WO2010076918A1

WO2010076918A1 - Micro endoscope with distal end adjustable in angle and curvature

Info

Publication number: WO2010076918A1
Application number: PCT/KR2009/001113
Authority: WO
Inventors: Byung-Ju Yi; Youngjin Choi; Hyunsoo Yoon; Se Min Oh
Original assignee: Iucf-Hyu(Industry-University Cooperation Foundation Hanyang University)
Priority date: 2009-01-05
Filing date: 2009-03-05
Publication date: 2010-07-08
Also published as: KR100990992B1; KR20100081149A

Abstract

A micro endoscope with a distal end adjustable in angle and curvature is provided in which a distal end of an insertion tube (1000) can be bended to 180° depending on applications and the curvature of the distal end can be adjusted. Here, the distal end of the insertion tube can be bent to an angle desired by a user by the use of a spring module (100), cylinders (200), and wires (300). In addition, since the distal end of the insertion tube (1000) can be fixed after the distal end is bent by the use of a fixing device such as a worm gear, it is possible to easily and accurately observe the inside of a human body desired by the user.

Description

MICRO ENDOSCOPE WITH DISTAL END ADJUSTABLE IN ANGLE AND CURVATURE

The present invention relates to a micro endoscope with a distal end adjustable in angle and curvature, and particularly to, a micro endoscope with a distal end adjustable in angle and curvature in which a distal end of an insertion tube can be bended to 180° depending on applications and the curvature of the distal end can be adjusted.

An endoscope is a medical instrument enabling to directly observe internal organs or coeloms of a human body. The endoscope is inserted into organs of which pathologies cannot be directly observed without operating or making an autopsy, for the purpose of observing the organs. Examples of the endoscope generally include a bronchoscope, an esophagoscope, a gastroscope, a duodenoscope, a rectoscope, a cystoscope, a laparoscope, a thoracoscope, a mediastinoscope, and a cardioscope

These endoscopes are generally configured so that an insertion tube is flexible to be bent along the internal bent portions of a human body, but the flexibility is limited. That is, a user does not adjust the bending of the insertion tube of the endoscope, but the insertion tube is naturally bent along the internal bent portions of a human body. Therefore, since the insertion tube cannot be bent in accordance with a user's intension at the time of inserting the endoscope into the inside of a human body, a camera disposed at a distal end of the insertion tube cannot be bent in a direction desired by the user.

An endoscope partially bendable has been developed to solve the above-mentioned problem. However, the bending angle and the curvature thereof are limited and the insertion tube cannot be fixed in a state where it is bent within the limited angle.

A technical goal of the invention is that it provided a micro endoscope with a distal end adjustable in angle and curvature in which an angle and a curvature of a distal end of an insertion tube can be adjusted.

Another technical goal of the invention is that it provides a micro endoscope with a distal end adjustable in angle and curvature in which the angle of the distal end of the insertion tube can be adjusted and then fixed.

According to an aspect of the invention, there is provided a micro endoscope with a distal end adjustable in angle and curvature, comprising: an insertion tube having a flexible spring module, one or more cylinders connected to one end of the spring module and separated from each other with a gap, a camera disposed at one end of the spring module, and one or more wires disposed around a main body of the spring module in a longitudinal direction thereof; and a driver connected to one end of the wires to tense or relax the wires. Here, the free length of the spring module and the length of the cylinders are determined on the basis of a bending angle of a final node of the insertion tube, a radius of curvature at the time of bending the insertion tube, a radius of the insertion tube, and the total number of nodes. Each node includes one cylinder and one spring module adjacent to the cylinder.

The bending angle of the final node of the insertion tube can be calculated by the following expression,

where θ_i represents the bending angle of the distal end of the respective nodes, i represents the number of a node and has a value of 1 to N, and N represents the total number of nodes. A bending radius of curvature of the insertion tube can be expressed by the following expression,

where X represents the position in the bending direction of the insertion tube, D represents a bending diameter of curvature of the insertion tube, and Z represents a longitudinal direction of the insertion tube.

The free length L of the spring module can be expressed by the following expression,

here N represents the total number of nodes, r represents a radius of the insertion tube, and θ₁ represents an angle of the distal end of the insertion tube. The length P of the cylinders is obtained by the following expression,

where a is expressed by

and D represents the bending diameter of the insertion tube.

The driver may further include a fixing device fixing the bending angle of the insertion tube. The driver may include a bidirectional motor and a roller and a bending shaft transmitting the power of the bidirectional motor to the wires, and the fixing device may be connected to the bending shaft. The fixing device may include a worm gear.

