JPH0511196A - Visual field direction conversion optical system for endoscope - Google Patents
Visual field direction conversion optical system for endoscopeInfo
- Publication number
- JPH0511196A JPH0511196A JP3166985A JP16698591A JPH0511196A JP H0511196 A JPH0511196 A JP H0511196A JP 3166985 A JP3166985 A JP 3166985A JP 16698591 A JP16698591 A JP 16698591A JP H0511196 A JPH0511196 A JP H0511196A
- Authority
- JP
- Japan
- Prior art keywords
- visual field
- light
- endoscope
- optical system
- field direction
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Landscapes
- Instruments For Viewing The Inside Of Hollow Bodies (AREA)
- Endoscopes (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、ファイバースコープ、
硬性鏡或いはビデオスコープ等の内視鏡に適用され、斜
視方向に位置する被写体を観察，撮像等するための内視
鏡用視野方向変換光学系に関する。BACKGROUND OF THE INVENTION The present invention relates to a fiberscope,
The present invention relates to a field-of-view direction changing optical system for an endoscope, which is applied to an endoscope such as a rigid endoscope or a videoscope and is used for observing and imaging a subject located in a perspective direction.
【０００２】[0002]
【従来の技術】外部から観察できない細長い穴の奥や、
入口の狭い空洞の内部例えば体内や航空機のエンジン内
部等を、開腹手術したり分解したりすることなく良好な
像として観察等できる手段として、内視鏡が用いられて
いることはよく知られている。特に、観察部位が内視鏡
の長手方向に対して斜め方向即ち斜視方向に位置する場
合には、上述の如き内視鏡用視野方向変換光学系が内視
鏡の先端に取り付けられ、斜め方向から入射する視野光
束を長手方向即ち直視方向に変換するようになってい
る。2. Description of the Related Art Deep holes that cannot be observed from the outside,
It is well known that an endoscope is used as a means for observing the inside of a narrow cavity with a narrow entrance, such as the inside of a body or the inside of an engine of an aircraft, as a good image without laparotomy or disassembling. There is. In particular, when the observation site is located diagonally to the longitudinal direction of the endoscope, that is, in the oblique direction, the above-mentioned endoscope visual field direction changing optical system is attached to the distal end of the endoscope, and The field light flux incident from the front is converted into the longitudinal direction, that is, the direct-viewing direction.
【０００３】従来の内視鏡用視野方向変換光学系とし
て、例えば特公昭５８−５６８４８号公報に記載された
ものがある。この内視鏡用視野方向変換光学系は、図１
５に示すように、内視鏡先端部枠１内に配置されてお
り、被写体側から凹レンズ２、補正プリズム３、視野方
向変換プリズム４、対物レンズ系５が順次配設されて構
成される。補正プリズム３は斜視方向からの入射光線の
入射光軸Ｏに対してほぼ垂直に位置する入射面３ａと、
入射光軸Ｏが屈折して射出するように配置された射出面
３ｂとを有する。又、視野方向変換プリズム４は補正プ
リズム３の射出面３ｂに近接して配置され且つ射出面３
ｂから射出した光軸Ｏを屈折させる屈折面４ａと、屈折
した光軸Ｏを反射させる反射面４ｂと、更にこの反射光
が屈折面４ａで反射されて直視方向に通過する、直視方
向に対してほぼ直交する射出面４ｃとを有している。そ
して、視野方向変換プリズム４を射出した光軸Ｏは、後
群の対物レンズ系５に導かれるようになっている。As a conventional visual field direction changing optical system for an endoscope, there is, for example, one described in Japanese Patent Publication No. 58-56848. This view direction changing optical system for an endoscope is shown in FIG.
As shown in FIG. 5, it is arranged in the endoscope front end frame 1, and is composed of a concave lens 2, a correction prism 3, a visual field direction conversion prism 4, and an objective lens system 5 sequentially arranged from the subject side. The correction prism 3 has an incident surface 3a positioned substantially perpendicular to an incident optical axis O of an incident light beam from the perspective direction,
And an emission surface 3b arranged so that the incident optical axis O is refracted and emitted. Further, the visual field direction conversion prism 4 is arranged close to the exit surface 3b of the correction prism 3 and the exit surface 3
A refracting surface 4a that refracts the optical axis O emitted from b, a reflecting surface 4b that reflects the refracting optical axis O, and further, this reflected light is reflected by the refracting surface 4a and passes in the direct viewing direction. And an emission surface 4c that is substantially orthogonal to each other. Then, the optical axis O emitted from the visual field direction conversion prism 4 is adapted to be guided to the objective lens system 5 of the rear group.
【０００４】このような視野方向変換光学系は、外径の
小型化を可能にして入射光の屈折作用を持たせることが
できる反面、非点収差を生じるが、この非点収差は補正
プリズム３を用いることにより、視野方向からの入射光
軸Ｏを補正プリズム３の入射面に対して垂直に入射させ
るようにして、取り除くことができるようになってい
る。In such a visual field direction changing optical system, the outer diameter can be reduced and the refracting action of the incident light can be provided, but astigmatism occurs, but this astigmatism is corrected by the correction prism 3. By using, the incident optical axis O from the visual field direction is made to enter perpendicularly to the incident surface of the correction prism 3 and can be removed.
