JP2003195364A - Optical component and optical switch using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical component which can selectively transmit, reflect, or half-transmit light by using metal nanoparticles and further to provide an optical switch which can be manufactured at low cost to small size by using the optical component. <P>SOLUTION: A container which constitutes the optical component 1 partially has a transparent member (glass substrate 3) and contains a transparent solution L, metal nanoparticles 5, and a dispersant. An electric field producing means 6 can produce an electric field nearby the transparent member and when the electric field is removed or made small in intensity, the metal nanoparticles 5 enter a dispersion state to transmit the light. When the intensity of the electric field is made large, on the other hand, the metal nanoparticles 5 are condensed on the transparent member to reflect the light. An optical switch which transmits or reflects light from one input optical path by a plurality of optical components 1 respectively and selectively guides it to one of a plurality of output optical paths can be constituted by using the plurality of optical components 1. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical component and an optical switch using the same, and more specifically, to an optical component that aggregates or disperses metal nanoparticles to switch between a light reflection state and a light transmission state and uses the same. Regarding optical switches.

[0002]

2. Description of the Related Art Conventionally, an optical switch disclosed in Japanese Patent Laid-Open No. 2001-228413 has been widely used. The optical switch has at least one input optical path,
It has a plurality of output optical paths with respect to the input optical path,
A reflecting plate as an optical component is provided in order to split the light incident from the input optical path into different output optical paths. The reflection plate is rotatably provided by a rotation support member or the like, and when the reflection plate rotates at a predetermined angle, the light incident from the input optical path is guided to the predetermined output optical path. Further, the above-mentioned publication describes a reflector having a reflecting surface such as a specular mirror that totally reflects light and a dichroic mirror that has an angle dependency of reflectance.

[0003]

However, in the conventional optical switch, since the light incident from the incident optical path cannot be branched to a different output optical path without rotating the reflecting plate, the reflecting plate is rotated. The mechanism is an essential component. Therefore, a large number of reflectors are required for an optical switch having a plurality of incident optical paths and a plurality of output optical paths that are used today, and a large number of mechanisms for rotating the reflectors are also required accordingly. Therefore, it is very difficult to manufacture the optical switch in a small size. Moreover, in order to instantly switch the light input to the optical switch to an arbitrary output optical path or to keep the optical axis of the light output from the output optical path constant, complicated control and expensive parts are required. Therefore, the cost of the optical switch increases. In view of the above problems, the present invention provides an optical component capable of selectively transmitting, reflecting, or semi-transmitting light by using metal nanoparticles, and by using this optical component, it is inexpensive and compact. The present invention provides a manufacturable optical switch.

[0004]

That is, an optical component according to the invention of claim 1 has a transparent member in at least a part thereof, and comprises a transparent solution and metal nanoparticles and a dispersant added to the transparent solution. A storage container and an electric field generating means for generating an electric field in the vicinity of the transparent member are provided, and the electric field generating means is a dispersed state capable of transmitting light through the metal nanoparticles with the electric field strength being zero or small. And
It is characterized in that the strength of the electric field is increased and the metal nanoparticles are aggregated on the transparent member to be in an aggregated state capable of reflecting light. Further, the optical component according to the invention of claim 5 has a transparent member in at least a part thereof, and a container storing a transparent solution and metal nanoparticles and a dispersant added to the transparent solution, and the vicinity of the transparent member. And an electric field generating means for generating an electric field, the electric field generating means,
It is characterized in that the intensity of the electric field is periodically changed to obtain a semi-transmissive state of light in which the metal nanoparticles are locally aggregated. Furthermore, the optical switch according to the invention of claim 7 is an optical switch having at least one input optical path and a plurality of output optical paths for the one input optical path, and the optical switch described above is provided between the input optical path and the output optical path. 5. A plurality of optical components having a configuration other than the optical components in 5 are arranged, and each of the optical components is selectively switched between a dispersed state and an aggregated state to transmit or reflect light from the input optical path to select any of a plurality of output optical paths. It is characterized by selectively guiding crab.