The number of wires may be even and the wires may be arranged with a constant gap.

According to the above-mentioned configuration, it is possible to provide a micro endoscope with a distal end adjustable in angle and curvature in which the distal end of the insertion tube can be bent to an angle desired by a user by the use of the spring module, the cylinders, and the wires.

In addition, since the distal end of the insertion tube can be bent and fixed in the bent state by the use of the fixing device such as a worm gear, it is possible to easily and accurately observe an internal part of a human body desired by a user.

FIG. 1 is a diagram illustrating a micro endoscope with a distal end adjustable in angle and curvature according to an embodiment of the invention and an operation control system thereof.

FIG. 2 is a perspective view illustrating a coupling relation among a main body, cylinders, and wires in the micro endoscope with a distal end adjustable in angle and curvature.

FIG. 3 is a conceptual diagram illustrating a bending of a spring module of an insertion tube in the micro endoscope with a distal end adjustable in angle and curvature.

FIG. 4 is a conceptual diagram illustrating the final node of the distal end of the insertion tube in the micro endoscope with a distal end adjustable in angle and curvature.

FIG. 5 is a conceptual diagram illustrating the first node of the distal end of the insertion tube in the micro endoscope with a distal end adjustable in angle and curvature.

FIG. 6 is a conceptual diagram illustrating a state where the insertion tube is bent to 180° in the micro endoscope with a distal end adjustable in angle and curvature.

FIG. 7 is a conceptual diagram illustrating a relation between the bending angle of the distal end of the insertion tube and the bending angle of the spring module in the micro endoscope with a distal end adjustable in angle and curvature.

FIG. 8 is a conceptual diagram illustrating inner and outer boundary lengths of the insertion tube in the micro endoscope with a distal end adjustable in angle and curvature.

Hereinafter, an embodiment of the invention will be described in detail with reference to the accompanying drawings.

However, the invention is not limited to the following embodiments, but can be modified in various forms. The embodiments are provided to complete the disclosure of the invention and to completely notify the scope of the invention to those skilled in the art. Like reference numerals in the drawings reference like elements.

FIG. 1 is a diagram illustrating a micro endoscope with a distal end adjustable in angle and curvature according to an embodiment of the invention and an operation control system thereof. FIG. 2 is a perspective view illustrating a coupling relation among a main body, cylinders, and wires in the micro endoscope with a distal end adjustable in angle and curvature.

As shown in FIG. 1, the micro endoscope with a distal end adjustable in angle and curvature according to an embodiment of the invention includes an insertion tube 1000 having a tube-like longitudinal shape and being bendable and a controller 2000 controlling the insertion tube 1000. Here, the insertion tube 1000 is a part that can be inserted into a human body and bent and includes a main body 100 bendable, cylinders 200 inserted onto the main body 100 and disposed with a constant gap, wires 300 used to bend the main body 100, and a camera 150. The controller 2000 serves to control the bending of the insertion tube 1000 and includes a driver 400, a manipulator 500, and a fixing device (not shown).

The main body 100 serves to give flexibility to the insertion tube 1000 to be bendable. For this purpose, the main body 100 is formed of a spring-like elastic member, that is, a spring module, having a predetermined length corresponding to the shape of the insertion tube 1000. The spring module can be elastically bent vertically and horizontally thanks to the basic feature of a spring and has a restoring force for restoring the shape to the original shape. Accordingly, when the insertion tube 1000 is bent and is then restored to the original shape, the insertion tube 1000 can be restored to the original shape thanks to the restoring force of the main body 100.

The cylinders 200 serve to receive the wires and to assist the bending and restoring of the main body 100 and each includes a cylinder body 210 having an opening 211 into which the main body 100 can be inserted and wire holes 212 formed to penetrate the cylinder body 210.

The cylinder body 210 comes in direct contact with the main body 100 so as to allow the main body 100 to be inserted therein and is formed of metal such as aluminum (Al) or alloy containing aluminum (Al). The cylinder body 210 is not limited to aluminum (Al), but may be formed of metal other than aluminum (Al) or non-metal as long as it is suitable for the application of the cylinder body 210.

The wire holes 212 are formed in the cylinder body 210 to receive the wires and penetrate the cylinder body 210 to be opened in the same direction as the opening direction of the opening 211 of the cylinder body 210. The number of wire holes 212 effectively corresponds to the number of wires, but the number of wire holes 212 may be greater than the number of wires as needed.

