防止している。このうち特許文献２では、光学ファインダーの開口部に逆入射光を遮断するシャッターを構成している。また特許文献３では、視野マスクの開口部をテーパー状の構造にすることにより、物理的に逆入射光ゴーストを防止している。 In Patent Documents 2 and 3, the back incident light ghost is prevented by physically shielding the optical path of the back incident light. Among these, in patent document 2, the shutter which interrupts | blocks reverse incident light is comprised at the opening part of the optical finder. Further, in Patent Document 3, a back-incident light ghost is physically prevented by making the opening of the field mask have a tapered structure.
観察光学系において所定面に形成された物体像を接眼レンズを介して良好なる光学性能を有しつつ観察するには、逆入射光によるゴーストが低いことが重要になってくる。例えば接眼光学系の各レンズ面からの逆入射光によるゴーストのうち、観察者の眼が感じる視認性の観点から、赤外域を含めた全波長範囲で反射率特性が低いことが重要になってくる。特に可視域での逆入射光ゴーストが低減されても赤色系の長波長側の逆入射光ゴーストが発生すると、この赤外域による逆入射ゴーストは目立ち、高い光学性能での観察が困難になる。 In order to observe an object image formed on a predetermined surface in an observation optical system through an eyepiece lens with good optical performance, it is important that the ghost due to back-incident light is low. For example, out of ghosts caused by back-incident light from each lens surface of the eyepiece optical system, it is important that the reflectance characteristics are low in the entire wavelength range including the infrared region from the viewpoint of visibility felt by the observer's eyes. come. In particular, even if the back-incident light ghost in the visible range is reduced, if a red-type back-incident light ghost on the long wavelength side is generated, the back-incident ghost in the infrared region is conspicuous and observation with high optical performance becomes difficult.
接眼光学系のレンズ面の反射による逆入射光ゴーストを効果的に軽減し、良好なる物体像の観察を行うには接眼レンズのレンズ構成及び反射防止膜を施す接眼レンズのレンズ面のレンズ形状等を適切に設定することが重要になってくる。この他、逆入射光のうちレンズ面への入射角が大きいと、逆入射光ゴーストの発生が多くなるため、レンズ面に施す反射防止膜は入射角度が増大しても反射率が低いこと等が重要になってくる。 To effectively reduce the back-incident light ghost caused by reflection of the lens surface of the eyepiece optical system and observe a good object image, the lens configuration of the eyepiece lens and the lens shape of the lens surface of the eyepiece lens to which an antireflection film is applied It is important to set up properly. In addition, if the incident angle to the lens surface is large, the anti-reflection film applied to the lens surface has a low reflectance even when the incident angle increases. Becomes important.
本発明は、視認性が強い波長を含んだ特定波長帯域で、斜入射による反射防止膜特性が優れ、逆入射光ゴーストの視認性が低く、良好なる観察が容易な観察光学系及びそれを有する双眼鏡の提供を目的とする。 The present invention has an observation optical system that has excellent antireflection film characteristics due to oblique incidence in a specific wavelength band including a wavelength with high visibility, low visibility of a back-incident light ghost, and good observation and an easy observation optical system. The purpose is to provide binoculars.
本発明の観察光学系は、所定面に形成される物体像を観察するための観察光学系であって、前記観察光学系は、複数の屈折光学素子からなる接眼光学系を有し、前記接眼光学系は、観察側から所定面側へ順に配置された、観察側に凸面を向けた正の屈折力の正レンズＧ１と、観察側に凸面を向けた正の屈折力の正レンズＧ２を有し、
前記正レンズＧ１の光学面又は前記正レンズＧ２の光学面のうち観察側に凸面を向けた光学面の少なくとも１つの光学面には多層膜からなる反射防止膜が施されており、波長７００ｎｍで入射角５０度での前記反射防止膜の反射率をＲ（Ｒ５０）、
波長４５０ｎｍで入射角５０度での前記反射防止膜の反射率をＲ（Ｂ５０）、
波長７００ｎｍで入射角０度での前記反射防止膜の反射率をＲ（Ｒ０）、
波長４５０ｎｍで入射角０度での前記反射防止膜の反射率をＲ（Ｂ０）、
とするとき、
Ｒ（Ｒ５０）／Ｒ（Ｂ５０）＜２．０
｜｛Ｒ（Ｒ５０）／Ｒ（Ｂ５０）｝−｛Ｒ（Ｒ０）／Ｒ（Ｂ０）｝｜＜２．０
なる条件式を満足することを特徴としている。
The observation optical system of the present invention is an observation optical system for observing an object image formed on a predetermined surface, and the observation optical system includes an eyepiece optical system including a plurality of refractive optical elements, and the eyepiece The optical system includes a positive lens G1 having a positive refractive power with a convex surface facing the observation side and a positive lens G2 having a positive refractive power with the convex surface facing the observation side, which are arranged in order from the observation side to the predetermined surface side. And
At least one optical surface of the optical surface of the positive lens G1 or the optical surface of the positive lens G2 with the convex surface facing the observation side is provided with an antireflection film made of a multilayer film at a wavelength of 700 nm. The reflectance of the antireflection film at an incident angle of 50 degrees is R (R50),
The reflectance of the antireflection film at a wavelength of 450 nm and an incident angle of 50 degrees is R (B50),
The reflectance of the antireflection film at a wavelength of 700 nm and an incident angle of 0 degree is R (R0),
The reflectance of the antireflection film at a wavelength of 450 nm and an incident angle of 0 degree is R (B0),
And when
R (R50) / R (B50) <2.0
| {R (R50) / R (B50)}-{R (R0) / R (B0)} | <2.0
It satisfies the following conditional expression.
