JP2005037691A - Element for controlling total reflecting condition of light - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an element for controlling total reflecting condition of light, the element which can be easily mass-produced, has the capability of efficiently using a reflection area, and operates under ordinary temperature. <P>SOLUTION: The element 20 for controlling total reflecting condition of light includes a translucent substrate 32 having a principal surface, a first film 34 made of elastomer formed on the principal surface, a magnetic material layer 36 formed with magnetic particles scattered evenly on the first film 34, a second film 38 made of elastomer formed on the magnetic material layer 36, and a grating 40 press-fixed from above the second film 38. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an optical communication system using light as a medium, and more particularly to an optical modulation device used in an optical spatial communication system using a retroreflective device typified by a corner cube prism.

  Recently, communication using radio waves has been widely used. However, radio waves are a limited resource, and it is necessary to appropriately allocate and operate radio resources to many wireless communication devices. For this reason, various laws are applied to communication using radio waves.

  On the other hand, the spread of mobile phones is progressing, and wireless communication is spreading not only in portable notebook computers but also in desktop computers. The amount of data carried by radio waves is also increasing. If radio waves with various restrictions are continuously used, there is a risk that the operation will not be distant and a failure may occur.

  Therefore, instead of communication using radio waves subject to restrictions, research is being conducted on communication systems using light that are not subject to legal restrictions and have only more lenient communication resources. Among such optical communication systems, an example of a communication system capable of carrying a lot of information at once is disclosed in Patent Document 1 described later.

  The communication system disclosed in Patent Document 1 is a bidirectional spatial optical communication system using a laser, and a laser oscillator is provided on one side and a corner cube is provided on the other side. By modulating the laser light emitted from the laser oscillator with an external signal, the light receiving side can demodulate the signal from the received laser light.

  The corner cube reflects this incident light to the laser oscillator side. At this time, as a characteristic of the corner cube, light incident from a certain direction is reflected in the same direction. Therefore, the reflected light always reaches very close to the laser oscillator. A modulator for modulating the reflected light is provided on one surface of the corner cube depending on whether the reflection on the corner cube surface is total reflection or non-reflection. Information can be placed on the reflected light by driving the modulator with an external signal. A light receiving sensor for receiving the reflected light is provided on the laser oscillator side, and a signal transmitted from the corner cube side can be demodulated from the output of the light receiving sensor.

  At this time, as the modulator, a light reflecting portion that is provided on one surface of the corner cube and that can control the total reflection condition is used. Each of these pixels is provided on the back surface of the transparent glass forming the reflection surface of the corner cube, and includes an element that controls total reflection on the total reflection surface (back surface) of the glass. In Patent Literature 1, as these elements, a digital micromirror device, a magnetic fluid that is encapsulated in a flat transparent capsule, moves by a magnetic force in a plane parallel to the total reflection surface, or a substance that changes in volume when receiving light. In order to control the total reflection condition on the total reflection surface by changing the position of these, it has been proposed.

JP 2001-298420 A

  When a digital micromirror device is used, it must be formed with high accuracy on the same plane so that a large number of devices are in close contact with the back surface of the glass. In particular, when the number of devices becomes large, the manufacture becomes difficult. For this reason, a technology that can easily create a large number of devices is being developed.

  If the magnetic fluid described in Patent Document 1 is used, only half the area of the reflecting surface can be used. Therefore, a technique that uses the reflecting surface more efficiently is desired.

  In addition, when using a substance whose volume changes when receiving light, its operating temperature becomes a problem. In particular, known substances having such properties generate heat upon receiving light, so that it is difficult to operate at room temperature at this time.

  Therefore, an object of the present invention is to provide a light total reflection condition control element that makes it easy to create a large number of elements and can efficiently use a reflecting surface.

  The light total reflection condition control element according to the present invention includes a translucent substrate having a main surface, a first film body made of an elastomer formed on the main surface, and a uniform film on the first film body. A magnetic layer formed by particles of the magnetic material dispersed on the second layer, a second film body made of an elastomer formed on the magnetic layer, and a lattice body pressed from above the second film body. .

  Normally, the light incident on the light total reflection condition control element is not totally reflected on the surface of the substrate due to the presence of the first film body. However, if a magnet is arranged above the lattice of this element, the first film body, the magnetic layer, and the second film body are integrally separated from the substrate surface by the magnetic force acting on the magnetic layer. Moving. As a result, a gap is formed between the surface of the substrate and the first film body, and light incident on the light total reflection condition control element is totally reflected on the surface of the substrate. Therefore, for example, by controlling the magnetic force of the electromagnet according to a signal using an electromagnet or the like, it is possible to control the total reflection condition of the optical element. Further, in this element, heat generation due to operation is small, and the influence of heat generation can be suppressed to a minimum.

