JPH0847274A - Optically-driven motor rotor - Google Patents

Abstract

PURPOSE:To provide an optically-driven motor rotor to which the resistance of medium is hardly applied. CONSTITUTION:An optically-driven motor rotor 5 is provided in a required medium and light is made to fall on the rotor 5 through the medium to rotate the rotor 5. In order to reduce the resistance against the rotation from the medium, the rotor 5 is housed in a covering member 6 for the relief of the unevenness of the rotor 5. A support shaft 7 is provided at the lower end of the rotor 5. The support shaft 7 can rotate relatively to a board 8 and a gear 9 is attached to the end of the support shaft 7. If light is projected to the rotor 5, the light is refracted at the boundary between the rotor 5 and the covering member 6. As photons have momenta, the light pressure are exerted on the rotor 5 by the refraction at the boundary. The light pressure acts in the directions of the normals of the boundary (the directions indicated by arrows A in Fig. 2 (a)). The rotor 5 is rotated in the direction indicated by arrow B by the resultant force.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotor for an optical drive motor.

[0002]

2. Description of the Related Art Recently, a method of transmitting energy in a micromechanism has attracted attention. Among them, the optical drive motor using the change of the momentum of light has attracted the most attention because it does not require wiring for energy transmission and can transmit energy from a distance.

This optical drive motor usually has a rotor for extracting the momentum of light as a rotational force. This rotor has a structure as shown in FIG. 6, for example.

As shown in FIG. 6B, a support shaft 31 is provided at the lower end of the rotor 30. This support shaft 31
Is rotatable with respect to the substrate 32, and a gear 33 is attached to the end thereof. The gear 33 is
It is connected to a transmission mechanism (not shown) for transmitting rotational force to other micromechanical elements. Also, usually
The rotor 30 is arranged in a medium such as water in order to reduce friction between the lower surface of the rotor 30 and the substrate 32.

When the rotor 30 is irradiated with the light 34, the light is refracted at the boundary surface between the rotor 30 and the medium. Further, since the photons have a momentum, the rotor 30 receives the recoil momentum, that is, the light pressure due to the refraction at the boundary surface. This light pressure acts in the normal direction of the boundary surface (direction of arrow A in FIG. 6A). The rotor 30 will rotate in the direction of arrow B due to these combined forces.

[0006]

However, since the rotor for the optical drive motor is arranged in the medium as described above, it receives resistance from the medium during rotation. Therefore, a large amount of energy is required to rotate the rotor at high speed.

In view of the above problems, it is an object of the present invention to provide a rotor for an optical drive motor which is less likely to receive resistance from a medium surrounding the rotor.

[0008]

According to a first aspect of the present invention for achieving the above object, an optical drive motor which is arranged in a predetermined medium and is rotated by being irradiated with light through the medium. In order to reduce the resistance from the medium at the time of rotation, the rotor for use is provided with a covering member for accommodating the rotor so as to alleviate the unevenness of the rotor, and the covering member is provided with light from the medium. There is provided a rotor for an optical drive motor, wherein the rotor is transmitted through the rotor.

According to a second aspect of the present invention for attaining the above object, in the first aspect, the covering member comprises:
A rotor for an optical drive motor, which has a circular outer shape in a cross section perpendicular to the rotation axis of the rotor.

According to a third aspect of the present invention for achieving the above object, in the first or second aspect, the refractive index of the covering member is equal to the refractive index of the medium. A rotor for a light driven motor is provided.

[0011]

The covering member accommodates the rotor so that the irregularities of the rotor are alleviated, thereby reducing the resistance from the medium during rotation. Further, the covering member transmits the light from the medium to the rotor.

[0012]

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

FIG. 1 shows an example of an optical drive motor to which the rotor for an optical drive motor according to the present invention is applied.

In FIG. 1, a light driving motor 1 has a light source 2 for irradiating light, a collimating lens 3 for collimating the radiated light, and a collimated light for condensing the light at a predetermined position. And a rotator 5 that receives light and rotates. In this embodiment, the rotor 5 is placed in water while being covered with the covering member 6.

A laser or the like is used as the light source 2. The light intensity is several mW or more and about several W, and the wavelength is 30
A film having a thickness of about 0 nm to about 2000 nm can be used. Specifically, for example, the wavelength is 1064 nm,
A YAG laser with an output of 200 mW can be used.
In the present invention, the type of the light source is not limited to the laser, and may be any type as long as it can generate light having a wavelength that is difficult to be absorbed by the constituent members of the rotor 5. As the collimating lens 3 and the condenser lens 4, ordinary optical lenses can be used. If the light emitted from the light source 2 is sufficiently narrowed, a collimating lens is not used and a mirror or the like can be used instead.

Next, the rotor 5 will be described with reference to FIG. 2 (b) is a side view of the rotor for an optical drive motor according to the present invention, and FIG. 2 (a) is a sectional view taken along the line AA 'of FIG. 2 (b).

In the present embodiment, the rotor 5 is a polystyrene member having four plate-like protrusions. The entire rotor 5 is made of polymethylmethacrylate (PMMA).
The covering member 6 made of metal is covered so that the irregularities (specifically, the above-mentioned protrusions) are alleviated. The refractive index of the rotor 5 is
It is 1.6, and the refractive index of the covering member 6 is 1.49.
Has become. The materials of the rotor 5 and the covering member 6 are not particularly limited as long as they can transmit the irradiation light, but it is necessary that at least the respective refractive indexes are different.