本発明によれば、視認性が強い波長を含んだ特定波長帯域で、斜入射による反射防止膜特性が優れ、逆入射光ゴーストの視認性が低く、良好なる観察が容易な観察光学系が得られる。 According to the present invention, it is possible to obtain an observation optical system that has excellent antireflection film characteristics due to oblique incidence in a specific wavelength band including a wavelength with high visibility, low visibility of a back-incident light ghost, and easy easy observation. It is done.
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説明する。本発明の観察光学系は、所定面に形成される物体像を観察するための観察光学系である。 Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. The observation optical system of the present invention is an observation optical system for observing an object image formed on a predetermined surface.
観察光学系は、複数の屈折光学素子からなる接眼光学系を有する。接眼光学系は観察側から所定面側へ順に配置された、観察側に凸面を向けた正の屈折力の正レンズＧ１、観察側に凸面を向けた正の屈折力の正レンズＧ２を有する。正レンズＧ１の光学面又は正レンズＧ２の光学面のうち観察側に凸面を向けた光学面のうち少なくとも１つの光学面には多層膜からなる反射防止膜が施されている。 The observation optical system has an eyepiece optical system composed of a plurality of refractive optical elements. The eyepiece optical system includes a positive lens G1 having a positive refractive power with a convex surface facing the observation side and a positive lens G2 having a positive refractive power with a convex surface facing the observation side, which are arranged in order from the observation side to the predetermined surface side. At least one of the optical surfaces of the positive lens G1 and the optical surface of the positive lens G2 with the convex surface facing the observation side is provided with an antireflection film made of a multilayer film.
図１は本発明の実施例１の観察光学系のレンズ断面図である。尚、本発明が双眼鏡のときは図１に示す観察光学系を１対有する。図１において、１は観察光学系である。１０１は対物光学系であり、物体像を所定面に形成する。１０２は物体像が形成される像面である。１０３はポロプリズムやペンタプリズムなどの物体像を正立像に変換する像反転手段である。像反転手段１０３はプリズム等により構成されるが、図中では簡単のため光路を展開してブロックで示している。１０４は観察光学系１の光軸、１０６は観察者の眼（瞳位置）が位置するアイポイントである。 FIG. 1 is a lens cross-sectional view of an observation optical system according to Example 1 of the present invention. When the present invention is binoculars, it has a pair of observation optical systems shown in FIG. In FIG. 1, reference numeral 1 denotes an observation optical system. An objective optical system 101 forms an object image on a predetermined surface. Reference numeral 102 denotes an image plane on which an object image is formed. Reference numeral 103 denotes image inversion means for converting an object image such as a Porro prism or a pentaprism into an erect image. The image inverting means 103 is constituted by a prism or the like, but in the drawing, the optical path is developed and shown as a block for simplicity. Reference numeral 104 denotes an optical axis of the observation optical system 1, and reference numeral 106 denotes an eye point where an observer's eye (pupil position) is located.
１０５は接眼光学系である。接眼光学系１０５は観察面側から対物光学系１０１側へ順に観察側のレンズ面が凸形状の正レンズＧ１、観察側のレンズ面が凸形状の正の屈折力の正レンズＧ２と負レンズＧ３を接合した接合レンズＧ２ａを有する。更に観察側に凸面を向けた正レンズＧ４、両凹形状の負レンズＧ５を有している。対物光学系１０１によって形成される物体像の像面１０２は正レンズＧ４と接合レンズＧ２ａの間に位置している。実施例１の観察光学系１では対物光学系１０１で形成した物体像を像反転手段１０３で反転して正立像とし、その正立像を接眼光学系１０５で拡大して拡大像をアイポイント１０６より観察する。 Reference numeral 105 denotes an eyepiece optical system. In the eyepiece optical system 105, a positive lens G1 having a convex lens surface on the observation side and a positive lens G2 having a positive refractive power and a negative lens G3 having a convex lens surface on the observation side are sequentially arranged from the observation surface side to the objective optical system 101 side. Has a cemented lens G2a. Furthermore, it has a positive lens G4 with a convex surface facing the observation side and a biconcave negative lens G5. The image plane 102 of the object image formed by the objective optical system 101 is located between the positive lens G4 and the cemented lens G2a. In the observation optical system 1 of the first embodiment, the object image formed by the objective optical system 101 is inverted by the image inverting means 103 to be an erect image, and the erect image is enlarged by the eyepiece optical system 105 and an enlarged image is obtained from the eye point 106. Observe.
