JPH0574055B2 - - Google Patents

Description

[Detailed description of the invention]

(a) Industrial application field This invention is a fiberscope that utilizes an image fiber that bundles a large number of fiber wires in an aligned state and directly transmits an image, and in particular uses a shape memory alloy to make the tip part freely adjustable. This invention relates to a fiberscope that can be bent or expanded. (b) Prior art In a fiberscope that uses an image fiber, for example, as in a gastric endoscope, the imaging section at the tip is bent by external operation to change the direction, or the focal length of the optical system is changed. They often need to be stretched lengthwise to fit. Therefore, conventionally, as shown in FIG. 1, a large number of nodal rings 2 are inserted around an image fiber 1, and each nodal ring 2 is abutted against each other at a spherical fulcrum 3 provided in the center. The image fiber 1 was bent by a manipulation wire 4 inserted through the holder. The fiberscope with the above-mentioned configuration has the disadvantage that it becomes thick due to the use of the joint ring 2, and the frictional force of the wire 4 accumulates as the length increases, so the controllable distance is 2 to 2. The length was within several meters, and there was a drawback that it could not be used with fiberscopes longer than that. On the other hand, recently, a new manufacturing method for image fibers has been developed, making it possible to produce extremely thin and long fiberscopes.In order to expand the field of application, the above-mentioned drawbacks have been resolved and new fiberscopes have been developed. There is a need to develop suitable tip drive means. In order to solve this problem, a configuration has been devised in which a deformable member made of a shape memory alloy is attached to the fiberscope main body into which the image fiber is inserted, and a heating means is provided on the deformable member. The conventional example shown in FIG. 2 is a fiberscope equipped with bending means at the tip. As shown in FIG. 3, this fiberscope 10 includes an image transmission section 12 made of an image fiber and an illumination light transmission section 13 parallel to the fiberscope body 11, which is made of an image fiber, in the inside of a fiberscope body 11 made of a heat insulating material. integrated,
Furthermore, a drug injection hole 14 and a forceps insertion hole 15 are provided in parallel with these. In addition, each of the parts close to the outer peripheral wall of the main body 11 is placed 90 degrees from the center.
Four linear deformable members 16 are integrated in parallel with each of the above-mentioned parts at intervals in the circumferential direction. These deformable members 16 are Au-Cd, In-Tl
The pair of left and right deformable members 16 in FIG. The switch 18 is connected in series to the DC power supply 19.
The deformable member 16 generates heat due to its own electric resistance. In addition, a pair of upper and lower deformable members 16
are also connected in series to other DC power supplies 19 in the same way. Note that as a heating means for the deformable member 16, a fourth
As shown in the figure, a resistance heating wire 16' such as a nichrome wire may be placed along each deformable member 16, and the above-mentioned DC power source 19 may be connected to each of the resistance heating wires 16'. As shown by arrow a, the pair of left and right deformable members 16 curve upward at room temperature, and when the transformation temperature is reached by heating, they bend downward to maintain their memorized shape, and return to room temperature again. It has the property of curving upward. Further, the pair of upper and lower deformable members 16 have the property of deforming as shown by the arrow b in the same manner as in the above case. The deforming force of these deformable members 16 is the main body 11,
It is configured to exert a force larger than the bending strength of the image fibers of the image transmission section 12 and the illumination light transmission section 13 and the other pair of deformable members 16 that are not energized. Therefore, when the switch 18 is closed and the pair of deformable members 16 are heated, the fiberscope 10
is deformed, for example, as shown by the dashed line in FIG. Further, the amount of deformation can be freely determined depending on the magnitude of the load applied to the deformable member 16 at room temperature. The configuration example described above is based on the fiberscope main body 1.
1, a linear deformable member 16 is incorporated in the length direction of the fiberscope 10 to bend the fiberscope 10 in the radial direction. In another embodiment shown in FIG. It is made to be able to expand and contract in the length direction. That is, an elastic cylindrical body 22 is fixed to the tip of a fiberscope main body 21 in which an image fiber 20 is incorporated, a lens holder 23 is fixed to the tip of the cylindrical body 22, and a lens 24 is attached to the holder 23. ing. A spiral deformable member 25 is integrally incorporated inside the elastic cylinder 22. The deformable member 25 is formed of a shape memory alloy into a pipe shape, into which a resistance heating wire 26 such as a nichrome wire is inserted. The deformable member 25 is elastic in the longitudinal direction at room temperature, and has the property of contracting when heated. Therefore, when the deformable member 25 is heated by energization, the distance d between the lens 24 and the image fiber 20 can be changed, and the focal length of the lens 24 can be adjusted. In addition, instead of the above-mentioned elastic cylinder 22, this cylinder itself can be formed into a bellows-shaped cylinder using a shape memory alloy, and a resistance heating wire can be incorporated into or run along the cylinder. As in the above case, the tip of the fiberscope 10 can be expanded and contracted in the length direction. In this configuration example, a deformable member made of a shape memory alloy is attached to the fiberscope main body, and the deformable member is provided with a heating means, so that the diameter of the fiberscope does not increase, and the deformable member is electrically connected. Since it can be controlled mechanically, it has the effect of making the control distance much longer than conventional mechanical control. However, since a DC power source is used, a lead wire with twice the degree of freedom of movement of the tip portion is required. By using one side of the pair of lead wires to reduce the number of lead wires, the number of lead wires can be increased by one more than the degree of freedom of movement of the tip portion. However, as the degree of freedom of movement increases, the number of lead wires increases, making assembly of the fiberscope difficult. (c) Means for Solving the Problems In order to solve the above-mentioned problems and achieve the purpose, the present invention provides a method of attaching a deformable member made of a shape memory alloy to the fiberscope body into which an image fiber is inserted. In this configuration, the heating means for the deformable member is improved. (d) Embodiment The embodiment shown in FIG. 6 is an application of the present invention to the conventional example shown in FIG. Figure 7 shows the electrical circuit. R ₁ and R ₂ in the figure are from Figures 2 to 4,
Deformable member 1 made of shape memory alloy in Fig. 6
6, or resistance heating wire 16'. A capacitor 28 and a coil 29 are connected in series to each deformable member 16 or resistance heating wire 16', and a portion in which the above circuits are connected in parallel is attached to the tip of the fiberscope. A variable frequency oscillator 27 is prepared for control at hand, and is connected to the tip with a pair of lead wires 30. When the output voltage of the oscillator 27 is expressed as υ=Vsin(ωt) (1) ω: oscillation angular frequency of the power supply, the power consumed in R ₁ is P=R ₁ V ² /2 {(ωL ₁ −1/ωc ₁ ) ² +R ₁ ² }……(2
),

