JP2008019493A - Dispersion of precious-metal particle, production method therefor, display method and display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dispersion liquid of precious-metal particles, which can be used in an electrophoresis type display device and the like; a production method; and a display method and a display device using the dispersion liquid of the precious-metal particles. <P>SOLUTION: The dispersion liquid of the precious-metal particles includes silicone oil 10, and the precious-metal particles 9 which are dispersed in the silicone oil; and needs to present color development properties in a state of making the precious-metal particles 9 dispersed in the silicone oil. The precious-metal particle preferably has a color development function due to plasmon. Gold, silver and the like are preferable as the precious metal for the particle. The display device has a modulated light layer in which a first electrode 2, a second electrode 4 and the dispersion of the precious-metal particles are enclosed, and a voltage-applying means; and shows the color of the precious-metal particles when the voltage is not applied, because the precious-metal particles are uniformly dispersed, and shows the color of the first substrate 1 when the voltage has been applied, because the precious-metal particles move toward the second electrode side. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a novel noble metal particle dispersion, particularly a noble metal particle dispersion that can also be used as a light control material for various display elements, a method for producing the same, and a display method and a display element using the noble metal particle dispersion. Is.

  With the advancement of an advanced information society, the need for electronic paper display systems is increasing. For this reason, as a promising technique for realizing this, display elements such as an electrophoresis system, a liquid crystal system, and an organic EL system are being studied.

  In an electrophoretic display element, display is performed by applying a voltage to a light control cell having a dispersion medium containing electrophoretic particles that move electrically. As the electrophoretic particles, typically, colored particles containing a colorant such as a pigment or a dye are used. In contrast, insulating, colorless and transparent low-molecular organic solvents such as hexane, cyclohexane, kerosene, and paraffin are generally used as the dispersion medium (see, for example, Patent Documents 1 and 2). In addition, Patent Documents 1 and 2 disclose that an organic solvent having a higher molecular weight such as silicone oil or high-purity petroleum can be used, although a specific example is not shown.

On the other hand, it is known that a metal colloid solution in which metal particles having a particle size on the order of several nanometers to several tens of nanometers are uniformly dispersed in a solution has a specific color due to plasmon absorption. Such a metal colloid solution is known to be prepared by reducing a metal salt such as a silver salt in an organic solvent such as an alkylamine (see Patent Documents 3 and 4).
JP 2005-352053 A JP 2004-174346 A JP 2004-027347 A Japanese Patent Laying-Open No. 2005-036309

Color development by metal particles dispersed in metal colloid solution is characterized by higher saturation and light transmittance and superior durability compared to conventional color particles containing colorants such as pigments and dyes. Have Therefore, the present inventors considered that it is preferable to use a metal colloid solution for an electrophoretic dimming cell.
On the other hand, as the dispersion medium used in the light control cell, it is considered preferable to use silicone oil because it is easier to handle than other dispersion media. Therefore, the present inventors tried various surface treatments on the colored particles containing a colorant such as a pigment or a dye, and tried to disperse the colored particles in the silicone oil. It could not be dispersed.
In view of such circumstances, the present invention provides a novel noble metal particle dispersion that can be used for an electrophoretic display element and the like, a manufacturing method thereof, and a display method and a display element using the noble metal particle dispersion. It is an issue to provide.

The above object is achieved by the present invention described below. That is, the present invention
<1>
A noble metal particle dispersion containing silicone oil and noble metal particles dispersed in the silicone oil.

<2>
The noble metal particle dispersion liquid according to <1>, wherein the noble metal particles have a plasmon coloring function.

<3>
The noble metal particle dispersion according to <1>, wherein the noble metal particles contain at least one kind of noble metal selected from gold and silver.

<4>
A noble metal particle is produced by adding a reducing agent to a silicone oil containing at least one kind of noble metal compound and at least one kind of silane coupling agent and reducing the noble metal compound. This is a method for producing a noble metal particle dispersion.

<5>
In this display method, the display is switched by electrically moving the noble metal particles contained in the silicone oil and controlling the state of dispersion and uneven distribution of the noble metal particles in the silicone oil.

<6>
A first electrode, a second electrode, a light control layer, and a voltage applying means for applying a voltage to the light control layer via the first electrode and the second electrode,
The light control layer includes a silicone oil and noble metal particles dispersed in the silicone oil.

  As described above, according to the present invention, a novel noble metal particle dispersion that can be used for an electrophoretic display element and the like, a manufacturing method thereof, and a display method and a display element using the noble metal particle dispersion Can be provided.

(Precious metal particle dispersion and production method thereof)
The noble metal particle dispersion of the present invention is characterized by containing silicone oil and noble metal particles dispersed in the silicone oil.
The use of such a noble metal particle dispersion of the present invention is not particularly limited, and can be used for any purpose depending on the purpose, but dispersion in which particles are dispersed for light control and display. It is suitable to use for various display elements using a medium, especially an electrophoretic display element.

In order to use the noble metal particle dispersion of the present invention for various display elements, it is necessary that the noble metal particles exhibit color developability when dispersed in silicone oil.
Here, “exhibiting color developability in a dispersed state” means exhibiting a hue that can be observed when the noble metal particle dispersion is visually observed in a state where the noble metal particles are dispersed in the silicone oil. Note that the observation of the hue in this case means that the thickness of the noble metal particle dispersion with respect to the viewing direction is observed within a range of about 10 μm to 1 cm. The hue can be varied by changing the shape and particle size of the noble metal particles and the kind of the noble metal contained in the noble metal particles.

The hue resulting from the noble metal particles may be one utilizing the light shielding properties of the particles themselves (that is, black), but may utilize the property that the particles themselves develop color. In the latter case, the noble metal particles particularly preferably have a plasmon coloring function.
Plasmon coloration of noble metal particles is caused by electron plasma oscillation and is due to a coloration mechanism called plasmon absorption. Color development due to this plasmon absorption is said to be because free electrons in the metal are shaken by the photoelectric field, electric charges appear on the particle surface, and nonlinear polarization occurs. The coloring by the noble metal particles has high saturation and light transmittance, and is excellent in durability. Such color development due to the noble metal particles is observed in so-called nanoparticles having a particle size of about several nm to several tens of nm. From the viewpoint of vividness of hue, it is advantageous that the metal particles have a narrow particle size distribution. Therefore, the average particle size (volume average particle size) of the noble metal particles is preferably in the range of 1 to 100 nm, and preferably in the range of 5 to 50 nm.

  The noble metal particles can be colored in various colors depending on the type of metal contained in the particles, the shape of the particles, and the volume average particle diameter. Therefore, various hues including RGB coloring can be obtained by using precious metal particles in which these are controlled. Therefore, color display is possible by producing a display element using the noble metal particle dispersion liquid of the present invention in which noble metal particles having a plasmon coloring function are dispersed, and also noble metal particles of each color corresponding to R, G, B If the dispersion liquid is used, an RGB display element can be manufactured.

