JP2727140B2 - Optical actuator device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an actuator device using an optical fiber, and more particularly to an optical actuator device suitable for application to micromachine technology requiring mechanical operation in a narrow area.

[0002]

2. Description of the Related Art In recent years, the use of a so-called micromachine device capable of performing a functional mechanical operation in an extremely limited space has been studied for medical use, or for inspection and repair of an aircraft engine or a nuclear power plant. I have. On the other hand, examples of a device that performs a functional mechanical operation include an actuator device. Generally, an actuator device is an electric type in which a driving piece is connected to a driving mechanism including a motor and a ball screw.

[0003] However, the mechanism of the electric actuator is complicated, and in order to reduce the size, it is necessary to miniaturize all components such as a motor. It was not suitable for application in the required fields.

[0004]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a completely new type of actuator device using an optical fiber, which does not use an electric mechanism, has a simple structure, and can be easily miniaturized.

[0005]

In the optical actuator device of the present invention, a tube is attached to the other end of an optical fiber having one end connected to a light source, and a driving piece movable in the axial direction of the tube is inserted into the tube. and has, and I a space is provided between the drive pieces and the optical fiber end faces in the tubes
Furthermore, the optical fiber end face is tapered .

FIG. 1 is a schematic sectional view showing the structure of the present invention, in which a light source 1 is provided at one end of an optical fiber 2 having a core 21 and a clad 22, and an end 20 at the other end (shown in an enlarged view).
The tube 3 in which the driving piece 5 is inserted is attached.
The tube 3 is fixed to the optical fiber end portion 20, but the driving piece 5 is movable in the tube 3 in the axial direction. A space 4 is provided in the tube 3 between the optical fiber end face 23 and the inner end of the driving piece 5.
Although not shown in FIG. 1, the above optical fiber
The end face 23 is tapered (as shown in FIG. 3).
You.

In operation, when light power such as laser light is transmitted from the light source 1 through the optical fiber 2 and emitted from the end face 23, the fluid S existing in the space 4 in the tube 3 is heated by the laser light. As a result, the driving piece 5, which is movable in the axial direction of the tube 3, is moved forward by the thermal expansion force. When the supply of the laser beam is stopped, the fluid S in the space 4 contracts, and the driving piece 5 returns to the original position. That is, the tube 3 and the driving piece 5 have a relationship like a cylinder and a piston, and the light source 1
The drive piece 5 performs a piston motion by ON-OFF of the supply of light from the camera.

As the light source 1, various laser light sources are suitable, and for example, a YAG laser, Ar laser, He-Ne laser, Nd-YAG laser, Ho-YAG laser or the like can be used. As the optical fiber 2, a glass-based optical fiber,
Various types such as plastic optical fibers can be used. Above all, a multi-mode type optical fiber having a pure silica core is preferable because the laser power can be transmitted with high efficiency. Although one optical fiber is usually sufficient, a plurality of optical fibers may be converged. Further, it is desirable to provide a resin coating layer or the like on the outer periphery of the optical fiber for the purpose of reinforcement.

Various tubes such as a plastic tube and a metal tube can be used as the tube 3, but it is desirable that the tube 3 has such a rigidity that it is not easily deformed by the thermal expansion force of the fluid S. A SUS tube or the like can be exemplified as a suitable one. The tube 3 can be adhered to the optical fiber end 20 by, for example, an adhesive or a contraction force of the tube itself.

The driving piece 5 may be the simplest one having the same shape as the inner peripheral shape of the tube 3, but is generally of a shape and material according to the application. Further, in order to facilitate the movement in the axial direction, it is desirable to apply a lubricant to a portion in contact with the tube 3.
When there is a risk that the driving piece 5 may fall out of the tube 3, it is desirable to provide a stopper mechanism for preventing the driving piece 5 from slipping out as described later.

Although the space 4 in the tube 3 is not necessarily an airtight space, it is preferable that the space be as airtight as possible in order to efficiently transmit the thermal expansion force to the driving piece. The space may simply contain air, or may be separately filled with various gases or liquids, and any of them can be used as the fluid S. In particular, it is preferable to encapsulate a light-absorbing fluid so that a large thermal expansion force can be obtained by short-time light irradiation. For example, H as a light source
When an o-YAG laser is used, its wavelength is 2.1.
It is one of the preferable examples that a small amount of water is sealed in the space 4 since the wavelength is μm and the wavelength is well absorbed by water. In addition to this, encapsulating black powder having excellent light absorption such as carbon powder is also a suitable means for improving the thermal expansion force. The diameter and length of the space 4 are appropriately selected depending on the outer diameter of the optical fiber 2, the required pressing force of the driving piece 5, and the like. Specifically, the diameter is about 30 to 300 μm and the length is 1 A range of about 100 mm is preferred.

