JPH0411211A - Endoscope optical system - Google Patents
Endoscope optical systemInfo
- Publication number
- JPH0411211A JPH0411211A JP2114190A JP11419090A JPH0411211A JP H0411211 A JPH0411211 A JP H0411211A JP 2114190 A JP2114190 A JP 2114190A JP 11419090 A JP11419090 A JP 11419090A JP H0411211 A JPH0411211 A JP H0411211A
- Authority
- JP
- Japan
- Prior art keywords
- lens
- magnetic fluid
- aperture
- optical system
- transparent
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 230000003287 optical effect Effects 0.000 title claims abstract description 50
- 230000005291 magnetic effect Effects 0.000 claims abstract description 13
- 239000012780 transparent material Substances 0.000 claims abstract description 3
- 239000011553 magnetic fluid Substances 0.000 claims description 59
- 230000002093 peripheral effect Effects 0.000 claims description 7
- 239000012530 fluid Substances 0.000 claims description 2
- 239000007788 liquid Substances 0.000 abstract description 35
- 238000005265 energy consumption Methods 0.000 abstract 1
- 239000011521 glass Substances 0.000 description 18
- 230000000694 effects Effects 0.000 description 13
- 239000004973 liquid crystal related substance Substances 0.000 description 8
- 238000002834 transmittance Methods 0.000 description 7
- 230000007246 mechanism Effects 0.000 description 6
- 238000000034 method Methods 0.000 description 6
- 230000008859 change Effects 0.000 description 5
- 239000000463 material Substances 0.000 description 5
- 230000008901 benefit Effects 0.000 description 4
- 230000005484 gravity Effects 0.000 description 4
- 238000000149 argon plasma sintering Methods 0.000 description 3
- 230000005540 biological transmission Effects 0.000 description 3
- 239000002904 solvent Substances 0.000 description 3
- BGPVFRJUHWVFKM-UHFFFAOYSA-N N1=C2C=CC=CC2=[N+]([O-])C1(CC1)CCC21N=C1C=CC=CC1=[N+]2[O-] Chemical compound N1=C2C=CC=CC2=[N+]([O-])C1(CC1)CCC21N=C1C=CC=CC1=[N+]2[O-] BGPVFRJUHWVFKM-UHFFFAOYSA-N 0.000 description 2
- 239000000853 adhesive Substances 0.000 description 2
- 230000001070 adhesive effect Effects 0.000 description 2
- 239000000470 constituent Substances 0.000 description 2
- 230000002517 constrictor effect Effects 0.000 description 2
- 239000006059 cover glass Substances 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 230000003247 decreasing effect Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 239000000835 fiber Substances 0.000 description 2
- 238000005286 illumination Methods 0.000 description 2
- 230000007774 longterm Effects 0.000 description 2
- 230000001133 acceleration Effects 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 210000004027 cell Anatomy 0.000 description 1
- 230000008094 contradictory effect Effects 0.000 description 1
- 210000002858 crystal cell Anatomy 0.000 description 1
- 238000004134 energy conservation Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000003302 ferromagnetic material Substances 0.000 description 1
- 229910052736 halogen Inorganic materials 0.000 description 1
- -1 halogen salt Chemical class 0.000 description 1
- 238000003384 imaging method Methods 0.000 description 1
- 229940057995 liquid paraffin Drugs 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 230000004044 response Effects 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 230000035939 shock Effects 0.000 description 1
- 239000004094 surface-active agent Substances 0.000 description 1
- 238000001356 surgical procedure Methods 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
- 229910000859 α-Fe Inorganic materials 0.000 description 1
Landscapes
- Instruments For Viewing The Inside Of Hollow Bodies (AREA)
- Mechanical Light Control Or Optical Switches (AREA)
- Endoscopes (AREA)
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は、内視鏡光学系特に絞り部材を備えた内視鏡光
学系に関する。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an endoscope optical system, and particularly to an endoscope optical system equipped with an aperture member.
現在、製品化されている内視鏡においては、手術中の繁
雑さをなくすために、光学系のピント。Currently, in commercialized endoscopes, the focus of the optical system is adjusted to eliminate complications during surgery.
絞り、焦点距離等を一切変えないで用いるものが主流と
なっている。そのため、最低必要な遠点物点（数十Ｍ）
と近点物点が観察出来るように、明るさ絞りを予め絞っ
てかなりの被写界深度を確保し、実用となるようにして
いる。しかしながら、明るさと被写界深度とは相反する
関係にあり、今以上の深度を得ようとすると明るさが減
少し、明るさを増せば深度が不足となるという問題があ
る。The mainstream is to use it without changing the aperture, focal length, etc. at all. Therefore, the minimum required far point object point (several tens of M)
In order to be able to observe the periapsis object point, the brightness aperture was stopped in advance to ensure a considerable depth of field, making it practical. However, there is a contradictory relationship between brightness and depth of field, and there is a problem in that if you try to obtain a greater depth of field, the brightness decreases, and if you increase the brightness, the depth becomes insufficient.
又、従来から要求があり、近年も要望の高い近接拡大を
実現するため、或は内視鏡の細径化に伴うライトガイド
径の細径化による光量域を補うために、新たな技術的進
展が望まれている。In addition, in order to achieve close-up magnification, which has been in demand for a long time and has been in high demand in recent years, or to compensate for the light intensity range due to the narrowing of the light guide diameter due to the thinning of endoscopes, new technological innovations are being developed. Progress is hoped for.
これを実現する手段としてオートアイリス（自動絞り）
がある。内視鏡は独自の特徴である自己照明を用いて被
写体像を得ているため、観察距離が近くなればなるほど
被写体像が明るくなる。そこで、光源の光量を調整する
のでなく対物レンズの絞り径を入射光量に応じて調整し
て適正な明るさを得ようというのがこの方式であり、こ
の方式を用いれば、近接物体観察時には絞りが絞られて
被写界深度が増すため、オートアイリスのないものに比
べより近接物体に対してもピントの合った像が得られる
という利点がある。Auto iris (automatic aperture) is a means to achieve this.
There is. Endoscopes use their unique feature of self-illumination to obtain images of objects, so the closer the observation distance, the brighter the object image becomes. Therefore, instead of adjusting the light intensity of the light source, this method adjusts the aperture diameter of the objective lens according to the amount of incident light to obtain the appropriate brightness. Since the depth of field is increased by narrowing down the field of view, it has the advantage of being able to obtain a more focused image of nearby objects compared to a camera without an auto iris.
そして、従来のオートアイリスとしては、絞り羽根を開
閉して絞り径を変化させる機械式のものや、特開昭６２
−１５５２４号公報に記載の如く、多重リング状の複数
の液晶セルから成っていて各セルの透過、不透過を制御
して絞り径を変化させる液晶式のものが知られている。Conventional auto iris systems include mechanical ones that change the diameter of the aperture by opening and closing the aperture blades, and
As described in Japanese Patent Application No. 15524, a liquid crystal type is known, which is composed of a plurality of liquid crystal cells in the form of multiple rings, and the aperture diameter is changed by controlling the transmission and non-transmission of each cell.
しかし、前者は、機械的動作によるため、長期信頼性に
問題があり、特に摩耗等の問題や耐衝撃性が劣っている
問題がある他、オートアイリスを構成するモータ等の駆
動源を併用せざるを得す、同様の問題が発生する。而も
、モータ等の駆動源を駆動するための電気エネルギーの
消費が大きいため、省エネルギー上の問題は勿論のこと
、内視鏡としての安全性に問題があり、更に何よりも内
視鏡先端部のスペース上の制約のため実装が困難である
という問題がある。However, since the former is based on mechanical operation, there are problems with long-term reliability, especially problems such as wear and poor shock resistance, and it is necessary to use a drive source such as a motor that makes up the auto iris. I get a similar problem. However, since a large amount of electrical energy is consumed to drive the drive source such as a motor, there are problems not only in terms of energy conservation but also in terms of safety as an endoscope. The problem is that it is difficult to implement due to space constraints.