According to the optical component of the above-mentioned claim 1, when the electric field strength is set to zero or small by the electric field generating means, the metal nanoparticles are in a dispersed state capable of transmitting light. Light can pass through the optical components. On the other hand, if the strength of the electric field is increased by the electric field generating means,
Since the metal nanoparticles are aggregated on the transparent member to be in an aggregated state capable of reflecting light, light is reflected by the optical component in this state. In this way, it is possible to switch between the light transmitting state and the light reflecting state simply by changing the strength of the electric field. According to the optical component of claim 5, the electric field strength is periodically changed by the electric field generating means, whereby the metal nanoparticles are locally aggregated in the transparent solution to obtain a semi-transmissive state of light. be able to. Further, in the optical switch according to claim 7, since a plurality of optical components having the above-mentioned configuration are used, the light from the input optical path is switched to any one of the plurality of output optical paths by switching the transmission state and the reflection state of each optical component. Can be selectively led to. Further, in this optical switch, it is not necessary to provide a reflecting plate and a movable mechanism for rotating the reflecting plate as in the conventional case, so that the optical switch can be manufactured in a small size and at a low cost.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below with reference to illustrated embodiments. In FIGS. 1 (a), 1 (b) and 1 (c), an optical component 1 comprises two glass substrates 2 and 3 as transparent members.
And the spacer 4 interposed between the glass substrates 2 and 3.
The inside of the optical component 1 is sealed by the two glass substrates 2 and 3 and the spacer 4 provided along the periphery of the glass substrates 2 and 3. Then, a transparent solution L having an electrically insulating property and a light transmitting property is enclosed inside the container constituted by the glass substrates 2 and 3 and the spacer 4. Metal nanoparticles 5 monodispersed with a low molecular dispersant are added therein. As the transparent solution L, for example, toluene or pure water can be used. The transparent solution L may be colored. Further, as the metal nanoparticles 5, nanoparticles having a property of reflecting light such as Au and Pt are used, and the diameter thereof is about 1 to 100 nm. In the present example, commercially available Au nanoparticles having an average diameter of 7 nm are used. Further, a low molecular weight ligand may be used as the low molecular weight dispersant, or it may be produced from a mixed solution of a surfactant and an organic solvent. As the surfactant, for example, an anionic surfactant can be used, and as the organic solvent, for example, toluene or alcohol can be used. A method for monodispersing the metal nanoparticles 5 with a low molecular weight dispersion material has already been known from JP 2000-117094 A and the like.

The metal nanoparticles 5 mixed in the transparent solution L are monodispersed by the low molecular dispersant mixed in the transparent solution L at the same time. That is, it is said that the metal nanoparticles 5 cohere with each other in the state as they are, and the cohesive force at that time is mainly van der Waals force. The above-mentioned low molecular weight dispersant is added in order to prevent the metal nanoparticles 5 from aggregating.
Due to the low molecular weight dispersant, the particles are in a monodispersed state in which the particles are separated from each other without agglomeration. Then, each metal nanoparticle 5 collides with the molecules constituting the transparent solution and is uniformly dispersed and floats in the transparent solution L by Brownian motion. In a state in which the metal nanoparticles 5 are monodispersed and suspended in the transparent solution L, visible light having a wavelength of 300 to 800 nm or laser light having a wavelength of about 1500 nm is applied to the transparent solution L. However, these lights are transmitted through the transparent solution L without being affected by reflection by the individual metal nanoparticles 5.

Next, of the two glass substrates 2 and 3, the glass substrate 3 on the lower side of the drawing is placed inside, that is, the transparent solution L.
A transparent electrode 7 forming the electric field generating means 6 is formed on the surface in contact with. In this embodiment, the transparent electrode 7
A conventionally known ITO film is used as, and the ITO film is formed on the glass substrate 3 by sputtering. The electric field generating means 6 has a power source 9 connected to the transparent electrode 7 via a switch 8. The negative pole of the power source 9 is connected to the transparent electrode 7 and the positive pole is grounded. ing.