【０００５】[0005]
【発明が解決しようとする課題】ところで、このような
視野方向変換光学系においては、被写体の像を形成する
ための正規光線（即ち視野方向から凹レンズ２の有効径
内へ入射する光線即ち有効光束）以外の光線、例えば図
１５で示す視野外光線のうちａ，ｂのような結像面に達
するいわゆる有害光線も入射することになる。By the way, in such a visual field direction converting optical system, a normal ray for forming an image of an object (that is, a light ray which is incident from the visual field direction into the effective diameter of the concave lens 2, that is, an effective light beam). Other than the above), for example, so-called harmful rays reaching the image plane such as a and b among the out-of-field rays shown in FIG.
【０００６】例えば、有害光線ａは、凹レンズ２を通過
した後、補正プリズム３、視野方向変換プリズム４で被
写体側に反射されることなく通過して、直接対物レンズ
系５に入射する。この場合、対物レンズ系５に入射した
光線ａは斜視方向からの視野内光線即ち正規光線と重な
るため、ゴースト或いはフレアとなる可能性が大きい。For example, the harmful ray a passes through the concave lens 2, then passes through the correction prism 3 and the field-of-view direction conversion prism 4 without being reflected to the subject side, and directly enters the objective lens system 5. In this case, since the light ray a incident on the objective lens system 5 overlaps with the light ray in the field of view from the perspective direction, that is, the normal ray, there is a high possibility of becoming a ghost or a flare.
【０００７】これと同様に、視野外光線ｂのような角度
で凹レンズ２へ入射する光線は、補正プリズム３を通過
した後、視野方向変換プリズム４内に入射し２回反射し
て対物レンズ系５へ入射する。そのため、この視野外光
線ｂも光線ａと同様に被写体の結像面に達し、観察時に
ゴーストやフレアとして確認される可能性がある。これ
ら有害光線は良好な被写体像を観察しようとする場合の
大きな障害となり、好ましくない。Similarly, a light beam incident on the concave lens 2 at an angle such as the out-of-field light beam b, after passing through the correction prism 3, enters the visual field direction conversion prism 4 and is reflected twice to be reflected by the objective lens system. Incident on 5. Therefore, this out-of-field light ray b may reach the image forming plane of the subject similarly to the light ray a, and may be recognized as a ghost or a flare during observation. These harmful rays are not preferable because they are a great obstacle to observing a good subject image.
【０００８】本発明は、このような問題点に鑑み、ゴー
ストやフレアの原因となり得る有害光線を排除して、よ
り良好な被写体像を得られるようにした内視鏡用視野方
向変換光学系を提供することを目的とする。In view of the above problems, the present invention provides an endoscope visual field direction changing optical system that eliminates harmful rays that may cause ghosts and flares and obtains a better subject image. The purpose is to provide.
【０００９】[0009]
【課題を解決するための手段及び作用】本発明による内
視鏡用視野方向変換光学系の原理を図１乃至図４に基づ
いて説明する。図１は内視鏡の先端部分に配置される視
野方向変換光学系を示すものであり、図中、７は斜視方
向からの入射光軸Ｏに対してほぼ垂直に配置されたカバ
ーガラス、８はカバーガラス７の後方に配置されていて
斜視方向から入射する光束を直視方向へ変更させる視野
方向変換プリズムであり、カバーガラス７に近接してい
て入射光束を屈折させる屈折面８ａと、その屈折した光
を反射させる直視方向と平行に形成された反射面８ｂ
と、反射光を屈折面８ａで反射させた後射出させる直視
方向に垂直な射出面８ｃとから構成されている。９はカ
バーガラス７と視野方向変換プリズム８との間に蒸着，
近接或いは接合等により配設された有害光線を遮光する
ための絞りであり、例えば円形の視野内光線透過用絞り
開口９ａとこの開口を囲むリング状の有害光線遮蔽用遮
光部９ｂとから成っている（図２参照）。The principle of the visual field direction changing optical system for an endoscope according to the present invention will be described with reference to FIGS. FIG. 1 shows a field-of-view direction conversion optical system arranged at the tip portion of an endoscope. In the figure, 7 is a cover glass arranged substantially perpendicular to an incident optical axis O from the perspective direction, and 8 Is a field-of-view direction conversion prism which is disposed behind the cover glass 7 and changes the light beam incident from the perspective direction to the direct-viewing direction. The refractive surface 8a is close to the cover glass 7 and refracts the incident light beam. Reflecting surface 8b formed parallel to the direct-viewing direction for reflecting the reflected light
And an emission surface 8c perpendicular to the direct-viewing direction for emitting the reflected light after it is reflected by the refracting surface 8a. 9 is vapor deposition between the cover glass 7 and the view direction changing prism 8,
A stop for blocking harmful rays provided by proximity or joining, and is composed of, for example, a circular aperture 9a for transmitting light rays in the field of view and a ring-shaped shield portion 9b for shielding harmful rays. (See Figure 2).
