JPH04308480A - Film actuator - Google Patents

Abstract

PURPOSE:To provide an improved film actuator which can be charged quickly, can be driven with high speed and can produce high power density with low attenuation of charge. CONSTITUTION:The film actuator comprises a stator 3 constituted of an insulating support 1 arranged with stripe electrodes at predetermined intervals and a mover 6 constituted of an insulating film 4 applied with a photoconductive layer 5 wherein the stator 3 and the mover 6 are disposed adjacently and a light source for irradiating the mover 6 is further provided.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a film actuator, and more particularly to a film actuator that has been improved so that it can be driven at high speed and generate a high force density.

0002

[Prior Art] A film actuator consists of a stator in which band-shaped electrodes are arranged at predetermined intervals on an insulating support, and a mover in which a resistor layer is provided on an insulating film, and the stator and the mover are in contact with each other. It is arranged and configured as follows. Then, due to the action of static electricity, the mover is momentarily levitated and moved while preventing friction, and is also called an electrostatic actuator. .5.2
9, pages 112-113, etc.).

Film actuators are characterized in that force density can be increased by reducing the dimensions of electrodes and gaps, and that they can be easily miniaturized. Therefore,
Film actuators are expected to be applied as small drive devices such as paper transport mechanisms in word processors, facsimile machines, etc., and drive devices for other micromechanical systems.

FIGS. 1(a) to 1(d) are explanatory diagrams of the operating principle of the above-mentioned film actuator. In the figure, (1)
is an insulating support, (2) is a strip electrode, (3) is a stator,
(4) is an insulating film, (5) is a resistor layer, (6) is a moving element, and (7) to (9) are electric wires.

First, as shown in FIG. 1(a), an electric wire (7
) and apply a negative voltage to the wire (8). As a result, the electric charge ■ existing in the electrode connected to the electric wire (7) and the electric wire (8
) A current flows through the resistor layer (5) due to the potential difference in the charge ■ existing in the electrode connected to the electrode, and a charge is induced at the boundary between the insulating film (4) of the mover (6) and the resistor layer (5). and reaches an equilibrium state. For convenience of explanation, this charge is shown in Figure 1(b).
can be replaced by the mirror image charge shown by the dotted line. Since the polarities of these charges ■ and ■ are different from the polarities of charges ■ and ■, respectively, in the state of FIG. 1(b), the mover (6)
is attracted to the stator (3).

Next, as shown in FIG. 1(c), the electric wire (7
), a positive voltage is applied to the electric wire (8), and a negative voltage is applied to the electric wire (9). As a result, the charges in the electrodes can be moved instantaneously, but the induced charges in the mover (6) cannot be moved immediately because the resistance value of the resistor layer (5) is high. As a result, a repulsive force is generated between the mover (6) and the stator (3). Due to the generation of repulsive force, the stator (3) and the mover (6)
) is reduced, and a driving force in the traveling direction is generated by the negative charge (■) and positive induced charge (■ in terms of mirror image charge) generated as a result of applying voltage to the electric wire (9).

FIG. 1(d) shows the result of the mover (6) being moved rightward by one electrode pitch due to the above driving force. When moving the mover (6) to the left,
A positive voltage may be applied to the electric wire (9). The applied voltage pattern (the pattern shown in FIG. 1(c)) in the above-described movement operation for each pitch of the electrodes is such that a voltage of the opposite sign to that shown in FIG. 1(a) is applied to the electric wires (7), (8). Therefore, the induced charges (in terms of mirror image charges, ■ and ■) in FIG. 1(c) are attenuated.

[0008] Therefore, in order to continuously move the mover (6) in the right direction one electrode pitch at a time, it is necessary to repeatedly apply a voltage in the following pattern by repeating charge charging and moving operations. The voltage pattern shown below is
This is the voltage pattern of one cycle, (G) shows the state where no voltage is applied, (C) and (A) respectively,
The charge charging operation and transfer operation are shown, and the first (C) is shown in Figure 1 (
The state shown in a), the first (A), is the state shown in FIG. 1(d).

[0009] In order to move the film actuator stably and continuously for each electrode pitch as described above, the surface specific resistivity of the surface of the mover (6), that is, the resistor layer (5) must be 1012 to 10. It is said that it is necessary to keep the resistance in the range of 1015Ω/□, preferably around 1014Ω/□. Furthermore, the time ratio between the charge charging operation and the moving operation is not particularly limited, but according to the findings of the present inventors, the most stable driving is achieved when the ratio is about 9:1.

However, as is clear from the operating principle of the film actuator described above, when the surface resistivity of the mover (6) is large, it takes a relatively long time to charge the charge, making high-speed driving difficult, and vice versa. On the other hand, if it is small, the generated charge will instantly attenuate and high force density cannot be generated.

[0011]

[Problems to be Solved by the Invention] The present invention has been made in view of the above-mentioned circumstances, and it solves the above-mentioned contradictory problems of film actuators, enables fast charge charging, high-speed driving, and reduces charge decay. The object of the present invention is to provide an improved film actuator that is small and capable of generating high force density.

