JP2004016455A - Distal end of endoscope - Google Patents

Distal end of endoscope Download PDF

Info

Publication number
JP2004016455A
JP2004016455A JP2002175148A JP2002175148A JP2004016455A JP 2004016455 A JP2004016455 A JP 2004016455A JP 2002175148 A JP2002175148 A JP 2002175148A JP 2002175148 A JP2002175148 A JP 2002175148A JP 2004016455 A JP2004016455 A JP 2004016455A
Authority
JP
Japan
Prior art keywords
surface
window
transparent cover
illumination
distal end
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.)
Granted
Application number
JP2002175148A
Other languages
Japanese (ja)
Other versions
JP4130940B2 (en
Inventor
Teruo Ouchi
大内 輝雄
Original Assignee
Pentax Corp
ペンタックス株式会社
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Pentax Corp, ペンタックス株式会社 filed Critical Pentax Corp
Priority to JP2002175148A priority Critical patent/JP4130940B2/en
Publication of JP2004016455A publication Critical patent/JP2004016455A/en
Application granted granted Critical
Publication of JP4130940B2 publication Critical patent/JP4130940B2/en
Application status is Expired - Fee Related legal-status Critical
Anticipated expiration legal-status Critical

Links

Images

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a satisfactory observation image free from a flare in a distal end of an endoscope where a surface of an illumination window and that of an observation window are covered with a same transparent cover. <P>SOLUTION: In the distal end of the endoscope where the illumination window 4 for emitting illumination light and the observation window 3 for taking in an optical image to an objective optical system 5 are arranged side by side at the distal end of an insertion part and the surface of the illumination window 4 and that of the observation window 3 are covered with the same transparent cover 11, a surface of a part of the cover 11 covering the illumination window 4 is formed in the state of a projecting surface to prevent light reflected by an inner surface of the projecting surface part 12 of the cover 11 in illumination light emitted from the illumination window 4 from advancing outward from an area of the the projecting surface part 12 in a thickness of the cover 11. <P>COPYRIGHT: (C)2004,JPO