  The volume average particle diameter of the noble metal particles for exhibiting R, G, and B colors of the RGB method depends on the metal used, the preparation conditions of the particles, the shape, etc., and can not be particularly limited. In the case of colloidal gold particles, as the volume average particle diameter increases, R color development, G color development, and B color development tend to be exhibited.

  As a method for measuring the volume average particle diameter in the present invention, a laser diffraction scattering method is employed in which a particle group is irradiated with laser light and the average particle diameter is measured from the intensity distribution pattern of diffraction and scattered light emitted therefrom. For example, the particle size can be measured using a Microtrack particle size distribution measuring device MT3300 manufactured by Nikkiso Co., Ltd.

  The noble metal contained in the noble metal particles is not particularly limited as long as it is a known noble metal such as gold, silver, ruthenium, rhodium, palladium, osmium, iridium and platinum, but gold and / or silver are particularly preferable. The noble metal particles may also contain metals other than noble metals (for example, copper).

  On the other hand, in order to use the noble metal particle dispersion liquid of the present invention for an electrophoretic display element, when an electric field (voltage) is applied to the noble metal particles, the noble metal particles can move in the silicone oil. It is necessary to have electrophoretic properties. In this respect, the noble metal particles used in the present invention have electrophoretic properties and can be applied to electrophoretic display elements. The electrophoretic characteristics can be controlled by controlling the chargeability and dispersibility of the noble metal particles by surface-treating the surface of the noble metal particles with a surface treatment agent such as a silane coupling agent.

As described above, the noble metal particle dispersion of the present invention can be used in an electrophoretic display element when the noble metal particles exhibit color developability in a state dispersed in silicone oil and have electrophoretic properties. It is. In addition, the noble metal particle dispersion of the present invention uses silicone oil as a dispersion medium for the noble metal particles.
This silicone oil is difficult to decompose even when a voltage higher than (1) is applied, compared to a dispersion medium such as hexane, cyclohexane, kerosene, and paraffin used in conventional electrophoretic display elements. (2) Since the viscosity is high, intense convection hardly occurs when noble metal particles are electrophoresed, and contrast deterioration and display disturbance due to such intense convection hardly occur. (3) In production, the dispersion medium has a characteristic that volatilization of the dispersion medium hardly occurs when a dispersion liquid in which colored particles are dispersed in a space serving as a light control layer of the display element is filled under reduced pressure.
Therefore, when producing a display element using the noble metal particle dispersion of the present invention, when using vacuum filling, the production is easier than before, and the durability of the produced display element is Reliability and display characteristics can be further improved.

  Furthermore, when the noble metal particles used in the present invention have a plasmon coloring function, the saturation and light transmittance are high and durable compared with the conventional coloring with colored particles containing a colorant such as a pigment or dye. It has characteristics such as excellent properties. Therefore, also in this respect, superior display characteristics and reliability can be obtained as compared with the conventional electrophoretic display elements.

As the silicone oil, any known silicone oil can be used without any particular limitation.
(1) The resistance value is preferably 10 ³ Ωcm or more, more preferably 10 ⁷ Ωcm to 10 ¹⁹ Ωcm, and further preferably 10 ¹⁰ to 10 ¹⁹ Ωcm. (2) The viscosity is 1-1000 cst, more preferably 1-100 cst. Specifically, dimethyl silicone oil such as KF-96 manufactured by Shin-Etsu Chemical Co., Ltd., DOW CORNING 200 manufactured by Dow Corning, and TSF451 manufactured by GE Toshiba Silicone Co., Ltd. can be used. In addition, modified silicone oil in which an organic group is introduced into a part of the methyl group of dimethylpolysiloxane (for example, KF-393, X22-3710 manufactured by Shin-Etsu Chemical Co., Ltd.) can be used.

  In addition, an acid, an alkali, a salt, a dispersion stabilizer, a stabilizer for the purpose of preventing oxidation or absorbing ultraviolet rays, an antibacterial agent, an antiseptic, and the like can be added to the silicone oil as necessary.

  Further, the content (% by mass) of the noble metal particles contained in the noble metal particle dispersion is not particularly limited, but the content of the noble metal particles when used in the display element is the thickness of the light control layer of the display element. Accordingly, the content can be adjusted appropriately. When the light control layer is thick, the content is small, and when the light control layer is thin, the content can be increased. In this case, the content is generally preferably in the range of 0.01 to 50% by mass.

-Preparation method of noble metal particle dispersion-
Next, a method for producing the noble metal particle dispersion of the present invention will be described. The method for producing the noble metal particle dispersion of the present invention is not particularly limited, but a reducing agent is added to silicone oil containing at least one kind of noble metal compound and at least one kind of silane coupling agent. In particular, it is particularly preferable to generate noble metal particles by reducing the noble metal compound.

As described above, the present inventors tried to disperse the colored particles containing pigments and the like in the silicone oil by performing various surface treatments, but they could not be sufficiently dispersed. From these results, the present inventors have found that silicone oil has a difference in viscosity and high molecular weight compared to low-molecular organic solvents such as hexane, so that the material in the particulate state is already dispersed. Was considered an inappropriate dispersion medium.
Therefore, if a method for forming particles from the particle precursor component in the silicone oil is prepared by dissolving and dispersing the particle forming component (particle precursor component) in the silicone oil in advance, the particles in the silicone oil are used. We thought it could be dispersed.

In addition, as a method of forming particles from a dispersion medium in which a particle precursor component is dissolved and dispersed, a noble metal compound such as a metal salt or a metal complex as shown in Patent Documents 3 and 4 is reduced in an organic solvent. How to do is known. Therefore, the present inventors considered that if this method is used, a dispersion in which noble metal particles are dispersed in silicone oil can be obtained. However, when using this method, simply replacing the dispersion medium used with silicone oil makes it difficult to dissolve and disperse the precious metal compound itself, so a low molecular dispersant such as dodecylbenzenesulfonic acid is also used. It seems to be effective.
On the other hand, since silicone oil has high insulating properties, there is an advantage that it can be used even under a higher voltage when used in an electrophoretic display element. However, when a high voltage is applied, there is a concern about decomposition of the low molecular dispersant. When such decomposition occurs, bubbles are generated due to the decomposition of the low molecular dispersant in the display element, not only causing deterioration of display characteristics, but also by reducing the dispersant in the silicone oil, noble metal particles It is considered that the dispersibility of the resin also decreases. Therefore, when a low molecular dispersant is used, it may be difficult to drive the display element under high voltage, which is an advantage of using silicone oil.

  However, the present inventors have found that such a problem can be solved by using a silane coupling agent as a dispersant. Silane coupling agents are generally used as surface treatment agents, but when added to silicone oil, they function as dispersants for noble metal compounds and reduce the noble metal compounds to produce noble metal particles. After that, it is considered that the dispersibility of the noble metal particles is ensured by reacting with the particle surface. Further, when a silane coupling agent is used, the chargeability and dispersibility of the noble metal particles can be easily controlled by selecting the kind thereof.