正レンズＧ１または正レンズＧ２のうち観察側の光学面には多層膜からなる反射防止膜を施している。一般的に反射防止膜の反射特性は、ある入射角度の光線が反射防止膜に入射した際の、各波長に対する反射率で示される。ある入射角範囲内において所望の反射防止性能が得られている反射防止膜であっても入射角度が大きくなる斜入射光に対しては、必ずしも所望の反射防止性能が得られない。そのため接眼光学系の観察側から光線が大きな入射角度でレンズ面に入ると逆入射光ゴーストが発生してくる。 Of the positive lens G1 or the positive lens G2, an optical surface on the observation side is provided with an antireflection film made of a multilayer film. In general, the reflection characteristic of an antireflection film is represented by the reflectance with respect to each wavelength when a light beam having a certain incident angle enters the antireflection film. Even with an antireflection film having a desired antireflection performance within a certain incident angle range, the desired antireflection performance is not necessarily obtained with respect to obliquely incident light having a large incident angle. For this reason, when a light ray enters the lens surface at a large incident angle from the observation side of the eyepiece optical system, a reverse incident light ghost is generated.
図２は、逆入射光ゴーストを示す説明図である。接眼光学系１０５の観察側から光線が入射し、レンズを通して鏡筒のメカ部品に反射して観察側に戻るとゴースト光として観察者が視認してしまう。ここでゴースト光の各波長に対する反射率に着目すると、観察者の視認性が高いとされている特定波長帯域、特に赤色系の長波長側の反射光が強いゴースト光が発生すると、観察者はゴースト光を強く感じる。 FIG. 2 is an explanatory view showing a reverse incident light ghost. When a light beam enters from the observation side of the eyepiece optical system 105, is reflected by a mechanical part of the lens barrel through the lens and returns to the observation side, the observer visually recognizes it as ghost light. Focusing on the reflectance of each wavelength of the ghost light here, when the ghost light having a strong reflected light on the specific wavelength band, particularly the red long wavelength side, which is considered to be highly visible to the observer, I feel a strong ghost light.
本発明に係る反射防止膜は、各波長に対する反射率を考慮することにより、逆入斜光ゴーストの視認性を低くすることができる構成となっている。 The antireflection film according to the present invention has a configuration in which the visibility of the reverse-incidence oblique light ghost can be lowered by considering the reflectance with respect to each wavelength.
反射防止膜の反射率は、波長７００ｎｍで入射角５０度での反射防止膜の反射率をＲ（Ｒ５０）とする。波長４５０ｎｍで入射角５０度での反射防止膜の反射率をＲ（Ｂ５０）とする。波長７００ｎｍで入射角０度での反射防止膜の反射率をＲ（Ｒ０）とする。波長４５０ｎｍで入射角０度での反射防止膜の反射率をＲ（Ｂ０）とする。このとき、
Ｒ（Ｒ５０）／Ｒ（Ｂ５０）＜２．０ ・・・（１）
｜｛Ｒ（Ｒ５０）／Ｒ（Ｂ５０）｝−｛Ｒ（Ｒ０）／Ｒ（Ｂ０）｝｜＜２．０
・・・（２）
なる条件式を満足する。
The reflectance of the antireflection film is defined as R (R50) when the wavelength is 700 nm and the incident angle is 50 degrees. The reflectance of the antireflection film at a wavelength of 450 nm and an incident angle of 50 degrees is R (B50). Let R (R0) be the reflectance of the antireflection film at a wavelength of 700 nm and an incident angle of 0 degree. Let R (B0) be the reflectance of the antireflection film at a wavelength of 450 nm and an incident angle of 0 degree. At this time,
R (R50) / R (B50) <2.0 (1)
| {R (R50) / R (B50)}-{R (R0) / R (B0)} | <2.0
... (2)
The following conditional expression is satisfied.
本発明では接眼光学系１０５の光学面（レンズ面）に施す反射防止膜を正レンズの観察側に凸面を向けたレンズ面に施すことによって逆入射光が凸面で反射したときの反射光を少なくしている。また凸面で反射した反射光が観察側の瞳位置（アイポイント）に逆入射する光量を軽減している。これによって、物体像を良好に観察することができるようにしている。 In the present invention, the antireflection film applied to the optical surface (lens surface) of the eyepiece optical system 105 is applied to the lens surface with the convex surface facing the observation side of the positive lens, thereby reducing the reflected light when the reverse incident light is reflected by the convex surface. doing. In addition, the amount of light reflected back from the convex surface and incident on the pupil position (eye point) on the observation side is reduced. This makes it possible to observe the object image satisfactorily.