The outer shape of the covering member 6 is spherical as shown in FIG. A support shaft 7 is provided at the lower end of the covering member 6. The support shaft 7 is rotatable with respect to the substrate 8, and a gear 9 is provided at the end of the support shaft 7.
Is attached. The gear 9 is connected to a transmission mechanism (not shown) for transmitting rotational force to other micromechanical elements.

Next, the driving principle of the rotor 5 is shown in FIG.
And it demonstrates using FIG.

The light beam emitted from the light source 2 is collimated by the collimating lens 3. The parallel light is condensed by the condenser lens 4 above the rotor 5, and then passes through the covering member 6 to reach the upper surface 5 m of the rotor 5. Thereafter, this light passes through the inside of the rotor 5 and goes out from the side surfaces 5a to 5h and the lower surface 5n. In addition, side surfaces 5i to 5l
Are formed in the radial direction from the rotation axis 10, and are parallel to the light reaching the upper surface 5m. Therefore,
Light hardly passes through the side surfaces 5i to 5l.

The photon has a momentum, and the momentum changes in refraction at each surface through which the light passes, that is, at the boundary surface between the rotor 5 and the covering member 6 housing the rotor 5. The change in the momentum of the photon gives a recoil momentum (light pressure) to each surface. Due to this light pressure, a force acts in the normal direction (direction of arrow A in FIG. 2A) on each surface. Therefore, these combined forces are generated in the rotor 5, and the rotor 5 rotates in the arrow B direction. Further, since the rotor 5 is covered with the covering member 6, the resistance from the medium is small, and the desired rotating force can be generated with light weaker than when the rotor 5 is not covered with the covering member 6. .

Further, the covering member 6 is shown in FIGS.
As shown in (b), it may be an ellipsoid. Also, FIG.
As shown in FIGS. 4A and 4B, it may be formed in a columnar shape. In any case, if the outer shape of the cross section perpendicular to the rotation axis 10 is circular, there is an effect of reducing the resistance from the medium.

The rotor according to the present invention may be constructed as shown in FIG.

The rotor 20 of this embodiment is composed of the condenser lens 4
4 made of polystyrene that receives the light flux from (see Fig. 1)
It has two blade portions (23 a to 23 d) and a main body portion 24. The rotor 20 is covered with the PMMA covering member 6 described above, and has the support shaft 7 and the gear 9 as described above. As the components for rotating the rotor 20, the light source 2, the collimating lens 3, and the condenser lens 4 shown in FIG. 1 can be used.

Then, the light emitted from the light source 2 passes through the collimating lens 3 and the condenser lens 4 and the rotor 2
It is irradiated to 0. As mentioned above, the photon has momentum, and in the refraction at the surfaces 21 and 22 of each blade,
Its momentum changes. Then, a force in the normal direction acts on each surface. Taking the blade portion 23a as an example,
As shown in FIG. 5B, the force in the arrow C direction acts on the surface 21, and the force in the arrow D direction acts on the surface 22. Therefore, a combined force of these is generated in the blade portion 23a. Of course, this combined force is generated not only by the blade portion 23a but also by the blade portions 23b, 23c, 23d.
The rotor 20 rotates in the arrow E direction due to these combined forces. Also in this embodiment, the resistance of the medium to the rotor is reduced by the covering member 6.

Although the configuration example of the rotor according to the present invention has been described above, the rotor according to the present invention can exert its effect not only in water but also in a medium such as oil. Further, even in the air, when the rotor rotates at a high speed, the air resistance can be reduced.

Further, when the covering member is made of PMMA,
If silicon oil or the like is used as the medium, the coating member and the medium can have the same refractive index. According to this structure, refraction or reflection of light does not occur at the boundary surface between the covering member and the medium. Therefore, a rotational force similar to that when the rotor is not covered with the covering member is generated.

[0028]

According to the rotor for an optical drive motor of the present invention, resistance from a medium is less likely to occur during rotation.

[0029]

[Brief description of drawings]

FIG. 1 is a block diagram of an optical drive motor according to the present invention.

FIG. 2A is a cross-sectional view taken along the line AA ′ of FIG. FIG. 2 (b): a side view of the rotor for an optical drive motor according to the present invention.

FIG. 3A is a cross-sectional view taken along the line AA ′ of FIG. FIG. 3 (b): a side view of the rotor for an optical drive motor according to the present invention.

FIG. 4A is a cross-sectional view taken along the line AA ′ of FIG. FIG. 4 (b): a side view of the rotor for an optical drive motor according to the present invention.

5A is a cross-sectional view taken along the line AA ′ of FIG. 5A. FIG. 5 (b): a side view of the rotor for an optical drive motor according to the present invention.

6A is a cross-sectional view taken along the line AA ′ in FIG. 6A. FIG. 6B: A side view of a conventional rotor for an optical drive motor.

[Explanation of symbols]

1: Light-driving motor, 2: Light source, 3: Collimating lens, 4: Condensing lens, 5, 20, 30: Rotor,
6: coating member, 7, 31: support shaft, 8, 32: substrate, 9, 33: gear, 10: rotating shaft, 21, 2
2: surface, 23a to 23d: blade portion, 24: body portion,
34: Light

Claims (3)

[Claims] 1. A rotor for an optical drive motor, which is disposed in a predetermined medium and rotates by being irradiated with light through the medium, in order to reduce resistance from the medium during rotation.
A coating member that accommodates the rotor so that the irregularities of the rotor are alleviated, and the coating member allows light from the medium to pass through the rotor. Rotor. 2. The rotor for an optical drive motor according to claim 1, wherein the covering member has a circular outer shape in a cross section perpendicular to the rotation axis of the rotor. 3. The rotor for an optical drive motor according to claim 1, wherein the coating member has a refractive index equal to that of the medium.