In the above configuration, the state of FIG.
That is, in the state where the switch 8 is turned off and no electric field is generated around the transparent electrode 7, the metal nanoparticles 5 are uniformly dispersed and suspended in the transparent solution L. Even if the optical component 1 is irradiated with light in this state, the light is transmitted to the opposite side without being affected by the metal nanoparticles 5 as described above. Therefore, in this state, the optical component 1 transmits light. It is in a state. On the other hand, when the switch 8 is turned on as shown in FIGS. 1B and 1C, since the transparent electrode 7 is connected to the negative side of the power source 9, the surface of the transparent electrode 7 is negatively charged. Appears. Then, positive charges are collected on the transparent electrode 7 side by the action of electrostatic induction in the metal nanoparticles 5, whereby electrostatic forces act on each other, and the metal nanoparticles 5 are electrophoresed. Here, the number of the metal nanoparticles 5 is set to be substantially equal to the area of the transparent electrode 7 when the metal nanoparticles 5 are aggregated on the transparent electrode 7 in a single layer.
The dispersed metal nanoparticles 5 have the property of being electrophoresed on the transparent electrode 7 and then being arranged two-dimensionally in a two-dimensional plane without overlapping with each other, and the present invention utilizes this property. There is. Under this condition, if the voltage value of the power source 9 is adjusted to an appropriate value in advance, the dispersive force between the metal nanoparticles 5 by the low molecular weight dispersant will be small, so that the value shown in FIG. As in c), the metal nanoparticles 5 can be aggregated on the transparent electrode 7 in a plane without a gap. Therefore, when the optical component 1 is irradiated with light in this state, the metal nanoparticles 5 are aggregated at intervals less than or equal to the wavelength of light without a gap, so that light such as visible light or laser light is reflected, and The component 1 is in a light reflection state.

If the diameter of the metal nanoparticles 5 used is equal to or larger than the wavelength of light, the incident light will be scattered even if the metal nanoparticles 5 are flatly aggregated. Therefore, the optical component 1 cannot be used as a mirror. In addition, if the voltage value of the power source 9 is not appropriate, it takes a long time for the metal nanoparticles 5 to aggregate on the transparent electrode 7, or the metal nanoparticles 5 do not aggregate sufficiently, so A problem such as light passing through the gap occurs, and a good reflection state cannot be obtained. Furthermore, the transparent electrode 7 does not have to be provided inside the glass substrate 3, that is, on the transparent solution L side, and may be provided outside the glass substrate 3. Even with such a configuration, an electric field generated by applying a voltage to the transparent electrode 7 is also generated in the transparent solution L via the glass substrate 3, so that the metal nanoparticles 5 are attracted to the glass substrate 3. The particles can be aggregated in a plane, and the effects described above can be obtained.

FIGS. 2A, 2B and 2C show a second embodiment of the present invention. The optical component 1 of this embodiment is similar to the optical component 1 of the first embodiment. Two glass substrates 2,
3 and a spacer 4 interposed between the glass substrates 2 and 3, in which the metal nanoparticles 5 and the transparent insulating solution L are enclosed. However, in the present embodiment, unlike the optical component in the first embodiment, the metal nanoparticles 5 in the transparent solution L are monodispersed by the polymer dispersant. In the figure, this polymer dispersant is represented by several line segments surrounding each metal nanoparticle 5. Examples of the polymer dispersant include poly (N-vinyl-2).
-Pyrrolidone) (PVP), chain polymer, crosslinked polymer,
Inorganic polymers and the like are known, and for the metal nanoparticles 5 monodispersed using these polymer dispersants, the article “Controlling Particle Size of Metal Nanoparticles Using Surface Protection by Polymer” (Toshiharu Teranishi) , Mikio Miyake) (1997) and the like. And, as shown in FIG. 2A, the metal nanoparticles 5 monodispersed using the polymer dispersant have a gap between them even if the metal nanoparticles 5 are adjacent to each other. Existing.

Next, of the two glass substrates 2 and 3, the lower glass substrate 3 in the figure has an electric field generating means 6 similar to that of the first embodiment, on the outer surface of the transparent solution L. Is formed on the surface of the glass substrate 3 in contact with the transparent solution L, and a pair of transparent electrodes 7b and 7c are formed on the surface of the glass substrate 3 in order to generate a potential difference on the transparent electrode 7a. Are formed parallel to each other so as to be located on both sides of. Of the above transparent electrodes, the transparent electrodes 7a and 7b are provided with power sources 9a and 9b via switches 8a and 8b, respectively, and like the first optical component 1, the negative poles are transparent electrodes. The positive electrode is connected to 7a and 7b and is grounded. The transparent electrode 7c is grounded by a conductor. The voltages of the power supplies 9a and 9b are Va and Vb, respectively,
The strength of the voltage has a relationship of Va <Vb.