  Preferably, the lattice body has a plurality of cells formed by being separated from each other by a threshold plate.

  The total reflection conditions of the optical elements can be controlled independently in a plurality of cells. Therefore, it is possible to transmit information using light in parallel using a large number of cells arranged two-dimensionally.

  More preferably, the plurality of cells have the same planar shape, for example, a square shape.

  By making the planar shapes of the cells the same, it becomes easy to manufacture the light total reflection condition control element. Further, the amount of reflected light in each cell becomes equal, and signal processing for the reflected light is simplified.

  The end face of the threshold plate contacting the second film body may be formed by a curve.

  When the threshold plate is pressure-bonded to the second film body, the risk of destroying the second film body or the like is reduced by forming the end face of the threshold plate with a curved line.

  Preferably, the light total reflection condition control element includes a plurality of electromagnets disposed on an upper portion of the lattice body corresponding to each of the plurality of cells.

  The electromagnet can control the total reflection condition of light in each cell, and optical communication can be performed in parallel by a large number of cells arranged two-dimensionally.

  More preferably, the magnetic body is selected from the group consisting of iron, nickel, cobalt, and ferrite. The magnetic powder may be granular, and the particle size of the magnetic powder is preferably selected to be 1/10 or less of the maximum cell diameter.

  By setting the particle size of the magnetic powder to 1/10 or less of the maximum diameter of the cell, variation in the number of magnetic powders belonging to each cell can be reduced. Therefore, the total reflection control function of the cell can be made uniform.

  The light total reflection control element may further include a liquid layer made of a predetermined liquid sealed between the main surface of the substrate and the first film body.

  When there are variations in the size of the magnetic particles constituting the magnetic layer, irregularities are formed on the lower surface of the first film body, and as a result, the total reflection control characteristics of light are reduced due to the space formed. there's a possibility that. However, by enclosing the liquid between the main surface of the substrate and the first film body, it is possible to prevent the liquid from entering the space and reflecting light at that portion. When a magnetic force is applied, the liquid layer adheres to the lower surface of the first film body and moves upward, so that the total reflection of light can be performed at that portion. As a result, the total reflection characteristic of light can be improved.

  With the light total reflection condition control element according to the present invention, the total reflection condition of the optical element can be controlled by controlling the magnetic force of the electromagnet with a signal using, for example, an electromagnet. Since the total reflection conditions of the optical element can be controlled independently in a plurality of cells, information transmission using light in parallel can be performed using a number of cells arranged two-dimensionally.

  Hereinafter, the configuration of the light total reflection condition control element according to the embodiment of the present invention will be described. The “lattice” described in the following description is not only formed by the intersection of two straight lines each consisting of parallel lines, but also formed by the intersection of curves or broken lines. Including.

  FIG. 1 is an exploded perspective view showing the back surface of a light total reflection condition control element 20 showing the overall structure of the light total reflection condition control element according to an embodiment of the present invention. Referring to FIG. 1, light total reflection condition control element 20 includes transparent glass 32 having flat surface 48, lower layer film 34 made of polyvinyl chloride formed on surface 48, and lower layer film 34. A magnetic powder layer 36 made of magnetic powder uniformly distributed on the surface of the film, an upper film 38 made of polyvinyl chloride formed on the magnetic powder layer 36, and an upper layer from above the upper film 38. And a lattice body 40 having a large number of cells pressed toward the film 38.

  The transparent glass 32 forms a prism body, and uses a substance having a high light transmittance.

  As the lower layer film 34 and the upper layer film 38, a substance having a surface on which the magnetic powder 36 can be uniformly adsorbed is used. In particular, as will be described later, the lower film 34 and the upper film 38 are preferably elastic materials. In this embodiment, an elastomer is used as having such properties, and among them, polyvinyl chloride showing the properties of the elastomer is used. The lower layer film 34 and the upper layer film 38 need to have a density higher than the density of the transparent glass 32 in order to realize the function of controlling the total reflection of the transparent glass 32.

  The lattice body 40 only needs to have a certain degree of rigidity without magnetism. A large number of cells are formed by the threshold plate of the lattice body 40. In this embodiment, the planar shapes of these cells are equal to each other and are square. One pixel is formed by each cell. Therefore, in order to increase the number of pixels per unit area, it is desirable that the lattice body 40 be made of a material that can be finely processed. Typically, the lattice body 40 is formed by etching a metal or a semiconductor.