【００１０】更に、この絞り９について説明する。図１
は上述の視野方向変換光学系に関して、光軸Ｏを含み且
つ視野方向変換プリズム８の反射面８ｂに垂直な断面で
ある子午断面の図である。この子午断面内において、視
野方向変換プリズム８の反射面８ｂを０とし、射出面８
ｃを考慮して反射面８ｂに垂直な座標軸をとって、射出
面８ｃの高さを１（長さの単位）とする。そして、反射
面８ｂから開口９ａと遮光部９ｂとの境界をなす上縁Ａ
より上側及び下縁Ｂより下側の遮光部が存在する領域の
座標を、夫々ｌA 及びｌB とする。このような座標上で
絞り９の存在領域を考える。Further, the diaphragm 9 will be described. Figure 1
FIG. 3 is a diagram of a meridional section that is a section that includes the optical axis O and is perpendicular to the reflecting surface 8 b of the field-of-view direction conversion prism 8 in the above-described field-of-view direction conversion optical system. In this meridional section, the reflecting surface 8b of the visual field direction conversion prism 8 is set to 0, and the exit surface 8
Taking c into consideration, a coordinate axis perpendicular to the reflecting surface 8b is taken, and the height of the exit surface 8c is set to 1 (unit of length). Then, an upper edge A that forms a boundary between the reflecting surface 8b and the opening 9a and the light shielding portion 9b.
The coordinates of the regions where the light-shielding portions on the upper side and the lower edge B are present are assumed to be l A and l B , respectively. Consider the existing area of the diaphragm 9 on such coordinates.
【００１１】図３は視野方向変換プリズム８と、これを
通過する光軸Ｏを有する正規光線によって被写体像が結
像される像面１０とを示すものである。この図で有害光
線について考えると、視野外光線ｃ，ｄのうち、光線ｃ
は視野方向変換プリズム８の入射面８ａから入射する
が、像面１０へは到達しないので必ずしも有害とは限ら
ない。しかし、光線ｄは視野方向変換プリズム８を通過
して像面１０へ達するため、有害光線になり得る。有害
光となるか否かは、視野方向変換プリズム８への入射位
置と入射角度（屈折角）とで決定されるので、この関係
を図面上や実験等で追求していくと入射角度と入射位置
との間に或る所定の関係を見いだすことができる。これ
によって、以下に示すような条件式を得ることができ
た。FIG. 3 shows the field-of-view direction conversion prism 8 and an image plane 10 on which a subject image is formed by a normal ray having an optical axis O passing therethrough. Considering harmful rays in this figure, of the rays c and d outside the visual field, the ray c
Is incident from the incident surface 8a of the field-of-view direction conversion prism 8, but does not reach the image plane 10 and is not necessarily harmful. However, since the light ray d passes through the view direction changing prism 8 and reaches the image plane 10, it can be a harmful ray. Whether or not it becomes harmful light is determined by the incident position and the incident angle (refraction angle) on the visual field direction conversion prism 8. Therefore, if this relationship is pursued in the drawings and experiments, the incident angle and the incident angle It is possible to find a certain relationship with the position. As a result, the following conditional expression could be obtained.
【００１２】即ち、内視鏡の長手方向に対して視野方向
の角度が２０°〜８０°の範囲である場合、絞り開口９
ａは遮光部９ｂの存在領域について、夫々下記条件式
（１），（２）を満たすように構成される。 −０．０４８・θ′＋１．８≦ｌA （１） ｌB ≦０．２５ （２） ここで、θ′は視野方向変換プリズム８内の有害光線と
法線Ｈとのなす角度であり、下記の式（３）により定義
される（図４参照）。 θ′＝ｓｉｎ-1｛（ｎ／ｎ′）ｓｉｎθ｝ （３） 但し、ｎ：視野方向変換プリズム８の屈折面８ａより被
写体側の媒質の屈折率 ｎ′：視野方向変換プリズム８の屈折率 θ：有害光線と視野方向変換プリズム８の屈折面８ａの
法線Ｈとの成す角度That is, when the angle in the visual field direction with respect to the longitudinal direction of the endoscope is in the range of 20 ° to 80 °, the diaphragm aperture 9
a is configured so as to satisfy the following conditional expressions (1) and (2) with respect to the existing region of the light shielding portion 9b. −0.048 · θ ′ + 1.8 ≦ l A (1) l B ≦ 0.25 (2) where θ ′ is the angle between the harmful ray in the view direction changing prism 8 and the normal line H. , Defined by the following equation (3) (see FIG. 4). θ ′ = sin −1 {(n / n ′) sin θ} (3) Here, n: Refractive index of the medium on the object side from the refracting surface 8a of the visual field direction conversion prism 8 n ′: Refractive index of the visual field direction conversion prism 8 θ: Angle formed by the harmful ray and the normal line H of the refracting surface 8a of the visual field direction conversion prism 8.
【００１３】尚、式（１）は、図１に示されたように、
絞り９の遮光部９ｂの上縁Ａが子午断面の座標上の−
０．０４８・θ′＋１．８の位置にあって、この位置よ
り上側は遮光部９ｂで遮蔽されていることを示してい
る。同様に式（２）は、遮光部９ｂの下縁Ｂが座標上の
０．２５の位置にあって、この位置より下側が遮光部９
ｂで遮蔽されていることを示している。又、式（３）に
おいて、角度θは、３６．６°≦θ≦８９．８°の領域
内にあるものとする。The equation (1) is as shown in FIG.
The upper edge A of the light-shielding portion 9b of the diaphragm 9 is − on the coordinates of the meridional section.
