JP3261458B2 - Optically driven actuator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optically driven actuator which uses a photo-induced phase change material which undergoes a phase transition and is deformed by light irradiation, particularly as an actuator for a micromachine or the like.

[0002]

2. Description of the Related Art In micromachines, it is important to promote their independence, and in particular, independence of energy supply is one of the biggest problems.

Many conventional micromachines are manufactured by performing thin film growth, photolithography, chemical etching, and the like from a silicon wafer using a semiconductor process. For this reason, it is difficult to incorporate an electromagnetic motor and a drive system such as hydraulic pressure and pneumatic pressure used in conventional machines. Therefore, as a mechanical driving method, an actuator unique to a micromachine, such as an electrostatic actuator or a thermal expansion actuator, which is easily compatible with a semiconductor process, is used.

The above-mentioned electrostatic actuator is, for example, shown in FIG.
In one shown in FIG. 1, one end of a movable film 33 formed of a silicon thin film or the like is fixed to a substrate 31 via an insulating film 32, and the other end is a movable portion 34. It is freely deformable. The movable film 33 and the substrate 31 are conductive and also serve as electrodes. When a voltage is applied between the movable film 33 and the substrate 31 from the high voltage power supply 35, the movable portion moves up and down in the drawing due to electrostatic attraction and repulsion, and this is used as an actuator.

In the thermal expansion actuator shown in FIG. 7, for example, both ends of a movable film 42 formed of a silicon thin film or the like are fixed to a substrate 41.
The central part is attached so that it can be deformed without being fixed. A thermal expansion thin film 43 having a linear expansion coefficient different from that of silicon, such as Au or Ti, is integrally fixed to the central surface thereof. When a current is supplied from a power supply 44, this portion is heated, The temperature of each material increases.
Accordingly, a bending moment is generated in the thermal expansion thin film 43 in which materials having different linear expansion coefficients are doubled based on the bimetal principle, and the movable film 42 is deformed accordingly. Also,
When the energization is stopped, the movable film 42 is cooled and returns to its original shape, so that the center thereof moves up and down in the figure. This operation is used as an actuator.

[0006]

The above-mentioned conventional actuators are all electrically driven, and have the following problems. That is, (1) When a mechanical system is integrated on a large scale, electric wiring for driving the actuator becomes complicated. (2) In the case of the electrostatic type, since a high voltage (approximately 100 V) is applied, there is a problem of electric discharge and electric shock. Further, a circuit for driving a high voltage is complicated. (3) In the case of the thermal expansion type, the temperature near the driving member becomes high, which may adversely affect the surroundings. Further, when used in a microchemical system or the like, there is a possibility of affecting a chemical reaction or altering a sample fluid.

[0007] On the other hand, conventionally, the use of an actuator using a photovoltaic cell that converts light into electricity has been considered. At that time, it is necessary to convert light into electricity and convert the electricity into mechanical motion. The need for a two-step process complicates the system and requires an electrical process.

As a material for directly converting light into mechanical energy, an “optical strain element” utilizing the piezoelectric effect has been reported at the present time. However, there is a problem that the response speed is slow, and the material is used as an actuator. There is no specific means to do so.

Therefore, an object of the present invention is to realize a novel actuator which has a simple structure, does not require wiring, and does not require high temperature and high voltage.

[0010]

According to the present invention, in order to solve the above-mentioned problems, the invention according to claim 1 irradiates two kinds of light to reversibly form a phase between two phases corresponding to each light. An optically-driven actuator characterized in that a mechanism is driven by the deformation using a light-induced phase transition material that undergoes a transition and deforms.

The invention according to claim 2 is that the photo-induced phase change material is formed into a film and fixed on the surface of a movable film, and the photo-induced phase change material is irradiated with two kinds of light to be movable. An optically driven actuator according to claim 1, wherein the film is reversibly deformed to form an actuator.

According to a third aspect of the present invention, there is provided the light-driven actuator according to the second aspect, wherein the valve is configured to open and close the opening by the movable film.

[0013]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows an example using “polydiacetylene” as a photo-induced phase change material, for which a vapor-deposited thin film can be easily manufactured. In this embodiment, a polydiacetylene (PD) is provided on the central surface of the movable film 2 made of a polysilicon thin film.
A) The thin film 1 is formed by vapor deposition. Both ends of the movable film 2 are fixed on a substrate 3 made of silicon, and a central portion can be freely deformed to constitute an optically driven actuator.

One of the above polydiacetylenes, [R =-
(CH₂)₄OCONH (CH₂)₂CH ₃]
Are phase A and phase B having different backbone bonding states as shown in FIG.
The two phases are both stable, and the wavelength of 450
Irradiation of the first light of ~ 550 nm causes phase transition to B phase
The volume expands and stabilizes in this state. On the other hand,
When the second light having a wavelength of 350 to 400 nm is irradiated in this state, A
A phase transition occurs in the phase and the volume shrinks. The light-induced phase inversion
The phenomenon of transfer keeps certain conditions such as temperature and pressure of a certain material constant.
Phase transition occurs only by irradiating
In the field of condensed matter physics
In addition to the structural phase transition, the electron spin system (magnetic) phase transition
And various types such as metal-insulator transition
Swelling.