接眼光学系１０５の負レンズの光学面が観察側に凹面を向けたているときには、逆入射光がこの凹面で反射して瞳位置に入射することが少ない。このため観察側に凸面を向けたレンズ面に反射防止膜を施している。 When the optical surface of the negative lens of the eyepiece optical system 105 has a concave surface facing the observation side, the reverse incident light is less likely to be reflected by the concave surface and enter the pupil position. For this reason, an antireflection film is applied to the lens surface with the convex surface facing the observation side.
次に前述の各条件式の技術的意味について説明する。条件式（１）の上限を超えると、長波長側の反射光が強い逆入射光ゴーストとなるため、観察者の視認性が非常に高くなり好ましくない。また条件式（２）の上限を超えた際においても、入射角度が０度に対して入射角度が５０度で、より長波長側の反射光が強い逆入射光ゴーストとなるため、同様に観察者の視認性が非常に高くなり好ましくない。 Next, the technical meaning of each conditional expression described above will be described. If the upper limit of conditional expression (1) is exceeded, the reflected light on the long wavelength side becomes a strong back-incident light ghost, which is not preferable because the visibility of the observer becomes very high. Even when the upper limit of conditional expression (2) is exceeded, the incident angle is 50 degrees with respect to the incident angle, and the reflected light on the longer wavelength side becomes a strong back incident light ghost. The visibility of a person becomes very high, which is not preferable.
以上のように本発明の観察光学系では視認性が強い波長を含んだ特定波長帯域で、斜入射特性が優れている反射防止性能を満足するような反射防止膜を適用している。この結果、逆入射光ゴーストの視認性を低くする観察光学系を容易に得ている。 As described above, in the observation optical system of the present invention, an antireflection film that satisfies the antireflection performance with excellent oblique incidence characteristics is applied in a specific wavelength band including a wavelength with high visibility. As a result, an observation optical system that reduces the visibility of the back-incident light ghost is easily obtained.
実施例１では正レンズＧ１と正レンズＧ２の観察側に凸面を向けた光学面のうちの少なくとも１つの光学面に多層膜からなる反射防止膜を施している。実施例１では正レンズＧ１の観察側の凸面及び正レンズＧ２の観察側の凸面に、多層膜からなる反射防止膜を施している。 In Example 1, an antireflection film made of a multilayer film is applied to at least one of the optical surfaces having convex surfaces facing the observation side of the positive lens G1 and the positive lens G2. In Example 1, an antireflection film made of a multilayer film is applied to the observation-side convex surface of the positive lens G1 and the observation-side convex surface of the positive lens G2.
図３は、実施例１で用いた反射防止膜３１の膜構成の説明図である。図３において、基板Ｇａは反射防止膜３１を有するレンズである。この反射防止膜３１は、基板Ｇａ側から空気側にかけて順に、第１、第３、第５、第７層が低屈折率層Ｌ、第２、第４、第６、第８層目が高屈折率層Ｈ、もっとも空気側の第９層はさらに低屈折率層ＬＬとなるように設計されている。高屈折率層Ｈと低屈折率層Ｌを組み合わせることによって、吸収を抑制し且つ基板Ｇａとの良好な密着性を得ている。また９層構造で高い反射防止効果を得ている。表１、表２に多層膜からなる２つの反射防止膜Ａ、反射防止膜Ｂの構成を示す。 FIG. 3 is an explanatory diagram of the film configuration of the antireflection film 31 used in the first embodiment. In FIG. 3, the substrate Ga is a lens having an antireflection film 31. The antireflection film 31 has a low refractive index layer L for the first, third, fifth, and seventh layers, and a second, fourth, sixth, and eighth layers in order from the substrate Ga side to the air side. The refractive index layer H, the ninth layer on the most air side, is further designed to be a low refractive index layer LL. By combining the high refractive index layer H and the low refractive index layer L, absorption is suppressed and good adhesion to the substrate Ga is obtained. In addition, a high antireflection effect is obtained with a nine-layer structure. Tables 1 and 2 show configurations of two antireflection films A and B made of multilayer films.
表２の反射防止膜Ｂは本発明に係る反射防止膜である。表１の反射防止膜Ａは本発明に係る反射防止膜Ｂの比較例である。 The antireflection film B in Table 2 is an antireflection film according to the present invention. The antireflection film A in Table 1 is a comparative example of the antireflection film B according to the present invention.