In the optical component 1 having the above structure, as shown in FIG.
In the state of (a), the switch 8a of the transparent electrode 7a has already been turned on, and the metal nanoparticles 5 are the same as in the first embodiment.
Are electrostatically induced by the negative charges generated in the transparent electrode 7a, and are attracted to the glass substrate 3 in a plane by electrophoresis. However, even if the optical component 1 is irradiated with light in this state, although the metal nanoparticles 5 are attracted onto the glass substrate 3, there is a gap between the metal nanoparticles 5 due to the polymer dispersant. Therefore, light such as visible light and laser light is transmitted through this gap, and therefore the optical component 1 is in a transmissive state with respect to light. And
When the switch 8b is turned on as shown in FIG. 2B, the power source 9b
As a result, a potential of −Vb is generated on the transparent electrode 7b, and one transparent electrode 7c is grounded.
A potential difference is generated between b and the transparent electrode 7c. Then, due to the generation of this potential difference, an electric field is generated from the transparent electrode 7c toward the transparent electrode 7b. When an electric field is generated, an electrostatic force is applied to each metal nanoparticle 5 to approach each other by electrostatic induction, and a compressive force is generated between the metal nanoparticles 5 to reduce a gap between the metal nanoparticles 5. become. Then, the gap between the metal nanoparticles 5 is reduced by adjusting the electric field, and when the gap is sufficiently narrower than the wavelength of light, the optical component 1 is irradiated with light such as visible light or laser light. However, light cannot pass through this gap, and the optical component 1 can obtain a reflective state. Further, when the optical component 1 of the present embodiment is used, since the metal nanoparticles 5 can be attracted onto the glass substrate 3 by the electrophoresis by the transparent electrode 7a in advance, the optical component 1 of the first embodiment can be obtained. In comparison with aggregating the metal nanoparticles 5 floating randomly in the transparent solution L on the transparent electrode 7, the optical component 1 can be switched from the transmissive state to the reflective state in a short time.

FIGS. 3A, 3B and 3C show a third embodiment of the present invention. The optical component 1 of this embodiment also includes two glass substrates 2 and 3 and the glass. It is provided with a spacer 4 interposed between the substrates 2 and 3, and the metal nanoparticles 5 are included therein.
And an insulative transparent solution L are enclosed. The metal nanoparticles 5 enclosed in the optical component 1 are monodispersed with a polymer dispersant, as in the second embodiment. Next, among the two glass substrates 2 and 3, the lower glass substrate 3 in the drawing is provided with a transparent electrode 7 constituting the electric field generating means 6 on its inner surface, that is, on the surface in contact with the transparent solution L. . A power source 9 is connected to one end of the transparent electrode 7 via a switch 8, the negative side pole of the power source 9 is connected to the transparent electrode 7, and the positive side pole is grounded. Further, the end of the transparent electrode 7 on the side not connected to the power source 9 is grounded by a conductive wire. The transparent electrode 7 is a body resistance electrode, and for this body resistance electrode, an ITO film formed thinner than the first and second embodiments can be used. Then, by energizing the transparent electrode 7, a potential difference is generated at both ends of the transparent electrode 7.
Further, the power supply 9 is capable of changing the voltage generated, and is configured to generate Vd in FIG. 3 (a) and Ve in FIG. 3 (b). Is set so that Vd <Ve.

