JP5159576B2 - Display device - Google Patents

Description

  The present invention relates to a reflective display device using surface plasmons.

  2. Description of the Related Art Conventionally, a reflection type display using outside light is known as a display that does not require a light source such as a backlight. A color filter is used to color the reflective display. In this color filter, a red transmissive part, a green transmissive part, and a blue transmissive part are alternately arranged in a matrix, and one color element part is constituted by a pair of red transmissive part, green transmissive part, and blue transmissive part. It is supposed to be. In color tone expression using such a color filter, there is a problem that light use efficiency is low and bright full-color display cannot be performed.

  As a method for realizing color display without using a color filter, use of localized plasmons that can be excited by outdoor white light is considered (Non-Patent Document 1).

However, since the shift width of the plasmon resonance wavelength with respect to the change in the refractive index of the surrounding medium is small in localized plasmons, W (white), R (red), G (green), B (blue), C (cyan), All colors of M (magenta), Y (yellow), and BL (black) cannot be displayed.
Nano letters, Vol 5, p. 1978 (2005)

  An object of the present invention is to provide a reflective display device (color conversion layer) capable of displaying all colors of W, R, G, B, C, M, Y, and BL.

  According to an embodiment of the present invention, a medium that is sandwiched between substrates and has a refractive index that is variable by an electric field, an electrode that changes the refractive index by applying an electric field to the medium, and a change in the refractive index of the medium There is provided a display device including a cell including a metal nanostructure having a plasmon resonance wavelength change, and including two types of metal nanostructures having different plasmon resonance wavelength ranges.

  According to the embodiment of the present invention, all colors of W, R, G, B, C, M, Y, and BL are obtained by changing the plasmon resonance wavelengths of two types of metal nanostructures having different plasmon resonance wavelength ranges. It is possible to provide a reflective display device (color conversion layer) capable of displaying the color.

  The display element of the present invention includes a light control layer including a nanostructure whose light absorption wavelength changes depending on the refractive index of a surrounding medium, and a medium whose refractive index can be controlled. The display element of the present invention has a configuration in which a TFT array is provided as means for changing the refractive index by applying an electric field to the medium of the light control layer, or means for controlling movement of the medium (for example, a nanostructure is fixed). In other words, an electric field is applied to the substrate to change the affinity for the medium. And based on this structure, it is the structure provided with two or more light control cells including a light control layer, or the structure provided with two or more light control layers. Hereinafter, specific configurations of the light control layer and the display element of the present invention will be described.

(Light control layer)
The light control layer includes a nanostructure that changes color according to the refractive index of the surrounding medium and a medium whose refractive index changes depending on the electric field. The light control layer is a layer that exhibits a function of displaying various colors when used as a display element.

(1) Nanostructure The nanostructure has a coloring function by localized surface plasmons, and controls the refractive index of the surrounding medium by adjusting the application of electric field (voltage), magnetism, or temperature. Color is developed by absorbing light at a desired wavelength in the visible range. The color development due to the plasmon absorption is attributed to the plasma oscillation of the electrons, and free electrons in the nanostructure are shaken by the photoelectric field, so that charges appear on the surface and nonlinear polarization occurs. Color development by plasmons is seen in nanostructures with dimensions of several nanometers to several tens of nanometers, and has high chroma and light transmittance and excellent durability. Considering application to color display, it is desirable that the dimensional variation is small.

  The volume average particle diameter of the nanostructure is preferably 10 to 100 nm, which is practical and has good color strength. The refractive index sensitivity of the nanostructure depends on the material and shape constituting the nanostructure, and the volume average particle diameter. Therefore, by controlling these, it is possible to develop a color at a desired wavelength, and the display element of the present invention can be a color display element. Furthermore, in nanostructures having shape anisotropy (for example, rod shape), the absorption wavelength varies depending on the polarization direction, and when the distance between adjacent nanostructures becomes smaller than about 200 nm, plasmon coupling occurs and new absorption occurs. Since the peak of the wavelength is generated, it is necessary to adjust the arrangement of the nanostructures, particularly when there is shape anisotropy, including the direction thereof. In order to display a sufficient concentration of color, the number of nanostructures immobilized on the substrate may be increased. However, in order to prevent bonding between the plasmons, the distance between adjacent nanostructures is the average volume particle size. It is necessary to be twice or more. This gives the upper limit of the surface density of the nanostructure.