表１の反射防止膜Ａ、は基板Ｇａとして屈折率１．６０３の光学ガラス（商品名Ｓ−ＢＳＭ１４／ＯＨＡＲＡ製）を使用している。表１にはこの反射防止膜３１の波長５８７．６ｎｍの光に対する屈折率と、各層の光学的膜厚（屈折率×幾何学的膜厚）を示す。第１、第３、第５層は屈折率１．６１０の低屈折率層Ｌであり、膜の材料にはＡｌ２Ｏ３が含まれる。第２、第４、第６層は屈折率２．０１７の高屈折率層Ｈであり、膜の材料にはＺｒＯ２が含まれる。もっとも空気側の第７層は屈折率１．３８６のさらに低屈折率層ＬＬであり、膜の材料にはＭｇＦ２が含まれる。 The antireflection film A in Table 1 uses optical glass (product name: S-BSM14 / OHARA) having a refractive index of 1.603 as the substrate Ga. Table 1 shows the refractive index of the antireflection film 31 with respect to light having a wavelength of 587.6 nm and the optical film thickness (refractive index × geometric film thickness) of each layer. The first, third, and fifth layers are low-refractive index layers L having a refractive index of 1.610, and the film material includes Al 2 O 3 . The second, fourth, and sixth layers are high-refractive index layers H having a refractive index of 2.017, and the film material includes ZrO 2 . The seventh layer on the most air side is a lower refractive index layer LL having a refractive index of 1.386, and the film material contains MgF 2 .
表２の本発明に係る反射防止膜Ｂ、は基板Ｇａとして屈折率１．６０３の光学ガラス（商品名Ｓ−ＢＳＭ１４／ＯＨＡＲＡ製）を使用している。表２にはこの反射防止膜３１の波長５８７．６ｎｍの光に対する屈折率と、各層の光学的膜厚（屈折率×幾何学的膜厚）を示す。第１、第３、第５、第７層は屈折率１．６１０の低屈折率層Ｌであり、膜の材料にはＡｌ２Ｏ３が含まれる。第２、第４、第６、第９層は屈折率２．０１７の高屈折率層Ｈであり、膜の材料にはＺｒＯ２が含まれる。もっとも空気側の第９層は屈折率１．３８６のさらなる低屈折率層ＬＬであり、膜の材料にはＭｇＦ２が含まれる。 The antireflection film B according to the present invention in Table 2 uses optical glass (product name: S-BSM14 / OHARA) having a refractive index of 1.603 as the substrate Ga. Table 2 shows the refractive index of the antireflection film 31 with respect to light having a wavelength of 587.6 nm and the optical film thickness (refractive index × geometric film thickness) of each layer. The first, third, fifth, and seventh layers are low-refractive index layers L having a refractive index of 1.610, and the material of the film includes Al 2 O 3 . The second, fourth, sixth, and ninth layers are high-refractive index layers H having a refractive index of 2.017, and the film material includes ZrO 2 . The ninth layer on the most air side is a further low refractive index layer LL having a refractive index of 1.386, and the film material contains MgF 2 .
図４には、実施例１の反射防止膜Ａ、Ｂの反射率特性を示す。図４において、横軸は波長（単位はｎｍ）、縦軸は反射率（単位は％）をあらわしている。図４に示した、短い点線４Ａ１と長い点線４Ａ２は、それぞれ反射防止膜Ａの入射角度が０°と、入射角度５０°の反射率特性をあらわしている。入射角度が０°の際には波長４００ｎｍ〜７００ｎｍの波長領域において反射率０．７％以下という高い反射防止性能を達成している。波長７００ｎｍを超えたあたりから反射率が少しずつ上がっていることがわかる。 FIG. 4 shows the reflectance characteristics of the antireflection films A and B of Example 1. In FIG. 4, the horizontal axis represents wavelength (unit: nm), and the vertical axis represents reflectance (unit:%). The short dotted line 4A1 and the long dotted line 4A2 shown in FIG. 4 represent the reflectance characteristics when the incident angle of the antireflection film A is 0 ° and the incident angle is 50 °, respectively. When the incident angle is 0 °, a high antireflection performance of a reflectance of 0.7% or less is achieved in the wavelength range of 400 nm to 700 nm. It can be seen that the reflectance gradually increases from around the wavelength of 700 nm.
また斜入射側の反射特性においては、入射角度が５０°の際に波長４００ｎｍ〜６３０ｎｍの波長領域において反射率２．０％以下という反射防止性能を達成している。赤色系の可視波長領域である波長６３０ｎｍ〜７５０ｎｍにおいての反射率は２．０％をはるかに超えている。赤色系の波長の反射率が高いため、接眼光学系をのぞいた観察者の眼が感じる逆入射光ゴーストは赤味がかって観察されている。 Further, in the reflection characteristics on the oblique incident side, the antireflection performance of a reflectance of 2.0% or less is achieved in the wavelength region of 400 nm to 630 nm when the incident angle is 50 °. The reflectance at a wavelength of 630 nm to 750 nm, which is a red visible wavelength region, far exceeds 2.0%. Since the reflectance of the red wavelength is high, the back-incident light ghost felt by the observer's eye looking through the eyepiece optical system is observed in reddishness.
