JPH0416793A - Light strain actuator - Google Patents

Abstract

PURPOSE:To make small the size of a light strain actuator and integrate by providing a light waveguide layer on the surface or the boundary of light strain materials. CONSTITUTION:A light strain actuator 1 consists of a light strain element 4 of bimorph type made of a pair of plates 2, 3 bonded together on which surfaces light waveguide layers 5 are formed. One side plate 2 of the element 4 is made of a light strain material which expands with light energy and the other side plate 3, of a light strain material which contracts with light energy. Layers 5 are formed on the whole outer surface of the plates 2 and 3. One end of the element 4 is fixed perpendicularly to a fixing part 6 and light fiber 7 is photo-coupled at the end of the light receiver end of both layers 5. When light is led into the layers 5 through both light fibers 7, the light energy is spread in the layers 5 and is absorbed in the element 4. Thus, if one plate 2 expands and the other plate 3 contracts, then the light strain actuator 1 bows and the free end 8 displaces.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an actuator that utilizes the optical distortion effect in which the shape is distorted by light energy.

[Background Art] What is shown in FIG. 13(a) is a conventional example of a photostrictive actuator, which includes a plate 102 made of a photostrictive material that expands with light energy and a plate 103 made of a photostrictive material that contracts with light energy. One end of a lot of bimorph photostrictive elements bonded together is fixed to a fixing part 104. When the surface of this photostrictive element 101 is irradiated with light 105, the photostrictive element 101 is curved due to the photostrictive effect, and its free end is curved at P, as shown in FIG. 13(b). Displaces from to P.

The principle of the photodistortion effect is the superposition of a phenomenon in which a ferroelectric material generates a large voltage when irradiated with light (photovoltaic effect) and a phenomenon in which it expands and contracts when a voltage is applied (piezoelectric effect). In addition,
The photovoltaic effect referred to here is completely different from that based on semiconductor PN junctions, and is caused by electrons excited by light moving in a specific direction due to the spontaneous polarization of a ferroelectric material. be. In addition, as a photostrictive material,
For example, piezoelectric ceramics such as lead lanthanum zirconate titanate (PLZT) to which niobium, tungsten, or the like is added can be used. A bimorph type photostrictive element is, for example, made by bonding two PLZT plates together, and the polarization directions of each PLZT plate are opposite to each other. When light hits the photostrictive element, a photovoltage is generated at both ends of the PLZT plate that is hit by the light. At the same time, due to the piezoelectric effect caused by the photovoltaic voltage, one of the PL
The length of the ZT plate is slightly extended due to the optical distortion effect, and the length of the other PL
The ZT plate will shrink slightly. Since the two PLZT plates are bonded together, as a result, the entire photostrictive element is bent by light irradiation.

[Problems to be Solved by the Invention] However, in conventional optical distortion actuators as shown in FIGS. 13(a) and 13(b), a space (a light source It is necessary to secure a space around the optical distortion actuator (space from Furthermore, there was a drawback that the seven cutuators could not be irradiated with light energy at high density.

The present invention has been made in view of the problems of the conventional example described above, and its main objectives are to reduce the size of the optical distortion actuator, increase the degree of integration, and
The purpose is to irradiate the actuator with high-density light energy to improve efficiency (distorting the actuator).

[Means for Solving the Problem] The photostrictive actuator of the present invention is a photostrictive actuator formed of one or more types of photostrictive materials that generate distortion by optical energy, wherein It is characterized in that an optical waveguide layer is provided on the surface or at the interface between the photostrictive materials.

[Function] In the present invention, when light is sent from the light-receiving end of the optical waveguide layer, the optical energy propagates and spreads within the optical waveguide layer, and the light energy is transmitted from the interface between the optical waveguide layer and the photostrictive material to the photostrictive material. is absorbed by the light and operates the optical distortion actuator.

Therefore, since the optical energy is propagated while being confined within the optical waveguide layer, it is possible to efficiently absorb the optical energy into the optical distortion material without escaping to the outside of the optical actuator. Since a high density of light energy can be sent through the layer, it is possible to effectively induce a photodistortion effect and increase the operation of the photodistortion actuator.