0012

[Means for Solving the Problems] The present invention has achieved the above object by utilizing a photoconductive material well known in the field of electrophotographic photoreceptors, and the gist thereof is to A stator in which band-shaped electrodes are arranged on a support at predetermined intervals, and a mover in which a photoconductive layer is provided on an insulating film or a mover made of a photoconductive material are arranged so as to be in contact with each other, and said mover The present invention relates to a film actuator characterized in that it is provided with a light source that irradiates light onto the film.

[0013]

[Operation] The movable element changes its surface resistivity depending on the presence or absence of light irradiation, thereby increasing the charge charging speed and suppressing charge attenuation.

【Example】

Examples of the present invention will be described below. The film actuator of the present invention uses a photoconductive layer instead of the resistor layer (5) in FIG.
6) Since it is basically the same as the above-mentioned known film actuator except that it is made of a photoconductive material,
For convenience, (5) in FIG. 1 is assumed to be a photoconductive layer, and the description will be made with reference to FIG.

First, the stator (3) will be explained. The stator (3), like a known film actuator, is composed of an insulating support (1) and strip-shaped electrodes (2) arranged at predetermined intervals.

The insulating support (1) is composed of a film, sheet, or the like made of an insulating material. The insulating material is not particularly limited, and ceramics with good insulation properties and various general-purpose resins can be used. Specific examples of the insulating resin include epoxy resin, polyimide resin, polyester resin, polypropylene resin, polyvinylidene chloride resin, polystyrene resin, polyamide resin, polyimide resin, polyvinyl chloride resin, polyethylene resin, polyvinyl alcohol resin, etc. It will be done. Preferred insulating resins are polyimide resins and polyester resins.

The strip electrodes (2) provided on the insulating support (1) may be arranged side by side on the surface of the insulating support (1) or embedded in the insulating support (1). It's okay. In addition, the interval between the strip electrodes (2) is not particularly limited, but is usually 0.1 to 2 mm. 2) It is desirable to make the spacing finer.

Next, the mover (6) will be explained. In the present invention, the mover (6) includes an insulating film (4)
It is constructed by providing a photoconductive layer (5) on the photoconductive layer (5). In addition, the mover (
6) can also be composed of a photoconductive material.

As the insulating film (4), a film made of the same insulating resin as the above-mentioned insulating resin constituting the stator (3) is used, similar to known film actuators. Insulating film (4) constituting the mover (6)
), a particularly preferred film is a polyethylene terephthalate film in terms of density, flexural modulus, wrinkle resistance, etc.

[0020] The thickness of the insulating film (4) is 10 to 2
00 μm, and preferably, the pitch of the strip electrodes (2) arranged on the insulating support (1) is P, and the pitch of the strip electrodes (2) is
When the distance between the surface of the insulating film (4) and the interface between the insulating film (4) and the resistor layer (5) is G, the thickness of the insulating film (4) is 0.15<G/P<0. It is preferable to set the value within a range that satisfies the relationship 4.

[0021] As the photoconductive material forming the photoconductive layer (5), any material can be used without limitation as long as the material changes so that its resistance value decreases depending on the irradiated light. For example, any photoconductive material well known in the field of electrophotographic photoreceptors can be used. Specifically, such materials include selenium and its alloys, and arsenic.
Examples include inorganic photoconductive materials such as selenium, cadmium sulfide, and zinc oxide, and organic photoconductive materials such as phthalocyanine, azo, quinacridone, polycyclic quinone, perylene, indigo, and benzimidazole. The phthalocyanine may be one in which a metal such as copper, indium chloride, gallium chloride, tin, oxytitanium, zinc, vanadium, or its oxide or chloride is coordinated.

In addition to the photoconductive materials mentioned above, conductive polymer materials well known in the field of secondary batteries may also be used as the photoconductive material forming the photoconductive layer (5). Such materials include polyaniline, polyacetylene, polyquinoline,
Examples include polyacene, polypyrrole and its derivatives, polythiophene and its derivatives, polyparaphenylene and its derivatives. In the case of a conductive polymer material, the mover (6) can also be constructed using this material. Note that conductive polymer materials easily deteriorate in the air, so they are used by appropriately covering them with a gas barrier film or the like.

The photoconductive layer (5) is formed as a single layer by vapor deposition or as a dispersed layer contained in a binder resin. As the binder resin, phenoxy resin, epoxy resin, polyester resin, acrylic resin, polyvinyl butyral resin, polycarbonate resin, etc. are used, and the binder resin containing the photoconductive material is used after being dissolved in the coating solution preparation solvent. .

As the coating solution preparation solvent, ethers such as tetrahydrofuran and 1,4-dioxane; ketones such as methyl ethyl ketone and cyclohexanone; toluene,
Aromatic hydrocarbons such as xylene; aprotic polar compounds such as N,N-dimethylformamide, acetonitrile, N-methylpyrrolidone, and dimethyl sulfoxide; esters such as methyl acetate, ethyl acetate, and methyl cellosolve acetate; dichloroethane, chloroform, etc. Examples include chlorinated hydrocarbons, and among these, those that dissolve the binder resin containing the photoconductive material are appropriately selected and used.