In the optical component 1 having the above structure, as shown in FIG.
In the state of (a), the switch 8 is already turned on,
An electric field toward the transparent electrode 7 is generated near the boundary between the transparent electrode 7 and the transparent solution L. Therefore, a force due to electrostatic induction is generated in the metal nanoparticles 5 and is attracted to the transparent electrode 7 by electrophoresis, so that the metal nanoparticles 5 are planarly aligned on the transparent electrode in advance as in the second embodiment. Become so. Further, a potential difference is generated at both ends of the transparent electrode 7, but the electric field generated by this potential difference is generated by each metal nanoparticle 5
It is set so that the gaps are not reduced by mutual attraction between them. When the optical component 1 is irradiated with light in this state, the metal nanoparticles 5 are attracted onto the glass substrate 3, but since there is a gap due to the polymer dispersant between the metal nanoparticles 5, there is a visible light. Light such as or laser light can be transmitted through this gap to obtain a light transmission state. And FIG.
When the voltage of the power source 9 is switched to a higher voltage Ve as shown in (b) and (c), the potential difference at both ends of the transparent electrode 7 increases, so that the voltage difference between the transparent electrode 7 and the transparent electrode 7 generated around the transparent electrode 7 is increased. Since the electric field in the direction becomes strong, the metal nanoparticles 5 come close to each other. If the gap between the metal nanoparticles 5 is reduced and the gap is sufficiently smaller than the wavelength of light, the light reflection state can be obtained as in the second embodiment. Further, like the optical component 1 of the second embodiment, the optical component 1 of the present embodiment has the metal nanoparticles 5 attracted onto the glass substrate 3 by the transparent electrode 7 in advance, so that the optical component 1 can be transmitted in a short time. It is possible to switch from the state to the reflective state.

FIG. 4 shows an optical switch 11 using the optical component 1 having any configuration of the first to third embodiments. As shown in FIG. 4, the main body 12 of the optical switch 11 incorporates a large number of switching members 16 that switch between a reflective state and a transmissive state with respect to the laser light. Each switching member 16 uses a part of the optical component 1 and has a glass substrate 3 on which transparent electrodes are formed.
And an electric field generating means 6 including the transparent electrode. The main body 12 is formed with a recess 12a having a required shape in advance for incorporating each switching member 16 and the like, and as shown in an enlarged view in FIG. 5, each switching is performed on a support surface formed on the wall surface of the recess 12a. The members 16 are closely adhered to each other by elastic rods 18 while maintaining liquid tightness. An optical axis compensating member 17 for compensating the deviation of the optical axis of the laser beam transmitted through the switching member 16 is closely attached to the other supporting surface formed on the wall surface of the recess 12a, and each optical axis compensating member. 17 are also fixed by elastic rods 18 while maintaining liquid tightness. A sealed space is formed by the wall surface of the concave portion 12a, the switching member 16, the optical axis compensating member 17, and a lid body (not shown) that is superposed on the upper surface of the main body portion 12, and in this embodiment, the elastic rod 18 is sealed. The transparent solution L containing the metal nanoparticles 5 is enclosed in all the sealed spaces on the side not provided. On the other hand, in the sealed space on the side where the elastic rod 18 is provided, a transparent liquid,
Or gas is enclosed. 4 and 5,
A portion in which the metal nanoparticles 5 and the transparent solution L are enclosed is shown by a large number of dots.

The switching member 16 and the optical axis compensating member 17
Have glass plates each having the same thickness and whose front and back surfaces are manufactured in parallel with each other, and the front and back surfaces thereof are provided with an AR coating for preventing reflection of laser light. Further, of the switching member 16 and the optical axis compensating member 17, those which are vertically and horizontally adjacent to each other are 90
It is installed with an angle of °, and is always installed so as to maintain an incident angle of 45 ° with respect to incident laser light. As described above, each switching member 16 has an optical component 1 of any one of the first to third embodiments.
The transparent electrodes 7 constituting the above are formed, and the switches 8 connected to all the transparent electrodes 7 can be individually switched between a conductive state and a non-conductive state by a control device (not shown). Therefore, when the control device controls the switch 8 of each switching member 16, each switching member 16 can be switched between the reflection state and the transmission state of the laser light.

Further, in FIG. 4, four optical fibers 1 as an input optical path for laser light are provided on the left side of the main body 12.
3A to 13D, and four optical fibers 13E to 13L are provided as output optical paths, four on each of the right side and the lower side in the drawing. Each of the optical fibers 13A to 13L has a holder 14 with its tip inserted into the recess 12a.
Is fixed to the main body 12 by the optical fiber 13
Laser light output from A to 13D and the optical fiber 13
The optical axes of the laser beams input to E to 13L are prevented from being displaced. Moreover, each optical fiber 13A-13
Collimator lenses 15 are provided on the respective optical axes in the vicinity of the distal end of L to adjust the parallelism of the laser light output from the optical fibers 13A to 13D, and the optical fiber 13E.
The laser light input to 13L is focused. The optical switch 11 having the above structure is generally called a 4 × 8 channel optical switch, and such a structure is also suitable for 1 × N, 2 × 2, N × 2, etc. It is possible to easily cope with an optical switch having a large number of channels.