In addition, since light is propagated through the optical waveguide layer without passing through space, there is no need for a space around the optical distortion actuator as a path for optical energy propagation, making it possible to downsize the element shape of the optical actuator. If several optical elements are integrally formed, the degree of integration can be improved.

Furthermore, since the optical energy can be propagated through the optical waveguide layer, it becomes possible to operate the optical distortion actuator even under usage environments where it is difficult to irradiate the optical distortion actuator with light from space.

[Example code] Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

What is shown in FIG. 1 is an optical distortion actuator 1 according to a first embodiment of the present invention, in which light guides are provided on both sides of a bimorph-shaped optical distortion element 4 made by bonding a pair of plates 2.3 together. A wave layer 5 is formed. Photodistortion element 4
One plate 2 of the is formed of a photostrictive material that is stretched by light energy, and the other plate 3
is made of a photostrictive material that contracts with light energy. The optical waveguide layer 5 is formed on the entire outer surface of both plates 2.3, and the refractive index of the waveguide layer 5 is larger than the refractive index of the external space (air).
It is preferable that the refractive index is smaller than 3. Therefore, the light propagating within the optical waveguide layer 5 has very little leakage to the outside space side, and is absorbed toward the photostrictive element 4 side while being propagated within the optical waveguide layer 5. In addition, the optical waveguide layer 5
Although the material is not particularly limited, for example, Sm
O2 or the like can be vapor-deposited on the surfaces of the plates 2, 3, or a transparent organic material can be applied on the surfaces of the plates 2, 3 by the 22 method or the like.

This photostrictive element 4 has one end vertically fixed to a fixing part 6, and an optical fiber 7 is optically coupled to the light receiving ends of both optical waveguide layers 5.

When light is incident on the optical waveguide layer 5 from both optical fibers 7, the optical energy spreads within the optical waveguide layer 5 and is absorbed by the photostrictive element 4. Therefore, due to the optical distortion effect, one plate 2 stretches while the other plate 3
is contracted and both plates 2.3 are pasted together, so that the optical distortion actuator 1 is bent and its self-contained end 8 is displaced.

What is shown in FIG. 2 is an optical distortion actuator 11 according to a second embodiment of the present invention. This optical distortion actuator 1
1, a light guide is provided on one entire surface of a plate-shaped photostrictive element 12 made of a photostrictive material that contracts with light energy (or may also be a photostrictive material that expands with light energy). A wave layer 13 is laminated, and an optical fiber 7 is optically coupled to one end of the optical waveguide layer 13. Further, one end of the optical distortion actuator 11 is fixed perpendicularly to the fixed NI 6, as shown in FIG.

Therefore, when light enters the optical waveguide layer 13 from the optical fiber 7, the optical energy spreads within the optical waveguide layer 13,
The light is absorbed into the photostrictive element 12 only from one side. One side of the photostriction element 12 that absorbs optical energy from the optical waveguide layer 13 contracts, but the other side does not absorb optical energy and therefore does not expand or contract. As a result, the photostriction actuator 11 curves and loses its freedom. End 14 is displaced. By forming the optical waveguide layer 13 on the surface of the photostrictive element 12 in this way, it is possible to manufacture a photostrictive actuator with a single layer structure other than a bimorph type.

What is shown in FIGS. 4(a) and 4(b) is an optical distortion actuator 21 according to a third embodiment of the present invention. In this embodiment, an optical waveguide layer 13 is formed on one side of a plate-shaped photostrictive element 12 made of a photostrictive material, and one end of this photostrictive element 12 is approximately attached to the end surface of the fixed part 22. fixed in parallel. The upper surface of the photostrictive element 12 and the upper surface of the fixed part 22 are connected to each other, and an optical waveguide 23 formed on the upper surface of the fixed part 22 is optically coupled to the light receiving end of the optical waveguide layer 13.

However, when no light is input from the optical waveguide 23 to the optical waveguide layer 13, the optical distortion actuator 21 maintains a straight state as shown in FIG. When light enters the optical waveguide layer 13, the optical distortion actuator 21 reacts, and as shown in FIG. 4(b)
(In this case, it is assumed that the photo-distortion material contracts due to light energy.)