As the noble metal compound that can be used in the preparation of the noble metal particle dispersion, any known metal complex or metal salt containing the above-mentioned noble metal can be used.
Specific examples of the noble metal compound include chloroauric acid, silver nitrate, aliphatic silver salt, silver acetate, silver perchlorate, chloroplatinic acid, and potassium chloroplatinate. Moreover, when using together metals other than a noble metal, copper chloride (II), copper acetate (II), copper sulfate (II) etc. can be utilized, for example.
The amount of the noble metal compound added to the silicone oil can be appropriately selected according to the noble metal particles contained in the noble metal particle dispersion to be produced, but is not particularly limited, but is generally within the range of 0.01 to 10% by mass. Is preferred.

A known silane coupling agent can be used as the silane coupling agent that can be used in the preparation of the noble metal particle dispersion.
Specifically, mention may be made Phenethyltrimethoxysilane, Aminopropyltriethoxysilane, 3-Aminopropyltrimethoxysilane, Metacryloxytrimethoxysilane, Methoxytrimethylsilane, 3-Aminopropyldiethoxymethylsilane, N- (2-Aminoethyl) -3-aminopropyltrimethoxysilane, N- and (2-Aminoethyl) -3-aminopropylmethyldimethoxysilane, etc. .

  The addition amount of the silane coupling agent is preferably 0.1 times or more in molar ratio with respect to the noble metal compound, and more preferably 1 time or more in molar ratio. When the addition amount is less than 0.1 times the molar ratio to the noble metal compound, it may be difficult to sufficiently disperse the noble metal compound or the noble metal particles obtained by reducing the noble metal compound. On the other hand, the upper limit of the addition amount of the silane coupling agent is not particularly limited, but in practice, it is preferably 100 times or less in molar ratio to the noble metal compound.

A known reducing agent can be used as a reducing agent that can be used in preparing the noble metal particle dispersion.
Specific examples include ascorbic acid, alkali metal borohydride salts such as sodium borohydride, hydrazine compounds, citric acid or salts thereof, succinic acid or salts thereof, and the like.

  The addition amount of the reducing agent is preferably 1 or more times in molar ratio with respect to the noble metal compound, and more preferably 1.5 or more in molar ratio with respect to the noble metal compound. If the addition amount is less than 1 time in molar ratio with respect to the noble metal compound, the reduction of the noble metal compound may be insufficient, and the noble metal particles may not be sufficiently generated. On the other hand, the upper limit of the addition amount of the reducing agent is not particularly limited, but is practically preferably 50 times or less in molar ratio to the noble metal compound.

(Display method and display element)
-Display method-
Next, a display method and a display element using the noble metal particle dispersion of the present invention will be described.
The switching of the display using the noble metal particle dispersion of the present invention is performed by electrically moving the noble metal particles contained in the silicone oil to control the state of dispersion and uneven distribution of the noble metal particles in the silicone oil. The electrical movement (electrophoresis) of the noble metal particles is performed by applying an electric field to the silicone oil. By controlling the applied electric field, the dispersion and uneven distribution state of the noble metal particles in the silicone oil is controlled.
Here, when the noble metal particles are dispersed in the silicone oil, the silicone oil basically exhibits a hue due to the noble metal particles, and when the silicone oil is unevenly distributed, the hue of the silicone oil itself ( When colored components other than the noble metal particles are not dissolved, it is usually colorless. Therefore, it is possible to switch the display by using such a difference in the dispersion and uneven distribution state of the noble metal particles.

  Moreover, when performing display using the noble metal particle dispersion liquid of the present invention, particles (isomer particles) having characteristics different from the noble metal particles may be added to the noble metal particle dispersion liquid. For example, when an isoelectric particle is white and does not move due to an electric field and has a characteristic of being always dispersed in silicone oil, applying an electric field that causes the precious metal particles to be unevenly distributed observes the precious metal particle dispersion. Although it depends on the direction and the uneven distribution of the noble metal particles, the hue of the noble metal particle dispersion can be apparently white (color of isomeric particles).

-Display element-
Although the structure of the display element of the present invention using such a display method is not particularly limited, the first electrode, the second electrode, the light control layer, the first electrode and the second electrode are interposed. It is preferable to include a voltage applying means for applying a voltage to the light control layer. The light control layer of the display element contains the noble metal particle dispersion of the present invention.

Although various aspects are mentioned as a concrete structure of a display element, generally it is preferable that a light control layer is provided between a pair of board | substrates in which at least any one is transparent. Further, although only one light control layer may be provided in the display element, it is preferable to provide two or more light control layers. In this case, various displays are possible by independently controlling the voltage applied to each light control layer, or by using different types of noble metal particle dispersions.
For example, full color display can be performed by using three kinds of a noble metal particle dispersion liquid exhibiting a red color, a noble metal particle dispersion liquid exhibiting a green color, and a noble metal particle dispersion liquid exhibiting a blue color when the noble metal particles are dispersed in silicone oil. . Each of the light control layers corresponding to R, G, and B may be disposed in the plane direction of the display element as a set of RGB light control cells, but is stacked in the thickness direction of the display element. May be. In the latter case, since the substrate and each adjustment cell are sequentially laminated, at least the remaining substrates except for at least one of the substrates constituting both surfaces of the display element are all transparent. It is necessary.

  On the other hand, the first electrode and the second electrode can be arranged at any position of the display element as long as voltage can be applied to the light control layer, and are not in contact with the noble metal particle dispersion liquid contained in the light control layer. Although it may be provided, it is preferable that both electrodes are provided in contact with the noble metal particle dispersion. When both electrodes are provided in contact with the noble metal particle dispersion, in a conventional electrophoretic display element, when a high voltage is applied, the dispersion medium decomposes and deteriorates, and the reliability and display of the display element are improved. Although there was a risk of degrading the characteristics, in the present invention, since silicone oil that is difficult to be decomposed even when a high voltage is applied is used, even if the display element is driven by applying a high voltage, it will last for a long time. It is easy to maintain high reliability and display characteristics.

Moreover, the above-mentioned isomer particles may be contained in the noble metal particle dispersion used for the light control layer, if necessary. In addition, preferable characteristics of isomer particles when using isomer particles as display elements include different hues (including shades), different forms (different volume average particle diameters, different shapes, etc.), different mobility, Examples thereof include, but are not limited to, different functions (for example, that noble metal particles have a color display function and isomeric particles have a spacer function). In particular, when the isomeric particles are white, the viewing angle dependency is further reduced because the isomeric particles are located in the vicinity of the observation surface.
Considering the improvement of the contrast of the display element, the color of the isomer particles is preferably white. When the isomer particles are white, the shade is not limited and may be visually white.

  The volume average particle diameter (X) of the isomer particles is preferably larger than the volume average particle diameter (Y) of the noble metal particles, and the ratio (X / Y) thereof is more preferably 2 to 50000. More preferably, it is 20-10000. If the isomeric particle is larger than the noble metal particle, the noble metal particle can easily move through the gap between the isomeric particles, and the responsiveness of color display by the noble metal particle can be improved.

  The volume average particle diameter of the isomer particles is preferably 0.1 to 50 μm, and more preferably 1 to 20 μm. By being 0.1-50 micrometers, the effect that the said isomeric particle can be utilized as a spacer can be exhibited.