又、後者は、実際には絞り径を連続的に変化させるよう
な機構を内視鏡先端に組み込むのが難しいため、二段と
か三段程度の絞り径の変更を不連続に行わざるを得ない
という問題がある。又、偏光板を用いているために、光
透過率を最大にする時に於いても、光透過率が１／３以
乍となり、低照度下における撮影、撮像に支障をきたす
ほか光透過量を最小にする場合においては、十分な光量
制限が行われず、１／２０〜１１５０程度の光透過率に
とどまり、実用上必要とされる１／１００〜１／１００
０という光透過率は実現できないという問題がある。又
、液晶がその温度特性により常温の領域でしか動作しな
いという問題がある。In addition, in the latter case, it is difficult to incorporate a mechanism that continuously changes the aperture diameter into the tip of the endoscope, so the aperture diameter must be changed in two or three steps discontinuously. The problem is that there is no. In addition, since a polarizing plate is used, even when the light transmittance is maximized, the light transmittance is 1/3 or more, which not only hinders photography and imaging under low illumination, but also reduces the amount of light transmitted. In the case of minimizing the amount of light, sufficient light quantity restriction is not performed and the light transmittance remains at about 1/20 to 1150, which is 1/100 to 1/100 which is practically required.
There is a problem that a light transmittance of 0 cannot be achieved. Another problem is that liquid crystals only operate in the room temperature range due to their temperature characteristics.
又、液晶分子が基本的に常にゆらぎを持っているため、
該液晶分子による光の散乱により画像のシャープさが劣
化してしまうという問題がある。更に、液晶の光透過率
が入射角度に依存するために、明るさむらを生じるとい
う問題もある。Also, since liquid crystal molecules basically always have fluctuations,
There is a problem in that the sharpness of the image deteriorates due to the scattering of light by the liquid crystal molecules. Furthermore, since the light transmittance of the liquid crystal depends on the angle of incidence, there is also the problem of uneven brightness.
そこで、従来の機械式や液晶式のオートアイリス機構の
問題点をある程度解決したものとして、例えば特開昭６
２−１０５１２５号公報に記載の磁性流体絞りがある。Therefore, as a way to solve the problems of conventional mechanical and liquid crystal auto iris mechanisms to some extent, for example,
There is a magnetic fluid aperture described in Japanese Patent No. 2-105125.
これは、環状の磁石により、磁性流体が環状に固定され
るように構成し、軸方向に磁界を印加することにより磁
性流体が軸中心に向って一様に幅を広げる現象を用いる
ことを特徴としており、その構成によれば、軸方向の磁
界の強さを増減することにより、絞りの中央を中心とす
るほぼ円形の光透過領域の面積が増減し、絞りの効果が
得られるようにしたものである。This is characterized by the fact that the magnetic fluid is fixed in an annular shape by an annular magnet, and by applying a magnetic field in the axial direction, the magnetic fluid uniformly widens toward the center of the axis. According to this structure, by increasing or decreasing the strength of the magnetic field in the axial direction, the area of the almost circular light transmission region centered on the center of the aperture increases or decreases, thereby achieving the effect of an aperture. It is something.
以下、これについて説明する。This will be explained below.
第１６図はその一例の断面図である。この例はｘ−ｘ’
を軸とする回転体の形態を有するものである。第１６図
に於いて、磁性流体１と透明液体２が透明容器３に封入
され、透明容器３の中央部に透明のセパレータ４が構成
されている。セパレータ４及び透明容器３は同材質若し
くは同等の光学特性を有する材料若しくは同一構成体で
ある。FIG. 16 is a sectional view of one example. This example is x-x'
It has the form of a rotating body whose axis is . In FIG. 16, a magnetic fluid 1 and a transparent liquid 2 are sealed in a transparent container 3, and a transparent separator 4 is formed in the center of the transparent container 3. The separator 4 and the transparent container 3 are made of the same material, have the same optical properties, or have the same structure.
そして、軸方向に着磁した環状の磁石５が容器３に同軸
で近接され、容器３の外周部に環状のコイル６が同軸で
配置されている。An annular magnet 5 magnetized in the axial direction is coaxially proximate to the container 3, and an annular coil 6 is coaxially arranged around the outer periphery of the container 3.
コイル６に通電しない時、磁性流体１１は磁石１５の磁
場により外周部下端に環状に固定されている。いまコイ
ル６に直流電流を流すと、軸方向に磁界が発生し、環状
に固定されていた磁性流体１が形状変化し、軸中心に向
って延びて１′のようになり、絞り効果をなす。When the coil 6 is not energized, the magnetic fluid 11 is annularly fixed to the lower end of the outer periphery by the magnetic field of the magnet 15. Now, when a direct current is applied to the coil 6, a magnetic field is generated in the axial direction, and the magnetic fluid 1, which was fixed in an annular shape, changes its shape and extends toward the axial center, becoming like 1', creating a constriction effect. .
第１７図は他の例の断面図である。この実施例も、ｘ−
ｘ’を軸とする回転体の形態を有する。FIG. 17 is a sectional view of another example. This example also has x-
It has the form of a rotating body with x' as the axis.
第１７図に於いて、磁性流体１と透明液体２はガラス板
７及び８と、着磁が可能な材質を用いた環状の部材１０
と、接着剤１１との間に密封されており、部材１０は径
方向に着磁されている。９はガラス板７及び８の間で中
央部に設けられた透明のセパレータである。前記と同様
に、コイル６に直流電流を流すことにより、ｘ−ｘ’力
方向磁場が発生し、磁性流体１が１′のように形状変化
するため、同様な絞り効果が得られる。In FIG. 17, the magnetic fluid 1 and the transparent liquid 2 are connected to glass plates 7 and 8, and an annular member 10 made of a magnetizable material.
and the adhesive 11, and the member 10 is magnetized in the radial direction. 9 is a transparent separator provided in the center between the glass plates 7 and 8. Similarly to the above, by passing a direct current through the coil 6, a magnetic field in the x-x' force direction is generated, and the shape of the magnetic fluid 1 changes as shown by 1', so that a similar constriction effect can be obtained.
磁性流体１は、フェライト等の強磁性体を材質とする直
径５００Å以下の粒子を界面活性体を用いて溶媒中に分
散させた液体である。透明液体２は、該溶媒と親和しな
い材質であって磁性流体ｌとほぼ同じ比重のものである
。該溶媒として、流動パラフィンを用いた場合、この比
重は１．２〜１゜４程度となり、透明液体２としてはハ
ロゲン塩の水溶液等が適切な材料となる。比重をほぼ等
しくする理由は、重力等の加速度が加わった場合に、磁
性流体ｌが形成する環状形状が歪むことを防ぐためであ
る。セパレータ４及び９の存在理由は、軸方向の磁界を
強めて行った場合、環状の磁性流体ｌの中心部即ち開口
部の穴径がＯにまで減少することを防ぐためである。即
ち、開口部がなくなった場合、軸方向の磁界を弱めても
磁性流体ｌの表面張力により開口部が再び発生しなくな
る場合があるからである。又、セパレータ４，９及び透
明容器３．ガラス板７，８を形成する材質の屈折率は、
透明液体２の屈折率とほぼ等しくする必要がある。その
理由は、両者の界面において、光の屈折１反射が発生し
画像に歪みや不要像を発せしめることになるのを防ぐた
めである。The magnetic fluid 1 is a liquid in which particles made of a ferromagnetic material such as ferrite and having a diameter of 500 Å or less are dispersed in a solvent using a surfactant. The transparent liquid 2 is made of a material that has no affinity with the solvent and has approximately the same specific gravity as the magnetic fluid 1. When liquid paraffin is used as the solvent, its specific gravity is about 1.2 to 1.4 degrees, and a suitable material for the transparent liquid 2 is an aqueous solution of a halogen salt. The reason why the specific gravity is made almost equal is to prevent the annular shape formed by the magnetic fluid 1 from being distorted when acceleration such as gravity is applied. The reason for the presence of the separators 4 and 9 is to prevent the diameter of the hole at the center, that is, the opening, of the annular magnetic fluid l from decreasing to O when the axial magnetic field is strengthened. That is, if the opening disappears, the opening may not be generated again due to the surface tension of the magnetic fluid l even if the axial magnetic field is weakened. Also, separators 4, 9 and transparent container 3. The refractive index of the material forming the glass plates 7 and 8 is
It is necessary to make the refractive index approximately equal to the refractive index of the transparent liquid 2. The reason for this is to prevent refraction and reflection of light from occurring at the interface between the two, which would cause image distortion and unnecessary images.