  2 to 6 are cross-sectional views showing the manufacturing steps of the light total reflection condition control element 20. With reference to FIG. 2, first, a transparent glass 32 having a flat surface 48 is prepared.

  Referring to FIG. 3, lower layer film 34 is formed on flat surface 48. Further, referring to FIG. 4, magnetic powder layer 36 is formed by uniformly adhering magnetic powder to the surface of lower layer film 34.

  When the magnetic powder layer 36 is formed, an upper film 38 is further formed thereon as shown in FIG. Then, from above, the lattice body 40 prepared in advance as shown in FIG. 6 is pressed against the surface of the transparent glass 32. Therefore, it is preferable that the lower end surface of each of the threshold plates 42 forming the lattice body 40 is formed in a curved line so as to be rounded as shown in FIG.

  In this way, elements for light reflection are formed in most areas on the flat surface 48 of the transparent glass 32. FIG. 7 and FIG. 8 show one of them as an enlarged cross-sectional view. Hereinafter, how this element controls total reflection of light on the surface of the transparent glass 32 will be described with reference to FIGS.

  Referring to FIG. 7, normally, as is apparent from the above description of the apparatus, the three-layer structure including the lower layer film 34, the magnetic powder layer 36, and the upper layer film 38 is in close contact with the surface 48 of the transparent glass 32. ing. The density of the lower layer film 34 is higher than the density of the transparent glass 32 as described above. Therefore, the light incident on the transparent glass 32 from below is not reflected by the surface 48 of the transparent glass 32 as shown by the light 50 in FIG.

  On the other hand, as shown in FIG. 8, the case where the magnet 60 is arrange | positioned inside the grating | lattice of this element is considered. In this case, the magnetic powder constituting the magnetic powder layer 36 is attracted toward the magnet 60 and tends to move away from the surface of the lattice body 40. Since both the lower layer film 34 and the upper layer film 38 are elastomers, they move together with the magnetic powder in the direction of the magnet 60, that is, in the direction away from the surface of the lattice body 40. As a result, a gap 62 is formed between the surface 48 of the transparent glass 32 and the lower surface of the lower layer film 34.

  When such a gap 62 is formed, the light 50 incident on the transparent glass 32 from below is reflected by the surface 48. This is indicated by reflected light 52. That is, when a magnet is placed in a portion corresponding to each element, light incident on that portion is reflected.

  By utilizing the above-described properties of this element, reflection / non-reflection of each partition of the grating can be controlled by an electric signal. That is, a small electromagnet is prepared above each partition of the lattice body 40, and this electromagnet may be driven by an electric signal for modulating reflected light. When the electromagnet generates magnetic force, the light is reflected from the lattice. If the electromagnet does not generate magnetic force, no light is reflected in the cell.

  As a result, as shown in FIG. 9, it is possible to control whether or not light is reflected for each partition of the grating constituting the light total reflection condition control element 20.

  As the magnetic material, iron, nickel, cobalt, or ferrite is particularly preferable. Their shape is preferably granular, and the particle sizes are preferably substantially equal to each other. In addition, it is desirable that the particle size of the magnetic material is considerably smaller than the maximum diameter of the cell so that the number of magnetic powders contained in each cell is as uniform as possible. For example, it may be 1/10 or less, preferably 1/20 or less of the maximum cell diameter.

  In view of the use of an electromagnet in this way, it is desirable to use a material that is not a magnetic material as the threshold plate. This is to prevent the threshold plate from being deformed or damaged by the magnetic force. Of course, if there is no possibility of breakage, the slit plate may be made of a magnetic material.

  FIG. 10 shows a block diagram of an optical communication system 100 using this light total reflection condition control element. Referring to FIG. 10, the optical communication system 100 includes an information transmission device 110 and an information reception device 112.

  The information transmission device 110 includes an integrated device 146 for collecting signals 150 from a large number of signal sources, a modulation device 142 including a large number of light total reflection condition control elements described above, and each signal integrated by the integrated device 146. Are independently connected to the electromagnet of the total reflection condition control element of each light of the modulation device 142, a driver device 148 for driving the modulation device 142, and the modulation device 142 is one of the reflection surfaces thereof. And a corner cube prism 140 disposed on one back surface.

  The information receiving apparatus 112 includes a light source 120, a half mirror 122 disposed in the optical path of the light beam emitted from the light source 120, and a CCD (Charge-Coupled Device) disposed at a position for receiving the light beam branched by the half mirror 122. 124 and a branch circuit 126 for receiving and amplifying the output of each photoelectric conversion element from the CCD 124 in parallel, converting it to a digital signal 128, branching it, and outputting it.