  The material of the isomeric particle is not particularly limited, such as an organic substance or an inorganic substance, and can be used. For example, examples of the organic material include melamine resin, acrylic resin, and polyester resin. Examples of the inorganic substance include titanium oxide, silica, and magnesium oxide.

The volume filling rate of the isomer particles in the light control layer is preferably 30 to 95 vol%, and more preferably 50 to 90 vol%. When the volume filling factor is 30 to 95 vol%, the color of the isomeric particle, for example, white can be effectively displayed.
The isomeric particle can be used as a color display particle exhibiting a hue different from that of the noble metal particle, but can also be used as a spacer from the viewpoint of uniform thickness of the light control layer.

  Hereinafter, specific examples of the display element of the present invention will be described with reference to the drawings. In addition, the same code | symbol is provided to the member which has the same function throughout all the drawings, and the description is abbreviate | omitted.

FIG. 1 is a schematic cross-sectional view showing an example of a display element of the present invention and a process for manufacturing the same.
FIGS. 1A and 1B are diagrams illustrating a process in the middle of manufacturing a display element. FIG. 1C illustrates a display element completed through the processes shown in FIGS. 1A and 1B. FIG. 1D is a diagram illustrating a configuration, and FIG. 1D is a diagram illustrating a state in which a voltage is applied by connecting the display element illustrated in FIG. 1C to a power source.

  The display element shown in FIG. 1C covers the first substrate 1, the first electrode 2 provided so as to cover the entire surface of one surface of the first substrate 1, and the entire surface of the first electrode 2. An end portion of a cell composed of the provided insulating layer 5, the second substrate 8 opposed to the side on which the insulating layer 5 of the first substrate 1 is provided, and the first substrate 1 and the second substrate 8 is sealed. A partition wall 6 disposed between the insulating layer 5 and the surface of the second substrate 8 facing the first substrate 1 so as to stop, and between the insulating layer 5 and the partition wall 6 and the first substrate 1. The first substrate 1, the second substrate 8, and the partition wall 6 include a strip-shaped second electrode 4 provided along one side (side in a direction orthogonal to the cross section (paper surface in the drawing)). One cell part in which a noble metal particle dispersion liquid containing noble metal particles 10 and silicone oil 9 is enclosed in a sealed space (a space part corresponding to a light control layer) There is shown with. The second electrode 4 is formed so that its width is longer than the width of the partition wall 6.

As described above, in the display element shown in FIG. 1C, the first electrode and the second electrode are stacked on one side of one substrate while being displaced in the horizontal and vertical directions with respect to the substrate surface. In addition, the second electrode has a region that overlaps the first electrode in the horizontal direction.
Further, the bonding surface between the partition wall 6 and the second substrate 8 is bonded by the adhesive layer 7. Note that the display element shown in FIG. 1C is shown for one cell portion, but a plurality of cells are arranged in a one-dimensional manner in the substrate plane direction in such a manner that it is partitioned from other adjacent cells by a partition. You may arrange | position continuously two-dimensionally.

The display element shown in FIG. 1C can be manufactured as follows, for example. First, the first electrode 2 and the insulating layer 5 are laminated in this order on the entire surface of one side of the first substrate 1 (FIG. 1A). Subsequently, a linear second electrode 4 is stacked on the surface of the insulating layer 5 along one side of the first substrate 1 (FIG. 1B). Thereafter, a partition wall 6 is laminated on the surface of the first substrate 1 on which the insulating layer 5 is provided (partition wall forming step). Subsequently, the partition wall 6 and the second substrate 8 are bonded via the bonding layer 7 (bonding process).
Here, the noble metal particle dispersion is sealed in the light control layer as follows. First, in the partition forming step, a filling port for the noble metal particle dispersion is formed at the same time without forming a part of the partition 6 so that the noble metal particle dispersion can be filled under reduced pressure into the light control layer portion in a later step. Subsequently, after performing the bonding step, the noble metal particle dispersion is sealed in the light control layer portion by vacuum filling using the filling port. Then, a display element can be obtained by sealing a filling port (FIG.1 (c)).
1D shows that a positive voltage is applied to the first electrode 1 by a power source connected as voltage applying means to the first electrode 1 and the second electrode 4 of the display element shown in FIG. The state where a negative voltage is applied to the second electrode 4 is shown.

Next, the operation of the display element of the present invention illustrated in FIG. 1 will be described below with reference to FIGS.
In describing the operation, the second substrate 8, the insulating layer 5, and the first electrode 2 are transparent to visible light, the first substrate 1 is opaque to visible light, and the noble metal particles 10 are positive. The color that is charged and displayed by the display element is observed from the surface of the display element on the side where the second substrate 8 is provided.
First, when no voltage is applied, the noble metal particles 10 are uniformly dispersed in the light control layer as shown in FIG. 1C, and the color of the noble metal particles 10 is displayed (for example, red). Observed. On the other hand, when a voltage is applied, the noble metal particles 10 move to the negative electrode (second electrode 4) side. For this reason, the color of the first substrate is observed, and if the color of the first substrate is, for example, white, white is displayed on the display element.
When a voltage is applied to the display element, the noble metal particles 10 move in a direction substantially parallel to the surfaces of the first substrate 1 and the second substrate 8.

As the first substrate 1 and the second substrate 8, polyester (for example, polyethylene terephthalate), polyimide, polymethyl methacrylate, polystyrene, polypropylene, polyethylene, polyamide, nylon, polyvinyl chloride, polyvinylidene chloride, polycarbonate, polyether Polymer films such as sulfone, silicone resin, polyacetal resin, fluororesin, cellulose derivative, and polyolefin, and inorganic substrates such as plate substrates, glass substrates, metal substrates, and ceramic substrates are preferably used.
Note that at least one of these two substrates is a transparent substrate that is transparent to visible light. When a transmissive display element is manufactured, the first substrate 1 and the second substrate 8 are used. In both cases, a transparent substrate is used. The transparent substrate preferably has a light transmittance of at least 50% for light in the visible range, and the light transmittance is preferably as close to 100%.

As the material of the first electrode 2 and the second electrode 4, a material in which a metal oxide layer typified by tin oxide-indium oxide (ITO), tin oxide, zinc oxide or the like is formed is preferably used. A transparent electrode having a light transmittance of 50% or more for at least visible light is preferably used. In the case of a reflective optical element application, as an electrode material used for an electrode located far from the viewing direction, metals represented by the above-mentioned tin oxide-indium oxide (ITO), tin oxide, zinc oxide, etc. In addition to the oxide layer, a conductive polymer or a metal layer typified by carbon, copper, aluminum, gold, silver, nickel, platinum, or the like can be used.
As materials of the first electrode 2 and the second electrode 4, these materials can be used alone or a plurality of kinds of materials can be laminated.

  In the case of manufacturing a transmissive display element, both the first electrode 2 and the second electrode 4 are transparent electrodes. Various thicknesses and sizes of the first electrode 2 and the second electrode 4 can be used depending on the display element, and are not particularly limited.