If the switching member 16 is installed in the arrangement as shown in FIG. 4, the switching member 16 switches between the reflection state and the transmission state of the laser light, so that the laser light output from the optical fibers 13A to 13D is output. Will be input to each of the optical fibers 13E to 13L through a predetermined route. For example, as shown in FIG. 4, the laser light output from the optical fiber 13B is supplied to the optical fiber 13
In order to input to H, two switching members 16a provided on the optical axis of the optical fiber 13B, the switching member 16a from the left and the switching member 16b provided below the switching member 16a, are used. The switching member 16 may be in the reflective state, and the other switching members 16 provided on the optical path of the laser light may be in the transmissive state. Needless to say, the path of the laser beam can be considered in addition to this, and the arrangement of the switching member 16 is not limited to the arrangement shown in FIG.

Next, the optical axis compensating member 17 will be described. FIG. 5 is an enlarged view showing the range indicated by A of the optical switch 11 shown in FIG. 4, and the laser light shown by the solid line in the figure is until the laser light output from the optical fiber 13C enters the optical fiber 13H. Is shown. The laser light shown by the imaginary line in the figure shows the optical path of the laser light when the optical axis compensating member 17 is not provided.
In FIG. 5, the laser beam shown by the solid line entering from the left is the switching member 1 which is first switched to the transmission state.
It is transmitted through 6c and 16d. At this time, the switching member 16
Since the glass plate constituting the above has a thickness, the following phenomenon as shown in FIG. 6 occurs.

The above-mentioned FIG. 6 shows the switching member 16c shown in FIG.
This is an enlarged view of the vicinity, and the thicknesses of the switching member 16 and the optical axis compensating member 17 can be understood. When the laser light reaches the left side surface of the switching member 16c, refraction of the light occurs, the direction of the laser light changes once, and the laser light reaches the right side surface of the switching member 16c. It can be seen that it refracts again. Since the front and back surfaces of the glass plates forming the switching member 16 and the optical axis compensating member 17 used in this embodiment are parallel to each other, the light of the laser light incident on the switching member 16c is emitted. Shaft and switching member 16
The optical axes of the laser light refracted by c are parallel. Therefore, the refraction of the above-mentioned two times causes the optical axis of the laser beam to shift in parallel by a predetermined amount. The optical axis of the laser beam deviated by the switching member 16c can be returned to the original state by installing the switching member 16d switched to the transmission state on the laser beam path. That is, as described above, the switching member 16d is the switching member 16c.
Since they are installed at an angle of 90 ° with respect to each other, the laser light incident on the switching member 16d with the optical axis deviated first enters the switching member 16c after undergoing the refraction of 2 degrees as described above. It becomes the same optical axis as the optical axis of the laser light and is transmitted through the switching member 16d. further,
The optical axis of the laser light reflected by the switching plate 16e can also be restored by installing the optical axis compensating plate 17a on the path of the laser light. That is, as described above, since the optical axis compensating plate 17 has the same thickness as the switching plate 16 and is installed at an angle of 90 ° to each other, the optical axis compensating plate 17 is incident on the optical axis compensating plate 17a with the optical axis deviated. The laser light emitted can be compensated as in the case of the switching member 16d. In addition, when the laser light is reflected by the switching member 16 which is switched to the reflective state, FIG.
As shown by the switching members 16e and 16f, even if the surface on which the laser light is reflected, that is, the transparent electrode 7 is on the other side of the glass substrate 3 with respect to the traveling direction of the laser light (the switching member 16e), it is on the front side. Even (switching member 1
6f), the optical axis does not shift.