  The optical communication system 100 operates as follows. The light emitted from the light source 120 of the information receiving device 112 enters the corner cube prism 140 of the information transmitting device 110. This light is normally reflected by the three surfaces of the corner cube prism 140 and returns straight toward the light source 120.

  In the information transmitting apparatus 110, signals 150 collected from a large number of separate signal sources are integrated by an integrated apparatus 146 and provided to a modulating apparatus 142 by a connection line 144. Each element of the modulation device 142 takes in a signal given to each element from the connection line 144 for each predetermined section according to the control of the driver device 148, and applies it to the electromagnet drive circuit of the corresponding total reflection condition control element for light. The electromagnet of each element changes the position of the three-layer structure including the lower layer film 34, the magnetic powder layer 36, and the upper layer film 38 in the corresponding lattice according to the values of these signals.

  That is, if the applied signal is at a high level, the three-layer structure including the lower layer film 34, the magnetic powder layer 36, and the upper layer film 38 is attracted toward the magnet 60 as shown in FIG. As a result, a gap 62 is formed between the surface 48 of the transparent glass 32 and the lower surface of the lower layer film 34, and light is reflected at this portion. On the other hand, if the applied signal is at a low level, the three-layer structure adheres to the surface 48 of the transparent glass 32 as shown in FIG. As a result, no light is reflected at that portion. Therefore, the light reflected from the corner cube prism 140 toward the half mirror 122 is a multi-channel optical signal that carries the signal modulated by the modulator 142 for each channel. In this case, a signal of one channel is transmitted for each grid partition of the modulation device 142.

  The light reflected by the corner cube prism 140 of the information transmitting device 110 is bent 90 degrees by the half mirror 122 of the information receiving device 112 and is incident on the light receiving surface of the CCD 124. The CCD 124 gives an electric signal corresponding to the intensity of incident light to the branch circuit 126. The branch circuit 126 restores the signal given from the information transmission device 110 for each element according to the magnitude of the electric signal given from the CCD 124 for each element, and branches the signal 128.

  As described above, a large number of signals given to the information transmission device 110 are transmitted in parallel in the space by the information transmission device 110 and the light source 120, and are given to the multiple devices on the information reception device 112 side. .

  The light total reflection condition control element according to this embodiment can be easily manufactured as described with reference to FIGS. Even if the number of elements increases, the number of manufacturing processes is basically the same. Manufacture is not so difficult as the number of elements increases. Further, in this light total reflection condition control element, the reflection of light can be controlled by utilizing most of the reflection surface. Further, the amount of heat generated by the operation of the magnet 60 and the operations of the lower layer film 34, the magnetic powder layer 36, and the upper layer film 38 is small, and there is little possibility of causing the problem of accuracy due to the heat generation.

  In the optical communication system of this embodiment, the number of signal sources and the light total reflection condition control elements on the corner cube prism are in a one-to-one relationship, so that the number of light total reflection condition control elements is the same. As many optical communication channels can be provided. As a result, it is possible to stably transmit a large number of channel signals in a very compact manner. For example, if the arrangement of light total reflection condition control elements is 1000 × 1000, the number of channels provided is 1000 × 1000 = 1,000,000, and broadband communication using optical communication can be performed.

  In the embodiment described above, the size and the planar shape of each cell of the lattice body are equal to each other. As a result, the grating body can be easily manufactured, and hence the light total reflection condition control element can be easily manufactured. In addition, since the size and the planar shape of the cells are equal to each other, the amount of light reflected by each cell is also equal, and signal processing performed on the light receiving side is facilitated.

  However, the present invention is not limited to such. The sizes of the cells may be different from each other, and the planar shapes may be different from each other. For example, the planar shape may be not only a square but also a rectangle, or a general polygon such as a hexagon. Alternatively, a lattice having a combination of complementary shapes may be used.

  Further, the shape of the magnetic powder is not limited to a granular shape, and may be any shape such as a plate shape. In addition, although it is preferable that the magnitude | sizes of the magnetic body which comprises magnetic powder are as comparable as possible, a magnitude | size may differ. However, in the case where particles having extremely different sizes are included, a problem may occur due to a difference in particle size. The solution is shown in FIG. In FIG. 11, the same components as those shown in FIGS. 7 and 8 are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated here.

  As shown in FIG. 11, when a large particle is included in a part, the lower surface of the lower layer film 34 swells downward in that part, and the surface of the lower layer film 34 and the transparent glass 32 is formed around the convex part. There is a possibility that a space will be created. When such a space is formed, there arises a problem that, depending on the size of the space, the incident light 50 may be reflected at that portion even though no magnetic force is applied to the element.

