JPH07274416A - Power supply system in micromachine - Google Patents

Abstract

PURPOSE:To supply power to an inner micromachine by a cableless method to make the power permeate through pipe walls and partitions. CONSTITUTION:Outer peripheral surface of the main body of a micromachine 1 is covered and an photovoltaic element 3 is arranged, a fluorescent substance layer, which fluoresces by receiving radiation 6 radiated toward the main body from outside of the micromachine 1 and radiates fluorescence 8 to the photovoltaic element 3, is formed, and the electromotive force of the photovoltaic element 3 is supplied to an inner circuit system 5 of the main body of the micromachine.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a micromachine, which is a micromachine having a size of several millimeters or less, and more particularly to a system for supplying electric power from the outside of a machine body without a cable.

[0002]

2. Description of the Related Art In recent years, a micromachine called a micromachine, which has a size of several millimeters or less, has been proposed, and various researches and developments have been carried out for practical use.
As a drive system for such a micromachine, a cable-operated system for supplying energy (electric power) and control signals from outside to a machine body equipped with various actuators via a cable, and an energy source such as a storage battery in the machine body are provided. It is also known that there is a wireless system in which only control signals are wirelessly supplied from the outside.

In the case of the corded system, since the energy source is outside the machine body, the machine body can be miniaturized and the amount of driving energy is not limited, so that the degree of freedom in designing the micromachine is large. However, on the other hand, since the cable for supplying energy is indispensable, there are restrictions on the operating range and movement of the machine body.

On the other hand, in the case of the ropeless system, the movement of the machine body is not limited, but the energy source for driving the machine body must be mounted on the machine body.
There is a drawback that the size and weight of the entire machine increase and the functions of the micromachine are impaired.

Therefore, in the ropeless micromachine, the energy source is not mounted in the machine body, but the machine body is irradiated with a light ray such as sunlight to supply energy from the outside. A method is being studied (for example, Japanese Patent Application No. 3-7243).

FIG. 3 shows a configuration example of a conventional micromachine adopting an energy supply system by light rays,
The micromachine (1) is a tube with a diameter of approximately 5 to 10 mm.
The drive legs (2) and the micromachine (1) main body, which are inserted into the pipe (9) and project toward the inner wall of the pipe (9), are expanded and contracted to move forward and backward.

The surface of the micromachine (1) has a large number of photovoltaic elements for converting light energy of a laser beam into electric power.
It is covered by (3). Specifically, the photovoltaic element (3) is an a-Si solar cell and, for example, when a micromachine is loaded into the tube (9) to function, the micromachine ( A light beam is emitted toward 1). The electric power generated by the photovoltaic element (3) receiving the irradiation of light is supplied to the internal circuit system (5) to realize a predetermined functional operation.

[0008]

However, when the micromachine (1) passes through the bent portion of the tube (9) or advances deep inside the tube, the light energy reaching the micromachine (1) is significantly reduced. It becomes difficult to make the micromachine (1) function sufficiently. Further, in a micromachine for inspecting the inside of a condenser thin tube of a nuclear power plant, there is a great danger in the work of irradiating the inside of the narrow tube with a light beam, and therefore various problems remain in the energy supply system using a light beam.

A photovoltaic device such as a solar cell cannot provide sufficient sensitivity in a short wavelength region of 0.3 to 0.4 μm or less. In particular, micromachines have been miniaturized as much as possible, so that the surface area on which the photovoltaic element should be arranged is also limited, and the load of functional operation that the micromachine should exert becomes large. In this case, the power shortage may occur only with the electromotive force of the photovoltaic element.

An object of the present invention is to provide a power supply system in a micromachine which can transmit energy to a micromachine therein by passing through a tube wall or a partition wall. Another object of the present invention is, for example, in a micromachine for inspecting the inside of a condenser thin tube of a nuclear power plant, α rays existing in the working environment of the micromachine,
An object of the present invention is to provide a power supply system that can use radiation such as β rays and γ rays as an energy source.

Still another object of the present invention is to obtain spectral sensitivity to short wavelength radiation contained in sunlight or the like, especially to ultraviolet rays, which is sufficient when used in combination with an energy converter such as a solar cell. It is to provide an electric power supply system capable of supplying electric power.