The cylinders having the above-mentioned structure are inserted in the longitudinal direction of the main body 100 and are preferably disposed at the distal end of the insertion tube 1000 which should be inserted into a human body and bent. The cylinders 200 are disposed at the distal end of the insertion tube 1000 with regular or irregular gaps from each other and thus enable the spring module between the cylinders to be bent.

On the other hand, the length of the cylinders and the length of the spring module can be determined on the basis of the bending angle of the distal end of the insertion tube 1000, the bending radius of curvature of the distal end of the insertion tube 1000, the radius of the insertion tube 1000, and the total number of nodes in the insertion tube 1000, which are set depending on the application of the endoscope. The determination will be described now with reference to the accompanying drawings.

FIG. 3 is a conceptual diagram illustrating the bending of the spring module of the insertion tube in the micro endoscope with a distal end adjustable in angle and curvature. In FIG. 3, F represents a force applied to the spring module and L represents a free length of the spring module.

As shown in FIG. 3, when one wire disposed at one side of the spring module according to this embodiment is pulled, the corresponding portion of the spring module is contracted and thus the other side of the spring module is expanded. A shape in which the spring module is bent to one side can be embodied by this operation. Here, it is assumed that the free length L of the center line is always constant due to the symmetry of the spring module.

FIG. 4 is a conceptual diagram illustrating the final node of the distal end of the insertion tube in the micro endoscope with a distal end adjustable in angle and curvature. FIG. 5 is a conceptual diagram illustrating the first node of the distal end of the insertion tube in the micro endoscope with a distal end adjustable in angle and curvature. FIG. 6 is a conceptual diagram illustrating a state where the insertion tube is bent to 180° in the micro endoscope with a distal end adjustable in angle and curvature. FIG. 7 is a conceptual diagram illustrating a relation between the bending angle of the distal end of the insertion tube and the bending angle of the spring module in the micro endoscope with a distal end adjustable in angle and curvature. FIG. 8 is a conceptual diagram illustrating inner and outer boundary lengths of the insertion tube in the micro endoscope with a distal end adjustable in angle and curvature. Here, P represents the length of the cylinders, L represents the free length of the spring module, i represents the number of a node, N represents the total number of nodes, β represents the bending angle (=θ₁) of the distal end of the insertion tube, and θ₁ represents the bending angle of the respective nodes. The node means a basic unit of a bendable structure and includes one cylinder and one spring module.

Referring to FIGS. 4 and 5, the bending angle θ_i of the respective nodes of the insertion tube can be calculated by Expression 1 from the geometric relation.

Expression 1

To determine the length P of the cylinders and the free length L of the spring module on the basis of the angle θ₁(=β) of the final node of the insertion tube expressed by Expression 1, the bending radius of curvature D/2 of the insertion tube, the radius r of the insertion tube, and the total number of nodes N, the position of the distal end of the insertion tube 1000 is first calculated. Functions of position of the final node of the insertion tube 1000 and the first node of the endoscope can be obtained from the geometric relation of FIGS. 4 and 5. Here, the function of position of the final node of the endoscope can be expressed by Expression 2.

Expression 2

Here, H_i represents the function of the position in the bending direction of the insertion tube 100 and W_i represents the function of the position in the longitudinal direction of the insertion tube 1000. The function of the position of the first node can be expressed by Expression 3.

Expression 3

Here, parameter a in the function of position (Expression 3) of the first node is expressed by Expression 4.

Expression 4

As a result, the position of the distal end of the insertion tube 1000 can be expressed by Expression 5.

Expression 5

Here, since the total number of nodes N and the angle θ₁(=β) of the final node of the insertion tube are set, that is, given, depending on the application of the endoscope, the function (Z) of the end-position in the longitudinal direction of the insertion tube and the function (X) of the end-position in the bending direction of the insertion tube are a function of the length P of the cylinders and the free length L of the spring module as seen from FIGS. 4 and 5. To bend the insertion tube 1000 with the radius of curvature D/2 under the given condition, the insertion tube 1000 should satisfy Expression 6.

Expression 6

Here, since the distal end of the insertion tube 1000 of the endoscope should be bent to 180°, 180° is set as the angle θ₁(=β) of the final node of the insertion tube 1000. As a result, Expression 6 can be expressed again by Expression 7.

Expression 7

Referring to FIG. 7, a relational expression between the bending angle θ₁(=β) of the final node of the insertion tube and the bending angle θ_v of the spring module can be defined as Expression 8. Here, θ_v denotes a bending angle of a spring module.

