JP3010577B2 - Optically driven manipulator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optically driven manipulator which heats and drives a driving member made of a shape memory member by irradiating light from an optical fiber, and more particularly to use in a medical device such as an endoscope. The present invention relates to a suitable optically driven manipulator.

[0002]

2. Description of the Related Art In recent years, a bending mechanism for a long object such as an endoscope and a driving mechanism for a micro valve, a micro robot, and the like have been developed by using a driving member formed of a shape memory member. In general, a shape memory alloy is used for a driving member used in such an application, and heating of the shape memory alloy is performed by electric heating because of easy control.

[0003] However, when it is used for medical purposes and the like, it is necessary to ensure electrical safety. Therefore, a method of heating a shape memory alloy by irradiating light has been proposed. As a heating method by this light irradiation, directly to one end of a driving member made of a shape memory alloy,
A method of heating by irradiating light is conceivable. However, since the shape memory alloy has poor heat conduction, only the portion directly irradiated with light is heated, and the driving member does not operate.

Another method is disclosed in Japanese Patent Application Laid-Open No. 63-194.
No. 628, a method of exposing a core by exposing a core by partially removing a clad part of an optical fiber, irradiating the shape memory alloy with light by leakage of light from a side surface of the exposed core, and heating the core. Has been proposed. However,
Simply removing the clad portion results in poor light leakage efficiency from the core side surface, and most of the light is emitted from the core tip.

[0005]

Therefore, according to the present invention, it is possible to drive a driving member consisting of a shape memory member by efficiently irradiating light over a wide range and heating the driving member. Another object of the present invention is to provide an optically driven manipulator that can be easily controlled.

[0006]

According to the present invention, there is provided an optically driven manipulator driven by heating a driving member comprising a shape memory member by irradiating light, wherein the driving member is in a contracted state. A light emitting end of an optical fiber having an exposed core tapered in a hollow portion of the shape memory alloy coil so that a part of the shape memory alloy coil can be irradiated. By arranging, the irradiated part of the shape memory alloy coil becomes a coil having a contracting operation force, the non-irradiated part becomes a coil having a bias force, and one shape memory alloy coil operates as an antagonistic coil. It is a feature.

[0007] The shape of the exposed core is not particularly limited as long as it is tapered.
Preferably, light can be emitted uniformly. For example, it can be determined as appropriate depending on the shape and size of the driving member such as a cone, a triangular pyramid, a shape gradually narrowing in a step shape, among which the core portion is stepped toward the optical fiber tip. The shape in which the core diameter is reduced is preferable from the viewpoint of easy production.

The drive member is not particularly limited as long as it is a shape memory alloy coil. For example, a TiNi shape memory alloy is particularly preferable in terms of stability and controllability of the shape memory operation. In addition, by irradiating a part of the coil to form an antagonistic shape memory alloy coil having a bias force by itself, for example, by halving the irradiable range, it is the same as using two identical coils. This is preferable because the design and control of the driving member becomes easy.

[0009] Furthermore, inserting the emission end of the optical fiber with the core exposed in the hollow portion of the shape memory alloy coil,
The exit end of the optical fiber that is physically weakened, such as being easily broken due to exposure of the core, can be protected by the shape memory alloy coil.

[0010] Further, even when light is emitted from the tapered core to the driving member, the installation conditions, the shape of the tapered portion,
Depending on the shape of the driving member, a temperature difference may occur in the driving member. In such a case, it is desirable to make the heating state of the driving member uniform. It is preferable to coat with a material having better heat conductivity than the shape memory alloy.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail. FIG. 1 is a view showing one embodiment of the optically driven manipulator of the present invention. To explain according to the figure,
1 is an optical fiber comprising a core 2 and a clad 3,
The exit end of the optical fiber 1 is in a state where the clad 3 is removed and the core 2 is exposed. The exposed core portion 12 is tapered toward the distal end, and a shape memory alloy coil 4 serving as a driving member is attached to the outer periphery of the exposed core portion in an outer fitting shape.

The core 2 is exposed by removing the cladding 3 at the emission end of the optical fiber 1 in this manner, and the exposed core 12
Is tapered, so that light can be efficiently emitted from the exposed side surface of the core 12, and the shape memory alloy coil 4 can be irradiated with light over a wide range.
Therefore, the shape memory alloy coil 4 can be substantially uniformly heated over a wide range, and the shape memory alloy coil can be favorably operated.

The optical fiber only needs to be able to guide light to the exit end, and examples thereof include a quartz type, a multi-component glass type, and a plastic type.