この絞りは、モータ、歯車、遮光板の移動等の機械的動
作を伴うものがないため、長期信頼性が高く、８０℃以
下の環境下では半永久的に安定動作する。透明液体２の
選択によっては、磁性流体１の分離が生ずる２００℃ま
での温度範囲まで動作させることが可能である。This aperture has high long-term reliability because it does not involve mechanical operations such as movement of motors, gears, and light-shielding plates, and operates stably semi-permanently in an environment of 80° C. or lower. Depending on the choice of transparent liquid 2, it is possible to operate up to a temperature range of up to 200° C., at which separation of the magnetic fluid 1 occurs.
又、この絞りを駆動するためのコイル６に供給する電力
は、電流計程度の消費量であり、最大でも１Ｏ−２Ｗと
非常に少なく、従来の絞りに比べて低電力のものが実現
でき、特に電池駆動の携帯機器に適している。In addition, the power supplied to the coil 6 for driving this diaphragm is about the same as that of an ammeter, and is extremely small at 1O-2W at maximum, making it possible to achieve lower power consumption than conventional diaphragms. It is particularly suitable for battery-powered portable devices.
機械的動作を伴わない絞りとして従来からある液晶を用
いた絞りは、光透過率の最大値が３０％前後であるのに
対し、この絞りの同最大値は９０％以上となり、透明容
器３の光透過部に反射防止膜を形成することにより９８
％程度にまで上げることも可能である。また光透過率の
最小値は、セパレータ４，９の径で決まり、最小値は０
．１ ＋ｉｍ以下にすることが可能であるため１０−′
程度までは充分実現可能である。While conventional apertures using liquid crystal, which do not involve mechanical movement, have a maximum light transmittance of around 30%, the maximum value of this aperture is over 90%, and the transparent container 3 98 by forming an anti-reflection film on the light transmitting part.
It is also possible to increase it to about %. The minimum value of light transmittance is determined by the diameter of separators 4 and 9, and the minimum value is 0.
．． Since it is possible to make it less than 1 +im, 10-'
It is fully achievable to some extent.
又、上記オートアイリスにおいては、絞りが絞られるの
は近接物体の観察時であるので、遠点側の深度が伸びて
も何ら利点は生ぜず、又近点側の深度の延びは全く不十
分なものであるので、実用観察範囲が飛躍的に伸びたと
は言い難い。そこで、遠点側に伸びた深度を無駄にしな
いように、絞り込むと同時にピントの位置を近点に合わ
せることにより実用観察範囲を飛躍的に広げることが考
えられた。In addition, in the auto iris described above, the aperture is narrowed down when observing a nearby object, so there is no advantage in extending the depth on the far point side, and the extension of the depth on the near point side is completely insufficient. Therefore, it is difficult to say that the practical observation range has increased dramatically. Therefore, in order not to waste the extended depth toward the far point, we thought of dramatically expanding the practical observation range by narrowing down and simultaneously aligning the focal point to the near point.
その場合の移動については、従来より幾つかの方式が考
案されてきている。その一つは、近接物体の観察時に、
絞りの開度を小とすると共に対物レンズの焦点を近点に
合わせるべくレンズの位置を変える方式である。これは
、電磁力や圧電素子を用いてレンズを駆動する方式であ
る。或は、固体撮像素子を移動したり、イメージガイド
端面位置を移動したりする方式についても、同様に考え
られてきた。Regarding movement in this case, several methods have been devised in the past. One of them is when observing a nearby object,
This method reduces the opening of the diaphragm and changes the position of the objective lens to bring the focal point to the near point. This is a method in which the lens is driven using electromagnetic force or a piezoelectric element. Alternatively, methods of moving the solid-state image sensor or moving the position of the end face of the image guide have been similarly considered.
しかしながら、内視鏡等の細径部の中にそれら機構を収
めることは難しく、又駆動部を持つものは、信頼性が低
いという欠点もある。However, it is difficult to fit these mechanisms into a small-diameter part of an endoscope or the like, and devices with a drive section also have the disadvantage of low reliability.
これらの問題点を解決する方式のものとしては、例えば
特開昭６３−７８１１９号公報に記載の内視鏡光学系が
知られている。As a system for solving these problems, for example, an endoscope optical system described in Japanese Patent Application Laid-open No. 78119/1983 is known.
これは、複数の開口状態を選択的にとり得る可変絞りと
、該絞りの位置若しくはそれと共役な位置又は夫々の近
傍に配置され、光軸からの距離に応じて段階的又は連続
的に複数の焦点距離を有するように構成された対物レン
ズとを具備していることにより、オートアイリス機構と
連動しつつ、レンズ、受光面の位置を変えることなく焦
点位置が変えられるようにしたものである。This system consists of a variable aperture that can selectively take on a plurality of aperture states, and a variable aperture that is placed at the position of the aperture, or at a position conjugate to it, or in the vicinity of each, and that creates multiple focal points in stages or continuously depending on the distance from the optical axis. By including an objective lens configured to have a distance, the focal position can be changed without changing the position of the lens or the light-receiving surface while interlocking with the auto-iris mechanism.
具体的には、第１８図に示した如く、常時光が遮光され
る部分（イ）と少なくとも一個以上の透明状態及び遮光
状態のどちらかに切替えられる部分（ロ）、（ハ）とを
有している絞り１２と、該絞り１２の位置の近傍に配置
された少なくとも二つ以上の異なった焦点距離を持つレ
ンズ面１３とを有していることを特徴としている。尚、
１４は固体撮像素子である。Specifically, as shown in FIG. 18, it has a part (a) where light is always blocked and at least one part (b) and (c) which can be switched to either a transparent state or a light-blocking state. It is characterized by having a diaphragm 12 having a diaphragm 12, and a lens surface 13 having at least two different focal lengths arranged near the position of the diaphragm 12. still,
14 is a solid-state image sensor.
第１９図はこの内視鏡光学系の動作状態を示している。FIG. 19 shows the operating state of this endoscope optical system.
状態（Ｉ）は、通常の内視鏡対物レンズ系と同じ焦点距
離とＦナンバーを有し、被写界深度も同様の値となって
いる。又、可変絞り１２は部分（ロ）のみが透過状態に
なっており、この部分を通った光線束がレンズ１３の周
辺部の焦点距離ｆの長い部分を通って固体撮像素子１４
上に結像している。状態（ＩＩ）は、観察物体が近づい
て被写体が明るくなった時に相当し、この時オートアイ
リス機構が作動して可変絞り１の部分（）＼）が透過と
なり且つそれまで透明であった部分（ロ）は遮光される
。この時部分（ロ）の面積に比べて部分（ハ）の面積の
ほうが十分小さく設定しであるので状態（ＩＩ）におけ
る光量を十分に落とすことができ、近接による光量過剰
を防止できる。State (I) has the same focal length and F number as a normal endoscope objective lens system, and also has the same depth of field. In addition, only the portion (b) of the variable aperture 12 is in a transmitting state, and the light beam passing through this portion passes through the portion with a long focal length f at the periphery of the lens 13 and reaches the solid-state image sensor 14.
imaged above. State (II) corresponds to when the observation object approaches and the subject becomes bright.At this time, the auto iris mechanism is activated and the variable aperture 1 part ()\) becomes transparent, and the previously transparent part (ro) becomes transparent. ) are shaded. At this time, since the area of the portion (c) is set to be sufficiently smaller than the area of the portion (b), the amount of light in state (II) can be sufficiently reduced, and excessive amount of light due to proximity can be prevented.