The position is 0.048 · θ ′ + 1.8, and the upper side of this position is shielded by the light shielding portion 9b. Similarly, in the equation (2), the lower edge B of the light shielding portion 9b is at the position of 0.25 on the coordinates, and the lower side of this position is the light shielding portion 9b.
It is shown that it is shielded by b. Further, in the equation (3), the angle θ is assumed to be within the range of 36.6 ° ≦ θ ≦ 89.8 °.
【００１４】そして、開口９ａの上縁Ａが、図１で例え
ば位置Ａ′のように、−０．０４８・θ′＋１．８で与
えられる位置より上方にあった場合、開口９ａが大きく
なり（換言すれば絞り９の遮光部９ｂの幅が小さくな
り）有害光線を除去する効果が不十分となり、望ましく
ない。又、長さｌB が図１における下側の遮光部９ｂの
垂直方向の幅を示すものとした場合、遮光部９ｂの下縁
Ｂの反対側縁部について少なくとも以下の条件式（４）
を満たせば、この部分の領域の有害光線を遮光できる。 −０．０２４θ′＋０．６≦ｌB （４） 更に、この式と（２）式とから、 −０．０２４θ′＋０．６≦ｌB ≦０．２５ （５） という条件式が成立することになる。しかし、遮光部９
ｂの開口９ａと反対側縁部（外径側）では、遮光部９ｂ
はいくら大きくなっても支障はないので、上記（４）式
を遵守する必要はない。When the upper edge A of the opening 9a is located above the position given by -0.048θ '+ 1.8, as in the position A'in FIG. 1, the opening 9a becomes large. (In other words, the width of the light shielding portion 9b of the diaphragm 9 becomes smaller), and the effect of removing harmful rays becomes insufficient, which is not desirable. Further, when the length l B indicates the vertical width of the lower light-shielding portion 9b in FIG. 1, at least the following conditional expression (4) for the edge portion on the opposite side of the lower edge B of the light-shielding portion 9b.
If the above condition is satisfied, harmful rays in this area can be blocked. −0.024θ ′ + 0.6 ≦ l B (4) Furthermore, from this expression and the expression (2), the conditional expression −0.024θ ′ + 0.6 ≦ l B ≦ 0.25 (5) is established. It will be. However, the light shield 9
In the edge portion (outer diameter side) opposite to the opening 9a of b, the light shielding portion 9b
There is no problem even if the size becomes large, so it is not necessary to comply with the above formula (4).
【００１５】[0015]
【実施例】以下、本発明の第一実施例を図５に基づいて
詳細に説明するが、上述の原理図で示された部材と同様
な部材には同一の符号を用いてその説明を省略する。図
５は内視鏡の先端部分に配置される視野方向変換光学系
を示すものであり、図中、１２は斜視方向からの入射光
軸Ｏ（視野方向は６０°とする）に対してほぼ垂直に配
置された平行平板状のカバーガラスであり、このカバー
ガラス１２の後方に視野方向変換プリズム８が配設され
ており、カバーガラス１２と視野方向変換プリズム８と
の間に位置する有害光線を遮光するための絞り９は、カ
バーガラス１２に接合蒸着されている。１３は視野方向
変換プリズム８の後方に配置された凸レンズである。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described in detail below with reference to FIG. 5, but the same members as those shown in the above-mentioned principle diagram are designated by the same reference numerals and the description thereof will be omitted. To do. FIG. 5 shows a visual field direction changing optical system arranged at the distal end portion of the endoscope. In the figure, 12 is almost with respect to an incident optical axis O from the oblique direction (the visual field direction is 60 °). It is a parallel flat plate-shaped cover glass arranged vertically, and a view direction changing prism 8 is arranged behind the cover glass 12, and a harmful light beam located between the cover glass 12 and the view direction changing prism 8. A diaphragm 9 for shielding the light is bonded and vapor-deposited on the cover glass 12. Reference numeral 13 is a convex lens arranged behind the visual field direction conversion prism 8.
【００１６】本実施例は上述のように構成されているか
ら、図５に示すように、図示しない被写体から射出され
て視野方向を直進する視野内光線（有効光束）は、カバ
ーガラス１２を介して絞り９の絞り開口９ａを通過し、
視野方向変換プリズム８の屈折面８ａで屈折した後、反
射面８ｂそして屈折面８ａで反射して、直視方向に光路
を変換されて射出面８ｃから射出し、凸レンズ９を介し
て対物レンズ系へ導かれて結像する。Since the present embodiment is constructed as described above, as shown in FIG. 5, an in-field light ray (effective luminous flux) which is emitted from an object (not shown) and advances straight in the field of view passes through the cover glass 12. Passing through the diaphragm opening 9a of the diaphragm 9,
After refracting at the refraction surface 8a of the visual field direction conversion prism 8, the light is reflected by the reflection surface 8b and the refraction surface 8a, the optical path is changed in the direct-viewing direction, the light is emitted from the emission surface 8c, and the convex lens 9 is passed to the objective lens system. It is guided and imaged.
【００１７】これに対して、有害光線はカバーガラス１
２で屈折した後絞り９の遮光部９ｂで遮光されるため、
視野方向変換プリズム８への入射は阻止される。On the other hand, the harmful rays are cover glass 1
After being refracted at 2, the light is blocked by the light blocking portion 9b of the diaphragm 9,
The incidence on the visual field direction conversion prism 8 is blocked.
