JPH06213139A - Light pressure actuator and manufacture thereof - Google Patents

Abstract

PURPOSE:To make a noncontact drive with the light pressure used as a drive source for resolving the problems of the unremote radiation and abrasion of a rotating mechanism by electrostatic force and unknown points such as the low revolving speed of light pressure rotation and the shape and manufacture of a fine object suitable for rotation. CONSTITUTION:A light pressure actuator 14 is provided with a circular moving body 15 having the specific thickness. A light pressure generating face 16 and a cut face 17 are formed in the rotating direction of the moving body 15 on part of the surface of the moving body 15. A moving body support section 19 is provided at a gap 18 on the outer periphery side of the moving body 15 to freely rotate the moving body 15 in the specific direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a micrometer-scale light pressure actuator using light pressure as a driving source and a method for manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, as a microactuator of this type, for example, "Micromachine" by Takaya and Esashi is used.
Motors such as those described in the Yomiuri Scientific Selection, 1991 are known. Figure 11 shows this motor,
The diameter is about 100 μm. This motor uses silicon and is manufactured by a micromachining technique (sacrificial layer etching technique).

In FIGS. 11A and 11B, the motor comprises a rotor (rotor) 1, an electrostatic electrode portion (stator) 2, and a rotor pressing support portion 3. The motor having such a structure rotates by using an electrostatic force as a drive source, but has a drawback that it requires wiring for power supply and cannot be operated by remote rotation. Further, since the rotor and the stator are severely rubbed and worn, the durability thereof is only about 10 minutes, and there is a drawback that the reliability is insufficient.

On the other hand, there are the following reports regarding the rotary drive utilizing light pressure. (1) Sugiura, Kawata, Minami: Rotation of particles under a microscope using circularly polarized laser beam, spectroscopic study, 39, pp. 342-346 (1990).
(2) S. Sato, M .; Ishigure and
H. Inaba: “Optical trapping
and rotation manipulation
ofmicroscopic particles
andbiological cells using
higher-order mode Nd: YAG
laser beams ", Electron Let
t. , 27, pp. 1831-1832 (1991).
(3) Sasaki, Koshioka, Misawa, Kitamura, Masuhara: Laser-operated micromanipulation III. Assembly and driving of microstructure, Autumn Proceedings of Applied Physics, Proceedings, 9P-ZP-7,
841 (1991). (4) Sato, Ishizuka, Inaba: Proposal of optical micromotor and basic experiment, Autumn Proceedings of Applied Physics, Proceedings, 6a-N-10, 774 (1992).

[0005]

The above (1) is,
The latex particles dispersed in water are continuously rotated by the angular momentum of circularly polarized light.

FIG. 12 shows the configuration of the rotation experimental apparatus. In the figure, the laser light emitted from the Ar laser 4 is applied to the sample 8 via the λ / 4 plate 5, the dichroic mirror 6, and the objective lens 7. The sample 8 is again photographed by the CCD camera 11 and the VTR 12 through the objective lens 7, the dichroic mirror 6, the filter 9, and the relay lens 10, and is projected on the monitor 13. With such an experimental apparatus, a micro object can be rotationally driven by remote irradiation without contact. However, 1
The time required for rotation is extremely slow, from several tens of seconds to several tens of minutes.

In the above (2), the red blood cells are trapped by the steep light intensity distribution of the higher-order transverse mode light, and the red blood cells rotate following the rotation of the laser light. However, even with such a technique, the time required for one rotation is 10
It was about a second.

In the technique (3), one of two laser beams is used to fix a rod-shaped object and the other laser beam is rotated to rotate the object. Further, the technique according to the above (4) is that among the minute objects of LiNbO ₃ and KTiOPO ₄ , those having a relatively flat shape rotate at a high speed only by irradiating the laser beam. However, what shape is effective for the light pressure is not known, including its manufacturing method. Further, there is a problem that not only the actuators that rotate by light irradiation but also the conditions that the actuators that make linear motions should have are not clear.