The height of the partition wall 6 is not particularly limited, and is usually about 20 μm to 1 mm.
The width of the partition wall 6 is not particularly limited, but in general, a smaller width is more effective from the viewpoint of the resolution of the display element, and is usually about 10 μm to 1 mm.
Moreover, it does not specifically limit as a material of the partition 6, For example, a well-known photosensitive resin can be used.

The material of the adhesive layer 7 is not particularly limited, and a thermosetting resin, an ultraviolet light curable resin, or the like can be used, but it does not affect the material of the partition wall, the light control layer, or the like. The material is selected.
The material of the insulating layer 5 is not particularly limited, and a known insulating material can be used. For example, an acrylic resin, a polyimide resin, an amorphous fluororesin, or the like can be used, and a transmissive display element is manufactured. A material having optical transparency with respect to visible light is used for.

Next, a display element having a configuration different from that of the display element illustrated in FIG. 1 will be described.
2 is a schematic cross-sectional view showing another example of the display element of the present invention and a process for manufacturing the display element, and FIG. 2A is a diagram for explaining a process in the middle of manufacturing the display element. FIG. 2B is a diagram showing the configuration of the display element completed through the process shown in FIG. 2A, and FIG. 2C is a diagram showing the voltage when the display element shown in FIG. It is a figure shown about the state which applied.

The display element shown in FIG. 2B has a first substrate 1 and two parallel sides facing each other on one side of the first substrate 1 (sides perpendicular to the cross section (paper surface in the drawing)). A first electrode 2 and a second electrode 4 that are disposed along the first substrate 2, a second substrate 8 that is disposed opposite to the side of the first substrate 1 on which the first electrode 2 and the second electrode 4 are provided, A space having a partition wall 6 provided so as to seal an end portion of a cell including the first substrate 1 and the second substrate 8 and sealed with the first substrate 1, the second substrate 8, and the partition wall 6 ( This shows one cell portion in which a noble metal particle dispersion liquid containing noble metal particles 10 and silicone oil 9 is enclosed in a space portion corresponding to a light control layer. The bonding surface between the partition wall 6 and the second substrate 8 is bonded by the adhesive layer 7, and the widths of the first electrode 2 and the second electrode 4 are longer than the width of the partition wall 6. Is formed.
Note that the display element shown in FIG. 2 (b) is shown for one cell portion, but the plurality of cells are one-dimensionally arranged in the substrate plane direction in such a manner that they are separated from other adjacent cells by partition walls. You may arrange | position continuously two-dimensionally.

Here, the line width of both electrodes 2 and 4 is not particularly limited, but it is usually preferably about 20 μm to 1 mm, and the thickness of both electrodes 2 and 4 is not particularly limited. Usually, about 10 nm to 1 μm is preferable. Although it does not specifically limit as a height of the partition 6, Usually, it is about 20 micrometers-about 1 mm. Although it does not specifically limit as a width | variety of the partition 6, Usually, it is about 10 micrometers-1 mm.
Moreover, about each member used for the display element shown in FIG.2 (b), the thing similar to FIG.1 (c) can be utilized.

  The display element shown in FIG. 2B can be manufactured as follows, for example. First, the strip-shaped first electrode 2 and the second electrode 4 are formed so as to be along one side of the first substrate 1 and two opposite parallel sides (sides perpendicular to the cross section (paper surface in the drawing)). Form (FIG. 2A). Thereafter, the partition walls 6 are stacked on the surface of the first substrate 1 on which the first electrode 2 and the second electrode 4 are provided (partition wall forming step). Subsequently, the partition wall 6 and the second substrate 8 are bonded through the bonding layer 7 (bonding process). Note that the noble metal particle dispersion liquid can be sealed in the light control layer portion in the same manner as in the display element shown in FIG. 1, whereby a display element can be obtained (FIG. 2B).

  2C shows a case where a negative voltage is applied to the first electrode 2 by a power source connected as voltage applying means to the first electrode 1 and the second electrode 4 of the display element shown in FIG. The state where a positive voltage is applied to the second electrode 4 is shown. Here, if the noble metal particle 10 is positively charged, the noble metal particle 10 moves to the negative electrode (first electrode 2) side as shown in FIG. Therefore, when no voltage is applied (FIG. 2B), the color of the noble metal particles 10 is observed as the display color, and when the voltage is applied (FIG. 2C), the display element is transmitted. If the mold is transparent, the color of the first substrate 1 (or the second substrate 8) is observed if the display element is a reflective type.

Next, a display element having a configuration different from the display element shown in FIGS.
3 is a schematic cross-sectional view showing another example of the display element of the present invention and a process for manufacturing the display element, and FIG. 3A is a diagram for explaining a process in the middle of manufacturing the display element. FIG. 3B is a diagram showing the configuration of the display element completed through the process shown in FIG. 3A, and FIG. 3C is a diagram showing the voltage when the display element shown in FIG. It is a figure shown about the state which applied.

The display element shown in FIG. 3B has a first substrate 1 and two parallel sides facing each other on one side of the first substrate 1 (sides in a direction perpendicular to the cross section (paper surface in the drawing)). A portion where the first electrode 2 and the second electrode 4 are also disposed so as to insulate the first electrode 2 and the second electrode 4, which also serve as a partition wall disposed along the first electrode 2 and the second electrode 4. A partition wall (not shown) provided on the first substrate 1 and a second substrate disposed opposite to the first substrate 2 on the side where the first electrode 2, the second electrode 4 and the partition wall (not shown) are provided. 8 and a noble metal particle dispersion liquid containing noble metal particles 10 and silicone oil 9 in a space sealed by the first substrate 1, the second substrate 8, and the partition wall 6 (a space portion corresponding to a light control layer). Is shown for one cell portion in which is enclosed.
The bonding surfaces of the first electrode 2, the second electrode 4, the partition wall (not shown) and the second substrate 8 are bonded by an adhesive layer 7.
Note that the display element shown in FIG. 3B is shown for one cell portion, but the plurality of cells are arranged in a one-dimensional manner in the substrate plane direction in such a manner that they are separated from other adjacent cells by partition walls. You may arrange | position continuously two-dimensionally.

The widths of both electrodes 2 and 4 are not particularly limited, but are usually about 10 μm to 1 mm. Although the height of both the electrodes 2 and 4 is not specifically limited, It is about 20 micrometers-1 mm. Note that the width and height of the partition walls (not shown) are the same as those of the electrodes 2 and 4.
The display element shown in FIG. 3B can be manufactured as follows, for example. First, the strip-shaped first electrode 2 and the second electrode 4 are formed so as to be along one side of the first substrate 1 and two opposite parallel sides (sides orthogonal to the cross section (paper surface in the drawing)). A partition wall (not shown) made of an insulating material in a portion where the first electrode 2 and the second electrode 4 are not disposed so as to insulate the first electrode 2 and the second electrode 4 (FIG. 2A). (Electrode and partition wall forming step). Then, the 1st electrode 2, the 2nd electrode 4, the partition not shown, and the 2nd board | substrate 8 are adhere | attached through the contact bonding layer 7 (adhesion process). The noble metal particle dispersion liquid can be sealed in the light control layer portion in the same manner as in the display element shown in FIG. 1, thereby obtaining a display element (FIG. 3B).