As shown by the imaginary line laser light in FIG. 5, in the optical switch 11 not provided with the optical axis compensating member 17, the laser light transmitted through the switching member 16 has its optical axis deviated without being compensated. Since the laser light proceeds as it is, the laser light may not be incident on the optical axis of the optical fiber 13H. On the other hand, by providing the optical axis compensating members 17a and 17b at appropriate positions as indicated by the solid line laser light, the deviation of the optical axis can be compensated. Therefore, the laser light is input to the optical axis of the optical fiber 13H via the collimator lens 15.

In the above-mentioned optical switch 11, even if the entire interior of the main body 12 is filled with the transparent solution L containing the metal nanoparticles 5, the same effect as described above can be obtained. Further, by disposing the optical components according to the second or third embodiment in the optical switch 11, it becomes possible to provide an optical switch capable of switching at high speed. further,
The above embodiment is an example in which the optical component of the present invention is applied to an optical switch. However, the present invention is not limited to this, and can be used for, for example, a window of a car, a window of a house, a display, etc. by switching a reflection state or a transmission state of light. You can

Further, according to the optical component 1 in the following embodiments, it is possible to obtain a semi-transmissive state of light. FIG. 7 shows an optical component 1 having the same configuration as the optical component 1 of the first embodiment. The difference from the optical component 1 of the first embodiment is that
The power supply 9 can variably adjust its output voltage. Then, FIG. 7 shows a state where a predetermined voltage is applied to the transparent electrode 7 and the plurality of metal nanoparticles 5 are aggregated in the transparent solution L. This shows exactly the intermediate state between FIG. 1A and FIG. 1B of the first embodiment, and in this embodiment, this state is maintained by adjusting the voltage by the power supply 9. . Specifically, when a voltage is applied to the transparent electrode 7, the metal nanoparticles 5 are electrophoresed to the transparent electrode 7 while approaching each other evenly.
They are agglomerated with each other and are connected to each other so as to form a strip toward the transparent electrode. By the aggregation of the metal nanoparticles 5 in this way, the density of the metal nanoparticles 5 in the relevant portion of the transparent solution L becomes high, and the light incident on the relevant portion is scattered by the metal nanoparticles 5 and the transmitted amount of the light. Is reduced. On the other hand, in the other transparent solutions L, the density of the metal nanoparticles 5 is reduced, so that light is transmitted without being scattered. Therefore, in the state as shown in FIG.
Since a part of the light incident on the optical component 1 is scattered by the metal nanoparticles 5 and the remaining light is transmitted as it is, the optical component 1 is in a semi-transmissive state of light.

In order to actually obtain the state shown in FIG. 7, for example, the power supply 9 has a cycle shown in the graph of FIG.
It is sufficient to adjust the voltage at. In this graph, the vertical axis represents the voltage height and the horizontal axis represents the time for applying the voltage.
Then, when a predetermined voltage is applied to the transparent electrode 7, the metal nanoparticles 5 aggregate with each other in a band shape as described above, and are attracted to the transparent electrode 7 by electrophoresis. However, since the above voltage is released for a certain period of time, the cohesive force does not act on the metal nanoparticles 5, and the coagulated metal nanoparticles 5 are dispersed on the transparent electrode 7 again by the Brownian motion without agglomeration. Attempt to return to the state of 1 (a). However, the voltage is applied to the transparent electrode 7 again before the metal nanoparticles 5 are completely dispersed, so that the metal nanoparticles 5 are aggregated again.
You can keep the state like. The amount of aggregation of the metal nanoparticles 5 can be changed depending on the strength of this voltage and the time for which the voltage is applied.
The amount of light transmitted can be adjusted by changing the amount of scattered light. Such an optical component 1 can be adopted in a product such as a window glass which requires light control.

[0026]

As described above, according to the optical component of the present invention, it is not necessary to rotate the reflector as in the conventional case, and the transmission state and the reflection state of light can be changed only by changing the strength of the electric field. The effect that it can be switched is obtained. Further, since the optical switch of the present invention uses a plurality of optical components having the above-mentioned configuration, it is possible to obtain the effect that the optical switch can be manufactured in a small size and at low cost. Further, it is possible to obtain a semi-transmissive state of light by periodically changing the magnitude of the electric field by the transparent electrode.