  Nanostructures include metal nanoparticles, semiconductor nanoparticles, and metal nanopatterns. The metal nanopattern can be formed by the following method. For example, it may be produced by vapor deposition or sputtering using an alumina membrane having nanopores as a mask. In this case, the shape and arrangement of the gold nanostructure depend on the cross section of the nanopore, and the height can be controlled by the metal film formation time. Alternatively, the microspheres may be removed by depositing or sputtering metal using the microspheres arranged in a self-organized manner as a mask. In this case, the shape of the gold nanostructure is a triangle, and the size and arrangement of the triangle depend on the diameter of the microsphere used. The height can be controlled by the gold deposition time. Or you may produce by EB lithography. First, after depositing a uniform metal thin film on a substrate, an EB resist is applied thereon and irradiated with an electron beam to form a resist pattern, and the underlying metal thin film is etched using the prepared resist pattern as a mask. The resulting metal nanostructure has a disk shape, the shape and arrangement can be defined by a resist drawing pattern, and the height can be controlled by the metal deposition time.

  In the case of metal and semiconductor nanoparticles, it may be physical adsorption onto the substrate by dropping the nanoparticle dispersion onto the substrate and letting it dry naturally, or a dispersion that is weakly charged around the nanoparticles A self-assembled monolayer (SAM) having a functional group charged with a polarity opposite to that of the substrate or a site chemically bonded to the nanoparticle itself is formed on the substrate, and the nanoparticle is fixed to the substrate through the SAM. It may be a method. The shape of the nanostructure depends on the shape of the nanoparticles used, and the distance between adjacent particles is determined by the repulsive force acting between the nanoparticles and the strength of the adsorption force between the substrate surface and the nanoparticles.

  Examples of the metal component constituting the metal nanoparticles include noble metals (gold, silver, ruthenium, rhodium, palladium, osmium, iridium, platinum, etc.) and copper. Among the metals, gold, silver, platinum, or an alloy including at least one of these is preferable, and it is more preferable that at least one of gold and silver is included. An example of the semiconductor component constituting the semiconductor nanoparticles is cadmium selenium.

  Considering that the plasmon resonance peak wavelength and the shift amount of the plasmon resonance peak wavelength with respect to the refractive index change of the surrounding medium depend on the shape of the metal nanostructure and the distance between adjacent particles, desired display characteristics can be obtained. Thus, it is desirable that the shape and arrangement be calculated and then produced by EB lithography.

(2) Medium The medium is colorless and transparent, and the refractive index can be controlled by applying a voltage. There are two ways to control the refractive index: changing the refractive index of the medium itself by the electric field without moving the medium, and applying a voltage to the substrate with the nanostructure fixed to change the affinity between the substrate and the medium. There is a method (electrowetting) for switching between contact and non-contact between the nanostructure and the medium according to the voltage. A liquid crystal is an example of the medium of the former method. For example, when the nanostructure is a gold sphere with a diameter of 80 nm, the color changes from magenta to transparent when the refractive index of the liquid crystal changes from 1.5 to 1.85. In this case, examples of the liquid crystal include cyanobiphenyl-based nematic liquid crystal 4-cyano4′-pentylbiphenyl (5CB) (manufactured by Aldrich), cyano-based liquid crystal, and fluorine-based liquid crystal. The material of the latter method is not particularly specified as long as it is a transparent oil.

(3) Substrate The substrate is not particularly limited as long as it is transparent and insulating. Usually, a glass substrate is desirable.

(4) Electrode As a method of applying a voltage to the light control layer, a method in which the electrode is comb-shaped and applied in the in-plane direction of the light control layer, and the medium is sandwiched between the upper electrode and the lower electrode, There is a method of applying in the thickness direction.

  In the case of the former method, the electrode and the nanostructure are produced in the same plane. Specifically, first, a nanostructure is produced by leaving an electrode space. After producing the nanostructure, spin-coat the resist on the entire surface, align the nanostructure pattern and the electrode pattern so that they do not overlap, draw the resist by photolithography, and lift off using the resist pattern as a mask An electrode is produced.