【００１８】これに関して、例えば図５に示す視野外光
線ｅ（θ＝５７．２°）、ｆ（θ＝６７．１°）、ｇ
（θ＝７１．８°）、ｈ（θ＝７１．８°）が、視野方
向変換光学系のカバーガラス１２へ入射した場合につい
て説明する。まず、視野外光線ｅ，ｆ，ｇは、絞り９の
遮光部９ｂの上部で遮蔽されて入射を阻止されるが、こ
こで開口９ａの上縁Ａが、（１）式において例えば−
０．０４８０θ′＋１．８より大きい位置にあった場
合、開口９ａの径が大きすぎるために視野外光線ｅ，
ｆ，ｇは開口９ａを通過し得て視野方向変換プリズム８
へ入射することがある。そのため、視野内光束と重なっ
て、結像面でゴースト，フレアの原因となり得るもので
ある。In this regard, for example, out-of-field rays e (θ = 57.2 °), f (θ = 67.1 °), g shown in FIG.
A case where (θ = 71.8 °) and h (θ = 71.8 °) are incident on the cover glass 12 of the visual field direction conversion optical system will be described. First, the out-of-field light rays e, f, and g are blocked by the upper portion of the light shielding portion 9b of the diaphragm 9 to be blocked from entering. Here, the upper edge A of the opening 9a is, for example, − in Expression (1).
If the position is larger than 0.0480θ ′ + 1.8, the diameter of the opening 9a is too large, and the out-of-field light ray e,
f and g can pass through the opening 9a, and the view direction conversion prism 8
May be incident on. Therefore, it may cause a ghost and a flare on the image forming plane by overlapping with the light flux in the visual field.
【００１９】一方、視野外光線ｈは、絞り９の遮光部９
ｂの下部で遮蔽されて入射を阻止されるが、開口９ａの
下縁Ｂが（２）式において例えば０．２５より大きい場
合には、開口９ａの径が小さすぎて視野方向の視野内光
線をも遮光することになり、得られる像は周辺光量が足
りず、鮮明さに欠ける欠点が生じる。On the other hand, the light rays h out of the visual field are shielded from the light-shielding portion 9 of the diaphragm 9.
Although the light is blocked at the lower part of b to block the incidence, if the lower edge B of the opening 9a is larger than, for example, 0.25 in the expression (2), the diameter of the opening 9a is too small and the rays within the visual field in the visual field direction. This also blocks light, and the resulting image lacks the amount of peripheral light, resulting in a defect that the image is not sharp.
【００２０】尚、子午断面における絞り９の遮光部９ｂ
の存在する領域ｌA及びｌB は、上述の条件式（１）お
よび（２）に基づいて、夫々ｌA ≧０．３４６、−０．
１２７≦ｌB ≦０．２５（このとき、ｎ＝１，ｎ′＝
１．８８３，θ＝７１．８°，θ′＝３０．３°）とな
っている。The light-shielding portion 9b of the diaphragm 9 in the meridional section.
Regions 1 A and 1 B in which the presence of each of them exists, based on the conditional expressions (1) and (2) described above, respectively, l A ≧ 0.346, −0.
127 ≦ l B ≦ 0.25 (at this time, n = 1, n ′ =
1.883, θ = 71.8 °, θ ′ = 30.3 °).
【００２１】上述のように、本実施例によれば、被写体
像の結像に有用な視野内光線のみを通過させて、有害光
線を遮光することができるので、被写体観察時等にゴー
ストやフレアの発生を防止して良好な画像を得ることが
できる。As described above, according to the present embodiment, it is possible to pass only the rays within the field of view useful for forming a subject image and to block the harmful rays, so that ghosts and flares are observed when observing the subject. It is possible to obtain a good image by preventing the occurrence of.
【００２２】次に、本発明の第二実施例を図６に基づい
て説明する。図中、視野方向は５０°の斜視になってい
る。又、絞り９は、第一実施例とは異なって視野方向変
換プリズム８の屈折面８ａに蒸着されており、更に絞り
９の遮光部９ｂの裏面部分の屈折面８ａには、アルミニ
ウムの薄膜から成る全反射コート１４が施され、反射率
を向上させている。Next, a second embodiment of the present invention will be described with reference to FIG. In the figure, the visual field direction is a perspective of 50 °. Unlike the first embodiment, the diaphragm 9 is vapor-deposited on the refracting surface 8a of the visual field direction conversion prism 8, and the refracting surface 8a of the back surface of the light-shielding portion 9b of the diaphragm 9 is made of an aluminum thin film. The total reflection coating 14 is formed to improve the reflectance.
【００２３】又、条件式（１）及び（２）により、絞り
９の遮光部９ｂの存在する領域ｌA 及びｌB は、夫々ｌ
A ≧０．２８８、−０．１５６≦ｌB ≦０．２５（この
とき、ｎ＝１，ｎ′＝１．８８３，θ＝８０°，θ′＝
３１．５°）となっている。Further, according to the conditional expressions (1) and (2), the regions l A and l B in which the light-shielding portion 9b of the diaphragm 9 exists are respectively l
A ≧ 0.288, −0.156 ≦ l B ≦ 0.25 (where n = 1, n ′ = 1.883, θ = 80 °, θ ′ =
31.5 °).