それと同時に、絞り込んでいるのでＦナンバーが大きく
なり、被写界深度が深くなる。ここまでは、前述のオー
トアイリスとあまり変わらないが、可変絞り１２が切り
換えられるのに伴いレンズ１３を通る光路が変わって焦
点距離が短（なり、ピント位置が近接物点に合うように
なる。これにより焦点位置が近点になると同時にＦナン
バーが大きくなって深度が深くなるので、近接物体を深
い深度で観察できる。同時に明るさ調整も行われるので
、適切な明るさになる。At the same time, since you are stopping down, the F number increases and the depth of field becomes deeper. Up to this point, the process is not much different from the auto iris described above, but as the variable aperture 12 is switched, the optical path passing through the lens 13 changes, the focal length becomes shorter (and the focus position matches the nearby object point). As the focal position becomes the periapsis, the F-number increases and the depth becomes deeper, allowing nearby objects to be observed at a greater depth.At the same time, the brightness is adjusted so that the brightness is appropriate.
以上のように、この内視鏡光学系は、近接時には光量を
適切に減光すると同時に絞り効果により被写界深度を増
加せしめながら焦点位置を近点にするようにしているの
で、実用的な明るさを確保しつつも従来に比べて広い実
用的観察範囲を確保できる。又、遠点状態と近点状態の
被写界深度の遠点側を揃えることにより、実用的観察範
囲を確保しつつも従来より明るい像が得られる。而も、
オートアイリス機構と連動しつつ、レンズ、受光面の光
軸上での位置を変えることなく焦点位置を変えるように
なっているので、内視鏡等の細径部の中に収納するのが
容易で信頼性も高い。As described above, this endoscope optical system appropriately reduces the amount of light when approaching the object, increases the depth of field using the aperture effect, and brings the focal point to the near point, making it practical. While maintaining brightness, it is possible to secure a wider practical observation range than before. Furthermore, by aligning the far point side of the depth of field in the far point state and the near point state, a brighter image than before can be obtained while ensuring a practical observation range. However,
It works in conjunction with the auto iris mechanism and changes the focal position without changing the position of the lens or light-receiving surface on the optical axis, making it easy to store in narrow diameter parts such as endoscopes. It is also highly reliable.
ところが、上記磁性流体絞りは、光軸に沿って環状の磁
石５や環状の部材を配置しているので、光軸方向のスペ
ースが必要である。又、磁性流体１自身が伸縮できるよ
うにある程度光軸方向の厚みが必要であり、且つこれを
封入する容器もある程度光軸方向の厚みが必要である。However, since the magnetic fluid diaphragm has an annular magnet 5 and an annular member arranged along the optical axis, a space in the optical axis direction is required. Further, the magnetic fluid 1 itself needs to have some thickness in the optical axis direction so that it can expand and contract, and the container that encloses it also needs to have some thickness in the optical axis direction.
そして、これら光軸方向のスペース、厚みは、全体とし
て内視鏡的には無視できない厚みである。従って、ただ
単にこの磁性流体絞りを内視鏡光学系に組み入れると光
学系の全長が伸びてしまい、内視鏡の使い勝手が悪くな
る。又、光学系の全長が伸びるとどうしてもその周囲の
支持枠等の構成部材の径が太くなるので、最近の内視鏡
の細径化の要望に対しても好ましくない。The space and thickness in the optical axis direction as a whole are too large to be ignored from an endoscope perspective. Therefore, simply incorporating this magnetic fluid diaphragm into an endoscope optical system increases the overall length of the optical system, making the endoscope less convenient to use. Furthermore, if the overall length of the optical system increases, the diameters of surrounding components such as the support frame inevitably become thicker, which is not preferable in response to the recent demand for smaller diameter endoscopes.
又、上述の如く、磁性流体１を封入した容器の周囲には
、絞り駆動用のコイル６が配置され、これに電流を流す
ことで駆動するようになっているので、コイル６のため
の径方向のスペース及び電流を送る配線等のスペースが
必要である。従って、内視鏡の径が太くなってしまい易
いという問題がある。Further, as mentioned above, the coil 6 for driving the aperture is placed around the container containing the magnetic fluid 1, and is driven by passing a current through the coil 6. Therefore, the diameter of the coil 6 is Space for direction and space for wiring to send current are required. Therefore, there is a problem in that the diameter of the endoscope tends to increase.
又、上記のオートアイリスに多焦点レンズを組み合わせ
たものは、絞り１２と多焦点レンズ１３とが離れている
ため夫々の近点観察用部分と遠点観察用部分との一致の
度合が不十分となり、それ故近点観察時に絞り１２の中
央部分（）＼）のみを透過状態にしてもそこを通過した
光束の一部が多焦点レンズ１３の周辺部を通ったり又遠
点観察時に絞り１２の周辺部分（ロ）のみを透過状態に
してもそこを通過した光束の一部が多焦点レンズ１３の
中央部を通ったりして像の歪みが発生してしまう。又、
上記一致の度合の不十分により、多焦点レンズ１３の焦
点距離の異なる部分の境界部分での光の散乱も発生する
。更に、絞り１２と多焦点レンズ１３が離れていると、
絞り１２を通過した主光線が近点観察時と遠点観察時と
で多焦点レンズ１３の焦点距離の異なる部分を通ったり
して画角が変化してしまい易い。そして、上記像の歪み
や画角の変化等で高画質化が困難であり、像の歪み等を
防ぐために多焦点レンズ１３の焦点距離の異なる部分の
境界部分に遮光部分を設けたりすると、光学素子として
の構造が複雑化してしまう。Furthermore, in the case where the auto iris described above is combined with a multifocal lens, the diaphragm 12 and the multifocal lens 13 are separated, so the degree of coincidence between the near point observation part and the far point observation part is insufficient. Therefore, even if only the central part ()\) of the diaphragm 12 is set to a transmitting state during near-point observation, a part of the light beam that has passed there may pass through the periphery of the multifocal lens 13, or the part of the iris 12 may pass through the central part ()\) of the diaphragm 12 during far-point observation. Even if only the peripheral portion (b) is set to a transmitting state, a portion of the light beam that has passed there will pass through the center of the multifocal lens 13, causing image distortion. or,
Due to the insufficient degree of matching, light scattering occurs at the boundary between portions of the multifocal lens 13 having different focal lengths. Furthermore, if the aperture 12 and the multifocal lens 13 are separated,
The principal ray that has passed through the diaphragm 12 passes through parts of the multifocal lens 13 with different focal lengths during near-point observation and far-point observation, and the angle of view tends to change. It is difficult to achieve high image quality due to the above-mentioned image distortion, changes in the angle of view, etc., and if a light-shielding portion is provided at the boundary between portions of the multifocal lens 13 with different focal lengths in order to prevent image distortion, etc., optical The structure of the element becomes complicated.
本発明は、上記問題点に鑑み、省エネルギーであり、安
全性が高く、耐熱性に優れ、構造が簡単であり、省スペ
ースであり、明るさむらがなく、明るくて高画質の像が
得られ、近点撮影時に充分な被写界深度が得られる内視
鏡光学系を提供することを目的としている。In view of the above problems, the present invention is energy-saving, highly safe, has excellent heat resistance, has a simple structure, saves space, has no uneven brightness, and can provide bright, high-quality images. The object of the present invention is to provide an endoscope optical system that can obtain a sufficient depth of field during near-point photography.
本発明による内視鏡光学系の一つは、
前後の壁が透明な物質から成る空室を備えた光学部材の
該空室内に透明流体と磁性流体とを封入し、外部から印
加される磁界により前記空室内における前記磁性流体の
形状を変化させて前記空室を透過する光量を制御する絞
り部材を備えた内視鏡光学系において、
前記前後の壁の少なくとも一方が有限の焦点距離を有す
る屈折部材から成ることを特徴としている。One of the endoscope optical systems according to the present invention includes a transparent fluid and a magnetic fluid sealed in the cavity of an optical member having a cavity whose front and rear walls are made of a transparent material, and a magnetic field applied from the outside. In an endoscope optical system including an aperture member that controls the amount of light transmitted through the cavity by changing the shape of the magnetic fluid in the cavity, at least one of the front and rear walls has a finite focal length. It is characterized by being made of a refractive member.