[0012]

Embodiments of the present invention will be described below. FIG.
In the equation, when the sectional area of the space 4 is S, the internal volume is V, the density of the fluid filled in the space 4 is d, and the specific heat is C, the heat capacity Q of the fluid in the space 4 is Q = V · d · It is represented by C [J / K]. The energy E of the laser light emitted from the optical fiber 2 into the space 4 depends on the laser power density P of the optical fiber 2 and the irradiation time t, and is expressed by E = S · P · t [J]. Therefore, the temperature of the fluid in the space 4 rises by ΔT = E / Q [K] due to the irradiation of the energy E. When the fluid is a gas, the initial temperature and pressure are To and Po, respectively, due to the temperature rise ΔT. The pressure will increase by ΔP = ΔT · Po / To [kg / cm ² ] according to Boyle-Charles law. Then, the driving piece 5 receives the pressure rise ΔP
In response to this, a pressing force F = ΔP · S [k
g weight], so that the driving piece 5 is
In the axial direction.

For example, if the diameter of the core 21 of the optical fiber 2 is 2
0 μm, the inner diameter of the tube 3 was 100 μm, the length of the space 4 was 10 mm, and air (density: 1.2 × 10 ⁻³ g / cm
^{3. When} a specific heat of 1 J / g · K) is filled and a laser beam is irradiated for 0.1 ^{second under} the condition that the laser power density of the optical fiber 2 is 10 ⁶ W / cm ² , the pressing force F = 0.79
An initial pressing force on the driving piece 5 having a weight of kg can be obtained.

As described above, the tube 3 having an inner diameter of about 100 μm, the optical fiber 2 and the driving piece 5 only have a simple structure.
It is possible to realize an extremely small drive system.

As described above, it is desirable that the driving piece 5 is provided with a stopper mechanism so as not to get out of the tube 3. FIG. 2 shows an example of such a stopper mechanism, in which a slit 30 is provided in a part of the tube 3 and a locking piece 51 protruding from the slit 30 is provided on the periphery of the driving piece 5. In this way, the moving range of the driving piece 5 is restricted by the width of the slit 30, and it is possible to prevent the driving piece 5 from slipping out.

FIG. 3 shows another embodiment of the present invention, in which a locking piece 51 is provided around a driving piece 5, and the locking piece 51 is provided.
And the end of the tube 3 are connected by a spring 62, and a cover 61 is provided to cover this connection portion and to have a contact portion with the locking piece 51 and also to prevent the driving piece 5 from coming off the tube 3. Configuration. The drawing shows a state in which the laser beam is irradiated from the optical fiber 2, the fluid in the space 4 thermally expands, and the driving piece 5 is pressed and moved to the maximum. When the irradiation of the laser beam is stopped, the spring 62 is moved. Immediately, the driving piece 5 is forcibly returned to the original state. The configuration as in the present embodiment is useful when the driving piece 5 needs to be moved at a high speed by a piston.

By irradiating the laser beam into the space 4 as uniformly as possible over the entire space, all of the fluid existing in the space 4 undergoes thermal expansion to efficiently generate a pressing force. This is desirable. For this reason, in the embodiment shown in FIG. 3, the end face 210 of the optical fiber 20 is tapered and the core 21 is formed as an end face 210 which is exposed for a relatively long distance so that light can be irradiated into the space 4 as uniformly as possible. Is what it is.

The actuator device as described above includes:
The optical fiber itself usually has an outer diameter of about 40 to 200 μm and is inherently suitable as a small actuator device, so that it can be used as a power source of a micromachine. For example, when a micro scalpel or the like is attached to the distal end of the driving piece 5 via a gear mechanism, it can be easily applied to the medical field, such as being inserted into a human body to perform a surgical operation on an affected part.

[0019]

According to the optical actuator device of the present invention as described above, the actuator device basically includes only one optical fiber, a tube, and a driving piece. It has a very simple configuration that does not require a driving source and no power supply lead wire, and has a simple configuration, so that microfabrication is extremely easy. In addition, since electricity is not used, there is no fear of electric shock even when applied to the inside of a human body or the like, so that it is safe. Therefore, the present invention is an actuator device that is extremely useful as a power source for a medical micromachine or the like.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a cross-sectional view illustrating an example of a drive piece detachment prevention mechanism.

FIG. 3 is a sectional view showing another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Light source 2 Optical fiber 20 Optical fiber end part 3 Tube 4 Space 5 Drive piece

Claims (1)

(57) [Claims] 1. A tube is attached to the other end of an optical fiber having one end connected to a light source, and a driving piece movable in the axial direction of the tube is inserted into the tube. A space is provided between the optical fiber end face and the driving piece, and the optical fiber end face is tapered.
An optical actuator device characterized by being processed .