The light emitted from the exposed core is not applied to the entire shape memory alloy coil,
By irradiating a part of the manipulator, an antagonistic light-driven manipulator excellent in design and control can be obtained. For example, by fixing both ends of a shape memory alloy coil and arranging the exposed core so as to be able to irradiate a part of the coil, an antagonistic driving member having a bias force with one coil can be obtained. By halving the irradiable range, it becomes the same as the state using two identical coils, so that the design and control of the driving member can be easily performed.

Further, by arranging the driving member so as to be able to irradiate at least half of the driving member and coating the driving member with a material having good heat conductivity, the driving member can be heated substantially as compared with a case where the driving member is not coated. And the design of drive members,
An optically driven manipulator that can be easily controlled can be provided.

The material having good thermal conductivity to be coated on the driving member can be appropriately determined, such as metal or resin, and the coating may be performed by a conventionally well-known method such as plating or vapor deposition. Can be.

[0017]

Embodiment 1 A specific embodiment will be described below. In this example, an optically driven manipulator having the structure shown in FIG. 1 was manufactured. FIG. 1 is a longitudinal sectional view of the optically driven manipulator of the present embodiment. According to the figure,
The output end of the optical fiber 1 has the clad 3 removed and the core 2
Is exposed, and the exposed core 12
, So that the core diameter gradually decreases in two steps toward the tip,
That is, first, the base side of the core exposed portion is connected to the first reduced diameter portion 12a.
The diameter of the core is smaller than the core diameter of the optical fiber 1, and the distal end side of the core exposed portion is formed as a second reduced diameter portion 12b, which is further narrower than the first reduced diameter portion 12a. In addition, a shape memory alloy coil is used for the driving member 4. Then, the exposed core portion 12 was inserted into the hollow portion of the shape memory alloy coil 4 to produce an optically driven manipulator.

The operation of the manipulator thus manufactured will be described. When the optical fiber 1 is connected to a light source and light enters, light is emitted from the exposed side surface of each stage of the core portion 12, The inner surface of the shape memory alloy coil 4 was irradiated. As a result, shape memory alloy coil 4
Is heated, recovers its shape, and the manipulator operates.

[0019]

Embodiment 2 In this embodiment, only the optical fiber 1 of the optically driven manipulator having the structure shown in Embodiment 1 is changed to the structure shown in FIG. As shown in FIG. 2, the optical fiber 1 used in the present embodiment has a shape in which the exposed core portion 12 has a conical shape with the tip as an apex.

[0020]

Comparative Example 1 As Comparative Example 1, as shown in FIG. 5, an optically driven manipulator in which a shape memory alloy coil 4 was arranged at a light emitting end of an optical fiber 1 at a small interval was manufactured.

[0021]

Comparative Example 2 In this comparative example, only the optical fiber 1 of the optically driven manipulator having the structure shown in Embodiment 1 is changed to the structure shown in FIG. As shown in FIG. 6, the optical fiber 1 used in this comparative example has the core 2 exposed by removing the cladding 3 at the emission end of the optical fiber 1, and the exposed core portion 12 is tapered. It is not something.

In order to examine the heatable range of the shape memory alloy coil 4 in the above-described Examples 1 and 2 and Comparative Examples 1 and 2, a wire diameter of 150 μm was used for the shape memory alloy coil 4.
T in a tightly wound state with a coil outer diameter of 450 μm and a length of 15 mm
In Examples 1 and 2 and Comparative Example 2 using an iNi alloy coil, a laser light source having a wavelength of 1.48 μm was used as the light source, and a diameter 50 made of GeO 2 —SiO 2 was used as the optical fiber 1.
A multi-mode fiber having a 2 μm core 2 and a 125 μm diameter clad 3 made of SiO 2 was used. In Comparative Example 1, a laser light source having a wavelength of 810 nm was used as a light source, and an optical fiber 1 had a core diameter of 400 μm. The shape memory alloy coil 4 was irradiated with laser light using a multi-mode fiber having a cladding diameter of 600 μm, and the temperature of the shape memory alloy coil 4 was measured with a radiation thermometer. Examples 1 and 2
The length of the exposed core portion 12 of Comparative Example 2 was 10 mm, and the entire length of the exposed core portion 12 was inserted into the shape memory alloy coil 4.

FIG. 3 shows the results. In the figure, the vertical axis represents the temperature of the shape memory alloy coil, and the point Af in the figure represents the transformation temperature of the shape memory alloy coil 4 used. The horizontal axis represents the measurement point, that is, the distance from one end of the shape memory alloy coil 4, and is based on the end of the shape memory alloy coil 4 on the optical fiber 1 side. As shown in FIG. 3, in Comparative Example 1, only the fiber-side end of the shape memory alloy coil 4 was heated,
In Comparative Example 2, the temperature of the shape memory alloy coil 4 increased only near the tip of the exposed core portion 12. In contrast,
In Examples 1 and 2, which are examples of the present invention, the temperature could be increased over a wide range of the shape memory alloy coil 4. Therefore, the shape of the shape memory alloy coil 4 can be recovered over a wide range, and the manipulator can be efficiently operated by optical driving.