Description

【0001】 [0001]
【発明の属する技術分野】 BACKGROUND OF THE INVENTION
この発明は内視鏡の先端部に関し、特に挿入部の先端に設けられた照明窓と観察窓とが同じ透明カバーによって被覆された内視鏡の先端部に関する。 It relates tip of the present invention is an endoscope, and a particular illumination window and an observation window provided at a distal end of the insertion portion relating to the distal end portion of the endoscope which is covered by the same transparent cover.
【0002】 [0002]
【従来の技術】 BACKGROUND OF THE INVENTION
近年、内視鏡を介しての患者から患者への感染を未然に確実に防止する必要性が高まっている。 Recently, there is an increasing need to advance to reliably prevent infection to the patient from the patient through the endoscope.
【0003】 [0003]
その方策として、内視鏡の挿入部に対して被脱自在な水密性のシースを設けて、内視鏡にシースを被覆した状態で使用し、使用後にそのシースを新しいものと交換するのが一つの有力な手段である。 As a measure, provided the detachably watertightness of the sheath with respect to the insertion portion of the endoscope, and used in a state of covering the sheath to the endoscope, it is to replace with a new one that sheath after use it is one of the effective means. そのようにする場合、照明窓と観察窓の表面にあたるシース部分は透明に形成しなければならない。 In so doing, the sheath portion corresponding surface of the illumination window and observation window must form transparent.
【0004】 [0004]
しかし、両窓の表面を連続的な一枚の透明カバーで被覆すると、例えば図4に示されるように、照明窓101から出射された照明光が透明カバー102の厚みの中で反射を繰り返して観察窓103内に入射し、観察視野にゴーストやフレアーが発生してしまう。 However, when coating the surfaces of the windows in a continuous single transparent cover, for example, as shown in FIG. 4, the illumination light emitted from the illumination window 101 is repeatedly reflected in the thickness of the transparent cover 102 incident on the observation window 103, ghost and flare occurs in the observation field.
【0005】 [0005]
そこで従来は、透明カバーを例えば照明窓側から観察窓側へ次第に肉薄に形成し、照明窓から射出された光が透明カバーの厚みの中で観察窓側に向かう方向に反射を繰り返すと次第に反射角度が小さくなって観察窓まで達しないようにしていた(特許第2868228号)。 Therefore, conventionally forms gradually thinner to observe window side of the transparent cover, for example, from the illumination window side, gradually reflection angle when repeatedly reflected in the direction toward the observation window side in the thickness of the light transparent cover which is emitted from the illumination window is small it which was as not to reach the observation window (Japanese Patent No. 2868228).
【0006】 [0006]
【発明が解決しようとする課題】 [Problems that the Invention is to Solve
しかし、上述のように透明カバーを例えば照明窓側から観察窓側へ次第に肉薄に形成しても、透明カバー中のその他の方向へは照明窓から射出された光が拡散して透明カバーの厚みの中を反射光が飛び交ってしまい、透明カバー内全体が照らされて明るくなることにより、観察像の明度を低下させるフレアーになっていた。 However, it is formed gradually thinner to observe window side of the transparent cover, as described above, for example, from the illumination window side, the the other direction in the transparent cover and diffuses the light emitted from the illumination window in the transparent cover thickness the cause flying about the reflected light, by becoming bright throughout the transparent cover is illuminated, it was to flare to reduce the brightness of the observation image.
【0007】 [0007]
そこで本発明は、照明窓の表面と観察窓の表面とが同じ透明カバーで被覆された内視鏡の先端部において、フレアーのない良好な観察像を得ることができる内視鏡の先端部を提供することを目的とする。 The present invention, in the distal portion of the endoscope and the surface of the surface and the observation window of the illumination window is covered with the same transparent cover, a tip portion of the endoscope can be obtained flare without good observation image an object of the present invention is to provide.
【0008】 [0008]
【課題を解決するための手段】 In order to solve the problems]
上記の目的を達成するため、本発明の内視鏡の先端部は、照明光を射出する照明窓と対物光学系に光像をとり入れる観察窓とが挿入部の先端に並んで配置され、照明窓の表面と観察窓の表面とが同じ透明カバーで被覆された内視鏡の先端部において、透明カバーの照明窓を被覆する部分の表面を凸面状に形成して、照明窓から射出された照明光のうち透明カバーの凸面部の内面で反射された光が透明カバーの厚みの中において凸面部の領域から外側に向かわないようにしたものである。 To achieve the above object, the distal end portion of the endoscope of the present invention, and the observation window to incorporate an optical image is arranged in the distal end of the insertion portion to the illumination window and an objective optical system for emitting illumination light, the illumination at the tip of the endoscope and the surface and the observation window of the surface of the window is covered with the same transparent cover, the surface of the portion covering the illumination window of the transparent cover formed in a convex shape, emitted from the illumination window in which light reflected by the inner surface of the convex portion of the transparent cover of the illumination light is prevented directed from the area of ​​the convex portion on the outside in the inside of the thickness of the transparent cover.
【0009】 [0009]
なお、凸面が球面又は非球面状の曲面等であってもよく、透明カバーが、凸面部の外縁部分においてその周囲より肉薄に形成されていてもよい。 Incidentally, may be a convex spherical or aspherical curved surface such as a transparent cover may be formed thinner than its surroundings at the outer edge portion of the convex portion.
【0010】 [0010]
【発明の実施の形態】 DETAILED DESCRIPTION OF THE INVENTION
図面を参照して本発明の実施例を説明する。 With reference to the accompanying drawings illustrating the embodiment of the present invention.
図1において、1は、内視鏡の挿入部可撓管の先端部分であり、その先端に連結された先端部本体2の先端面に観察窓3と照明窓4とが並んで配置されている。 In Figure 1, 1 is the front end portion of the flexible tube of the endoscope, are arranged side by side and the observation window 3 and the illumination window 4 is the front end surface of the distal end portion main body 2 which is connected at its distal end there. 照明窓4には凹レンズが嵌め込まれている。 The illumination window 4 are fitted into the concave lens.
【0011】 [0011]
観察窓3の内側には対物光学系5が配置され、その対物光学系5による被写体の投影位置にイメージガイドファイババンドル6の像入射面(又は固体撮像素子の撮像面)が配置されている。 Inside the observation window 3 is arranged the objective optical system 5, the image incidence surface of the image guide fiber bundle 6 to the projection position of the object by the objective optical system 5 (or the imaging plane of the solid-state image sensor) is disposed. 照明窓4の内側には、ライトガイドファイババンドル7の射出端が配置されている。 Inside the illumination window 4, the exit end of the light guide fiber bundle 7 is arranged.