又、他の一つは、上記構成において、前記屈折力を有す
る壁の屈折力が光軸を含む中心部とその外周部とで異な
ることを特徴としている。Another feature is that in the above structure, the refractive power of the wall having the refractive power is different between a central portion including the optical axis and an outer peripheral portion thereof.
上記構成によれば、磁性流体絞りの壁自体をレンズとし
て構成しているので、光学系の光軸方向の長さを短くで
きる。又、光学系の光軸方向の長さが短くなることから
、その周囲の支持枠等の構成部材の径も細くなり、全体
として省スペースな内視鏡光学系を構成できる。又、レ
ンズ枚数が少なくなるので、構造も簡単になる。又、磁
性流体絞りを用いているので、省略エネルギーであり、
安全性が高く、明るさむらもない。According to the above configuration, since the wall of the magnetic fluid aperture itself is configured as a lens, the length of the optical system in the optical axis direction can be shortened. Furthermore, since the length of the optical system in the optical axis direction is shortened, the diameters of constituent members such as the support frame around the optical system are also reduced, making it possible to construct an endoscope optical system that saves space as a whole. Furthermore, since the number of lenses is reduced, the structure becomes simpler. Also, since a magnetic fluid aperture is used, energy is omitted.
It is highly safe and has no uneven brightness.
更に、磁性流体絞りの壁自体を多焦点レンズとして構成
しているので、絞り面と多焦点レンズ面が一致し、その
結果像の歪み、光の散乱９画角の変化等が生じず高画質
の像が得られると共に、多焦点レンズに遮光部を設ける
必要もなく構造が一層簡単になる。又、オートアイリス
と多焦点レンズとの組合せにより近点撮影時に十分な被
写界深度が得られ且つ明るい像も得られる。Furthermore, since the wall of the magnetic fluid aperture itself is constructed as a multifocal lens, the aperture surface and the multifocal lens surface coincide, resulting in high image quality without image distortion, light scattering, or changes in the angle of view. image can be obtained, and there is no need to provide a light shielding part to the multifocal lens, making the structure even simpler. Furthermore, by combining an auto iris and a multifocal lens, a sufficient depth of field can be obtained during near-point photography, and a bright image can also be obtained.
以下、図示した実施例に基づき上記従来例と同一の部材
には同一符号を付して本発明の詳細な説明する。Hereinafter, the present invention will be described in detail based on the illustrated embodiment, with the same reference numerals assigned to the same members as in the above-mentioned conventional example.
第１図は本発明による内視鏡光学系の第１実施例を示し
ており、１５はカバーガラスを兼ねた凹レンズ、１６は
壁自体をレンズとして構成して成る磁性流体絞り、１７
は正レンズ、１８は接合正レンズであって、これらが対
物レンズを構成している。１９はフィールドレンズ、２
０はイメージガイドファイバ束の入射端である。FIG. 1 shows a first embodiment of an endoscope optical system according to the present invention, in which 15 is a concave lens that also serves as a cover glass, 16 is a magnetic fluid diaphragm constituted by the wall itself as a lens, and 17 is a concave lens that also serves as a cover glass.
1 is a positive lens, and 18 is a cemented positive lens, which constitute an objective lens. 19 is a field lens, 2
0 is the input end of the image guide fiber bundle.
第２図は磁性流体絞り１６の拡大断面図であって、これ
は軸方向着磁タイプのものの透明容器３の後壁３ｂに後
面が曲面の正レンズ２１を貼り付けて成るものである。FIG. 2 is an enlarged cross-sectional view of the magnetic fluid diaphragm 16, which is made up of a positive lens 21 having a curved rear surface attached to the rear wall 3b of a transparent container 3 of the axially magnetized type.
軸ｘ−ｘ’は第１図に示した光学系の光軸と一致してい
る。又、透明容器３の前壁３ａ、透明液体２．セパレー
タ４．透明容器３の後壁３ｂ、正レンズ２１の各屈折率
を夫々ｒｌ＋＋ ｎｚ＋ ｎ３＋ ｎ＋＋ ｎ
ｓ とする時λｎ２：ｎ ｓ ” ｎ ＊である０
本実施例は上述の如く構成されており、磁性流体絞り１
６の後壁３ｂに正レンズ２１を貼り付けているので、光
学系の光軸方向の長さを短くできる。又、光学系の光軸
方向の長さが短くなるので、その周囲の支持枠等の構成
部材の径も細くなり、全体として省スペースな内視鏡光
学系を構成できる。又、レンズ枚数が少なくなるので、
構造も簡単になる。又、磁性流体絞り１６を用いている
ので、省エネルギーであり、安全性が高く、明るさむら
もない。The axis x-x' coincides with the optical axis of the optical system shown in FIG. Also, the front wall 3a of the transparent container 3, the transparent liquid 2. Separator 4. The refractive index of the rear wall 3b of the transparent container 3 and the positive lens 21 are rl++ nz+ n3+ n++ n, respectively.
s, λn2:n s ” n *0 This embodiment is constructed as described above, and the magnetic fluid aperture 1
Since the positive lens 21 is attached to the rear wall 3b of the lens 6, the length of the optical system in the optical axis direction can be shortened. Furthermore, since the length of the optical system in the optical axis direction is shortened, the diameters of constituent members such as the support frame around the optical system are also reduced, so that an overall space-saving endoscope optical system can be constructed. Also, since the number of lenses is reduced,
The structure is also simpler. Furthermore, since the magnetic fluid diaphragm 16 is used, energy is saved, safety is high, and there is no uneven brightness.
第３図は第２実施例の７磁性流体絞り１６の拡大断面図
であって、これは径方向着磁タイプのものの後側のガラ
ス板８に後面が曲面の正レンズ２１を貼り付けて成るも
のである。前側のガラス板７゜透明液体２．セパレータ
９．後側のガラス板８゜正レンズ２１の各屈折率を夫々
ｎ＋ ！ ｎｔ ＋ ｎａ ＋ｎ １ ＋ ｎ Ｉ
とする時、ｎ ２ ＝ ｎ ＋である。この場合、第１
実施例と同じ効果を有する。FIG. 3 is an enlarged cross-sectional view of the seven magnetic fluid apertures 16 of the second embodiment, which is a radially magnetized type, and is made up of a positive lens 21 with a curved rear surface attached to the rear glass plate 8. It is something. Front glass plate 7° transparent liquid 2. Separator 9. Each refractive index of the rear glass plate 8° positive lens 21 is n+! nt + na + n 1 + n I
When, n 2 = n +. In this case, the first
It has the same effect as the example.
第４図は第３実施例の磁性流体絞り１６の拡大断面図で
あって、これは径方向着磁タイプのものの後側のガラス
板８に屈折率分布がラジアル分布（２乗分布）の不均質
媒質レンズ２２を貼り付けて成るものである。前側のガ
ラス板７．透明液体２、セパレータ９．後側のガラス板
８の屈折率を夫々ｎ＋ ＋ ｎ２＋ ｎｓ 、ｎ４とす
る時、ｎ２＝ｎ３である。又、不均質媒質レンズ２２の
屈折率分布はラジアル分布の場合次の式で表わされる。FIG. 4 is an enlarged sectional view of the magnetic fluid aperture 16 of the third embodiment, which shows that the rear glass plate 8 of the radially magnetized type has a refractive index distribution that is not a radial distribution (square distribution). It is made by pasting a homogeneous medium lens 22. Front glass plate 7. Transparent liquid 2, separator 9. When the refractive indexes of the rear glass plate 8 are respectively n+ + n2+ ns and n4, n2=n3. Further, the refractive index distribution of the inhomogeneous medium lens 22 is expressed by the following equation in the case of radial distribution.
ｎ （ｒ）＝ｎ、−ａｒ２ 但し、ｎｏは中心での屈折率、ｒは半径である。n (r) = n, -ar2 However, no is the refractive index at the center, and r is the radius.
この場合、絞り１６の後面が平面になるので、その周囲
の支持枠等の構成部材の構造が一層簡略化でき、実装上
有利である。In this case, since the rear surface of the diaphragm 16 is flat, the structure of the surrounding components such as the support frame can be further simplified, which is advantageous in terms of mounting.