FIG. 4 shows an example in which the optically driven manipulator of the present invention is applied to a stereoscopic scope. More specifically, according to the drawing, two image guides 5 and 5 are arranged substantially in parallel, and an interlocking wire 7 is applied to the distal ends of the two image guides 5 and 5.
Is connected to the shape memory alloy coil 4, and both ends of the shape memory alloy coil 4 are fixed to the fixing member 8. The shape memory alloy coil 4 memorizes a tightly wound state, and is attached in an extended state. In the optical fiber 1, the core 2 is exposed by removing the cladding 3 at the emission end, and the exposed core 12 is formed in a conical shape. The conical core exposed portion 12 is
The entire length is inserted into and fixed to the hollow portion of the shape memory alloy coil 4, and is about 1/3 from the base end of the shape memory alloy coil 4.
It is located at the position. The stereoscopic scope has a structure in which a jacket 10 is covered and a cap 9 is attached to the end of the scope.

In the stereoscopic scope thus configured, when laser light is incident on the optical fiber 1 from the light source, the laser light is emitted from the exposed core portion 12 at the emission end of the optical fiber 1 and is transmitted to the shape memory alloy coil 4. Irradiate laser light. Approximately half of the shape memory alloy coil 4 on the base end side irradiated with the laser beam is heated to recover its shape and contract. Thereby, the pulling wire 6 connected to the shape memory alloy coil 4 is pulled, and the interlocking wire 7 to which the pulling wire 6 is connected is connected.
Is pulled, and the interlocking wire 7 is
The book image guides 5, 5 are pulled toward the center of the scope, the convergence angle changes, and a stereoscopic image is obtained. When the laser beam irradiation is stopped, the portion of the shape memory alloy coil 4 where the shape has not been recovered becomes a bias spring, and returns to the initial state.

As described above, an optically driven stereoscopic scope can be obtained by using the optically driven manipulator of the present invention. It is needless to say that the optically driven manipulator is not limited to application to a stereoscopic scope, but can be widely used as a drive source such as a bending mechanism of an endoscope, a microvalve, or a microrobot.

[0027]

According to the optically driven manipulator of the present invention as described above, the core at the exit end of the optical fiber is exposed, and the exposed core is tapered, so that the drive comprising the shape memory member is achieved. The member can be efficiently irradiated with light over a wide range, the driving member can be efficiently and uniformly heated over a wide range, and the driving member can be favorably operated. .

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of an optically driven manipulator according to the present invention.

FIG. 2 is a longitudinal sectional view of another embodiment of the optical fiber used in the optically driven manipulator of the present invention.

FIG. 3 is a diagram showing a measurement result of a heatable range of the optically driven manipulators of Examples 1 and 2 and Comparative Examples 1 and 2.

FIG. 4 is a longitudinal sectional view of a stereoscopic scope to which the optically driven manipulator of the present invention is applied.

FIG. 5 is a longitudinal sectional view of a conventional optically driven manipulator.

FIG. 6 is a longitudinal sectional view of another embodiment of the conventional optically driven manipulator.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Optical fiber 2 Core 3 Cladding 4 Driving member 5 Image guide 6 Pulling wire 7 Interlocking wire 8 Fixing member 9 Tip cap 10 Jacket 12 Core exposed part 12a First reduced diameter part of core exposed part 12b First of core exposed part 2 reduced diameter part

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-62-124893 (JP, A) JP-A-61-203413 (JP, A) JP-A-63-21586 (JP, U) JP-A-64 3607 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) B25J 19/00 B25J 7/00 F03G 7/06 G02B 6/10

Claims (2)

(57) [Claims] 1. An optically driven manipulator driven by heating a drive member made of a shape memory member by irradiation of light, wherein the drive member is a shape memory alloy coil storing a contracted state, An irradiation end of the shape memory alloy coil is provided by disposing an emission end of an optical fiber having an exposed core tapered in a hollow portion of the memory alloy coil so that a part of the shape memory alloy coil can be irradiated. An optically driven manipulator characterized in that is a coil having a contracting operation force, a non-irradiated part is a coil having a biasing force, and one shape memory alloy coil operates as an antagonistic coil. 2. The optically driven manipulator according to claim 1, wherein the shape memory alloy coil is coated with a material having better heat conductivity than the shape memory alloy.