[Brief description of drawings]

FIG. 1 shows an optical component 1 as a first embodiment, (a)
Shows a light transmitting state, (b) shows a light reflecting state, and (c) shows a cross-sectional view taken along line cc of (b).

FIG. 2 shows an optical component 1 as a second embodiment, (a)
Shows a light transmitting state, (b) shows a light reflecting state, and (c) shows a cross-sectional view taken along line cc of (b).

FIG. 3 shows an optical component 1 as a third embodiment, (a)
Shows a light transmitting state, (b) shows a light reflecting state, and (c) shows a cross-sectional view taken along line cc of (b).

FIG. 4 is a plan view showing the outline of the internal structure of an optical switch.

FIG. 5 is an enlarged view showing a portion A of FIG.

FIG. 6 is an enlarged view of FIG. 5 showing the effect of the optical axis compensation member 17.

FIG. 7 is a diagram showing an optical component 1 as a fourth embodiment.

FIG. 8 is a graph showing the voltage cycle of the power supply 9 in the fourth embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Optical parts 2,3 Glass substrate 5 Metal nanoparticles 7 Transparent electrode 8 Switch 9 Power supply 11 Optical switch 13A-13L Optical fiber 16 Switching member 17 Optical axis compensation member L Transparent solution

Claims (8)

[Claims] 1. A container having a transparent member in at least a part thereof and storing a transparent solution, metal nanoparticles added to the transparent solution and a dispersant, and an electric field generating for generating an electric field in the vicinity of the transparent member. The means for generating an electric field, wherein the electric field strength is zero or small, the metal nanoparticles are in a dispersed state capable of transmitting light, and the electric field strength is large, and the metal nanoparticles are Is agglomerated on a transparent member so as to be able to reflect light into an agglomerated state. 2. The electric field generating means includes a transparent electrode formed on the transparent member and a power source connected to the transparent electrode, and the dispersant is a low molecular weight dispersant, and an electric field is generated on the transparent electrode. The optical component according to claim 1, wherein the metal nanoparticles are suspended and dispersed in a transparent solution in the undispersed state. 3. The electric field generating means includes a transparent first electrode formed on the transparent member, a first power source connected to the first electrode, and arranged on both sides of the first electrode. A pair of second electrodes and a second power source connected to one of the second electrodes, wherein the dispersant is a polymer dispersant, and a weak electric field is generated by the first power source. Is generated, the metal nanoparticles are attracted to the first electrode to be in a dispersed state, and when a strong electric field is generated by the second power source, the metal nanoparticles are attracted to the first electrode to be in a dispersed state. The optical component according to claim 1, wherein the particles are aggregated to be in an aggregated state. 4. The electric field generating means comprises a transparent electrode formed on the transparent member and a power source connected to the transparent electrode, and the dispersant is a polymer dispersant, and the dispersant is a polymer dispersant. When a small potential difference is generated between both ends of the transparent electrode, the metal nanoparticles are attracted to the transparent electrode to be in a dispersed state, and when a large potential difference is generated by the power source, the metal nanoparticles are attracted to the transparent electrode and are in a dispersed state. The optical component according to claim 1, wherein the metal nanoparticles that have been formed are aggregated to be in an aggregated state. 5. A container having a transparent member in at least a part thereof and storing a transparent solution and metal nanoparticles and a dispersant added to the transparent solution, and an electric field generating an electric field in the vicinity of the transparent member. And a means for generating a semi-transmissive state of light in which the metal nanoparticles are locally aggregated by periodically changing the strength of the electric field. 6. The metal nanoparticles have a diameter of 1 to 100 nm.
The optical component according to any one of claims 1 to 5, wherein 7. An optical switch having at least one input optical path and a plurality of output optical paths with respect to the one input optical path, wherein the input optical path and the output optical path are provided between the optical switch and the optical switch. Item 7. A plurality of optical components according to any one of items 6 are arranged, and each optical component is selectively switched between a dispersed state and an aggregated state to transmit or reflect light from an input optical path to output one of a plurality of output optical paths. An optical switch characterized by being selectively led to. 8. The optical switch according to claim 7, further comprising an optical axis compensating member for returning an optical axis deviated by the passage of light through an optical component by the deviated amount.