[0012]

According to the present invention, the photovoltaic element (3) is arranged so as to cover the outer peripheral surface of the main body of the micromachine (1), and the light is emitted from the outside of the micromachine (1) toward the main body of the machine. To form a phosphor layer (4) that fluoresces upon receiving radiant energy such as generated radiation, X-rays, ultraviolet rays, charged particle beams, etc., and irradiates the photovoltaic element (3) with the fluorescence (8). The electromotive force of the electromotive force element (3) is applied to the circuit system of the machine body.
Supply to (5).

In a concrete structure, a micromachine is further provided.
In (1), a radiation battery is arranged side by side with the photovoltaic element (3). Further, the phosphor layer (4) can be formed by an inorganic scintillator, an organic scintillator, sodium salicylate, or calcium tungstate.

[0014]

[Operation] A micromachine inserted in a pipe or in a narrow space
For (1), radiation, X-rays, ultraviolet rays, or charged particle beams are irradiated as energy rays. Since radiation and X-rays can pass through the tube wall or the partition, the radiation source of these energy rays is arranged outside the tube wall or the partition, and the energy ray from the radiation source passes through the tube wall or the partition. It penetrates and reaches the micromachine (1). On the other hand, a radiation source of ultraviolet rays or charged particle beams is arranged in, for example, one opening of the tube, and these energy rays travel along the tube wall or partition wall and reach the micromachine (1). The phosphor layer (4) of the machine body receives the above-mentioned various energy rays and is excited to emit fluorescence (8) having a wavelength in the visible light region of 0.4 μm or more, for example. The fluorescence (8) enters the photovoltaic element (3). This causes the photovoltaic element (3) to generate power,
The electric power is supplied to the internal circuit system (5) of the machine body.

In the specific construction in which the radiation cell is arranged side by side with the photovoltaic element (3), the energy rays, especially the radiation, which have passed through the phosphor layer (4) without being converted into fluorescence (8) Upon entering the battery, its radiant energy is converted to electrical power. The electric power is supplied to the internal circuit system (5) together with the electric power from the photovoltaic element (3).

[0016]

According to the power supply system for the micromachine of the present invention, energy can be supplied to the internal micromachine through the pipe wall or partition wall.
Sufficient power can be supplied regardless of the working position of the micromachine in the pipe or the narrow space. In the case of a micromachine that conducts an internal inspection of condenser tubes in a nuclear power plant, α
Since radiation such as gamma rays, beta rays, and gamma rays can be used as an energy source, it is not necessary to dispose a special energy source and the inspection work is safe. Furthermore, spectral sensitivity can be obtained with respect to short-wavelength radiation contained in sunlight or the like, especially ultraviolet rays, and sufficient power can be provided by using it together with an energy converter such as a solar cell.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An example in which the present invention is applied to a micromachine for inspecting the condenser tube of a nuclear power plant will be described in detail with reference to the drawings. It should be noted that the micromachine, which is supplied with electric power, advances and retreats in the thin tube to execute desired functional operations at predetermined positions. Regarding the structure and circuit configuration of the machine body for performing these operations, Although illustration and description are omitted, a system for supplying power to the machine body will be described below.

As shown in FIG. 1, the surface of the main body of the micromachine (1) is covered with a photovoltaic element (3) made of, for example, GaAs, and further covers the photovoltaic element (3) to form, for example, one type of inorganic scintillator. A phosphor layer (4) made of sodium iodide is provided.

The electrodes (not shown) of the photovoltaic element (3) are the circuit system (5) provided inside the main body of the micromachine (1).
And the electromotive force of the photovoltaic element (3) is supplied to the circuit system.

For the micromachine (1), for example, radiation from the outside of the stainless steel tube (9) is passed through the tube wall.
(6) is irradiated. The radiation (6) penetrates the tube (9),
The light enters the phosphor layer (4) on the surface of the micromachine (1). As a result, the phosphor layer (4) is excited, and the phosphor layer (4) is excited.
Emits fluorescence (8). The fluorescent light (8) is incident on the photovoltaic element (3), which causes the photovoltaic element (3) to generate electric power, which is supplied to the internal circuit system (5) of the machine body.