第５図は第４実施例の磁性流体絞り１６の拡大断面図で
あって、これは径方向着磁タイプのものの後側のガラス
板の代わりに不均質媒質レンズ２２を用い、不均質媒質
レンズ２２自体に磁性流体１及び透明液体２を封入する
役割をもたせて成るものである。前側のガラス板７．透
明液体２．セパレータ９の屈折率を夫々ｎ１ｒ ｎ２
＋ ｎｓとする時、ｎ２ ＝ｎ、である。FIG. 5 is an enlarged sectional view of the magnetic fluid diaphragm 16 of the fourth embodiment, in which a heterogeneous medium lens 22 is used instead of the rear glass plate of the radially magnetized type. The magnetic fluid 1 and the transparent liquid 2 are sealed in the magnetic fluid 22 itself. Front glass plate 7. Transparent liquid 2. The refractive index of the separator 9 is n1r n2, respectively.
+ ns, n2 = n.
この場合、更に光軸方向の厚みが薄くなるので、−層省
スペースな内視鏡光学系を構成できる。In this case, since the thickness in the optical axis direction is further reduced, it is possible to configure an endoscope optical system that saves space.
第６図は第５実施例の磁性流体絞り１６の拡大断面図で
あって、これは軸方向着磁タイプのものの透明容器３の
後壁の代わりに内側の面（前面）が曲面の正レンズ２３
を用い、正レンズ２３自体に磁性流体１及び透明液体２
を封入する役割を持たせて成るものである。透明容器３
の前壁３ａ。FIG. 6 is an enlarged sectional view of the magnetic fluid diaphragm 16 of the fifth embodiment, which is a positive lens whose inner surface (front surface) is curved instead of the rear wall of the transparent container 3 of the axially magnetized type. 23
magnetic fluid 1 and transparent liquid 2 in the positive lens 23 itself.
It has the role of enclosing. Transparent container 3
front wall 3a.
透明液体２．セパレータ４．正レンズ２３の屈折率を夫
々ｎｌ＋ ｎ！＋ ｎａ＋ ｎｉとする時、ｎ２” ｎ
ｓ≠ｎ４である。Transparent liquid 2. Separator 4. The refractive index of the positive lens 23 is nl+n! + na + ni, n2” n
s≠n4.
この場合、第３実施例と第４実施例の両方の効果を有す
る。In this case, it has the effects of both the third and fourth embodiments.
第７図は第６実施例の磁性流体絞り１６の拡大断面図で
あって、これは径方向着磁タイプのものの後側のガラス
板の代わりに内側の面（前面）が曲面の正レンズ２３を
用い、正レンズ２３自体に磁性流体１及び透明液体２を
封入する役割を持たせて成るものである。前側のガラス
板７．透明液体２．セパレータ９．正レンズ２３の屈折
率を夫々ｎ１ ｎ２＋ ｎｉ ＋ ｎｉ とする
時％ ｎ ２” ｎ ｈ≠ｎ、である。FIG. 7 is an enlarged sectional view of the magnetic fluid diaphragm 16 of the sixth embodiment, which shows a positive lens 23 whose inner surface (front surface) is curved instead of the rear glass plate of the radially magnetized type. The positive lens 23 itself has the role of enclosing the magnetic fluid 1 and the transparent liquid 2. Front glass plate 7. Transparent liquid 2. Separator 9. When the refractive index of the positive lens 23 is n1 n2+ ni + ni, respectively, % n 2'' n h≠n.
この場合、第５実施例と同じ効果を有する。In this case, it has the same effect as the fifth embodiment.
第８図は第７実施例の磁性流体絞り１６の拡大断面図で
あって、これは軸方向着磁タイプのものの透明容器３の
前壁の代わりに内側の面（後面）が曲面の正レンズ２１
を用い、正レンズ２１自体に磁性流体１及び透明液体２
を封入する役割を持たせて成るものである。正レンズ２
１．透明液体２、セパレータ９．透明容器３の後壁３ｂ
の屈折率を夫々ｎｌ＋ ｎ２＋ ｎｉ＋ ｎｌとする
時、ｎ≠ｎ２＝ｎ＊＝ｎ４である。FIG. 8 is an enlarged sectional view of the magnetic fluid diaphragm 16 of the seventh embodiment, which is a positive lens whose inner surface (rear surface) is curved instead of the front wall of the transparent container 3 of the axially magnetized type. 21
magnetic fluid 1 and transparent liquid 2 on the positive lens 21 itself.
It has the role of enclosing. positive lens 2
1. Transparent liquid 2, separator 9. Rear wall 3b of transparent container 3
When the refractive indices of nl+n2+ni+nl respectively, n≠n2=n*=n4.
この場合、第５実施例と同じ効果を有する。In this case, it has the same effect as the fifth embodiment.
第９図は第８実施例の磁性流体絞り１６の拡大断面図で
あって、これは軸方向着磁タイプのものの透明容器３の
後壁の代わりに内側の面（前面）が曲面の正レンズ２３
を用い、正レンズ２３自体に磁性流体１及び透明液体２
を封入する役割を持たせると共に、正レンズ２３とセパ
レータ４の屈折率差を正レンズ２３と透明液体２の屈折
差より大きくして正レンズ２３の中央部の屈折力が周辺
部の屈折力よりも大きい所謂多焦点レンズとして作用す
るようにしたものである。透明容器３の前壁３ａ、透明
液体２．セパレータ４．正レンズ２３の屈折率を夫々ｎ
１＋ ｎ２＋ ｒｌ＋ ＋ ｎｉとする時、ｎｉ
＞１２＞ｎ３である。FIG. 9 is an enlarged sectional view of the magnetic fluid diaphragm 16 of the eighth embodiment, which is a positive lens whose inner surface (front surface) is curved instead of the rear wall of the transparent container 3 of the axially magnetized type. 23
magnetic fluid 1 and transparent liquid 2 in the positive lens 23 itself.
At the same time, the refractive index difference between the positive lens 23 and the separator 4 is made larger than the refractive difference between the positive lens 23 and the transparent liquid 2, so that the refractive power of the central part of the positive lens 23 is greater than that of the peripheral part. It is designed to act as a so-called multifocal lens with a large lens. Front wall 3a of transparent container 3, transparent liquid 2. Separator 4. The refractive index of the positive lens 23 is n
When 1+ n2+ rl+ + ni, ni
>12>n3.
本実施例は上述の如く構成されており、磁性流体絞り１
６の壁自体を多焦点レンズとして構成しているので、絞
り面と多焦点レンズ面が一致し、その結果像の歪み、光
の散乱９画角の変化等が生じず高画質の像が得られると
共に、多焦点レンズに遮光部を設ける必要もなく構造が
一層簡単になる。又、オートアイリスと多焦点レンズと
の組み合わせにより近点観察時に十分な被写界深度が得
られ且つ明るい像が得られる。勿論、第５実施例と同じ
効果も有する。This embodiment is configured as described above, and the magnetic fluid aperture 1
Since the wall 6 itself is configured as a multifocal lens, the aperture surface and the multifocal lens surface coincide, resulting in high-quality images without image distortion, light scattering, or changes in the angle of view. In addition, there is no need to provide a light shielding part to the multifocal lens, and the structure becomes simpler. Furthermore, the combination of an auto iris and a multifocal lens provides a sufficient depth of field and a bright image during near-point observation. Of course, it also has the same effects as the fifth embodiment.
第１０図は第９実施例の磁性流体絞り１６の拡大断面図
であって、これは軸方向着磁タイプのものの透明容器３
の後壁の代わりに内側の面（前面）が曲面の正レンズ２
４を用い、正レンズ２４自体に磁性流体１及び透明液体
２を封入する役割を持たせると共に、正レンズ２４の曲
面の中央部の曲率が一定であり且つ周辺に向う程曲率が
緩くなるようにして正レンズ２４の中央部の屈折力が周
辺部の屈折力よりも大きい所謂多焦点レンズとして作用
するようにしたものである。透明容器３の前壁３ａ、透
明液体２．セパレータ４．正レンズ２４の屈折率を夫々
ｎ１＋ ｎ２＋ ｎｓ＋ ｎ、とする時、ｎ ＜ ＞
ｎ’ ｔ ＝ ｎ ２ ＝ ｎ ＠である。FIG. 10 is an enlarged sectional view of the magnetic fluid aperture 16 of the ninth embodiment, which shows the transparent container 3 of the axially magnetized type.