  When the nanostructure is a nanoparticle, a selective chemical bond between the nanoparticle and the organic molecule that has modified the substrate surface is used to immobilize the nanoparticle. At this time, the organic molecule that modifies the substrate surface is preliminarily electroded. Then, patterning is performed so as to leave a space, and a nanoparticle dispersion is dropped onto the entire surface of the substrate to selectively fix the nanoparticles only on the organic molecular film on the surface of the substrate. At this time, excess nanoparticles adsorbed in the electrode space are washed away by a rinsing step after the dispersed droplets.

  When metal nanostructures are fabricated by EB lithography, a uniform metal thin film is first deposited on a substrate, and then an EB resist is applied thereon, and an electrode and a nanostructure resist pattern are simultaneously fabricated by EB lithography. Also good. The produced resist pattern is used as a mask for etching the underlying metal thin film. In addition, if the electrode pattern is drawn by EB lithography and the throughput is drastically reduced, a uniform metal thin film is deposited on the substrate, and then a negative EB resist is applied thereon to form a nanostructure resist pattern only. Then, the underlying metal thin film is etched using the produced resist pattern as a mask. After creating the metal nanostructure for the electrode, apply a photolithography resist on the entire substrate surface, align the metal nanostructure pattern and the electrode pattern so that they do not overlap, and draw the resist by photolithography. An electrode is produced by lift-off using the resist pattern as a mask.

  In the latter method, metal thin film electrodes are formed on the opposing surface of the upper substrate and the surface of the lower substrate. When the light control layer has a multilayer structure, an intermediate substrate is inserted between the upper substrate and the lower substrate. For example, in the case of a two-layer structure, a single intermediate substrate is inserted, and thin film electrodes are formed on the opposing surface of the upper substrate, the surface and the opposing surface of the intermediate substrate, and the surface of the lower substrate.

  A TFT array is manufactured as a means for supplying a voltage to the surface on which the electrodes are formed and the opposing surface. The electrode is preferably transparent, such as ITO.

(Display method)
When one type of nanostructure is used, the color in the entire visible region is developed with a single nanostructure. When there are a plurality of types of nanostructures, the light control layer has a laminated structure. In the case of three types, full color display is performed by independently controlling the color development in each layer of the light control layer from transparent to red, transparent to green, and transparent to blue. In the case of the two types, any color light can be displayed by independently controlling the refractive index of the nanostructure medium in which the shift occurs in the short wavelength region and the nanostructure medium in which the shift occurs in the long wavelength region. Hereinafter, a method of developing a full color using two types of nanostructures will be described (FIG. 1). In FIG. 1, the horizontal axis indicates the wavelength, and the vertical axis indicates the intensity of the absorption spectrum. Moreover, the spectrum of the broken line of FIG. 1 shows that it is transparent visually.

  When displaying blue to cyan and magenta, the metal nanostructure resonance peak that shifts in the short wavelength region is shifted to the ultraviolet region, and the metal nanostructure resonance peak that shifts in the long wavelength region is shifted from green to red. Change in the wavelength range.

  When displaying yellow to red, shift the resonance peak of the metal nanostructure that shifts in the long wavelength region to the infrared region, and shift the resonance peak of the metal nanostructure that shifts in the short wavelength region to the blue to cyan wavelength region. Change.

  When displaying green, the resonance peak of the metal nanostructure where the shift occurs in the long wavelength region is changed to the red wavelength, and the resonance peak of the metal nanostructure where the shift occurs in the short wavelength region is changed to the blue wavelength.

  When displaying white, the resonance peak of the metal nanostructure that shifts in the long wavelength region is shifted to the infrared region, and the resonance peak of the metal nanostructure that shifts in the short wavelength region is shifted to the ultraviolet region. Is displayed.

  When displaying black, create multiple layers of metal nanostructures that shift in the short wavelength region and multiple metal nanostructures that shift in the long wavelength region, and absorb all visible light in these layers. To display black.

  The medium whose refractive index is changed by an electric field may be common to a nanostructure in which a shift occurs in a short wavelength region and a nanostructure in which a shift occurs in a long wavelength region, or an upper substrate and a lower layer using an intermediate substrate. Different media may be used by separating them.

