ENDOSCOPE

• US 3,561,432 A
• Filed: 06/27/1968
• Issued: 02/09/1971
• Est. Priority Date: 07/29/1967
• Status: Expired due to Term

• Current Assignee: Murata Rikizo, Yamaki Shigeru
• Original Assignee: Murata Rikizo, Yamaki Shigeru
• Inventors: YAMAKI SHIGERU, MURATA RIKIZO
• Application Number:
  US04/740,737
• Time in Patent Office: 957 Days
• US Class Current: 600/167
• CPC Class Codes: A61B 1/00098 Deflecting means for inserted tools
• CPC Class Codes: A61B 1/00165 with light-conductive means, e.g. fibre optics A61B1/07 takes precedence
• CPC Class Codes: A61B 1/00188 with focusing or zooming features
• CPC Class Codes: A61B 1/018 for receiving instruments

Abstract

An endoscope having a forward end casing adapted to be inserted into a hollow portion of a living body and provided with an objective lens system for forming an image of an object by the light therefrom, a control casing provided with ocular means, an elongated tube connecting the forward end casing and the control casing, and an image transmitting optical system extending through the elongated tube. The forward end of the image transmitting optical system is located behind the objective lens system adjacent thereto so as to form the image of the object on the forward end of the image transmitting optical system so that the image is transmitted through the image transmitting optical system to the rearward end thereof, while the rearward end of the image transmitting optical system is located in front of the ocular means adjacent thereto so that the image thus transmitted to the rearward end of the image transmitting optical system is viewed through the ocular means. The objective lens system comprises at least two lens elements or lens groups each movable along the optical axis. The two lens elements or lens groups are operatively coupled with each other so that the movement of one of the two lens elements or lens groups causes the other to be moved relative thereto to thereby permit the distance between the two lens elements or lens groups to be varied, thus resulting in the variation in the focal length of the objective lens system. String means extends through the elongated tube with its one end connected to a control mechanism provided in the control casing and with its other end connected to one of the two lens elements or lens groups so that the two lens elements or lens groups are moved simultaneously by actuating the string means by the control mechanism.

Claims

1. An endoscope having a forward end casing adapted to be inserted into a hollow portion of a living body and provided with an objective lens system for forming an image of an object by the light therefrom, a control casing provided with ocular means, an elongated tube connecting said forward end casing and said control casing, and an image transmitting optical system extending through said elongated tube with its forward end located behind said objective lens system adjacent thereto so that the image of the object is formed on said forward end thereby to permit the image to be transmitted to the rearward end of said image transmitting optical system therethrough, the rearward end of said image transmitting optical system being located in front of said ocular means adjacent thereto thereby to permit the image thus transmitted to said rearward end to be viewed through said ocular means, wherein the improvement comprises:

at least two lens elements or lens groups provided in said objective lens system movable along the optical axis for varying the focal length of said objective lens system and operatively coupled with each other by at least a pair of links with their one ends swingably connected to each other and with their other ends swingably connected to said two lens elements or lens groups, respectively, said one end of said pair of links being guided for movement transverse to the direction of the optical axis of said objective lens system, so that said two lens elements or lens groups are relatively moved simultaneously along the optical axis from each other or toward each other, and string means extending through said elongated tube with its one end portion connected to a control mechanism provided in said control casing and with its other end portion connected to at least one of said two lens elements or lens groups to thereby permit said two lens elements or lens groups to be moved by actuating said string means by said control mechanism.

2. An endoscope according to claim 1, wherein spring means is provided for urging one of said two lens elements or lens groups in one direction so that the other of said two lens elements or lens groups is urged in the opposite direction, said other end portion of said string means being connected to one of said two lens elements or lens groups which is urged forwardly apart from said control mechanism by said spring means thereby permitting said two lens elements or lens groups to be moved by only pulling said string means by means of said control mechanism against the action of said spring means.

3. An endoscope having a forward end casing adapted to be inserted into a hollow portion of a living body and provided with an objective lens system for forming an image of an object by the light therefrom, a control casing provided with ocular means, an elongated tube connecting said forward end casing and said control casing, and an image transmitting optical system extending through said elongated tube with its forward end located behind said objective lens system adjacent thereto so that the image of the object is formed on said forward end thereby to permit the image to be transmitted to the rearward end of said image transmitting optical system therethrough, the rearward end of said image transmitting optical system being located in front of said ocular means adjacent thereto thereby to permit the image thus transmitted to said rearward end to be viewed through said ocular means, wherein the improvement comprises:

at least two lens elements or lens groups provided in said objective lens systems movably along the optical axis for varying the focal length of said objective lens system, string means extending through said elongated tube forwardly toward the forward end of said forward end casing beyond said two lens elements or lens groups to lead-back means located in said forward end of said forward end casing for leading back said string means rearwardly therefrom with its one end portion connected to a control mechanism in said control casing and with its other end portion which is thus lead rearwardly from said lead-back means connected to spring means for urging said other end portion apart from said forward end thereby resiliently keeping said string means in tensioned state, one of said two lens elements or lens groups being connected to the portion of said string means extending between said lead-back means and said spring means while the other of said lens elements or lens groups is connected to a portion of said string means extending from said lead-back means toward said control mechanism so that the movement of one of said two lens elements or lens groups in one direction causes the other to be moved in the opposite direction relative thereto thereby permitting said two lens elements or lens groups to be moved simultaneously in opposite directions to each other by only pulling said string means by means of said control mechanism against the action of said spring.

4. An endoscope according to claim 3, wherein said lead-back means comprises pulley means rotatably mounted in the forward end of said forward end casing around which said string means is stretched.

5. An endoscope according to claim 3, wherein said lead-back means comprises lever means swingably mounted at the midway thereof in the forward end of said forward end casing, said string means being divided into two portions, one of said two portions being connected with its one end to one end of said lever means and with its other end to said spring means while the other of said two portions is connEcted with its one end to the other end of said lever means and with its other end to said control mechanism.

6. An endoscope according to claim 3, wherein one of said two lens elements or lens groups is mounted in a lens holder guided for movement along the optical axis of said objective lens system and provided with a plurality of arms extending therefrom toward the other of said lens elements or lens groups in spaced relationship from each other parallel to the optical axis while the other of said lens elements or lens groups is mounted in a lens holder guided for movement along the optical axis of said objective lens system and provided with the corresponding number of arms to those of the first mentioned lens holder extending therefrom toward said one of said lens elements or lens groups in spaced relationship from each other parallel to the optical axis, each of the arms of said last-mentioned lens holder being slidably fitted snugly in the respective spaces between the adjacent two arms of said first-mentioned lens holder so that said two lens elements or lens groups are smoothly moved in opposite directions to each other by the actuation of said string means.