In addition to the above-mentioned problems of non-remote irradiation and wear of the rotating mechanism by electrostatic force, the present invention is unclear about the conventional low rotation speed of light pressure rotation, the shape of a minute object suitable for rotation, and its manufacturing method. In order to solve the problem, it is an object of the present invention to provide a minute light pressure actuator capable of non-contact driving using light pressure as a driving source, and a manufacturing method thereof.

[0010]

That is, according to the present invention, there is provided a moving body having at least one light pressure generating slope formed on the surface thereof, and the moving body being arranged at a predetermined interval from the moving body.
And a movable body supporting portion for movably supporting the movable body in a predetermined direction, wherein the movable body is driven in the predetermined direction by the pressure of laser light so as to be remotely irradiated.

Further, according to the present invention, a photolithography process for forming a slit-shaped mask in a portion which becomes a moving body so that a slope for generating a light pressure is formed, and the photolithography process is aligned obliquely to the surface of the moving body. A step of forming a light pressure generating slope having opposing asymmetric angles on the movable body by etching using the beam component, and a movable body supporting portion and a predetermined body for supporting the movable body movably in a predetermined direction. And a step of placing the moving body at intervals.

[0012]

The light pressure actuator of the present invention has an inclined surface with respect to the optical axis on the surface of the moving body, and moves using a change in the momentum of light when the laser light is refracted and reflected by the inclined surface as a power source. By arranging the light pressure generating surface in this way, when the light is irradiated, the rotation torque is generated for the cylindrical moving body,
Linear movement is possible for a rectangular parallelepiped moving body.

Further, in the method for manufacturing a light pressure actuator according to the present invention, a slit-shaped mask is formed on a moving body, and etching is performed using a beam component aligned obliquely with respect to the mask surface of the moving body. A microscale actuator can be formed by forming light pressure generating slopes having asymmetrical angles facing each other.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a first embodiment of the light pressure actuator of the present invention, (a) is a perspective view showing the structure of the light pressure actuator of the first embodiment, and (b) is a view. It is the figure which showed a part of moving body. Light pressure actuator 1
4 is a moving body 15 having a predetermined thickness and formed in an annular shape.
have. On a part of the surface of the moving body 15, a light pressure generating surface 16 and a cutting surface 17 are formed as shown in the drawing in the rotation direction (direction of arrow A in the drawing) described later. Further, on the outer peripheral side of the moving body 15, a moving body supporting portion 19 for supporting the moving body with a gap 18 is provided. A medium may exist in the gap 18.

FIG. 2 is a cross-sectional view of the light pressure actuator 14, showing the irradiation state of the laser light 20. FIG. 2A shows a case where the moving body support portion 19 is a medium such as a liquid on which the moving body 15 is placed. In this case, the moving body 15 is three-dimensionally trapped and rotated by the laser light 20 as shown in FIG. Figure 2 (b)
Shows the case where the refractive index of the moving body 15 is smaller than the refractive index of the medium, or the case where the reflectance of the moving body 15 is high. As a result, the light pressure becomes a repulsive force, and the moving body 15 is pressed against the moving body supporting portion 19 by the laser light 20 to rotate. Further, FIG. 2C shows an example in which a support frame 21 for securely holding the moving body 15 is provided in the moving body supporting portion 19. Generally, the moving body 15 is trapped by the laser light 20 and floats up from the moving body supporting portion 19 with a minute gap. For this reason, it rotates without contact and no abrasion occurs.

Next, with reference to FIG. 1 (b), the principle of generating a rotational force by light pressure will be described.

When the refractive index of the moving body 15 is larger than the refractive index of the gap 18, the laser light 20 incident on the light pressure generating surface 16 in the figure is refracted at the surface and the optical path is changed as shown in the figure. . The change in the momentum of the photon corresponding to this change is the force (light pressure) F applied thereto, which is in the plane formed by the incident light 20 ₁ and the refracted light 20 ₂ , and the light pressure generating surface 1
6 becomes the vertical force. The light pressure generating surface 16 is the moving body 1.
Since it is inclined with respect to the tangential direction of 5, it has a rotational torque component.