Positive lens 2 whose inner surface (front surface) is curved instead of the rear wall
4, the positive lens 24 itself has the role of enclosing the magnetic fluid 1 and the transparent liquid 2, and the curvature of the central part of the curved surface of the positive lens 24 is constant, and the curvature becomes gentler towards the periphery. Thus, the positive lens 24 functions as a so-called multifocal lens in which the refractive power at the central portion is greater than the refractive power at the peripheral portion. Front wall 3a of transparent container 3, transparent liquid 2. Separator 4. When the refractive index of the positive lens 24 is respectively n1+ n2+ ns+ n, n <>
n' t = n 2 = n @.
この場合、第８実施例と同じ効果を有する。In this case, it has the same effect as the eighth embodiment.
第１１図は第１０実施例の磁性流体絞り１６の拡大断面
図であって、これは径方向着磁タイプのものの後側のガ
ラス板の代わりに後面が曲面の正レンズ２５を用い、正
レンズ２５自体に磁性流体１及び透明液体２を封入する
役割を持たせると共に、正レンズ２５の曲面の中央部の
曲率が一定であり且つ周辺に向う程曲率が緩くなるよう
にして正レンズ２５の中央部の屈折力が周辺部の屈折力
よりも大きい所謂多焦点レンズとして作用するようにし
たものである。前側のガラス板７．透明液体２．セパレ
ータ９．正レンズ２５の屈折率を夫々ｎ＋ Ｉ ｎ２＋
ｎ３＋ ｎ４ とする時、ｎ２＝ｎ、である。FIG. 11 is an enlarged sectional view of the magnetic fluid diaphragm 16 of the tenth embodiment, which uses a positive lens 25 with a curved rear surface instead of the rear glass plate of the radially magnetized type. 25 itself has the role of enclosing the magnetic fluid 1 and the transparent liquid 2, and the center of the positive lens 25 is made such that the curvature of the central part of the curved surface of the positive lens 25 is constant and the curvature becomes gentler towards the periphery. The lens is designed to function as a so-called multifocal lens in which the refractive power of the central portion is greater than that of the peripheral portion. Front glass plate 7. Transparent liquid 2. Separator 9. The refractive index of the positive lens 25 is n+ I n2+
When n3+n4, n2=n.
この場合、第８実施例と同じ効果を有する。In this case, it has the same effect as the eighth embodiment.
第１２図は第１１実施例の磁性流体絞り１６の拡大断面
図であって、これは軸方向着磁タイプのものの透明容器
３の前壁３ａの前面のセパレータ４に対応した部分即ち
中央部のみを曲面にして、該前壁３ａが中央部に屈折力
を有する所謂多焦点レンズとして作用するようにしたも
のである。透明容器３の前壁３ａ、透明液体２．セパレ
ータ４の屈折率を夫々ｒｌ＋ ＋ ｎ２＋ ｎｓとす
る時、ｎ＝ｎ２＝ｎａである。FIG. 12 is an enlarged sectional view of the magnetic fluid aperture 16 of the eleventh embodiment, and this shows only the central portion of the front wall 3a of the transparent container 3 of the axially magnetized type, corresponding to the front separator 4. is curved so that the front wall 3a functions as a so-called multifocal lens having refractive power in the center. Front wall 3a of transparent container 3, transparent liquid 2. When the refractive index of the separator 4 is rl+ + n2+ ns, n=n2=na.
この場合、第８実施例と同じ効果を有する。In this case, it has the same effect as the eighth embodiment.
第１３図は第１２実施例の磁性流体絞り１６の拡大断面
図であって、これは径方向着磁タイプのものの後側のガ
ラス板の代わりに屈折率分布がラジアル分布（２乗分布
）の不均質媒質レンズ２６を用い、不均質媒質レンズ２
６自体に磁性流体１及び透明液体２を封入する役割をも
たせると共に、不均質媒質レンズ２６の屈折率分布を、
第１４図に示した如く、中央部での変化の度合が周辺部
での変化の度合よりも大きくなるようにして、不均質媒
質レンズ２６の中央部の屈折力が周辺部の屈折力よりも
大きい所謂多焦点レンズとして作用するようにしたもの
である。前側のガラス板７．透明液体２．セパレータ９
の屈折率を夫々ｎｎ ！ ＋ ｎ Ｉとする時、ｎ ｘ
＝ ｎ ｓである。又、不均質媒質レンズ２６の屈折
率分布は次の式で表わされる。FIG. 13 is an enlarged sectional view of the magnetic fluid aperture 16 of the twelfth embodiment, in which the refractive index distribution is a radial distribution (square distribution) instead of the rear glass plate of the radially magnetized type. Using the heterogeneous medium lens 26, the heterogeneous medium lens 2
6 itself has the role of enclosing the magnetic fluid 1 and the transparent liquid 2, and the refractive index distribution of the heterogeneous medium lens 26 is
As shown in FIG. 14, the degree of change at the center is greater than the degree of change at the periphery, so that the refractive power at the center of the heterogeneous medium lens 26 is greater than the refractive power at the periphery. It is designed to function as a large so-called multifocal lens. Front glass plate 7. Transparent liquid 2. Separator 9
The refractive index of each is nn! + n I, n x
= ns. Further, the refractive index distribution of the inhomogeneous medium lens 26 is expressed by the following equation.
ｒ ］＜ｒ、 ｎ （ｒ）＝ｎｏ ａＩ ｒ”
ｒ ｌ ＞ｒ＋ ｎ （ｒ） ＝ｉｌｏ’ −ａ２
ｒ２ｒ ＝ ｒ Ｉ Ｉｌ＋−ａｌ
ｒ ＝Ｉｌ＋ −８＋ｒｎｏ ＞ｎｏ 、ａ＋ ＞
８２
但し、ｎＯ＋ｎｏ′は中心での屈折率、ｒは半径、ａｌ
ｇａ）は屈折率分布の変化の度合を示している。r ] < r, n (r) = no aI r”
r l > r+ n (r) = ilo' - a2
r2r = r I Il+-al
r = Il+ -8+rno >no, a+ >
82 However, nO+no' is the refractive index at the center, r is the radius, and al
ga) indicates the degree of change in the refractive index distribution.
この場合、第８実施例と同じ効果を有する。In this case, it has the same effect as the eighth embodiment.
第１５図は第１３実施例の磁性流体絞り１６の拡大断面
図であって、これは軸方向着磁タイプのものの透明容器
３の後壁の代わりに屈折率分布がアキシャル分布の不均
質媒質レンズ２７を用い、不均質媒質レンズ２７自体に
磁性流体ｌ及び透明液体２を封入する役割を持たせると
共に、不均質媒質レンズ２７の内側の面（前面）を曲面
にして、該曲面の周辺部の屈折力が中央部の屈折力より
も小さくなるように連続的に変化する所謂多焦点レンズ
として作用するようにして成るものである。FIG. 15 is an enlarged cross-sectional view of the magnetic fluid aperture 16 of the thirteenth embodiment, in which a heterogeneous medium lens with an axial refractive index distribution is used instead of the rear wall of the transparent container 3 of the axially magnetized type. 27, the heterogeneous medium lens 27 itself has the role of enclosing the magnetic fluid l and the transparent liquid 2, and the inner surface (front surface) of the heterogeneous medium lens 27 is curved, and the peripheral part of the curved surface is It functions as a so-called multifocal lens whose refractive power changes continuously so that it becomes smaller than the refractive power of the central portion.
透明容器３の前壁３ａ、透明液体２．セパレータ４、不
均質媒質レンズ２７の屈折率を夫々ｎｎｔ ＋ ｎａ
＋ ｎｔとする時、ｎ ２ ＝ １１≠ｎ４である。Front wall 3a of transparent container 3, transparent liquid 2. The refractive index of the separator 4 and the heterogeneous medium lens 27 is nnt + na, respectively.