As the material of the phosphor layer (4), various inorganic scintillators or organic scintillators can be adopted as shown in Tables 1 and 2. As an inorganic scintillator,
Zinc sulfide ZnS (Ag), sodium iodide NaI (T
l), cesium iodide CsI, potassium iodide KI, silver iodide AgI, bismuth-germanium BGO, cadmium-tungsten, calcium fluoride, and barium fluoride are typical. Typical organic scintillators are anthracene, polystyrene, polyvinyltoluene, p-terphenyltoluene, terphenyl, naphthalene, and transstilbene.

The wavelength of fluorescence emitted when these scintillators are irradiated with radiation, the fluorescence efficiency, the decay time of light, and the energy selectivity are as shown in Tables 1 and 2.

[0023]

[Table 1]

[Table 2]

As shown by the energy selectivity in the table, each scintillator has selectivity depending on the energy beam with which it is irradiated, and for example, zinc sulfide efficiently fluoresces by being irradiated with α-rays. Regarding gamma rays, the performance of organic scintillators is inferior to that of inorganic scintillators,
It is possible to improve the sensitivity by forming a large film thickness.

When an inorganic scintillator is used as the material of the phosphor layer, it can be formed in a state suitable for the purpose, such as powder, thin film, or single crystal. For example, a method of forming a crystal of an inorganic scintillator can be adopted. .

On the other hand, when an organic scintillator is used as the material of the phosphor layer, terphenyl is dissolved in an organic solvent such as xylene to form a liquid, which is applied to the surface of the micromachine (1). Further, in the solid plastic scintillator, a high molecular substance is used as a base instead of the solvent, and is applied on the surface of the micromachine (1).

FIG. 2 shows a power supply system in which a phosphor layer (41) is formed on the inner wall of the tube (9) in addition to the structure of the micromachine (1) of FIG. In this case, a part of the radiation (6) transmitted through the tube wall is part of the phosphor layer (41) on the inner wall of the tube (9).
Is converted into fluorescence (8) at the micromachine.
(1) Transmitting through the phosphor layer (4) on the surface, photovoltaic element (3)
Incident on. Also, the phosphor layer (41) is not converted into fluorescence (8).
The radiation that has passed through is incident on the phosphor layer (4) on the surface of the micromachine (1) and converted into fluorescence. The fluorescence enters the photovoltaic element (3) and is converted into electric power. The electric power thus obtained is supplied to the internal circuit system (5) of the machine body.

When an inorganic scintillator is used as the material of the phosphor layer (41), powder, thin film, single crystal, etc.
It can be formed in a state suitable for the purpose, and for example, a method of powdering the inorganic scintillator and applying it to the inner wall of the tube (9) can be adopted. When an organic scintillator is used as the material of the phosphor layer (41), it is made into a liquid form by dissolving terphenyl in an organic solvent such as xylene, and this is applied to the inner wall of the tube (9). Further, in the solid plastic scintillator, a polymer substance is used as a base material instead of the solvent, and a method of applying it to the inner wall of the tube (9) is adopted.

According to the configuration of FIG. 2, a large amount of electric power can be supplied to the micromachine (1) as shown in the following trial calculation example. For example, a phosphor layer (4) made of sodium iodide
The fluorescent efficiency of (41) is 10%, the thickness of the phosphor layer (4) on the surface of the micromachine (1) is 0.1 mm, and the phosphor layer on the inner wall of the tube (9)
The film thickness of (41) is 0.5 mm, and the wavelength of the fluorescence emitted from the phosphor layers (4) and (41) is 413 nm. Further, the conversion efficiency of the photovoltaic element (3) made of GaAs at a wavelength of 413 nm is 10%, and the surface area on which the photovoltaic element (3) is formed is 1
cm ² and the wall thickness of the stainless steel tube (9) is 1.5 mm.

In the above structure, when radiant energy of 0.2 × 10 ¹² MeV / s · cm ² is supplied to the micromachine (1), the emission energy of the phosphor layer (41) on the inner wall of the tube (9). E1 is E1 = 0.2 × 0.1 = 0.02 (× 10 ¹² MeV / s ·
cm ² ).