A similar force acts on the cut surface 17 shown in FIG. 1A, but since the cut surface 17 is substantially parallel to the laser light 20, it does not have a rotational torque component. As a result, the moving body 15 is, as shown by the arrow A in the figure,
Rotate to the left.

In order to actually cause the light pressure actuator 14 to rotate, an experimental apparatus as shown in FIGS. 3 (a) and 3 (b) is used. That is, the YAG laser 23
Is focused and emitted toward the stage 22 from. And
The state on the stage 22 is the CCD camera 11 and the VT.
It is adapted to be displayed on the monitor 13 via R12.

Next, the operation will be described using such an experimental apparatus. First, the light pressure actuator 14 is dispersed in the liquid 24. Actually, the light pressure actuator 14 is sandwiched between the slide glass 25 and the cover glass 26. This light pressure actuator 1
4 is mounted on the stage 22 of the optical microscope. Then, in this state, the laser light 20 is focused and irradiated onto the light pressure actuator 14 via the objective lens 27.

The state of the light pressure actuator 14 is C
It is photographed by the CD camera 11 and the VTR 12 and can be observed using the monitor 13. Laser light 2
The wavelength of 0 is not particularly limited, but in consideration of damage to the light pressure actuator 14 due to light absorption, it is preferable to use a near-infrared YAG laser as shown in FIG.

In FIGS. 2 and 3, if the light output is increased by the amount corresponding to the buoyancy of the liquid, the moving body 15 should be rotated by the light pressure not in the liquid but in the air or vacuum. Is also possible.

Next, an example of a method of manufacturing the light pressure actuator thus constructed will be described with reference to FIG.

First, as shown in FIG. 4 (a), Ga
SiO ₂ as a material of the moving body is deposited on the As substrate by ion beam sputtering. Next, a light pressure generating surface of a portion that is a feature in manufacturing the light pressure actuator is manufactured. Therefore, as shown in FIG. 3B, a slit-shaped resist mask for forming a light pressure generating surface is manufactured by a photolithography process.

Next, a slit-shaped pattern as shown in FIG. 4C is formed by ion beam sputter etching in an oblique direction Ar having an incident direction inclined from the direction normal to the substrate surface to the light pressure generating surface. To convert. At this time, in the direction in which the ion beam is blocked by the mask, the etching surface is tilted more than the surface not blocked by the mask. Therefore, it is possible to form asymmetrical inclined surfaces facing each other.

Here, as shown in FIGS. 5A and 5B, the side wall inclination angle θ when the beam is vertically incident is previously obtained. Then, if the setting of the oblique incident angle is controlled as shown in FIG. 6C, it is easy to make one surface vertical as shown in FIG.

Subsequently, the shape of the entire moving body is manufactured. That is, as shown in FIG. 4D, after removing the resist mask, the resist mask having a movable body-shaped hole is aligned again by the photolithography process so as to include the light pressure generating surface. Create. Then, as shown in FIG. 6E, chromium is deposited by ion beam sputtering, and the chromium is patterned by lift-off of the resist with acetone. Then, using this chromium as a mask, the SiO ₂ is etched until the GaAs substrate appears by reactive ion beam etching using a fluorine-based gas, as shown in FIG.

After removing the chromium of the mask, FIG.
As shown in (g), the GaAs substrate is immersed in an etching solution containing sulfuric acid, hydrogen peroxide, and pure water. Since SiO ₂ does not melt in the above etching solution, the moving body is separated from the substrate and separated into the etching solution. Further, as shown in FIG. 3H, the moving body is recovered by filtering the etching solution with a ceramic filter having finer meshes than the moving body.