+ nt, n 2 = 11≠n4.
但し、ｎ、は軸方向に変化する。However, n changes in the axial direction.
この場合、第８実施例と同じ効果に加えて、絞り径が連
続的に変化する絞りと組み合わせられるという利点もあ
る。In this case, in addition to the same effects as in the eighth embodiment, there is also the advantage that it can be combined with an aperture whose aperture diameter changes continuously.
本発明による内視鏡光学系は、省エネルギーであり、安
全性が高く、耐熱性に優れ、構造が簡単であり、省スペ
ースであり、明るさむらがなく、明るくて高画質の像が
得られ、近点撮影時に充分な被写界深度が得られるとい
う実用上重要な利点を有している。The endoscope optical system according to the present invention is energy-saving, highly safe, has excellent heat resistance, has a simple structure, saves space, has uniform brightness, and can obtain bright, high-quality images. , it has the practically important advantage that a sufficient depth of field can be obtained during near-point photography.
第１図は本発明による内視鏡光学系の第１実施例を示す
図、第２図は第１実施例の磁性流体絞りの拡大断面図、
第３図乃至第１２図は夫々第２乃至第１１実施例の磁性
流体絞りの拡大断面図、第１３図及び第１４図は夫々第
１２実施例の磁性流体絞りの拡大断面図及びそれに用い
られる不均質媒質レンズの屈折率分布を示す図、第１５
図は第１３実施例の磁性流体絞りの拡大断面図、第１６
図及び第１７図は夫々従来の磁性流体絞りの断面図、第
１８図及び第１９図は夫々従来例の基本構成及び動作状
態を示す図である。
１・・・・磁性流体、２・・・・透明液体、３・・・・
透明容器、４，９・・・・セパレータ、５・・・・磁石
、６・・・・コイル、７，８・・・・ガラス板、１０・
・・・環状の部材、１１・・・・接着剤、１５・・・・
凹レンズ、１６−・・・磁性流体絞り、１７，２１，２
３，２４．２５・・・・正レンズ、１８・・・・接合正
レンズ、１９・・・・フィールドレンズ、２０・・・・
イメージガイドファイバ束の入射端、２２，２６．２７
・・・・不均質媒質レンズ。
１Ｆ１３図
１−１４図
第１５図
１′
１′
１］
Ｕ
５Ｉ＃ｉｓ図
（ａ）
（ｂ）
１−１９図FIG. 1 is a diagram showing a first embodiment of an endoscope optical system according to the present invention, and FIG. 2 is an enlarged sectional view of a magnetic fluid diaphragm of the first embodiment.
3 to 12 are enlarged cross-sectional views of the magnetic fluid apertures of the second to eleventh embodiments, respectively, and FIGS. 13 and 14 are enlarged cross-sectional views of the magnetic fluid apertures of the twelfth embodiment, respectively, and the parts used therein. Diagram showing the refractive index distribution of a heterogeneous medium lens, No. 15
The figure is an enlarged sectional view of the magnetic fluid aperture of the 13th embodiment, and the 16th embodiment.
1 and 17 are sectional views of a conventional magnetic fluid aperture, and FIGS. 18 and 19 are views showing the basic configuration and operating state of the conventional example, respectively. 1...Magnetic fluid, 2...Transparent liquid, 3...
Transparent container, 4, 9... separator, 5... magnet, 6... coil, 7, 8... glass plate, 10...
...Annular member, 11...Adhesive, 15...
Concave lens, 16--magnetic fluid diaphragm, 17, 21, 2
3,24.25...Positive lens, 18...Cemented positive lens, 19...Field lens, 20...
Input end of image guide fiber bundle, 22, 26.27
...Heterogeneous medium lens. 1F13 Figure 1-14 Figure 15 1'1' 1] U 5I#is Figure (a) (b) Figure 1-19
Claims (2)
部材の該空室内に透明流体と磁性流体とを封入し、外部
から印加される磁界により前記空室内における前記磁性
流体の形状を変化させて前記空室を透過する光量を制御
する絞り部材を備えた内視鏡光学系において、 前記前後の壁の少なくとも一方が有限の焦点距離を有す
る屈折部材から成ることを特徴とする内視鏡。(1) A transparent fluid and a magnetic fluid are sealed in the cavity of an optical member having a cavity whose front and rear walls are made of a transparent material, and the shape of the magnetic fluid in the cavity is caused by a magnetic field applied from the outside. In the endoscope optical system, the endoscope optical system includes a diaphragm member that controls the amount of light transmitted through the cavity by changing the amount of light, wherein at least one of the front and rear walls is made of a refractive member having a finite focal length. Endoscope.
部とその外周部とで異なることを特徴とする請求項（１
）に記載の内視鏡光学系。(2) Claim (1) characterized in that the refractive power of the wall having refractive power is different between a central portion including the optical axis and an outer peripheral portion thereof.
).The endoscope optical system described in ).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2114190A JPH0411211A (en) | 1990-04-27 | 1990-04-27 | Endoscope optical system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2114190A JPH0411211A (en) | 1990-04-27 | 1990-04-27 | Endoscope optical system |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0411211A true JPH0411211A (en) | 1992-01-16 |
Family
ID=14631456
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2114190A Pending JPH0411211A (en) | 1990-04-27 | 1990-04-27 | Endoscope optical system |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0411211A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002169005A (en) * | 2000-11-30 | 2002-06-14 | Canon Inc | Optical element, optical device and photographing device |
| JP2004279556A (en) * | 2003-03-13 | 2004-10-07 | Olympus Corp | Imaging apparatus |
| JP2007052851A (en) * | 2005-08-17 | 2007-03-01 | Sony Corp | Optical element, optical pickup device, and optical recording and reproducing apparatus |
| US10162335B2 (en) | 2015-01-30 | 2018-12-25 | Fanuc Corporation | Numerical controller capable of neighboring point search with consideration for tool attitude |
-
1990
- 1990-04-27 JP JP2114190A patent/JPH0411211A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002169005A (en) * | 2000-11-30 | 2002-06-14 | Canon Inc | Optical element, optical device and photographing device |
| JP2004279556A (en) * | 2003-03-13 | 2004-10-07 | Olympus Corp | Imaging apparatus |
| JP2007052851A (en) * | 2005-08-17 | 2007-03-01 | Sony Corp | Optical element, optical pickup device, and optical recording and reproducing apparatus |
| US10162335B2 (en) | 2015-01-30 | 2018-12-25 | Fanuc Corporation | Numerical controller capable of neighboring point search with consideration for tool attitude |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4902115A (en) | Optical system for endoscopes | |
| JPS62220918A (en) | Endoscope optical system | |
| EP1069450A2 (en) | Optical element and optical device having it | |
| JP2503580B2 (en) | Optical system with variable bokeh | |
| CN105917254A (en) | Bifocal lens and imaging device including same | |
| CN111522186B (en) | lens | |
| CN106908936A (en) | A kind of panoramic optical camera lens and image acquisition device | |
| AU2016314795A1 (en) | Polarization dependent filter, system using the same, and associated kits and methods | |
| CN109782380A (en) | A kind of iris imaging system and iris recognition mould group | |
| JPH01133016A (en) | Triplet lens system having stop at rear position | |
| JPH0411211A (en) | Endoscope optical system | |
| US6033132A (en) | Iris apparatus | |
| CN109683291A (en) | Optical lens and imaging device | |
| KR20140115803A (en) | Compact lens system | |
| CN108919455B (en) | High-definition automobile rearview mirror | |
| JPH0289017A (en) | Image pickup system | |
| JP2603697B2 (en) | Imaging optical system for endoscope | |
| JPS58132207A (en) | Wide angle zoom lens | |
| JP2010032628A (en) | Zoom lens, lens barrel and image pickup apparatus | |
| JPH02148013A (en) | Endoscope | |
| JPH11125849A (en) | Optical diaphragm | |
| WO2017107909A1 (en) | Panoramic optical lens and image capturing device | |
| CN111983798A (en) | Compact small focal ratio catadioptric telescope | |
| US11960077B2 (en) | Optical apparatus | |
| JPS62206514A (en) | Switching type variable power optical system |