Expression 8

That is, the bending angle θ_v of the spring module and the angle θ₁(=β) of the final node of the insertion tube are proportional to each other. As the number of nodes increases, the bending angle θ_v of the spring module decreases. The contracted length k of one side of the spring module in FIG. 8 can be expressed by Expression 9.

Expression 9

The length L_s of the insertion tube 1000 in the contracted region in FIG. 8 can be calculated by adding the length P of the cylinders to the value, which is obtained by subtracting the contracted length 2k of both sides of the spring module from the free length L of the spring module, to obtain the length of one node and multiplying the length of one node by the total number of nodes N. The length L_c of the insertion tube 1000 in the free-length region can be calculated by multiplying the total number of nodes N by the value obtained by adding the length P of the cylinders to the free length L of the spring module. These can be expressed by Expressions 10 and 11.

Expression 10

Expression 11

To determine the length P of the cylinders and the free length L of the spring module, one condition, that is, information on the length by which one spring module should be contracted, is additionally required. This information can be obtained by dividing the contracted length of the entire spring module, which is obtained from Expressions 10 and 11, by the total number of nodes N. Accordingly, one condition for the free length L of the spring module, that is, the information on the length by which one spring module should be contracted, is added and is expressed by Expression 12.

Expression 12

Finally, the free length L of the spring module and the length P of the cylinders can be determined by Expressions 7 and 12.

In this way, when the bending angle θ₁ of the final node of the insertion tube, the bending radius of curvature D/2 of the distal end of the insertion tube, the radius r of the insertion tube, and the total number of nodes in the insertion tube, which are all set depending on the application of the endoscope, are given, the length P of the cylinders and the free length L of the spring module can be determined.

On the other hand, the wires 300 serves to bend the main body 100 by a user's manipulation and one or more wires are inserted into the wire holes 212 of the cylinder bodies 210 in the longitudinal direction of the main body 100. That is, four wires, that is, first to

fourth wires

310, 320, 330, and 340, are shown in FIG. 2, but the number of wires is not limited to four. The number of wires 300 can be changed depending on the application of the endoscope. Here, the first wire 310 is opposed to the fourth wire 340 and the second wire 320 is opposed to the third wire 330.

The camera 150 serves to acquire visible information and is preferably disposed at the distal end of the main body 100 to be bent.

The driver 400 serves to physically tense or relax the wires 300. Two wires 300 can be connected one driver 400. Since four wires are provided in this embodiment, the driver 400 includes two drivers, that is, first and

second drivers

410 and 420. The first driver 410 includes a first bidirectional motor 411, a first bending shaft 412, and a first roller 413. The second driver 420 includes a second bidirectional motor 421, a second bending shaft 422, and a second roller 423. The driver 400 can be driven with power externally supplied. The first and

second drivers

410 and 420 transmit the power of the first and second

bidirectional motors

411 and 412 for independently adjusting the tension to the first to

fourth wires

310, 320, 330, and 340 through the first and

second bending shafts

412 and 422 and the first and

second rollers

413 and 423. Here, the first to

fourth wires

310, 320, 330, and 340 are wound on or unwound from the first and

second bending shafts

412 and 422 with the operations of the first and second

bidirectional motors

411 and 421, thereby bending the main body 100 or restoring the main body 100 to the original status.

The driver 400 may further include a fixing device (not shown) to fix the bending status of the insertion tube 1000. The fixing device fixes the first and

second bending shafts

412 and 422 to maintain the bending status of the insertion tube 1000 and includes a structure such as a worm gear. The fixing device can be turned on and off by a user and thus the status of the insertion tube 1000 can be freely fixed.

The manipulator 500 serves to control the driver 400 and is electrically connected to the driver 400. The manipulator 500 includes a manipulation device such as a joy stick and buttons to enable the user to control the bending direction of the main body. Operation information of the first and second

bidirectional motors

411 and 421 of the driver 400 may be set in advance in the manipulator 500 on the basis of the bending direction information of the main body.

An operation of the micro endoscope with a distal end adjustable in angle and curvature having the above-mentioned structure will be described with reference to FIG. 1. When the distal end of the insertion tube 1000 is bent in direction A or B or direction C, the manipulator 500 can drive one or both of the first and second

bidirectional motors

411 and 421 on the basis of the predetermined operation information of the first and second

bidirectional motors

411 and 421. At this time, the bending of the distal end of the insertion tube 1000 in direction B drives the first bidirectional motor 411 in one direction to wind the first wire 310 on the first roller 413, thereby pulling the first wire 310. With this operation, the fourth wire 340 opposed to the first wire 310 is relaxed opposite to the first wire 310. With this operation, one side of the spring module is contracted and the other side is expanded, thereby bending the distal end of the insertion tube 1000 in direction B.