【００２４】次に、本発明の第三実施例を図７に基づい
て説明する。図中、斜視方向は７０°になっている。こ
れに合わせてカバーガラス１５の第一屈折面１５ａは、
非点収差を抑えるために入射光軸Ｏとほぼ直交するよう
に形成され、その結果第二屈折面１５ｂとはある角度を
形成している。又、視野方向変換プリズム８の反射面８
ｂは、入射面８ａ側の一部分を被写体方向へ傾斜させて
傾斜部８ｂ─１を形成している。これによって、斜視方
向を７０°にまで大きくさせることが可能になる。但
し、カバーガラス１５は視野方向変換プリズム８との間
隔が十分に小さいか、或いは互いに接合するように構成
されている。Next, a third embodiment of the present invention will be described with reference to FIG. In the figure, the perspective direction is 70 °. In accordance with this, the first refracting surface 15a of the cover glass 15 is
In order to suppress astigmatism, it is formed so as to be substantially orthogonal to the incident optical axis O, and as a result, forms an angle with the second refraction surface 15b. Also, the reflecting surface 8 of the viewing direction conversion prism 8
In part b, an inclined portion 8b-1 is formed by inclining a part of the incident surface 8a side toward the subject. This makes it possible to increase the perspective direction to 70 °. However, the cover glass 15 is configured to have a sufficiently small interval with the view direction conversion prism 8 or to be bonded to each other.
【００２５】ここで、条件式（１）および（２）に基づ
く絞り９の遮光部９ｂの存在する領域ｌA 及びｌB は、
夫々ｌA ≧０．７１、０．０５６≦ｌB ≦０．２５（こ
のとき、ｎ＝１，ｎ′＝１．８８３，θ＝８３．５°，
θ′＝２２．６６°）とした。Here, the regions l A and l B in which the light-shielding portion 9b of the diaphragm 9 based on the conditional expressions (1) and (2) exist are:
L A ≧ 0.71 and 0.056 ≦ l B ≦ 0.25 (at this time, n = 1, n ′ = 1.883, θ = 83.5 °,
θ ′ = 22.66 °).
【００２６】又、本発明の第四実施例を図８に基づいて
説明する。本実施例では、第一実施例におけるカバーガ
ラス１２に代えて凹レンズ１６が配設されており、これ
により観察範囲をより広角にすることができる。そし
て、条件式（１）及び（２）に基づく絞り９の遮光部９
ｂの存在する領域ｌA 及びｌB は、夫々ｌA ≧０．４０
１、−０．１２７≦ｌB ≦０．２５（このとき、ｎ＝
１，ｎ′＝１．８８３，θ＝７１．８°，θ′＝３０．
３°であり、第一実施例とは凹レンズ１６による有効径
のみが異なる）としている。A fourth embodiment of the present invention will be described with reference to FIG. In this embodiment, a concave lens 16 is provided in place of the cover glass 12 in the first embodiment, which allows a wider viewing angle. Then, the light shielding portion 9 of the diaphragm 9 based on the conditional expressions (1) and (2).
The regions l A and l B in which b exists are respectively l A ≧ 0.40
1, −0.127 ≦ l B ≦ 0.25 (where n =
1, n ′ = 1.883, θ = 71.8 °, θ ′ = 30.
It is 3 °, and is different from the first embodiment only in the effective diameter of the concave lens 16.
【００２７】尚、上述の第三及び第四実施例では、絞り
９はカバーガラス１５，１６に蒸着されている。又、絞
り９は、金属の薄板による機械的な絞りや、或いは黒マ
ジック塗り等低廉な部材によって構成するようにしても
差し支えない。又、内視鏡用視野方向変換光学系を構成
する物質の各材質はガラスに限定されることなく、プラ
スチック等でもよく、成形によって製作するものであっ
てもよい。In the third and fourth embodiments described above, the diaphragm 9 is vapor-deposited on the cover glasses 15 and 16. Further, the diaphragm 9 may be constituted by a mechanical diaphragm made of a thin metal plate or an inexpensive member such as black magic coating. Further, each material of the substance forming the visual field direction changing optical system for the endoscope is not limited to glass, and may be plastic or the like, or may be manufactured by molding.
【００２８】ところで、上述した各実施例は、夫々光学
系の外径φが１mm程度であり、極めて小さい。そのた
め、レンズ等の加工及び組み立ては非常に困難なものと
なり、光学系の偏心等の障害を来しやすく、好ましくな
い。そこで、各実施例による内視鏡用視野方向変換光学
系の加工方法を、図９により説明する。By the way, in each of the above-mentioned embodiments, the outer diameter φ of each optical system is about 1 mm, which is extremely small. Therefore, processing and assembling of the lens and the like become very difficult, and an obstacle such as decentering of the optical system is likely to occur, which is not preferable. Therefore, a method of processing the endoscope visual field direction changing optical system according to each embodiment will be described with reference to FIG.