【0012】 [0012]
10は、挿入部可撓管1に着脱自在に被覆される被覆シースであり、その先端部分には先端部本体2の先端面を被覆する例えばポロプロピレン又はポリエチレン等のような透明なプラスチックからなる透明カバー11が取り付けられており、観察窓3と照明窓4とが同じ透明カバー11により各々密着被覆された状態になっている。 10 is a coating sheath is detachably covered on the flexible tube 1, made of transparent plastic, such as, for example, such as polypropylene or polyethylene for covering the front end surface of the distal end portion main body 2 at its distal end portion and the transparent cover 11 is attached, in the state that are respectively in close contact coated with the observation window 3 and the illumination window 4 and the same transparent cover 11.
【0013】 [0013]
そのような透明カバー11の照明窓4を被覆する部分(少なくとも、照明窓4から射出される照明光が到達する部分)の表面は凸面状に形成されており、この実施例においてはその凸面部12は球面状に形成されている。 Part covering the illumination window 4 in such a transparent cover 11 (at least, part of illumination light emitted from the illumination window 4 reaches) the surface of which is formed in a convex shape, in this embodiment the convex surface portions 12 is formed in a spherical shape.
【0014】 [0014]
その結果、照明窓4から射出された照明光のうち透明カバー11の凸面部12の内面で反射されて透明カバー11の凸面部12内に戻された光が、透明カバー11の厚みの中において凸面部12の領域から外側に向かわない。 As a result, light returned to the convex portion 12 of the transparent cover 11 is reflected by the inner surface of the convex portion 12 of the transparent cover 11 of the illumination light emitted from the illumination window 4 is in in the thickness of the transparent cover 11 not directed to the outside from the region of the convex portion 12.
【0015】 [0015]
なお、図中にAで示されるように、凸面部12の中央寄りの位置で外方に向かって反射された光も、凸面部12中で反射を繰り返して凸面部12の外縁に近づくにしたがって、反射方向が内向きに変化する。 Incidentally, as shown by A in the figure, also the light reflected toward the outside at a position close to the center of the convex portion 12, toward the outer edge of the convex portion 12 is repeatedly reflected in the convex portion 12 , the reflection direction is changed inwardly.
【0016】 [0016]
凸面部12の領域より外側への漏光を理論的に完全に無くすためには、凸面部12の曲率半径を一定以下の大きさにする必要があるが、その値はライトガイドファイババンドル7から射出される照明光の最大射出角度、照明窓4に配置されている凹レンズの曲率半径、及び透明カバー11を形成する材料の屈折率等によって相違するので、それらを勘案して凸面部12の曲率半径を設定すればよい。 To eliminate light leakage to outside the region of the convex portion 12 theoretically completely, it is necessary to the radius of curvature of the convex surface portions 12 below a certain size, the value emitted from the light guide fiber bundle 7 maximum exit angle of the illumination light, the radius of curvature of the concave lens is placed in the illumination window 4, and so differs by the refractive index or the like of the material forming the transparent cover 11, the curvature of the convex portion 12 in consideration of their radius the may be set.
【0017】 [0017]
このように構成された実施例の内視鏡の先端部においては、照明窓4から射出された照明光のうち透明カバー11の凸面部12の内面で反射されて透明カバー11内に戻された光は、どの方向においても最終的に凸面部12の領域から外側に向かわないので、透明カバー11における内面反射に起因するフレアーの発生がほとんど皆無になり、観察窓3を通してコントラストのよい良好な観察像を得ることができる。 In the distal end portion of the endoscope of the thus constructed embodiment, were returned to the transparent cover 11 is reflected by the inner surface of the convex portion 12 of the transparent cover 11 of the illumination light emitted from the illumination window 4 light does not even finally directed from the area of ​​the convex portion 12 outward in any direction, becomes almost the occurrence of flare due to internal reflection nil in the transparent cover 11, the contrast good good viewing through the viewing window 3 image can be obtained.
【0018】 [0018]
なお、本発明は上記実施例に限定されるものではなく、例えば凸面部12は必ずしも球面である必要はなく、図2に示されるような楕円面その他の非球面状の曲面(例えば放物面等)であってもよい。 The present invention is not limited to the above embodiments, for example, the convex portion 12 is not necessarily spherical, ellipsoidal other non-spherical curved surface (e.g., parabolic, as shown in FIG. 2 it may be etc.).
【0019】 [0019]
また、図3に示されるように、透明カバー11を凸面部12の外縁部分においてその周囲より肉薄に形成することにより、凸面部12の領域からその外側への漏光をその部分でもカットすることができ、フレアー削減に寄与する。 Further, as shown in FIG. 3, by forming thinner than its surrounding transparent cover 11 at the outer edge portion of the convex portion 12, to be cut at that portion of the light leakage to the outside from the region of the convex portion 12 It can contribute to flare reduction.
【0020】 [0020]
【発明の効果】 【Effect of the invention】
本発明によれば、透明カバーの照明窓を被覆する部分の表面を凸面状に形成して、照明窓から射出された照明光のうち透明カバーの凸面部の内面で反射された光が透明カバーの厚みの中において凸面部の領域から外側に向かわないようにしたことにより、照明窓の表面と観察窓の表面とを同じ透明カバーで被覆してもフレアーのない良好な観察像を得ることができる。 According to the present invention, the surface of the portion covering the illumination window of the transparent cover formed in a convex shape, the light transparent cover that is reflected by the inner surface of the convex portion of the transparent cover of the illumination light emitted from the illumination window of the fact that from the area of ​​the convex surface portion so as not directed to the outside in the inside of the thickness, to obtain a good observation image without flare be coated with the surface of the surface and the observation window of the illumination window of the same transparent cover it can.
【図面の簡単な説明】 BRIEF DESCRIPTION OF THE DRAWINGS
【図1】本発明の第1の実施例の内視鏡の先端部の側面断面図である。 1 is a side sectional view of the distal end portion of the endoscope of the first embodiment of the present invention.
【図2】本発明の第2の実施例の内視鏡の先端部の側面断面図である。 2 is a side cross-sectional view of the distal end portion of the endoscope of the second embodiment of the present invention.
【図3】本発明の第3の実施例の内視鏡の先端部の側面断面図である。 3 is a side cross-sectional view of the endoscope front end portion of a third embodiment of the present invention.
【図4】従来の内視鏡の先端部の側面断面図である。 4 is a side sectional view of the distal end portion of a conventional endoscope.
【符号の説明】 DESCRIPTION OF SYMBOLS
2 先端部本体3 観察窓4 照明窓5 対物光学系10 被覆シース11 透明カバー12 凸面部 2 the distal end section body 3 observation window 4 illumination window 5 objective optical system 10 covering the sheath 11 the transparent cover 12 convex portion