一方、図４に示した、１点鎖線４Ｂ１と実線４Ｂ２は、それぞれ反射防止膜Ｂの入射角度が０°入射角度、５０°の反射率特性をあらわしている。入射角度が０°の際には波長４００ｎｍ〜７５０ｎｍの全波長領域に対して反射率１．０％以下という高い反射防止性能を達成している。反射防止膜Ａとは異なり反射防止膜Ｂは波長７００ｎｍを超えたあたりから反射率が少しずつ上がることはない。 On the other hand, an alternate long and short dash line 4B1 and a solid line 4B2 shown in FIG. 4 indicate reflectance characteristics when the incident angle of the antireflection film B is 0 ° and 50 °, respectively. When the incident angle is 0 °, a high antireflection performance of a reflectance of 1.0% or less is achieved for the entire wavelength region of wavelengths from 400 nm to 750 nm. Unlike the antireflective film A, the antireflective film B does not gradually increase its reflectivity from around the wavelength of 700 nm.
さらに斜入射側の反射特性においては、入射角度が５０°の際にも波長４００ｎｍ〜７５０ｎｍの全波長領域で反射率２．０％以下という反射防止性能を達成している。反射防止膜Ａと反射防止膜Ｂとを比較すると、反射防止膜Ｂは短波長側の反射率特性は若干劣っているが、全波長を通して同等の反射率である。したがって反射防止膜Ｂを用いると、接眼光学系をのぞいた観察者の眼が感じる逆入射光ゴーストは特定の色味が目立つことはなく、視認性の観点から高品位な光学性能が得られる。次に反射防止膜Ａ、Ｂに対する前述の条件式（１）、（２）に関する数値例を表３に示す。 Further, in the reflection characteristics on the oblique incident side, even when the incident angle is 50 °, the antireflection performance of a reflectance of 2.0% or less is achieved in the entire wavelength region of wavelengths from 400 nm to 750 nm. When the antireflection film A and the antireflection film B are compared, the antireflection film B is slightly inferior in reflectance characteristics on the short wavelength side, but has the same reflectance throughout all wavelengths. Therefore, when the antireflection film B is used, a specific color is not conspicuous in the back-incident light ghost felt by the observer's eyes except the eyepiece optical system, and high-quality optical performance can be obtained from the viewpoint of visibility. Next, Table 3 shows numerical examples related to the conditional expressions (1) and (2) for the antireflection films A and B.
本発明に係る接眼光学系１０５において、正レンズＧ１の観察側のレンズ面の曲率半径をｒ１１、正レンズＧ２の観察側のレンズ面の曲率半径をｒ２１とする。正レンズＧ１の焦点距離をｆ１、正レンズＧ２の焦点距離をｆ２とする。このとき、
｜ｒ１１／ｆ１｜＜２．０ ・・・（３）
｜ｒ２１／ｆ２｜＜０．６ ・・・（４）
なる条件式を満足するのが良い。
In the eyepiece optical system 105 according to the present invention, the radius of curvature of the observation-side lens surface of the positive lens G1 is r11, and the radius of curvature of the observation-side lens surface of the positive lens G2 is r21. The focal length of the positive lens G1 is f1, and the focal length of the positive lens G2 is f2. At this time,
| R11 / f1 | <2.0 (3)
| R21 / f2 | <0.6 (4)
It is good to satisfy the following conditional expression.
条件式（３）を超えて凸面の曲率半径が大きくなると、逆入射光の凸面からの反射光の多くが観察側に戻り、瞳位置に入射する光量が増加してくる。この結果、接眼光学系を介して物体像を観察するとき、ゴースト光が増加し、良好なる観察が困難になる。条件式（４）の技術的内容も条件式（３）と同様である。後述する本発明に係る接眼光学系１０５に関する前述の条件式（３）、（４）に関する数値を表４に示す。 When the curvature radius of the convex surface increases beyond the conditional expression (3), much of the reflected light from the convex surface of the reverse incident light returns to the observation side, and the amount of light incident on the pupil position increases. As a result, when observing an object image via an eyepiece optical system, ghost light increases, and good observation becomes difficult. The technical content of conditional expression (4) is the same as that of conditional expression (3). Table 4 shows numerical values related to the conditional expressions (3) and (4) regarding the eyepiece optical system 105 according to the present invention which will be described later.
本発明に係る接眼光学系１０５は観察面側から所定面側（対物光学系１０１側）へ順に次のレンズより構成されている。両凸形状の正レンズＧ１、両凸形状の正レンズＧ２と両凹形状の負レンズＧ３を接合した接合レンズＧ２ａ、観察側に凸面を向けたメニスカス形状の正レンズＧ４、両凹形状の負レンズＧ５より構成されている。 The eyepiece optical system 105 according to the present invention includes the following lenses in order from the observation surface side to the predetermined surface side (objective optical system 101 side). A biconvex positive lens G1, a cemented lens G2a obtained by cementing a biconvex positive lens G2 and a biconcave negative lens G3, a meniscus positive lens G4 having a convex surface facing the observation side, and a biconcave negative lens It is composed of G5.