【００２９】図９に示す視野方向変換光学系は、斜視方
向が６０°となっていて第一実施例と同様な構成を備え
ている。しかも、小さい外径による加工及び組み立て上
の支障を避けるために必要な外径寸法より大きくして、
加工及び組み立ての比較的容易な外径寸法のカバーガラ
ス１２，絞り９，視野方向変換プリズム８及び凸レンズ
１３を夫々加工した後、図に示すように組み立てて接合
或いは固定しておく。そして、所要の外径寸法間隔であ
る破線１８ａ及び１８ｂに沿って削りだすようにする。The visual field direction changing optical system shown in FIG. 9 has a configuration similar to that of the first embodiment with a perspective direction of 60 °. Moreover, it should be larger than the outer diameter required to avoid problems in processing and assembly due to the small outer diameter,
After processing the cover glass 12, the diaphragm 9, the visual field direction changing prism 8 and the convex lens 13 each having an outer diameter relatively easy to process and assemble, they are assembled and bonded or fixed as shown in the figure. Then, cutting is performed along the broken lines 18a and 18b, which are the required outer diameter dimension intervals.
【００３０】上述のような加工方法を採用することによ
り、加工が容易になり、各光学系の偏心を抑えることが
できる。By adopting the above-described processing method, the processing is facilitated and the decentering of each optical system can be suppressed.
【００３１】図１０，１１及び１２は第一実施例の光学
系を夫々硬性鏡，不均質媒質レンズを用いた硬性鏡及び
ファイバースコープに用いた構成を示しており、これら
を第五，第六及び第七実施例として、以下に説明する。
まず、図１０に示す第五実施例としての硬性鏡の構成を
説明すると、第一実施例の視野方向変換光学系の後方
に、対物レンズ系２０、像伝送光学系２１，接眼レンズ
系２２及びカバーガラス２３が順次配設されているもの
である。又、図１１に示す第六実施例は、視野方向変換
光学系の後方に、対物レンズ系２０、不均質媒質レンズ
２４、カバーガラス２５、像伝送光学系２１、接眼レン
ズ系２２及びカバーガラス２３が順次配設されている。
そして、図１２に示す第七実施例は、視野方向変換光学
系の後方に、対物レンズ系２０、カバーガラス２３、更
に像を伝送する手段としてファイバー繊維を束ねたもの
から成るイメージガイド２６が接続されており、その後
方に図示しない接眼レンズ系及びカバーガラスが順次配
設されている。FIGS. 10, 11 and 12 show a configuration in which the optical system of the first embodiment is used for a rigid mirror, a rigid mirror using an inhomogeneous medium lens, and a fiberscope, respectively. A seventh embodiment will be described below.
First, the structure of a rigid endoscope as a fifth embodiment shown in FIG. 10 will be described. Behind the visual field direction changing optical system of the first embodiment, an objective lens system 20, an image transmission optical system 21, an eyepiece lens system 22 and The cover glass 23 is sequentially arranged. In the sixth embodiment shown in FIG. 11, the objective lens system 20, the inhomogeneous medium lens 24, the cover glass 25, the image transmission optical system 21, the eyepiece lens system 22 and the cover glass 23 are provided behind the visual field direction changing optical system. Are sequentially arranged.
In the seventh embodiment shown in FIG. 12, an objective lens system 20, a cover glass 23, and an image guide 26 formed by bundling fiber fibers as a means for transmitting an image are connected behind the visual field direction changing optical system. An eyepiece system and a cover glass, which are not shown, are sequentially arranged behind it.
【００３２】又、図１３及び図１４は、従来の内視鏡用
視野方向変換光学系に本実施例による絞り９を配設した
ものであり、これらを第八及び第九実施例として説明す
る。図１３においては、凹レンズから成るカバーガラス
２と補正レンズ３との間に絞り９が配設されている。そ
して、その後方に屈折面４ａと反射面４ｂと射出面４ｃ
とを有する視野方向変換プリズム４と、凸レンズ５とが
配設されており、絞り９を通過した視野内光線は補正レ
ンズ３を介して視野方向変換プリズム４へ入射すること
になる。このような構成によっても、上述の各実施例と
同様な作用効果を得られる。図１３も同様に、凹レンズ
のカバーガラス２と補正レンズ３との間に絞り９が配設
されている。13 and 14 show a conventional endoscope field-of-view direction changing optical system provided with a diaphragm 9 according to this embodiment, which will be described as eighth and ninth embodiments. .. In FIG. 13, a diaphragm 9 is provided between the cover glass 2 composed of a concave lens and the correction lens 3. Then, behind it, the refracting surface 4a, the reflecting surface 4b, and the exit surface 4c.
A field-of-view direction conversion prism 4 having a and a convex lens 5 are provided, and a field-of-view light beam that has passed through the diaphragm 9 is incident on the field-of-view direction conversion prism 4 via the correction lens 3. Even with such a configuration, it is possible to obtain the same operational effects as those of the above-described embodiments. Similarly in FIG. 13, a diaphragm 9 is arranged between the cover glass 2 of the concave lens and the correction lens 3.
【００３３】[0033]
【発明の効果】上述のように本発明に係る内視鏡用視野
方向変換光学系は、視野方向変換プリズムの被写体側に
絞りを配設したから、ゴーストやフレア等の原因となる
有害光線を遮光して、より良好な画像を得ることができ
る。As described above, in the endoscope visual field direction changing optical system according to the present invention, since the diaphragm is arranged on the object side of the visual field direction converting prism, harmful rays causing ghosts, flares and the like are prevented. By shielding the light, a better image can be obtained.