Claims (3)

  1. 照明光を射出する照明窓と対物光学系に光像をとり入れる観察窓とが挿入部の先端に並んで配置され、上記照明窓の表面と上記観察窓の表面とが同じ透明カバーで被覆された内視鏡の先端部において、 And the observation window to incorporate an optical image is arranged in the distal end of the insertion portion to the illumination window and an objective optical system for emitting illumination light, the surface of the surface and the observation window of the illumination window is covered with the same transparent cover at the tip of the endoscope,
    上記透明カバーの上記照明窓を被覆する部分の表面を凸面状に形成して、上記照明窓から射出された照明光のうち上記透明カバーの凸面部の内面で反射された光が上記透明カバーの厚みの中において上記凸面部の領域から外側に向かわないようにしたことを特徴とする内視鏡の先端部。 The surface of the portion covering the illumination window of the transparent cover formed in a convex shape, the light reflected by the inner surface of the convex portion of the transparent cover of the illumination light emitted from the illumination window of the transparent cover distal end portion of the endoscope, characterized in that so as not directed to the outside from the region of the convex portion in the inside of the thickness.
  2. 上記凸面が球面又は非球面状の曲面である請求項1記載の内視鏡の先端部。 Distal end portion of the endoscope according to claim 1, wherein said convex surface is spherical or aspherical curved surface.
  3. 上記透明カバーが、上記凸面部の外縁部分においてその周囲より肉薄に形成されている請求項1又は2記載の内視鏡の先端部。 The transparent cover, the distal end portion of an endoscope according to claim 1 or 2, wherein is formed thinner than its surroundings at the outer edge portion of the convex portion.
JP2002175148A 2002-06-17 2002-06-17 Distal end portion of the endoscope Expired - Fee Related JP4130940B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2002175148A JP4130940B2 (en) 2002-06-17 2002-06-17 Distal end portion of the endoscope