In the case of FIG. 2 (a) described above, the moving body may be dispersed in the liquid serving as the moving body supporting portion.
Further, in the case of FIG. 2B, the moving body may be carried and assembled on a moving body supporting portion separately formed by photolithography and etching by an optical manipulation technique or the like. Further, needless to say, the formation of the movable body and the movable body supporting portion in FIG. 2 (c) can be performed in the same manner by using the formation technique using the sacrificial layer in the production of the electrostatic microactuator. .

Although the light pressure generating surface is etched by ion beam sputter etching using an Ar beam using a resist mask in the above-described embodiment, any etching method that can change the beam direction may be used. Of course, this does not depend on the type of beam constituent atoms or the presence or absence of charge.

Further, in this embodiment, the material of the moving body is SiO 2.
₂ , GaAs, which is a material different from SiO _2, is used as the substrate material, and an etching solution composed of sulfuric acid, hydrogen peroxide, and pure water that can selectively etch only the substrate is used, but other combinations may be used. There is no end. Further, it is obvious that the deposition method is not limited to the ion beam sputtering, but may be another method such as an RF sputtering method.
In addition, in the method of etching SiO ₂ of the moving body,
Although the dry etching method using the chrome mask has been described, it goes without saying that other methods such as using a Ni plating mask or an amorphous silicon mask may be used.

Next, a second embodiment of the present invention will be described.

FIG. 6 is a perspective view of a light pressure actuator according to the second embodiment of the present invention. In the figure, a plurality of light pressure generating slopes 16 ′ and a plurality of cutting surfaces 17 are formed on the entire upper surface of the annular moving body 29 of the light pressure actuator 28. The moving body 29 thus formed is supported by the moving body supporting portion 19 via the gap 18.

By forming the movable body 29 in this way, the rotational force and rotational torque of the light pressure actuator 28 are increased as well as the rotational force thereof.

FIG. 7 is a diagram showing the principle of operation and shows the irradiation state of the laser beam 20. The figure (a) is the same as that of the above-mentioned 1st Example. However, in the second embodiment, since a large number of the above-mentioned light pressure generating slopes are arranged on the moving body 29, as shown in FIG. It may be irradiated. This is because the moving body 29 rotates even if the laser light 20 is fixed,
This is because it is possible to continuously generate the rotational torque by irradiating the next light pressure generating slope 16 '.

It is needless to say that the light pressure actuator according to the second embodiment can be formed in the same manner as the above-described first embodiment except that the process of manufacturing the light pressure generating surface is repeated many times. .

Next, a third embodiment of the present invention will be described.

FIG. 8 is a perspective view of a light pressure actuator according to the third embodiment of the present invention. In the figure, a light pressure generating slope 32 is formed linearly on a moving body 31 of the light pressure actuator 30. And this moving body 3
1 is supported by the moving body supporting portion 33 through a gap (not shown). In this way, by arranging the light pressure generating slopes 32 on the moving body 31 in a straight line, a linear motor that moves linearly in the directions of arrows B and C in the drawing is obtained.

Further, in the column DD ′ in FIG. 8, FIG.
As shown in (a), rightward direction (direction of arrow B in FIG. 8)
The light pressure generating slope 32a that generates the moving force of
A light pressure generating slope 32b that generates a moving force in the left direction (direction of arrow C in FIG. 8) is arranged in the EE ′ column in the inside. In other words, the moving direction can be controlled depending on which row the light pressure generating slopes 32 are irradiated with light. 34
Reference characters a and 34b represent vertical surfaces, respectively.

FIG. 10 is a diagram showing the operating principle of the light pressure actuator 30. As in the case of FIG. 7B, even if the laser light 20 is fixedly irradiated, the moving body 30 is driven to the right or left, and the next light pressure generating slope 32a or 32b is generated.
Can be irradiated to continue the linear movement.

In the light pressure actuator according to the embodiment, the process of manufacturing the light pressure generating surface is repeated twice, except that the etching beam is tilted in the opposite direction at that time.
It goes without saying that it can be formed in the same manner as in the first embodiment described above.