  Embodiments according to the present invention will be described below.

[Example 1]
2 (a) and 2 (b) show an embodiment of the present invention. 2A is a cross-sectional view, and FIG. 2B is a plan view.

  In FIG. 2, the cell has a two-layer structure with the intermediate substrate 2 interposed therebetween, and an in-plane electrode 22 (comb structure) for changing the refractive index of the medium 21 is provided on the opposite surface of the upper substrate 3. A gold nanostructure 23 that shifts the peak wavelength of plasmon resonance in the long wavelength region from the visible region to the infrared region according to the change in the refractive index of the medium 21 is fabricated on the substrate. The electrode 22 is produced by photolithography or EB lithography. A transparent electrode such as ITO is desirable as the electrode material. Any material may be used for the mediums 21 and 11 as long as the refractive index is changed by an electric field, and examples thereof include liquid crystal. The gold nanostructure 23 has a true spherical shape with a diameter of 80 nm, and the absorption wavelength changes from green to infrared if the refractive index of the liquid crystal changes from 1.5 to 1.85. Examples of the liquid crystal include cyanobiphenyl-based nematic liquid crystal 4-cyano-4'-pentylbiphenyl (5CB) (manufactured by Aldrich), cyano-based liquid crystal, and fluorine-based liquid crystal.

  An electrode 12 for changing the refractive index of the medium 11 is provided on the opposite surface of the intermediate substrate 2, and a short wavelength from the ultraviolet region to the visible region is provided on the substrate of the lower substrate 1 in accordance with the refractive index change of the medium 11 in the lower layer. Silver nanostructures 13 are produced that shift the peak wavelength of plasmon resonance in the region. The refractive index that can be changed by the liquid crystal is approximately in the range of 1.5 to 1.9, whereas when the silver nanostructure is a true sphere (diameter 80 nm), it is necessary to change the absorption wavelength from ultraviolet to cyan. The refractive index is estimated from 1.15 to 1.55. Therefore, when using liquid crystal, the silver nanostructure is not a true sphere, but an elliptical shape is desirable. In general, the shape of an elliptical absorption spectrum splits into two peaks, so the short wavelength side peak after splitting is always in the ultraviolet region and long wavelength side within the refractive index range (1.5 to 1.9) of the liquid crystal. The peak may be changed from ultraviolet to cyan within the refractive index range (1.5 to 1.9) of the liquid crystal. Further, in order to exhibit a color change with respect to incident light having any polarization, the silver nanostructures 13 are arranged so that the long axes of the rods are not aligned in one direction but are dispersed in all directions. It is desirable. The liquid crystal includes cyanobiphenyl nematic liquid crystal 4-cyano 4'-pentylbiphenyl (5CB) (manufactured by Aldrich), cyano liquid crystal, and fluorine liquid crystal. The production method and material of the electrode 12 are the same as described above.

  The arrangement of the upper part 20 and the lower part 10 may be switched, and the medium 21 and the medium 11 may be the same material. Further, the intermediate substrate 2, the upper substrate 3, and the lower substrate 1 are transparent.