本発明の観察光学系は、双眼鏡や望遠鏡に適用可能である。双眼鏡は所定面上に物体像を形成する対物光学系１０１と、対物光学系１０１からの光束が入射する正立像形成用の像反転手段１０３、像反転手段１０３からの光束が入射する実施例１の接眼光学系１０５を１対有する。望遠鏡では実施例１の観察光学系は１つ有する。 The observation optical system of the present invention is applicable to binoculars and telescopes. The binoculars are an objective optical system 101 that forms an object image on a predetermined surface, an image inverting unit 103 for forming an erect image on which a light beam from the objective optical system 101 is incident, and a light beam from the image inverting unit 103 that is incident on the binoculars. A pair of eyepiece optical systems 105. The telescope has one observation optical system of the first embodiment.
以下、実施例１の観察光学系の具体的な数値データ１を示す。数値データ１において、ｉは物体側から数えた順序を示す。面番号ｉは物体側から順に数えている。Ｒｉは曲率半径、Ｄｉは第ｉ番目と第ｉ＋１番目の面間隔である。Ｎｄｉとνｄｉはそれぞれｄ線に対する第ｉ面と第（ｉ＋１）面との間の媒質の屈折率、アッベ数を表す。 Hereinafter, specific numerical data 1 of the observation optical system of Example 1 is shown. In the numerical data 1, i indicates the order counted from the object side. The surface number i is counted in order from the object side. Ri is the radius of curvature, and Di is the i-th and i + 1-th surface spacing. Ndi and νdi represent the refractive index and Abbe number of the medium between the i-th surface and the (i + 1) -th surface with respect to the d-line, respectively.
数値データ１において、Ｒ１〜Ｒ１１は対物光学系、Ｒ１２〜Ｒ１５は像反転手段１０３である。Ｒ１６〜Ｒ２４は接眼光学系である。Ｒ１６、Ｒ１７は第５レンズＧ５、Ｒ１８、Ｒ１９は第４レンズＧ４、Ｒ２０〜Ｒ２２は接合レンズＧ２ａ、Ｒ２３、Ｒ２４は正レンズＧ１である。
In the numerical data 1, R1 to R11 are the objective optical system, and R12 to R15 are the image inverting means 103. R16 to R24 are eyepiece optical systems. R16 and R17 are fifth lenses G5, R18, and R19 are fourth lenses G4, R20 to R22 are cemented lenses G2a, R23, and R24 are positive lenses G1.
（数値データ１）
単位 mm
面データ
面番号 R D Nd νd
1 50.603 4.80 1.80610 40.9
2 180.402 18.01 1.00000
3 71.663 1.40 1.68893 31.1
4 18.286 7.50 1.58913 61.1
5 ∞ 5.14 1.00000
6 -331.251 1.10 1.58913 61.1
7 31.023 8.27 1.00000
8 -27.828 2.00 1.69895 30.1
9 -49.872 9.98 1.00000
10 102.273 4.00 1.70154 41.2
11 -57.989 15.24 1.00000
12 ∞ 17.50 1.56883 56.4
13 ∞ 40.50 1.56883 56.4
14 ∞ 17.50 1.56883 56.4
15 ∞ 4.12 1.00000
16 -6.920 1.00 1.48749 70.2
17 23.099 1.97 1.00000
18 -14.854 5.59 1.83400 37.2
19 -9.287 11.48 1.00000
20 -151.081 1.20 1.84666 23.9
21 18.057 9.28 1.60311 60.6
22 -18.005 0.20 1.00000
23 23.819 7.40 1.69680 55.5
24 -43.617 14.50 1.00000
(Numeric data 1)
Unit mm
Surface data surface number RD Nd νd
1 50.603 4.80 1.80610 40.9
2 180.402 18.01 1.00000
3 71.663 1.40 1.68893 31.1
4 18.286 7.50 1.58913 61.1
5 ∞ 5.14 1.00000
6 -331.251 1.10 1.58913 61.1
7 31.023 8.27 1.00000
8 -27.828 2.00 1.69895 30.1
9 -49.872 9.98 1.00000
10 102.273 4.00 1.70154 41.2
11 -57.989 15.24 1.00000
12 ∞ 17.50 1.56883 56.4
13 ∞ 40.50 1.56883 56.4
14 ∞ 17.50 1.56883 56.4
15 ∞ 4.12 1.00000
16 -6.920 1.00 1.48749 70.2
17 23.099 1.97 1.00000
18 -14.854 5.59 1.83400 37.2
19 -9.287 11.48 1.00000
20 -151.081 1.20 1.84666 23.9
21 18.057 9.28 1.60311 60.6
22 -18.005 0.20 1.00000
23 23.819 7.40 1.69680 55.5
24 -43.617 14.50 1.00000
実施例１では、接眼光学系１０５として４群５枚のレンズ構成のものを示したが、これに限定するものでなく、ケルナー型等のものを使用しても良い。また、実施例１においての焦点調節は、対物光学系１０１中の一部、若しくは全部、あるいは接眼光学系１０５を移動させても良いし、あるいは像反転手段１０３によって行ってもよくその方法については任意の方法が適用できる。 In the first embodiment, the ocular optical system 105 has a four-group five-lens configuration, but the present invention is not limited to this, and a Kelner type or the like may be used. Further, the focus adjustment in the first embodiment may be performed by moving a part or all of the objective optical system 101 or the eyepiece optical system 105, or by the image inverting means 103. Any method can be applied.