[0043]

As described above, according to the present invention, in addition to the problems of non-remote irradiation and wear of the rotating mechanism due to electrostatic force, the conventional low rotation speed of light pressure rotation, the shape of a minute object suitable for rotation, and its shape. In order to solve the problem of unknown manufacturing method and the like, it is possible to provide a minute light pressure actuator capable of non-contact driving using light pressure as a driving source. It can rotate at high speed or move linearly at high speed by light.

Further, according to the method for manufacturing a light pressure actuator according to the present invention, since non-contact and remote driving are possible,
A microscale actuator can be formed and can be used for micro agitation, a micro motor, a micro piston, a micro linear motor, and the like.

[Brief description of drawings]

FIG. 1A is a perspective view showing the configuration of a light pressure actuator of a first embodiment of the present invention, and FIG. 1B is a view for explaining the principle of rotational force generation by light pressure. It is the figure shown.

FIG. 2 is a diagram showing a cross section of a light pressure actuator and a laser light irradiation state.

FIG. 3 is a configuration diagram of an experimental device for driving the light pressure actuator of FIG. 1 by light pressure.

FIG. 4 is a diagram showing steps in a method of manufacturing the light pressure actuator of FIG.

5A and 5B are detailed explanations of the method of forming the inclination angle of the light pressure generating surface in the manufacturing method of FIG. 4, and FIGS. 5A and 5B are views showing a case where a symmetrical inclined surface is formed. , (C) and (d) are views showing a case where an asymmetric inclined surface used in the present invention is obtained.

FIG. 6 is a perspective view showing a configuration of a light pressure actuator according to a second embodiment of the present invention.

FIG. 7 is a diagram showing a laser light irradiation state on a light pressure actuator according to a second embodiment.

FIG. 8 is a perspective view showing a configuration of a light pressure actuator according to a third embodiment of the present invention.

9 is a view showing a light pressure generating slope and a vertical surface formed on the moving body of FIG.

10 is a diagram showing the principle of operation of the light pressure actuator shown in FIG.

FIG. 11 is a diagram showing a conventional motor having a diameter of about 100 μm by electrostatic force.

FIG. 12 is a conventional light pressure rotation experiment diagram.

[Explanation of symbols]

14, 28, 30 ... Light pressure actuators, 15, 29,
31 ... Moving body, 16 ... Light pressure generating surface, 16 ', 32, 32
a, 32b ... Light pressure generating slope, 17 ... Cutting surface, 18 ... Gap, 19, 33 ... Moving body supporting part, 20 ... Laser light, 20
₁ ... Incident light, 20 ₂ ... Refracted light, 34a, 34b ... Vertical surface.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shun Oguchi 1-1-6, Uchisaiwaicho, Chiyoda-ku, Tokyo Nihon Telegraph and Telephone Corporation

Claims (4)

[Claims] 1. A movable body on which at least one light pressure generating slope is formed, and a movable body which is arranged at a predetermined distance from the movable body and movably supports the movable body in a predetermined direction. And a body support part, wherein the moving body is driven in the predetermined direction by the pressure of laser light so as to be remotely irradiated. 2. The moving body is formed in an annular shape having a predetermined thickness, and is rotationally driven by remotely irradiating the laser beam on the slope for generating the light pressure.
The light pressure actuator according to item 1. 3. The light pressure actuator according to claim 1, wherein the moving body is formed in a rectangular parallelepiped shape, and is linearly driven by remotely irradiating the slope for light pressure generation with the laser light. 4. A photolithography process of forming a slit-shaped mask in a portion to be a moving body so that a slope for generating light pressure is formed, and a beam component aligned obliquely with respect to the surface of the moving body. A step of forming a light pressure generating slope having asymmetrical angles facing each other on the moving body by the etching used, and a predetermined distance from the moving body supporting portion so as to support the moving body in a predetermined direction so as to be movable. And a step of mounting the moving body, the method for manufacturing a light pressure actuator.