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2002175148A JP4130940B2 (en) 2002-06-17 2002-06-17 Distal end portion of the endoscope

Publications (2)

Publication Number Publication Date
JP2004016455A true JP2004016455A (en) 2004-01-22
JP4130940B2 JP4130940B2 (en) 2008-08-13

Family

ID=31173884

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2002175148A Expired - Fee Related JP4130940B2 (en) 2002-06-17 2002-06-17 Distal end portion of the endoscope

Country Status (1)

Country Link
JP (1) JP4130940B2 (en)

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7976501B2 (en) 2007-12-07 2011-07-12 Ethicon Endo-Surgery, Inc. Trocar seal with reduced contact area
US7981092B2 (en) 2008-05-08 2011-07-19 Ethicon Endo-Surgery, Inc. Vibratory trocar
US8100929B2 (en) 2007-06-29 2012-01-24 Ethicon Endo-Surgery, Inc. Duckbill seal with fluid drainage feature
US8273060B2 (en) 2008-04-28 2012-09-25 Ethicon Endo-Surgery, Inc. Fluid removal in a surgical access device
US8568362B2 (en) 2008-04-28 2013-10-29 Ethicon Endo-Surgery, Inc. Surgical access device with sorbents
US8579807B2 (en) 2008-04-28 2013-11-12 Ethicon Endo-Surgery, Inc. Absorbing fluids in a surgical access device
US8636686B2 (en) 2008-04-28 2014-01-28 Ethicon Endo-Surgery, Inc. Surgical access device
USD700326S1 (en) 2008-04-28 2014-02-25 Ethicon Endo-Surgery, Inc. Trocar housing
US8690831B2 (en) 2008-04-25 2014-04-08 Ethicon Endo-Surgery, Inc. Gas jet fluid removal in a trocar
US8870747B2 (en) 2008-04-28 2014-10-28 Ethicon Endo-Surgery, Inc. Scraping fluid removal in a surgical access device
US9358041B2 (en) 2008-04-28 2016-06-07 Ethicon Endo-Surgery, Llc Wicking fluid management in a surgical access device