When the distal end of the insertion tube 1000 is bent in direction A, the manipulator 500 drives the first bidirectional motor 411 in the other direction to wind the fourth wire 340 on the first roller 413, thereby pulling the fourth wire. With this operation, the first wire 310 opposed to the fourth wire 340 is relaxed opposite to the fourth wire 340. With this operation, one side of the spring module is expanded and the other side is contracted, thereby bending the distal end of the insertion tube 1000 in direction A.

When the distal end of the insertion tube 1000 is bent in direction C perpendicular to direction A and direction B, the manipulator 500 drives the second bidirectional motor 421 in one direction to wind the second wire 320 on the second roller 423, thereby pulling the second wire 320. With this operation, the third wire 330 opposed to the second wire 320 is relaxed opposite to the second wire 320. With this operation, the distal end of the insertion tube 1000 is bent in direction C.

In addition to these operations, when the distal end of the insertion tube 1000 is bent in a diagonal direction between direction A and direction C, this operation can be embodied by driving at least one of the first and second

bidirectional motors

411 and 421 by the use of the manipulator 500. When it is desired by a user in the course of the bending operations, for example, when a nasal cavity is observed with the micro endoscope by the user, the bending status of the insertion tube 1000 can be fixed with the fixing device and then the inside part of a human body can be freely observed.

That is, when the number of wires 300 is four, two wires can be driven with the driving of one driver and thus the insertion tube 1000 can be bent in two opposite directions. Four wires can be driven with the driving of two drivers and thus the insertion tube 1000 can be bent in all directions.

As described above, according to the invention, the distal end of the insertion tube can be bent to an angle desired by a user, for example, to 180°, by the use of the spring module, the cylinders, and the wires. According to the invention, since the distal end of the insertion tube can be fixed to the bent status by the use of the fixing device such as a worm gear, it is possible to easily and accurately observe a desired inner part of a human body.

While the invention has been described with reference to the accompanying drawing and the exemplary embodiment, it will be understood by those skilled in the art that the invention can be modified in various forms without departing from the technical spirit of the invention taught from the appended claims.

For example, although the distal end of the insertion tube is bent to 180° in the above-mentioned embodiment, the invention is not limited to the angle, but the distal end of the insertion tube can be bent and fixed to an angle greater than or less than 180°.

Claims

A micro endoscope with a distal end adjustable in angle and curvature, comprising:

an insertion tube having a flexible spring module, one or more cylinders connected to one end of the spring module and separated from each other with a gap, a camera disposed at one end of the spring module, and one or more wires disposed around a main body of the spring module in a longitudinal direction thereof; and

a driver connected to one end of the wires to tense or relax the wires,

wherein the fee length of the spring module and the length of the cylinders are determined on the basis of a bending angle of a final node of the insertion tube, a radius of curvature at the time of bending the insertion tube, a radius of the insertion tube, and the total number of nodes, and

wherein each node includes one cylinder and one spring module adjacent to the cylinder.
The micro endoscope according to claim 1, wherein the bending angle of the final node of the insertion tube is calculated by the following expression,

where θ_i represents the bending angle of the distal end of the respective nodes, i represents the number of a node and has a value of 1 to N, and N represents the total number of nodes.
The micro endoscope according to claim 2, wherein a bending radius of curvature of the insertion tube is expressed by the following expression,

where X represents the position in the bending direction of the insertion tube, D represents a bending diameter of curvature of the insertion tube, and Z represents the position in the longitudinal direction of the insertion tube.
The micro endoscope according to claim 3, wherein the free length L of the spring module is expressed by the following expression,

where N represents the total number of nodes, r represents a radius of the insertion tube, and θ₁ represents an angle of the distal end of the insertion tube.
The micro endoscope according to claim 4, wherein the length P of the cylinders is obtained by the following expression,

where a is expressed by
The micro endoscope according to claim 1, wherein the driver further includes a fixing device fixing the bending angle of the insertion tube.
The micro endoscope according to claim 6, wherein the driver includes a bidirectional motor and a roller and a bending shaft transmitting the power of the bidirectional motor to the wires, and

wherein the fixing device is connected to the bending shaft.
The micro endoscope according to claim 6, wherein the fixing device includes a worm gear.
The micro endoscope according to claim 1, wherein the number of wires is even and the wires are arranged with a constant gap.