When [ ], the power consumed by R ₁ is maximum and heat is generated. On the other hand, if L _{2 and} C ₂ are taken so that L ₂ C ₂ ≠ L ₁ C ₁ ...(4), the impedance of the series circuit of L ₂ , C ₂ and R ₂ becomes high, and this series circuit Since the current flowing through is small, the heat generation in R ₂ is small. Therefore, by selecting the oscillation frequency of the oscillator 27, it is possible to control the movement of the fiberscope tip. Also, the resistance heating wire 2 in Fig. 5
By connecting a capacitor and a coil in series to 6, it is possible to control the expansion and contraction movement in the same way as before. Further, by closing each heating circuit and taking in electromagnetic energy from the outside through resonance, lead wires can be made unnecessary. (e) Effects As described above, the present invention is capable of controlling the movement of the tip of a fiberscope by connecting a resonant circuit as a heating means for the deformable member of a fiberscope equipped with a deformable member made of a shape memory alloy. By simply changing the oscillation frequency of the oscillator, there may be only one pair of lead wires or no lead wires. Therefore, even long fiberscopes with a large degree of freedom of movement can be easily assembled.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a conventional image fiber bending mechanism, Fig. 2 is a perspective view of a conventional fiberscope using a shape memory alloy, Fig. 3 is a sectional view thereof, and Fig. 4 is a modified example thereof. A cross-sectional view, FIG. 5, is a partial cross-sectional view of a conventional example for other motions. FIG. 6 is a perspective view of a fiberscope showing an embodiment of the present invention, and FIG. 7 is a circuit diagram illustrating its motion control. 10... Fiberscope, 11... Fiberscope body, 12... Image transmission section, 16... Deformable member, 16'... Resistance heating wire, 17... Connection,
19...DC power supply, 20...Image fiber,
21... Fiberscope body, 22... Cylindrical body,
25...Deformable member, 26...Resistance heating wire, 27...
...Oscillator, 28...Capacitor, 29...Coil, 30...Lead wire.

Claims (1)

[Scope of Claims] 1. A fiberscope in which an image fiber is inserted and a deformable member made of a shape memory alloy is attached, a heating means for the deformable member, a heating circuit in which a resonant circuit is connected to the heating means, and a heating power source. A fiberscope characterized by using an AC oscillator as an AC oscillator. 2. The fiberscope according to claim 1, wherein the resonant circuit is a series resonant circuit and is connected in series to the heating means. 3 Attach a plurality of the above deformable members, each or
Claim 1, characterized in that the resonant frequencies of the resonant circuits of some of the heating circuits are set to different values.
Fiberscope as described in Section. 4. The fiberscope according to claims 2 and 3, characterized in that a plurality of deformable member heating circuits connected to the resonant circuits are connected in parallel.