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.
１０１ 対物光学系 １０３ 像反転手段 １０５ 接眼光学系
Ｇ１ 正レンズ Ｇ２ 正レンズ
DESCRIPTION OF SYMBOLS 101 Objective optical system 103 Image inversion means 105 Eyepiece optical system G1 Positive lens G2 Positive lens
Claims (7)
前記正レンズＧ１の光学面又は前記正レンズＧ２の光学面のうち観察側に凸面を向けた光学面の少なくとも１つの光学面には多層膜からなる反射防止膜が施されており、波長７００ｎｍで入射角５０度での前記反射防止膜の反射率をＲ（Ｒ５０）、
波長４５０ｎｍで入射角５０度での前記反射防止膜の反射率をＲ（Ｂ５０）、
波長７００ｎｍで入射角０度での前記反射防止膜の反射率をＲ（Ｒ０）、
波長４５０ｎｍで入射角０度での前記反射防止膜の反射率をＲ（Ｂ０）、
とするとき、
Ｒ（Ｒ５０）／Ｒ（Ｂ５０）＜２．０
｜｛Ｒ（Ｒ５０）／Ｒ（Ｂ５０）｝−｛Ｒ（Ｒ０）／Ｒ（Ｂ０）｝｜＜２．０
なる条件式を満足することを特徴とする観察光学系。 An observation optical system for observing an object image formed on a predetermined surface, wherein the observation optical system includes an eyepiece optical system including a plurality of refractive optical elements, and the eyepiece optical system is predetermined from the observation side. A positive lens G1 having a positive refractive power with a convex surface facing the observation side and a positive lens G2 having a positive refractive power with a convex surface facing the observation side, which are arranged in order on the surface side;
At least one optical surface of the optical surface of the positive lens G1 or the optical surface of the positive lens G2 with the convex surface facing the observation side is provided with an antireflection film made of a multilayer film at a wavelength of 700 nm. The reflectance of the antireflection film at an incident angle of 50 degrees is R (R50),
The reflectance of the antireflection film at a wavelength of 450 nm and an incident angle of 50 degrees is R (B50),
The reflectance of the antireflection film at a wavelength of 700 nm and an incident angle of 0 degree is R (R0),
The reflectance of the antireflection film at a wavelength of 450 nm and an incident angle of 0 degree is R (B0),
And when
R (R50) / R (B50) <2.0
| {R (R50) / R (B50)}-{R (R0) / R (B0)} | <2.0
An observation optical system characterized by satisfying the following conditional expression:
｜ｒ１１／ｆ１｜＜２．０
なる条件式を満足することを特徴とする請求項１に記載の観察光学系。 When the radius of curvature of the observation lens surface of the positive lens G1 is r11 and the focal length of the positive lens G1 is f1,
| R11 / f1 | <2.0
The observation optical system according to claim 1, wherein the following conditional expression is satisfied.
｜ｒ２１／ｆ２｜＜０．６
なる条件式を満足することを特徴とする請求項１または２に記載の観察光学系。 When the radius of curvature of the lens surface on the observation side of the positive lens G2 is r21 and the focal length of the positive lens G2 is f2,
| R21 / f2 | <0.6
The observation optical system according to claim 1, wherein the following conditional expression is satisfied.
両凸形状の正レンズＧ２と両凹形状の負レンズを接合した接合レンズ、
観察側に凸面を向けたメニスカス形状の正レンズ、両凹形状の負レンズより構成されていることを特徴とする請求項１乃至３のいずれか１項に記載の観察光学系。 The observation optical system includes a biconvex positive lens G1 arranged in order from the observation side to the predetermined surface side,
A cemented lens in which a biconvex positive lens G2 and a biconcave negative lens are cemented;
4. The observation optical system according to claim 1, wherein the observation optical system includes a meniscus positive lens having a convex surface facing the observation side and a biconcave negative lens.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2017067091A JP2018169515A (en) | 2017-03-30 | 2017-03-30 | Observation optical system and binoculars having the same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2017067091A JP2018169515A (en) | 2017-03-30 | 2017-03-30 | Observation optical system and binoculars having the same |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP2018169515A true JP2018169515A (en) | 2018-11-01 |
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ID=64020345
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2017067091A Pending JP2018169515A (en) | 2017-03-30 | 2017-03-30 | Observation optical system and binoculars having the same |
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| Country | Link |
|---|---|
| JP (1) | JP2018169515A (en) |
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2017
- 2017-03-30 JP JP2017067091A patent/JP2018169515A/en active Pending
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