【図１】本発明による内視鏡用視野方向変換光学系の子
午断面からみた基本構成を示す原理図である。FIG. 1 is a principle diagram showing a basic configuration of a viewing direction changing optical system for an endoscope according to the present invention as seen from a meridional section.
【図２】図１の光学系について絞りの絞り開口を示す要
部正面図である。FIG. 2 is a front view of relevant parts showing a diaphragm aperture of a diaphragm of the optical system of FIG.
【図３】視野方向変換プリズムと結像面に対する有害光
線と視野外光線を説明するための図である。FIG. 3 is a diagram for explaining harmful rays and out-of-field rays with respect to a visual field direction conversion prism and an image plane.
【図４】視野方向変換プリズムへ入射する有害光線の角
度を説明するための図である。FIG. 4 is a diagram for explaining an angle of a harmful ray incident on a visual field direction conversion prism.
【図５】本発明による内視鏡用視野方向変換光学系の第
一実施例を示す子午断面図である。FIG. 5 is a meridional sectional view showing a first embodiment of a visual field direction changing optical system for an endoscope according to the present invention.
【図６】本発明による内視鏡用視野方向変換光学系の第
二実施例を示す子午断面図である。FIG. 6 is a meridional sectional view showing a second embodiment of the visual field direction changing optical system for an endoscope according to the present invention.
【図７】本発明による内視鏡用視野方向変換光学系の第
三実施例を示す子午断面図である。FIG. 7 is a meridional sectional view showing a third embodiment of the visual field direction changing optical system for an endoscope according to the present invention.
【図８】本発明による内視鏡用視野方向変換光学系の第
四実施例を示す子午断面図である。FIG. 8 is a meridional sectional view showing a fourth embodiment of the endoscope field-of-view direction changing optical system according to the present invention.
【図９】本発明の各実施例による視野方向変換光学系の
加工方法を説明するための図である。FIG. 9 is a diagram for explaining a method of processing the visual field direction changing optical system according to each example of the present invention.
【図１０】第一実施例を硬性鏡に採用した第五実施例を
示す図である。FIG. 10 is a diagram showing a fifth embodiment in which the first embodiment is adopted as a rigid endoscope.
【図１１】第一実施例を不均質媒質レンズを用いた硬性
鏡に採用した第六実施例を示す図である。FIG. 11 is a diagram showing a sixth example in which the first example is applied to a rigid endoscope using an inhomogeneous medium lens.
【図１２】第一実施例をファイバースコープに採用した
第七実施例を示す図である。FIG. 12 is a diagram showing a seventh embodiment in which the first embodiment is adopted as a fiberscope.
【図１３】本発明の第八実施例の構成を示す図である。FIG. 13 is a diagram showing a configuration of an eighth exemplary embodiment of the present invention.
【図１４】本発明の第九実施例の構成を示す図である。FIG. 14 is a diagram showing a configuration of a ninth exemplary embodiment of the present invention.
【図１５】従来の内視鏡用視野方向変換光学系の構成を
示す図である。FIG. 15 is a diagram showing a configuration of a conventional endoscope visual field direction changing optical system.
４，８ 視野方向変換プリズム ４ａ，８ａ 屈折面 ４ｂ，８ｂ 反射面 ４ｃ，８ｃ 射出面 ９ 絞り ９ａ 絞り開口 ９ｂ 遮光部 Ａ 絞り開口と遮光部との上縁 Ｂ 絞り開口と遮光部との下縁 4, 8 Field-of-view direction conversion prisms 4a, 8a Refractive surfaces 4b, 8b Reflective surfaces 4c, 8c Ejection surface 9 Aperture 9a Aperture opening 9b Light-shielding portion A Upper edge of aperture opening and light-shielding portion B Lower aperture and light-shielding edge
Claims (1)
において、斜視方向からの入射光が屈折する屈折面と該
屈折光を反射する反射面と該反射光が前記屈折面で反射
して射出する射出面とを有する視野方向変換プリズム
と、該視野方向変換プリズムの屈折面より被写体側に配
置されていて結像面に達し得る視野外光線を遮断する絞
りと、を備えたことを特徴とする内視鏡用視野方向変換
光学系。Claim: What is claimed is: 1. An endoscope capable of observing a subject in a perspective direction, wherein a refracting surface refracting incident light from the perspective direction, a reflecting surface reflecting the refracting light, and the reflected light are provided. A visual field direction conversion prism having an exit surface that reflects and exits the refraction surface, and a diaphragm that is arranged closer to the subject than the refractive surface of the visual field direction conversion prism and that blocks out-of-field light rays that can reach the image formation surface. A field-of-view direction changing optical system for an endoscope, comprising:
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3166985A JPH0511196A (en) | 1991-07-08 | 1991-07-08 | Visual field direction conversion optical system for endoscope |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3166985A JPH0511196A (en) | 1991-07-08 | 1991-07-08 | Visual field direction conversion optical system for endoscope |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0511196A true JPH0511196A (en) | 1993-01-19 |
Family
ID=15841264
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3166985A Pending JPH0511196A (en) | 1991-07-08 | 1991-07-08 | Visual field direction conversion optical system for endoscope |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0511196A (en) |
Cited By (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
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