Using such a light-induced phase change material, FIG.
As shown in (a), when the first light having a wavelength of 450 to 550 nm is irradiated to the PDA thin film 1 in the A phase in the state 1 in the figure as shown in FIG.
When the thin film 1 transitions to the B phase, the state becomes 2 and the movable film
Is driven upward in the figure. Conversely, when the second light having a wavelength of 350 to 400 nm is irradiated in this state 2, the PDA thin film transitions to the A phase, so that the movable film returns to the state 1 shown in FIG. The unit is driven downward in the figure and returns to the original position. By alternately irradiating two wavelengths of light in this manner, the central portion of the movable film 2 can reversibly move up and down in the drawing, and can be used as an actuator.

FIG. 4 shows an application example in which the optically driven actuator that operates as described above is used for a microvalve.
In this example, the orifice 1 opened in the substrate 13
The flow rate of the fluid passing through 4 is controlled by opening and closing a valve body 12 formed of a movable film. The PDA thin film 11 is vapor-deposited on the center upper portion of the valve body 12 in the same manner as described above, thereby forming the valve 10 as a whole. Such a valve 10
By irradiating the PDA thin film 11 with light from outside using the valve, the valve body 12 is driven in the mode shown in FIG. 3 and the orifice 14 can be opened and closed. Therefore, the flow path of various fluids can be opened and closed using the valve 10, and the flow rate of the analysis fluid in the field of microchemical analysis can be controlled, for example. Further, the present invention can be embodied as an actuator in various modes such as controlling the operation of a device driven by the fluid.

The light-driven microvalve as described above can be configured as shown in FIG. 5, for example. That is, two orifices, a first orifice 24 and a second orifice 25, are opened in the substrate 23. In the example shown in the figure, the first orifice 24 side is a fluid inlet, and the second flow path 25 side is a fluid outlet. Has become. In this valve 20, as in the case of FIG.
A thin film 21 is vapor-deposited to form an actuator. In this example, the entire outer periphery of the valve body 22 surrounds the openings of both orifices 24 and 25 of the substrate 23.
Is fixed in a sealed state on the surface.

With such a configuration, the valve body 22 is driven in the same manner as described above by irradiating light from the outside, and the opening and closing can be controlled. Also, the width of the flow path between the two orifices can be changed by the movement of the valve to selectively control the flow rate, and the flow rate can be controlled by controlling the open time ratio between the fully open state and the fully closed state. It can be carried out.

According to the present invention, in addition to the valve as described above, the reciprocating rod is driven by utilizing the deformation of the movable film as described above,
The power can be used as a power source, and in particular, since this device can be miniaturized, it can be used as a power source for a micromachine.

[0020]

Since the present invention is constructed as described above, the actuator can be driven without any need for electrical wiring, so that it is possible to avoid complicated and difficult wiring when integrated. . Further, since high voltage and heat are not used, there is little adverse effect on the periphery of the actuator. Therefore, when applied to a microvalve to configure a microchemical analysis system or the like, it is possible to reduce adverse effects on the control fluid. In addition, since the light-induced phase transition has a bistable property, energy is not continuously consumed to maintain the state of the movable film. Therefore, it is possible to reduce the amount of energy input to the actuator.

[Brief description of the drawings]

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

FIG. 2 is used as a photo-induced phase change material of the present invention;
It is a figure which shows the phase transition state of polydiacetylene.

FIGS. 3A and 3B are perspective views showing the operation of the optically driven actuator of the present invention, wherein FIG.
(B) shows the state of the B phase.

FIG. 4 is a perspective view of an embodiment using the optically driven actuator of the present invention for a valve.

FIG. 5 is a perspective view of another embodiment using the optically driven actuator of the present invention for a valve.

FIG. 6 is a perspective view of a conventional electrostatic actuator.

FIG. 7 is a perspective view of a conventional thermal expansion actuator.

[Explanation of symbols]

 1 PDA thin film 2 movable film 3 substrate

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-62-255967 (JP, A) JP-A-9-285161 (JP, A) JP-A-7-266428 (JP, A) JP-A-4- 17586 (JP, A) JP 8-845 (JP, B2) JP 5-501276 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) B81B 3/00 F03G 7 / 06 H02N 11/00

Claims (3)

(57) [Claims] 1. A light-induced phase transition material which reversibly causes a phase transition between two phases corresponding to each light by irradiating two kinds of light and deforms, and drives the mechanism by the deformation. Optical drive type actuator. 2. The photo-induced phase change material is formed into a film and fixed to the surface of a movable film, and the photo-induced phase change material is irradiated with two types of light to reversibly deform the movable film. 2. The optically driven actuator according to claim 1, wherein the actuator is an actuator. 3. An optically driven actuator according to claim 2, wherein said movable film is a valve body that opens and closes an opening.