By the way, in order to move the film actuator stably, as mentioned above, it is said that the surface resistivity of the mover (6) needs to be in the range of 1012 to 1015 Ω/□.

However, in the present invention, the surface resistivity does not necessarily have to be within the above range; for example, if the surface resistivity is within the above range when irradiated with light, it is 1 when not irradiated.
It may be 016Ω/□ or more.

In the present invention, the surface resistivity of the mover (6) is appropriately determined by adjusting the type of photoconductive material used and the amount of doping in the case of a doped type. In a preferred embodiment, the surface resistivity under light irradiation conditions is 1 x 1014 Ω/□ or less, and the surface resistivity under non-irradiation conditions is 5 x 14 Ω/□.
It is designed to meet the above requirements. Naturally, such a change in surface resistivity varies depending on the wavelength of the light used and the amount of irradiation light. Also, the wavelength mentioned here is
It refers to the wavelength at which the photoconductive material can change its resistance value upon irradiation; therefore, depending on the type of photoconductive material, even under non-irradiation conditions, it may be necessary to use a means (filter, etc.) for blocking sunlight. Needless to say, there are cases where this is necessary.

Incidentally, a dispersed and finely divided titanium oxyphthalocyanine pigment (1,2-dichloroethane solvent, 5% concentration by weight) was added to a 10% by weight polycarbonate solution (1,2-dichloroethane solvent, 5% concentration by weight).
2-dichloroethane solvent) in a 1:5 weight ratio to form a dispersion, which was then applied to a polyester film (50 μm).
The slider (6) was constructed by coating the surface to a dry thickness of 17 μm, and the results of measuring the change in surface resistivity due to white light are as follows. During irradiation 1 ×1
013Ω/□When not illuminated (dark field) 5×101
5Ω/□ or more

In the film actuator of the present invention, the stator (3) and the mover (6) are arranged so as to be in contact with each other, as in the known film actuator, but the arrangement of the mover (6) is as follows. Photoconductive layer (5
) is preferably located on the outer surface.

The film actuator of the present invention has the following features in the film actuator configured as described above:
The mover (6) is preferably provided with a light source (not shown) that irradiates the photoconductive layer (5) with light. As the light source, any light source suitable for the photoconductive material used is appropriately selected, and specific examples thereof include white light, semiconductor laser, and the like. Such a light source is usually provided by appropriate means so as to be able to directly irradiate the movable element (6), preferably the photoconductive layer (5), and is caused to emit light according to the driving mode described below.

The film actuator of the present invention is constructed as described above and is basically used in the following two driving modes.

(A) Use in a bright field environment Following the same operating principle as known film actuators, the voltage pattern of charge charging and transfer operations is repeated, and the photoconductive layer (5) is irradiated with light in synchronization with charge charging. do. According to the above-mentioned driving mode, the surface resistivity of the moving element (6) becomes small during charge charging to shorten the charging time, and becomes large during moving operation to suppress charge attenuation.

(B) Photoconductive layer (5) for use in dark field environment
Light is irradiated to perform initial charge charging, and then only the voltage pattern of the movement operation is repeated. The above driving mode is employed when the surface resistivity of the mover (6) is relatively large under non-light irradiation conditions and the film actuator is used by being incorporated into the device. And the mover (
The surface resistivity (6) is small at the initial stage of charging, and sufficient charging is performed, and after that, there is no need for charging because the attenuation of the charge is relatively small.

[0034] In addition to the above-mentioned driving mode, it is normally driven in the same way as a known film actuator without irradiating light, and for some reason the mover (6) moves every pitch of the electrode. When the synchronization occurs (step-out phenomenon), it can also be used in a driving mode in which light irradiation is performed in order to repair the synchronization phenomenon in a very short time.

[0035]Furthermore, the film actuator can be driven in minute steps below the electrode pitch by using a mover (6) with a small surface resistivity or by appropriately controlling the applied voltage. According to the film actuator described above, the surface resistivity of the mover (6) can be arbitrarily reduced depending on the wavelength of the light used and the amount of irradiation light, so that such minute step driving can be easily achieved.

[0036]

[Effects of the Invention] The film actuator of the present invention as described above can be driven at high speed and can generate high force density by combining a conventionally known electrostatic film actuator with a well-known photoconductive material. An improved film actuator is provided.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of the operating principle of a film actuator.

[Explanation of symbols]

(1): Insulating support (2): Strip electrode (3): Stator (4): Insulating film (5): Resistor layer or photoconductive layer (6): Mover (7) to (9): Electric wire

Claims (1)

[Claims] [Claim 1] A stator in which strip electrodes are arranged at predetermined intervals on an insulating support and a mover in which a photoconductive layer is provided on an insulating film or a mover made of a photoconductive material are arranged so as to be in contact with each other. What is claimed is: 1. A film actuator comprising: a light source for irradiating light to the movable element;