  FIG. 3C shows a case where a negative voltage is applied to the first electrode 2 by a power source connected as voltage applying means to the first electrode 1 and the second electrode 4 of the display element shown in FIG. The state where a positive voltage is applied to the second electrode 4 is shown. Here, if the noble metal particle 10 is positively charged, the noble metal particle 10 moves to the negative electrode (first electrode 2) side as shown in FIG. Therefore, when no voltage is applied (FIG. 3B), the color of the noble metal particles 10 is observed as the display color, and when the voltage is applied (FIG. 3C), the display element is transmitted. If the mold is transparent, the color of the first substrate 1 (or the second substrate 8) is observed if the display element is a reflective type.

Next, a display element having a configuration in which the display elements shown in FIG. 2 are stacked will be described.
FIG. 4 is a schematic cross-sectional view showing another example of the display element of the present invention and a process for manufacturing the display element. The display element (dimming cell) having the configuration shown in FIG. 3 shows a display element having a configuration in which three are stacked.
Here, FIGS. 4A and 4B are diagrams for explaining a process in the middle of manufacturing the display element, and FIG. 4C is completed through the processes shown in FIGS. 4A and 4B. FIG. 4D is a diagram showing a state in which a voltage is applied by connecting the display element shown in FIG. 4C to a power source.

The display element shown in FIG. 4C includes a first dimming cell 20A, a second dimming cell 20B, and a third dimming cell 20C having the same configuration as the display element shown in FIG. In this configuration, the substrate 11A is used as the second substrate of the first light control cell 20A, the substrate 11A is used as the first substrate of the second light control cell 20B, and the second light control cell 20B. The configuration of each dimming cell and its components are shown in FIG. 2B except that the substrate 11B is used as the second substrate and the substrate 11B is used as the first substrate of the third dimming cell 20C. It is the same as the display element.
In addition, the board | substrate 11A shown in FIG.4 (c) has the function of the 1st board | substrate of the 2nd board | substrate in the 1st light control cell 20A and the 2nd light control cell 20B, and the board | substrate 11B is 2nd The dimming cell 20B functions as the second substrate and the first substrate of the third dimming cell 20C. Whether the display element is a transmission type or a reflection type is used as the substrate 11A and the substrate 11B. Instead, a transparent substrate is used.

  Further, the noble metal particles 10A, 10B, and 10C used for the light control layer of the first light control cell 20A, the light control layer of the second light control cell 20B, and the light control layer of the third light control cell 20C, respectively, Each color may be the same or different. When the three types of noble metal particles 10A, 10B, and 10C have the same color, three-step gradation display can be performed, and when the three types of noble metal particles 10A, 10B, and 10C have different colors, When the color of the noble metal particle 10A is red (R), the color of the noble metal particle 10B is green (G), and the color of the noble metal particle 10C is blue (B), full color display can be performed.

The display element shown in FIG. 4C is manufactured through the process shown in FIG. 2A (FIG. 4A), and the first layer of the light control cell (first light control cell 20A). Make it. Subsequently, in order to stack the second dimming cell 20B on the surface of the second dimming cell 20A opposite to the side where the first substrate 1 is disposed of the second substrate (substrate 11A), The second electrode 4 is formed. The subsequent steps are the same as in the case of manufacturing the display element shown in FIG. Such a process is repeated again after the second dimming cell 20B is formed, thereby forming the third dimming cell 20C and obtaining a display element (FIG. 4C). .
However, in addition to the manufacturing method described above, for example, a display element as shown in FIG. 4C can be manufactured by separately manufacturing each light control cell and then stacking them. In this case, the substrate 11A and the substrate 11B have a configuration in which two substrates are stacked.

  4D is connected as voltage application means to the first electrode 1 and the second electrode 4 of the first dimming cell 20A and the third dimming cell 20C shown in FIG. 4C. A state is shown in which a negative voltage is applied to the second electrode 4 and a positive voltage is applied to the first electrode 2 by the power source.

Next, the operation of the display element of the present invention illustrated in FIG. 4 will be described below with reference to FIGS.
In the description of the operation, the second substrate 8 and the first electrode 2 are transparent to visible light, the first substrate 1 is opaque to visible light, and the color of the noble metal particle 10A is red (R). The color of the noble metal particles 10B is green (G), the color of the noble metal particles 10C is blue (B), and the color displayed by the display element is the surface of the display element on the side where the second substrate 8 is provided. Shall be observed.
First, when no voltage is applied, the noble metal particles 10A, 10B, and 10C are uniformly dispersed in the light control layer and the colors of the noble metal particles 10, 10B, and 10C overlap as shown in FIG. Observed as a black color.

On the other hand, as shown in FIG. 4D, when a voltage is applied to the first dimming cell 20A and the third dimming cell 20C, the noble metal particles 10A and 10C that are negatively charged become positive electrodes ( Move to the first electrode 2) side. However, since no voltage is applied to the second dimming cell 20B, the state in which the noble metal particles 10B are dispersed is maintained in the dimming layer of the second dimming cell 20B. For this reason, green (the color of the noble metal particle 10B) is displayed on the display element.
Similarly, when a voltage is applied only to the first dimming cell 20A and the second dimming cell 20B, blue is displayed, and only to the second dimming cell 20B and the third dimming cell 20C. When voltage is applied, red is displayed, and when voltage is applied to all three light control cells 20A, 20B, and 20C, white is displayed. Therefore, full color display is possible by controlling the voltage application to each of these three dimming cells.

Next, a display element having a configuration different from the display element shown in FIGS.
FIG. 5 is a schematic cross-sectional view showing another example of the display element of the present invention. FIG. 5A shows a state in which no voltage is applied to the display element, and FIG. FIG. 5C shows a state where a voltage in the opposite direction to that shown in FIG. 5B is applied to the display element.
The display element shown in FIG. 5 is formed so as to cover the first substrate 1 and the second substrate 8 arranged to face each other and the entire surface of the first substrate 1 on the side where the second substrate 8 is arranged. An end of a cell comprising the electrode 2, the second electrode 4 formed so as to cover the entire surface of the second substrate 8 on the side where the first substrate 1 is disposed, and the first substrate 1 and the second substrate 8. And a partition wall 6 provided to seal the noble metal particles 10 in a space (a space portion corresponding to the light control layer) sealed by the first substrate 1, the second substrate 8 and the partition wall 6. And a noble metal particle dispersion containing silicone oil 9 is shown for one cell portion enclosed with isomeric particles 12. Note that the display element shown in FIG. 5 is shown for one cell portion, but the plurality of cells are one-dimensionally or two-dimensionally arranged in the plane direction of the substrate in such a manner that they are separated from other adjacent cells by partition walls. May be arranged continuously.