Cited By (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8771307B2 (en) 2007-06-29 2014-07-08 Ethicon Endo-Surgery, Inc. Duckbill seal with fluid drainage feature
US8100929B2 (en) 2007-06-29 2012-01-24 Ethicon Endo-Surgery, Inc. Duckbill seal with fluid drainage feature
US8672890B2 (en) 2007-12-07 2014-03-18 Ethicon Endo-Surgery, Inc. Trocar seal with reduced contact area
US7976501B2 (en) 2007-12-07 2011-07-12 Ethicon Endo-Surgery, Inc. Trocar seal with reduced contact area
US8690831B2 (en) 2008-04-25 2014-04-08 Ethicon Endo-Surgery, Inc. Gas jet fluid removal in a trocar
US9827383B2 (en) 2008-04-28 2017-11-28 Ethicon Llc Surgical access device
US8636686B2 (en) 2008-04-28 2014-01-28 Ethicon Endo-Surgery, Inc. Surgical access device
USD700326S1 (en) 2008-04-28 2014-02-25 Ethicon Endo-Surgery, Inc. Trocar housing
US8273060B2 (en) 2008-04-28 2012-09-25 Ethicon Endo-Surgery, Inc. Fluid removal in a surgical access device
US8579807B2 (en) 2008-04-28 2013-11-12 Ethicon Endo-Surgery, Inc. Absorbing fluids in a surgical access device
US8568362B2 (en) 2008-04-28 2013-10-29 Ethicon Endo-Surgery, Inc. Surgical access device with sorbents
US8870747B2 (en) 2008-04-28 2014-10-28 Ethicon Endo-Surgery, Inc. Scraping fluid removal in a surgical access device
US9033929B2 (en) 2008-04-28 2015-05-19 Ethicon Endo-Surgery, Inc. Fluid removal in a surgical access device
USD735852S1 (en) 2008-04-28 2015-08-04 Ethicon Endo-Surgery, Inc. Fluid remover
USD736926S1 (en) 2008-04-28 2015-08-18 Ethicon Endo-Sugery, Inc. Trocar housing
US9358041B2 (en) 2008-04-28 2016-06-07 Ethicon Endo-Surgery, Llc Wicking fluid management in a surgical access device
US7981092B2 (en) 2008-05-08 2011-07-19 Ethicon Endo-Surgery, Inc. Vibratory trocar

Also Published As

Publication number Publication date
JP4130940B2 (en) 2008-08-13

Similar Documents

Publication Publication Date Title
JP3795393B2 (en) Optical system
US6855111B2 (en) Capsule endoscope
US5936773A (en) Image-forming optical apparatus having a decentered optical surface
CN102469924B (en) The endoscope apparatus and an endoscope
US5718664A (en) Light guide connection port for a disposable arthroscope
JP4054094B2 (en) Electronic endoscope
JP3872852B2 (en) Endoscopic tv observation system, a light source unit used in the endoscopic tv observation system, and an endoscope for small source unit
CN1126901C (en) Illumination device with side emitting light guide
US4610513A (en) Illumination optical system for an endoscope
JP5944912B2 (en) An optical system for a multi-sensor endoscopy
KR101049980B1 (en) Endoscope
ES2218694T3 (en) Portable capture unit image to the eye.
US20110196200A1 (en) Multi-view endoscopic imaging system
US20070213591A1 (en) Disposable Cap for Endoscope
JP2615006B2 (en) Fiber for elevation the laser beam side
US4929070A (en) Illumination optical system for endoscopes
US5630788A (en) Endoscope with curved end image guide
US3944341A (en) Wide-angle ophthalmoscope and fundus camera
US8517928B2 (en) Capsule-type endoscope
JP5084330B2 (en) Observation optical system
US4195904A (en) Optical system of viewing-direction changing attachment for endoscopes
GB2030313A (en) Endoscopes
KR20080068730A (en) Surgical wide-angle illuminator
JPH07104494B2 (en) Endoscope illumination optical system
US20080242935A1 (en) Endoscope

Legal Events

Date Code Title Description
A621 Written request for application examination

Free format text: JAPANESE INTERMEDIATE CODE: A621

Effective date: 20050407

A977 Report on retrieval

Free format text: JAPANESE INTERMEDIATE CODE: A971007

Effective date: 20071128

A131 Notification of reasons for refusal

Free format text: JAPANESE INTERMEDIATE CODE: A131

Effective date: 20071213

A521 Written amendment

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20080130

TRDD Decision of grant or rejection written
A01 Written decision to grant a patent or to grant a registration (utility model)

Free format text: JAPANESE INTERMEDIATE CODE: A01

Effective date: 20080403

A01 Written decision to grant a patent or to grant a registration (utility model)

Free format text: JAPANESE INTERMEDIATE CODE: A01

A61 First payment of annual fees (during grant procedure)

Free format text: JAPANESE INTERMEDIATE CODE: A61

Effective date: 20080417

A711 Notification of change in applicant

Free format text: JAPANESE INTERMEDIATE CODE: A712

Effective date: 20080430

R150 Certificate of patent or registration of utility model

Free format text: JAPANESE INTERMEDIATE CODE: R150

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20110606

Year of fee payment: 3

LAPS Cancellation because of no payment of annual fees