FIG. 5 shows an optical distortion actuator 31 according to a fourth embodiment of the present invention, and shows a structure for propagating light at right angles. In this embodiment, one end of a plate-shaped photostrictive element 32 made of a photostrictive material is fixed perpendicularly to the end surface of the fixing part 36, and the side of the fixing part 36 of the photostrictive element 32 An optical waveguide layer 33 is formed on the surface.

On the other hand, an end portion of an optical waveguide 37 formed on the upper surface of the fixed portion 36 is optically coupled to the light receiving end 34 of the optical waveguide layer 33. Further, at the light receiving end 34 of the optical waveguide layer 33, a mirror portion 35 having an inclination angle of 45° is provided on the surface of the photostrictive element 32. That is, this mirror part 35 forms an angle of 45 degrees with respect to the plane of the optical waveguide layer 33 and the plane of the optical waveguide 37, and a metal material with high reflectivity is formed on the surface by a method such as vapor deposition. It is coated with a membrane. And the optical waveguide layer 3
The light receiving end 34 of No. 3 is formed on the mirror part 35,
The optical waveguide 37 is coupled to the light receiving end 34 of the optical waveguide layer 33 at the mirror portion 35 .

Therefore, from the optical waveguide 37 to the light receiving end 34 of the optical waveguide layer 33
When light enters the light receiving end 34 perpendicularly, the light enters the light receiving end 34, is reflected by the mirror portion 35, is bent at right angles, and spreads into the optical waveguide layer 33.

What is shown in FIG. 6(a) is an optical distortion actuator 41 according to a fifth embodiment of the present invention. In this structure, an optical waveguide layer 13 is formed on one surface of a photostrictive element 12 made of a photostrictive material, and a light scattering layer 42 is provided on the entire surface of the optical waveguide layer 13, as shown in FIG. The optical actuator 11 has a structure in which a light scattering layer 42 is further added on the optical waveguide layer 13.

The light scattering layer 42 is intended to diffusely reflect the light coming from the optical waveguide layer 13, and can be formed of, for example, a layer of a low refractive index material whose surface has been roughened.

When light enters the optical waveguide layer 13 from the optical fiber 7 or the optical waveguide, the incident light beam spreads while repeating total reflection within the optical waveguide layer 13, but is diffusely reflected by the light scattering layer 42, so that the optical waveguide layer 13 and the optical distortion element 12, the incident angle becomes smaller than the total reflection angle, and the optical waveguide layer 1
It becomes easier for light to enter from the third side to the photostrictive element 12 side, and the absorption efficiency of light energy into the photostrictive element 12 is improved.

That is, what is shown in FIG. 6(b) is the light intensity within the optical waveguide layer 13, and the horizontal axis X is the distance from the light receiving end of the optical waveguide layer 13. In the optical distortion actuator 11 as shown in FIG. 2, for example, in which the light scattering layer 42 is not provided, the light intensity within the optical waveguide layer IS is as shown by the curved line (dashed line) in FIG. 6(b). When the light scattering layer 42 is provided on the front surface of the optical waveguide layer 13, the light intensity quickly decreases as shown by curve A (solid line). That is, by providing the light scattering layer 42, the efficiency of light absorption into the photostrictive element 12 is improved. In addition,
The light scattering layer 42 may be provided between the photostrictive element 12 and the optical waveguide layer 13.

What is shown in FIG. 7 is a photostriction actuator 51 according to a sixth embodiment of the present invention, in which a bimorph type photostriction element 4
An optically opaque layer 52 is provided on the entire surface of the optical waveguide layer 5 formed on both sides of the optical waveguide layer 5, and the optical waveguide layer 5 is covered with the optically opaque layer 52.

Since the optically opaque layer 52 is provided on the surface of the optical waveguide layer 5, light from the outside does not enter into the optical waveguide layer 5, and the influence of disturbance light can be blocked. This optically opaque layer 52 can be easily formed, for example, by printing an opaque coating or depositing a metal film, but if the optically opaque layer 52 is made of a metal film, it can be formed within the optical waveguide layer 5. Since the optical energy is reflected without being absorbed by the optically opaque layer 52, the optical distortion element 4 can effectively absorb the optical energy.