  Therefore, when there is a variation in the size of the magnetic material, it is desirable to enclose a predetermined liquid between the surface 48 of the transparent glass 32 and the lower layer film 34 to form the liquid layer 200. As this liquid, a liquid whose cohesive force is larger than the adhesive force to the surface 48 of the transparent glass 32 is used. This liquid should have a large cohesion (condensation power) like mercury.

  If no magnetic force is applied to the element due to the presence of the liquid layer 200, even if a space is formed between the lower layer film 34 and the transparent glass 32, the liquid exists in that portion. Therefore, the incident light 50 is not reflected at that portion. On the other hand, when a magnetic force is applied to this element, as shown in FIG. 12, most of the liquid constituting the liquid layer 200 moves away from the surface 48 of the transparent glass 32 and moves upward together with the lower surface of the lower layer surface 34. As a result, an empty space is formed between the surface 48 and the lower layer surface 34 of the transparent glass 32, and the incident light 50 is reflected at this portion. This is indicated by reflected light 52 as in FIG. As a result, good total reflection control characteristics can be obtained even if the size of the particles constituting the magnetic powder varies.

  In this embodiment, an example in which glass is used for the prism has been described. However, the prism is not limited to glass, and any prism can be used as long as it exhibits the same performance. For example, a resin retroreflective prism may be used.

  The embodiment disclosed herein is merely an example, and the present invention is not limited to the above-described embodiment. The scope of the present invention is indicated by each claim in the claims after taking into account the description of the detailed description of the invention, and all modifications within the meaning and scope equivalent to the wording described therein are intended. Including.

  The light control element according to the present invention is suitable for realizing multi-channel communication using light.

It is a disassembled perspective view of the total reflection condition control element of the light which concerns on one embodiment of this invention. It is sectional drawing which shows the manufacturing process of the light total reflection condition control element shown in FIG. It is sectional drawing which shows the manufacturing process of the light total reflection condition control element shown in FIG. It is sectional drawing which shows the manufacturing process of the light total reflection condition control element shown in FIG. It is sectional drawing which shows the manufacturing process of the light total reflection condition control element shown in FIG. It is sectional drawing which shows the manufacturing process of the light total reflection condition control element shown in FIG. It is sectional drawing which shows the principle of operation of the total reflection condition control element of light shown in FIG. It is sectional drawing which shows the principle of operation of the total reflection condition control element of light shown in FIG. It is a top view of the cell part of the total reflection condition control element of the light shown in FIG. It is a block diagram of the optical communication system using the total reflection condition control element of light shown in FIG. It is sectional drawing which shows the operation principle of the other example of the total reflection condition control element of light. FIG. 12 is a cross-sectional view showing the operating principle of the light total reflection condition control element shown in FIG. 11.

Explanation of symbols

  20 light total reflection condition control element, 32 transparent glass, 34 lower layer film, 36 magnetic powder layer, 38 upper layer film, 40 lattice, 48 surface, 50 light, 52 reflected light, 100 optical communication system, 110 information transmission device, 112 information receiver, 120 light source, 122 half mirror, 124 CCD, 126 branch circuit, 140 corner cube prism, 142 modulator, 144 connection line, 146 integrated device, 148 driver device

Claims (10)

A translucent substrate having a main surface;
A first film body made of an elastomer formed on the main surface;
A magnetic layer formed of magnetic particles uniformly dispersed on the first film body;
A second film body made of an elastomer formed on the magnetic layer;
A light total reflection condition control element including a lattice body pressed from above the second film body. 2. The light total reflection condition control element according to claim 1, wherein the lattice body includes a plurality of cells formed to be separated from each other by a threshold plate. The light total reflection condition control element according to claim 2, wherein the plurality of cells have the same planar shape. The light total reflection condition control element according to claim 3, wherein a planar shape of the plurality of cells is a square. The light total reflection condition control element according to claim 2, wherein a single surface of the threshold plate that is in contact with the second film body is formed by a curve. The light total reflection condition control element according to claim 2, further comprising a plurality of electromagnets disposed on the upper portion of the grid corresponding to each of the plurality of cells. The light total reflection condition control element according to claim 1, wherein the magnetic body is selected from the group consisting of iron, nickel, cobalt, and ferrite. The light total reflection condition control element according to claim 2, wherein the magnetic powder is granular. The light total reflection condition control element according to claim 8, wherein a particle diameter of the magnetic powder is selected to be 1/10 or less of a maximum diameter of the cell. The total reflection control element for light according to claim 1, further comprising a liquid layer made of a predetermined liquid sealed between the main surface of the base and the first film body.

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