  The constituent materials and sizes of the members other than the isomer particles 12 of the display element shown in FIG. 5 can be basically the same as those of the display element shown in FIG. As the isomer particles 12, those described above can be used. For example, white titanium oxide particles having a particle diameter of about 10 μm can be used for the purpose of improving the contrast. In this case, as shown in FIG. 5, the isomer particles 12 are arranged in the light control layer so as not to form a gap in the plane direction of the light control layer with other adjacent isomer particles 12.

Next, the operation of the display element of the present invention illustrated in FIG. 5 will be described below with reference to FIGS.
In describing the operation, the second substrate 8 and the second electrode 4 are transparent to visible light, the noble metal particles 10 are positively charged red particles, the isomeric particles 12 are white, and The color displayed by the display element is observed from the surface of the display element on the side where the second substrate 8 is provided.
First, when no voltage is applied, the noble metal particles 10 are uniformly dispersed in the light control layer as shown in FIG. Here, when a positive voltage is applied to the first electrode 2 and a negative voltage is applied to the second electrode 4 as shown in FIG. 5B, the noble metal particles 10 are on the negative electrode (second electrode 4) side. Move to. For this reason, dark red is displayed on the display element.
On the other hand, when a negative voltage is applied to the first electrode 2 and a positive voltage is applied to the second electrode 4 as shown in FIG. 5B, the noble metal particles 10 move toward the negative electrode (first electrode 2). Moving. For this reason, white (color of the isomeric particle 12) is displayed on the display element.

  In the display element of the present invention described above, a switching element for driving such as a wiring, a thin film transistor, a diode having a metal / insulating layer / metal structure, a variable capacitor, a ferroelectric, etc. is provided on the substrate according to the application. It may be formed.

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples.
<Preparation of precious metal particle dispersion>
(Example A1)
In a 100 ml flask, 4.0 × 10 ⁻⁵ mol of silver 2-ethylhexylate and 20 mL of octamethyltrisiloxane were sampled and dispersed by stirring using a magnetic stirrer. When 1.7 × 10 ⁻² mol of phenethyltrimethylsilane was added and 9.0 × 10 ⁻⁴ mol of 3-Aminopropyltrisiloxane was further added, the liquid became colorless and transparent. Furthermore, 1.2 × 10 ⁻⁵ mol of ascorbic acid was added as a reducing agent and stirred using a magnetic stirrer to obtain a yellow silver colloidal dispersion.
In addition, after putting this silver colloid dispersion liquid in a beaker and allowing to stand for one week, the color density, turbidity, and the presence or absence of colloidal particle sedimentation were visually observed again. No change was seen. Therefore, it was found that the produced silver colloid was stably dispersed in the dispersion.

(Example A2)
In a 100 ml flask, 2.0 × 10 ⁻⁵ mol of chloroauric acid and 20 mL of octamethyltrisiloxane were sampled and dispersed by stirring using a magnetic stirrer.
1.7 × 10 ⁻² mol of phenethyltrimethylsilane was added, and 9.0 × 10 ⁻⁴ mol of 3-aminopropyltrioxysilane was further added. Further, 4.0 × 10 ⁻⁴ mol of ascorbic acid was added as a reducing agent and stirred using a magnetic stirrer to obtain a red gold colloid dispersion.
The colloidal gold dispersion was placed in a beaker and allowed to stand for one week, and then visually observed again for color concentration, turbidity, colloidal particle sedimentation, etc. No change was seen. Therefore, it was found that the produced gold colloid was stably dispersed in the dispersion.

(Comparative Example A1)
2 g of red pigment particles (KET RED manufactured by Dainippon Ink & Chemicals, Inc.) are dispersed in 100 g of silicone oil (KF-96 manufactured by Shin-Etsu Chemical Co., Ltd.) and 8000 rpm, 100 ° C. using a homogenizer (Silent Crusher M manufactured by Heidolph). Although the treatment was performed for 1 hour, aggregation occurred and dispersion was not stably performed.

(Comparative Example A2)
2 g of red pigment particles (KET RED manufactured by Dainippon Ink & Chemicals, Inc.) are dispersed in 100 g of silicone oil (KF-96 manufactured by Shin-Etsu Chemical Co., Ltd.), 2 g of sodium dodecylbenzenesulfonate is added, and then a homogenizer (manufactured by Heidolph) Silent Crusher M) was used for processing at 8000 rpm and 100 ° C. for 1 hour, but agglomeration occurred and it was not stably dispersed.

(Comparative Example A3)
After dispersing 2 g of red pigment particles (KET RED, manufactured by Dainippon Ink & Chemicals, Inc.) in 100 g of silicone oil (KF-96 manufactured by Shin-Etsu Chemical Co., Ltd.) and adding 2 g of Neugen ET-65 manufactured by Daiichi Kogyo Seiyaku Co., Ltd. Treatment was performed at 8000 rpm and 100 ° C. for 1 hour using a homogenizer (Silent Crusher M manufactured by Heidolph). However, aggregation occurred and dispersion was not stably performed.

(Comparative Example A4)
2 g of red pigment particles (KET RED manufactured by Dainippon Ink & Chemicals, Inc.) are dispersed in 100 g of silicone oil (KF-96 manufactured by Shin-Etsu Chemical Co., Ltd.), 2 g of 3-Aminopropyltrioxysilane is added, and then a homogenizer (Silent Crusher manufactured by Heidolph) is added. M) was used to carry out the treatment at 8000 rpm, 100 ° C. for 1 hour, but agglomeration occurred and it was not stably dispersed.

(Example B1)
-Fabrication of display elements-
A display element having the configuration shown in FIG. 2B was manufactured by the following procedure.
First, polyethylene terephthalate (PET) having a length of 50 mm, a width of 50 mm, and a thickness of 200 μm is prepared as a first substrate, and an ITO film is formed on the first substrate to a thickness of 50 nm by sputtering, and then a pattern is formed in a strip shape. To form a first electrode and a second electrode. At this time, the length of each electrode was 10 mm, the line width was 200 μm, and the space between the two electrodes was 400 μm.
Subsequently, using a silicone rubber (Silpot 184 manufactured by Dow Corning) on the surface of the first substrate on which the ITO electrode is formed, the width is 100 μm and the thickness is so as to connect the two electrodes and both ends of the two electrodes. A 100 μm partition was formed. In addition, when forming the partition, the partition was formed so that a filling port for filling the noble metal particle dispersion later could be secured.

Thereafter, using a thermosetting epoxy adhesive, the first substrate on which the electrodes and the partition walls were formed was bonded to quartz glass having a length of 50 mm, a width of 50 mm, and a thickness of 0.7 mm, and heated to produce a cell.
Subsequently, after the silver colloid dispersion liquid produced in Example A1 was filled into the cell from the filling port, the filling port was sealed with the above-described silicone rubber, and the display was 10 mm in height, 50 mm in length, and 50 mm in width. An element was obtained.