The radiation (6) which has not been converted into fluorescence (8) and has passed through the phosphor layer (41) has the remaining energy (0.18 × 10).
Micromachine with ¹² MeV / s · cm ² )
(1) The light enters the phosphor layer (4) on the surface. At this time, the emission energy E2 of the phosphor layer (4) was as follows: E2 = 0.18 × 0.1 = 0.018 (× 10 ¹² MeV
/ S · cm ² ).

If one half of the emission energy is applied to the photovoltaic element (3), the irradiation energy E
3 is E3 = 0.5 × 10 ⁶ × (0.02 + 0.018) × 1.6 ×
10 ⁻¹⁹ × 10 ¹² = 3.04 × 10 ⁻³ (W / cm ² ) = 3.04 (mW / cm ² ). Therefore, the power P obtained from the photovoltaic element (3)
Is P = 3.04 × 0.1 = 0.304 (mW).

The micromachine (1) advances and retreats in the tube (9) in response to the supply of the electric power, and at the same time, inspects the tube wall for defects. According to the power supply system of the micromachine (1), since the radiation existing in the condenser of the nuclear power plant can be used as an energy source, it is not necessary to install a special energy source and the energy can be safely supplied. You can

In the above embodiment, the radiation (6) is supplied from the outside of the tube (9) through the tube wall. However, as shown by the chain line in FIGS. 1 and 2, in addition to the radiation (6), It is also possible to irradiate the ultraviolet ray (7) from the opening end of (9). in this case,
Sodium salicylate is a suitable material for the phosphor layers (4) and (41) to be formed on the surface of the micromachine (1) or the inner wall of the tube (9). The ultraviolet rays (7) enter the phosphor layer (4) on the surface of the micromachine (1) or the phosphor layer (41) on the inner wall of the tube (9),
As a result, the phosphor layers (4) and (41) are excited to emit fluorescence. Note that sunlight can be used as a source of the ultraviolet rays (7).

It is also possible to emit X-rays instead of the ultraviolet rays (7), and in this case, it is suitable that the phosphor layers (4) and (41) are made of calcium tungstate.

The above description of the embodiments is for explaining the present invention, and should not be construed as limiting the invention described in the claims or limiting the scope. The configuration of each part of the present invention is not limited to the above-mentioned embodiment, and it goes without saying that various modifications can be made within the technical scope described in the claims.

For example, a charged particle beam such as an ion beam or an electron beam can be used as the energy beam. or,
It is also possible to adopt a configuration in which a radiation battery is arranged side by side with the photovoltaic element (3), and the radiation transmitted through the phosphor layer (4) without being converted into fluorescence is converted into electric power by the radiation battery.
As a result, radiation can be converted into electric power with high efficiency, and large electric power can be supplied to the internal circuit system.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a configuration example of a power supply system in a micromachine.

FIG. 2 is a cross-sectional view showing the configuration of another power supply system.

FIG. 3 is a cross-sectional view showing a conventional micromachine.

[Explanation of symbols]

 (1) Micromachine (2) Driving leg (3) Photovoltaic device (4) Phosphor layer (41) Phosphor layer (5) Internal circuit system (6) Radiation (7) Ultraviolet ray (8) Fluorescent (9) Tube

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Takahisa Sakakibara 2-5-5 Keihan Hondori, Moriguchi City, Osaka Prefecture Sanyo Electric Co., Ltd. (72) Tatsuya Kura, 2-5 Keihan Hondori, Moriguchi City, Osaka Prefecture No. 5 Sanyo Electric Co., Ltd.

Claims (3)

[Claims] 1. A circuit system built in a micromachine (1)
A system for supplying electric power to (5), wherein the micromachine (1) covers the outer peripheral surface of the machine body with a photovoltaic element.
With the arrangement of (3), radiation emitted from the outside of the micromachine (1) toward the machine body, X-rays, ultraviolet rays,
Fluoresce when it receives radiant energy from a charged particle beam,
A phosphor layer (4) for irradiating the photovoltaic element (3) with (8) is formed, and the electromotive force of the photovoltaic element (3) is supplied to the circuit system (5). system. 2. The power supply system for a micromachine according to claim 1, further comprising a radiation battery arranged side by side with the photovoltaic element (3) in the micromachine (1). 3. The power supply system for a micromachine according to claim 1, wherein the phosphor layer (4) is an inorganic scintillator, an organic scintillator, sodium salicylate, or calcium tungstate.