In addition, in such a bimorph type optical distortion actuator, a light scattering layer as shown in FIG. 6 may be provided on the optical waveguide layer on both sides, or an optical waveguide layer may be provided on only one side as shown in FIG. In the optical distortion actuator having the above structure, an optically opaque layer as shown in FIG. 7 may be provided on one side of the optical waveguide layer. Furthermore, in a photostrictive actuator having an optical waveguide layer on only one side, an optically opaque layer may be provided on each surface of the optical waveguide layer and the photostrictive element to cut off the influence of disturbance light on the photostrictive element side as well.

FIG. 8 shows a photostrictive actuator 61 according to a seventh embodiment of the present invention, which includes a plate θ2 formed of a photostrictive material that expands by absorbing optical energy, and a plate θ2 that expands by absorbing optical energy. An optical waveguide layer 6S having a substantially uniform thickness is sandwiched between the plate 63 made of a photo-distortion material that contracts and the plate 63 is bonded together. This is both plates 82.63
It has a structure in which an optical waveguide layer 65 is inserted into the inside of a photostrictive element 84, and the optical fiber 7 or an optical waveguide is connected to the optical waveguide layer 85.

When light enters the optical waveguide layer 65 from the optical fiber 7 or the like, the light spreads within the optical waveguide layer 65 and is absorbed by both plates 62 and 63 from both sides of the optical waveguide layer 65.
The light distortion actuator 61 is curved to displace the light end.

In this embodiment, an optically opaque layer or a light scattering layer may be formed on the end surface (the upper end surface in the figure) of the optical waveguide layer 65 opposite to the light receiving end.

What is shown in FIG. 9 is an optical distortion actuator 71 according to an eighth embodiment of the present invention. In this embodiment, a wedge-shaped optical waveguide layer 72 is formed inside a photostrictive element 64 consisting of a pair of plates 62 and 63. That is, the thickness of the optical waveguide layer 72 is increased on the light receiving end 73 side,
At an end 74 opposite to the light receiving end 73, the thickness of the optical waveguide layer 72 is O, and the ends of both plates 62 and 63 are in contact with each other. In this embodiment, since the end 74 of the optical waveguide layer 72 opposite to the light receiving end 73 is closed, the light inside the optical waveguide layer 72 is not forced out from the side opposite to the light receiving end, and the light is not forced out. The absorption efficiency of optical energy into the distortion element 64 is improved. Furthermore, in this embodiment, since the propagating light tends to be in the radiation mode, there is no restriction on the material (refractive index) of the optical waveguide layer 72.

The optical distortion actuator of the present invention can be used in various devices, for example, in microvalves. In FIG. 10, a micro valve 82 for adjusting the flow rate is provided in a fluid pipe 81 for sending fluid such as liquid or gas, and a micro valve 82 for adjusting the flow rate is provided on the downstream side of the fluid pipe 81. Flow rate sensor 83 such as a laser Doppler meter
is provided. Further, the flow rate sensor 83 and the light amount control section 84 are connected by an optical fiber 85, and the flow rate signal detected by the flow rate sensor 83 is sent to the light amount control section 84 through the optical fiber 85. The light amount control section 84 mainly includes a light source such as a semiconductor laser element or a light emitting diode, and an internal modulator (or an external modulator).

Further, the light amount control section 84 and the optical distortion actuator in the micro valve 82 are also connected by an optical fiber 86, and when the flow rate value detected by the flow rate sensor 83 deviates from the set value, the light amount control section 54 The intensity of the optical energy being transmitted to the optical distortion actuator of the microvalve 82 is modulated, and the microvalve 82 is feedback-controlled so that a set flow rate is obtained. In this way, by using optical energy instead of electricity in the flow rate control system, it is possible to safely control the flow rate of fluids that are likely to be ignited by electrical sparks or the like.