-Evaluation-
The color displayed on the display element before voltage application was yellow (the color of the silver colloidal dispersion), but when a DC voltage of 20 V was applied so that the first electrode was a negative electrode and the second electrode was a positive electrode, Since the silver colloidal particles moved to the first electrode side, the color displayed on the display element was white. From this result, it was found that the silver colloid particles were positively charged.
Subsequently, when an AC voltage was applied to the two electrodes, the silver colloidal particles were dispersed again throughout the light control layer, and the color displayed on the display element was yellow.

(Example B2)
-Fabrication of display elements-
A display element having the configuration shown in FIG. 3B was manufactured by the following procedure.
First, a 50 mm long, 50 mm wide, 200 μm thick polyethylene terephthalate (PET) is prepared as the first substrate, and a quartz glass substrate of 50 mm long, 50 mm wide, 0.7 mm thick is prepared as the second substrate. After forming a gold film to a thickness of 1 mm by plating, the first electrode and the second electrode were formed by patterning in a strip shape. At this time, the length of each electrode was 10 mm, the line width was 200 μm, and the space between the two electrodes was 400 μm.
Subsequently, a partition having a thickness of 1 mm and a width of 1 mm was formed so as to connect both ends of the two gold electrodes using silicone rubber (Silpot 184 manufactured by Dow Corning). In addition, when forming the partition, the partition was formed so that a filling port for filling the noble metal particle dispersion later could be secured.

After that, using a thermosetting epoxy adhesive, the second substrate on which the electrodes and the partition walls were formed was bonded to the first substrate and heated to produce a cell.
Subsequently, after filling the cell with the gold colloid dispersion liquid produced in Example A2 from the filling port, the filling port was sealed with the above-described silicone rubber, and the height was 1.9 mm, the height was 50 mm, and the width was 50 mm. The display element was obtained.

-Evaluation-
The color displayed on the display element before voltage application was red (color of colloidal gold dispersion), but when a DC voltage of 20 V was applied so that the first electrode was a negative electrode and the second electrode was a positive electrode, Since the silver colloidal particles moved to the first electrode side, the color displayed on the display element was white. From this result, it was found that the colloidal gold particles are positively charged.
Subsequently, when an alternating voltage was applied to the two electrodes, the colloidal gold particles were dispersed again throughout the light control layer, and the color displayed on the display element was red.

(Example B3)
-Fabrication of display elements-
A display element having the configuration shown in FIG. 5A was produced by the following procedure.
First, a 50 mm long, 50 mm wide, 200 μm thick polyethylene terephthalate (PET) was prepared as the first substrate, and a quartz glass substrate of 50 mm long, 50 mm wide, 0.7 mm thick was prepared as the second substrate. A transparent electrode having a thickness of 50 nm made of ITO (Indium Tin Oxide) was formed on the entire surface of one side by sputtering.
Next, using the prepared first substrate, a photo-sensitive epoxy resin (SU-8 manufactured by MicroChem Corp.) was applied to the electrode surface side by spin coating to form a coating film, and then the coating film was exposed. Then, a wet etching process was performed for patterning to form a partition wall having a vertical and horizontal size of 10 × 10 mm, a height of 50 μm, and a width of 20 μm.

Subsequently, a heat-fusible epoxy adhesive was applied to the upper surface of the partition wall, and then manufactured in Example A2 together with white particles (titanium oxide, particle size 10 μm) in the area partitioned by the partition wall. Filled with gold colloid dispersion. The white particles were used in such an amount that evenly covers the entire area partitioned by the partition walls.
Thereafter, the second glass substrate with an ITO electrode was bonded so that the electrode surfaces face each other, and then heated to bond the partition wall with the second glass substrate with an ITO electrode to obtain a display element. It was.

-Evaluation-
When a DC voltage of 15 V was applied so that the first electrode was a positive electrode and the second electrode was a negative electrode, the colloidal gold particles moved to the second electrode side. At this time, when the color displayed by the display element was continuously observed from the surface on the side where the second electrode of the element was provided, the color was red before the voltage application, but after the voltage application, before the voltage application. As the voltage was continuously applied, the brightness of the display element gradually became darker and became deep red.
Subsequently, when a DC voltage of 15 V was applied so that the first electrode was a negative electrode and the second electrode was a positive electrode, the gold particles moved to the first electrode side. When the color displayed by the display element at this time was continuously observed from the surface on the side where the second electrode of the element was provided, the color changed from dark red to white.

(Comparative Example B1)
An ethanol dispersion of silver colloid in which a yellow silver colloid was dispersed in ethanol was produced in the same manner as in Example A1 except that the solvent was changed from octamethyltrisiloxane to ethanol.
Further, in Example B1, a display element was produced in the same manner as in Example B1 except that an ethanol dispersion of silver colloid was used instead of the silver colloid dispersion prepared in Example A1. When a voltage of 30 V was applied to the display element, intense convection occurred. Also, the display at this time was not stable and the contrast was insufficient.

(Comparative Example B2)
In a 100 ml flask, 4.0 × 10 ⁻⁵ mol of silver 2-ethylhexylate and 20 mL of cyclohexane were collected and dispersed by stirring using a magnetic stirrer. Subsequently, when 3.0 × 10 ⁻³ mol of sodium n-dodecylbenzenesulfonate was added and added, the liquid became colorless and transparent. Furthermore, 1.2 × 10 ⁻⁶ mol of ascorbic acid was added as a reducing agent and stirred using a magnetic stirrer to obtain a yellow silver colloid dispersion.
A display element was produced in the same manner as in Example B1, except that this silver colloid dispersion was used. Subsequently, a voltage of 5 V was applied to the device, but bubbles were generated from the electrode.

It is a schematic cross section which shows an example of the display element of this invention, and the process of manufacturing it. It is a schematic cross section which shows the other example of the display element of this invention, and the process which manufactures it. It is a schematic cross section which shows the other example of the display element of this invention, and the process which manufactures it. It is a schematic cross section which shows the other example of the display element of this invention, and the process which manufactures it. It is a schematic cross section which shows the other example of the display element of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st board | substrate 2 1st electrode 4 2nd electrode 5 Insulating layer 6 Partition 7 Adhesion layer 8 2nd board | substrate 9 Silicone oil 10, 10A, 10B, 10C Noble metal particle 11A, 11B Substrate 12 Isomeric particle 20A, 20B, 20C Light control cell

Claims (6)

  A noble metal particle dispersion liquid comprising silicone oil and noble metal particles dispersed in the silicone oil.   The noble metal particle dispersion according to claim 1, wherein the noble metal particles have a plasmon coloring function.   The noble metal particle dispersion according to claim 1, wherein the noble metal particles contain at least one kind of noble metal selected from gold and silver.   A noble metal particle is produced by adding a reducing agent to a silicone oil containing at least one kind of noble metal compound and at least one kind of silane coupling agent and reducing the noble metal compound. A method for producing a noble metal particle dispersion.   A display method in which display is switched by electrically moving noble metal particles contained in silicone oil to control a dispersion / localization state of the noble metal particles in the silicone oil. A first electrode, a second electrode, a light control layer, and a voltage applying means for applying a voltage to the light control layer via the first electrode and the second electrode,
The display device, wherein the light control layer includes silicone oil and noble metal particles dispersed in the silicone oil.

Images