FIGS. 11(a), 11(b), and 11(c) are cross-sectional views showing the specific structure and operation of the microvalve 82 provided in the fluid pipe 81 as described above. That is,
An optical distortion actuator 88 is arranged perpendicularly to the flow path inside the cylinder 87 of the microvalve 82. One end of the optical distortion actuator 88 is fixed to the cylinder 87, and a free end is attached to the inner surface of the cylinder 87. It is housed in a recess 89 provided therein. The optical distortion actuator 88 includes an optical fiber 88.
is connected, and no optical energy is transmitted from the light amount control unit 84, the free end of the optical distortion actuator 88 touches the stopper 90 on the edge of the recess 89, as shown in FIG. 11(a). They come into contact, completely closing the flow path of the microvalve 82, and the flow rate becomes zero. On the other hand, when the optical energy transmitted through the optical fiber 86 increases, the optical distortion actuator 88 curves and bends significantly (for example, as shown in FIGS. 11(b) and (C)).
Figure (b) shows the light intensity at 10%, and Figure 11 (c) shows the light intensity at 5o.
%], the gap between the inner periphery of the cylinder 87 and the free end of the optical distortion actuator 88 becomes larger, and the flow rate increases.

Note that when used in an atmosphere of corrosive gas or reactive gas, the entire photostrictive actuator may be coated with a fluororesin such as polytetrafluoroethylene (PTPE).

12(a) and 12(b) are cross-sectional views showing a microvalve 82 having a different structure. In this example,
A recess 92 parallel to the axial direction of the cylinder 91 is provided on the inner surface of the cylinder 91 of the microvalve 82, the optical distortion actuator 9'3 is disposed within the recess 92, and one end of the optical distortion actuator 93 is inserted into the recess 92. It is fixed at the inner end. When no optical energy is transmitted from the optical fiber 86, the optical distortion actuator 93 does not deform and the aperture ratio of the microvalve 82 is 100%, as shown in FIG. 12(a). A large flow rate can be obtained. On the other hand, when high-intensity optical energy is transmitted from the optical fiber 86, the optical distortion actuator 9
3 is bent sharply, and as shown in Section 12 (b), the flow path of the microvalve 82 is completely closed and the flow rate of the fluid is set to O. Then, the state shown in FIG. 12(a) and the state shown in FIG. 12(b)
An appropriate flow rate can be obtained between the conditions of .

[Effects of the Invention] According to the present invention, since optical energy can be sent to the optical distortion actuator through the optical waveguide layer, it is possible to input high-density optical energy, and the optical energy is difficult to escape to the outside. can be used efficiently to increase the operation of the optical distortion actuator. Furthermore, since there is no need for a space around the optical distortion actuator for propagating light and irradiating optical energy, the element shape of the optical distortion actuator can be made smaller, and the degree of integration can also be improved.

Furthermore, it can be used in environments where it is difficult to irradiate light from space, and since it can be controlled optically, it can also be used in places where it is difficult to use an electric actuator. Furthermore, optical distortion actuators with various structures other than the bimorph type can be manufactured.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing a first embodiment of the present invention, Fig. 2 is a perspective view showing a second embodiment of the invention, Fig. 3 is a sectional view of the same embodiment, and Fig. 4 ( a) and (b) are both sectional views showing the third embodiment of the present invention, FIG. 5 is a sectional view showing the fourth embodiment of the present invention, and FIG. 6(a) is a sectional view showing the fifth embodiment of the present invention. FIG. 6(b) is a cross-sectional view showing the relationship between the optical waveguide layer distance and the light intensity in the same example, and FIG. 7 is a cross-sectional view showing the sixth example of the present invention. , FIG. 8 is a cross-sectional view showing a seventh embodiment of the present invention, FIG. 9 is a cross-sectional view showing a seventh embodiment of the present invention, and FIG. Schematic diagram showing an example of use, 1st
Figures 1 (a), (b), and (c) are cross-sectional views explaining the operation of the optical distortion actuator inside the same microvalve, and Figures 12 (a) and (b) are different structures of the optical distortion actuator inside the microvalve. 13(a) and 13(b) are cross-sectional views showing a conventional optical distortion actuator. 1.11, 21, 31, 41, 51, 61, 71.88
．． 93 is optical distortion actuator, 5, 13.33.85
．． 72 is an optical waveguide layer.

Claims (1)

[Claims] (1) A photostrictive actuator formed of one or more types of photostrictive materials that generate distortion by optical energy, and an optical waveguide layer on the surface of the photostrictive material or the interface between the photostrictive materials. An optical distortion actuator characterized by being provided with.