[Example 2]
FIG. 3 shows an embodiment of the present invention. In FIG. 3, the cell has a two-layer structure with the intermediate substrate 2 interposed therebetween. In order to change the refractive index of the medium 21, the thin film electrode 222 on the opposite surface of the upper substrate 3 and the thin film electrode 221 on the substrate of the intermediate substrate 2. Has been made. On the thin film electrode 221, a gold nanostructure 23 that shifts the peak wavelength of plasmon resonance in the long wavelength region from the visible region to the infrared region according to the change in the refractive index of the medium 21 is fabricated. The material of the thin film electrodes 221 and 222 is preferably a transparent electrode such as ITO. Any material may be used for the mediums 21 and 11 as long as the refractive index is changed by an electric field, and examples thereof include liquid crystal. The gold nanostructure 23 has a true spherical shape with a diameter of 80 nm, and the absorption wavelength changes from green to infrared if the refractive index of the liquid crystal changes from 1.5 to 1.85. Examples of the liquid crystal include cyanobiphenyl-based nematic liquid crystal 4-cyano-4′-pentylbiphenyl (5CB) (manufactured by Aldrich), cyano-based liquid crystal, and fluorine-based liquid crystal. In order to change the refractive index of the medium 11, the thin film electrode 122 is formed on the opposite surface of the intermediate substrate 1 and the thin film electrode 121 is formed on the substrate of the lower substrate 1. A silver nanostructure 13 that shifts the peak wavelength of plasmon resonance in the short wavelength region from the ultraviolet region to the visible region according to the change in the refractive index of the medium 11 is fabricated on the lower substrate 1. The refractive index that can be changed by the liquid crystal is approximately in the range of 1.5 to 1.9, whereas when the silver nanostructure is a true sphere (diameter 80 nm), it is necessary to change the absorption wavelength from ultraviolet to cyan. The refractive index is estimated from 1.15 to 1.55. Therefore, when using liquid crystal, the silver nanostructure is not a true sphere, but an elliptical shape is desirable. In general, the shape of an elliptical absorption spectrum splits into two peaks, so the short wavelength side peak after splitting is always in the ultraviolet region and long wavelength side within the refractive index range (1.5 to 1.9) of the liquid crystal. The peak may be changed from ultraviolet to cyan within the refractive index range (1.5 to 1.9) of the liquid crystal. Further, in order to exhibit a color change with respect to incident light having any polarization, the silver nanostructures 13 are arranged so that the long axes of the rods are not aligned in one direction but are dispersed in all directions. It is desirable. Examples of the liquid crystal include cyano liquid crystal and fluorine liquid crystal in addition to cyanobiphenyl-based nematic liquid crystal 4-cyano 4′-pentylbiphenyl (5CB) (manufactured by Aldrich).

  The arrangement of the upper layer 20 and the lower layer 10 may be switched, and the medium 11 and the medium 21 may be the same material. Further, the intermediate substrate 2, the upper substrate 3, and the lower substrate 1 are transparent.

[Example 3]
4 (a) and 4 (b) show an embodiment of the present invention. 4A is a cross-sectional view, and FIG. 4B is a plan view. In FIG. 4, the electrode 32 for changing the refractive index of the medium 11 on the upper substrate 3 of the cell and the gold nano-wave that shifts the peak wavelength of plasmon resonance in the long wavelength region from the visible region to the infrared region in accordance with the refractive index change of the medium. Structure 33 is fabricated in the same plane. First, the gold nanostructure 33 is formed on the substrate with a space for the electrode 32. After the gold nanostructure 33 is fabricated, a resist is spin coated on the entire surface, aligned so that the space of the metal nanostructure 33 and the space of the electrode 32 do not overlap, and then the resist is drawn by photolithography or EB lithography. Then, the electrode 32 is fabricated by lift-off using the resist pattern as a mask. The gold nanostructure 4 has a true spherical shape with a diameter of 80 nm, and the absorption wavelength changes from green to infrared if the refractive index of the liquid crystal changes from 1.5 to 1.85. Any material may be used as the material of the medium 11 as long as its refractive index is changed by an electric field, and examples thereof include liquid crystals. Examples of the liquid crystal include cyano liquid crystal and fluorine liquid crystal in addition to cyanobiphenyl-based nematic liquid crystal 4-cyano 4′-pentyl biphenyl (5CB) (manufactured by Aldrich). An electrode 12 for changing the refractive index of the medium 11 on the lower substrate 1 of the cell, and a silver nanostructure 13 for shifting the peak wavelength of plasmon resonance in the short wavelength region from the ultraviolet region to the visible region according to the refractive index change of the medium, respectively. It is made in the same plane. The silver nanostructures 13 have the elliptical shape described above, and are arranged so that the major axes are not aligned in one direction but are dispersed in all directions. The manufacturing method of the electrode 12 and the silver nanostructure 13 is the same as described above.

  The arrangement of the electrode 32, the gold nanostructure 33, the electrode 12, and the silver nanostructure 13 may be interchanged. The upper substrate 3 and the lower substrate 1 are transparent.

[Example 4]
FIG. 5 shows an embodiment of the present invention. In FIG. 5, the cell has a three-layer structure. In the upper layer 5, the absorption wavelength is changed from red to infrared, and from cyan to transparent. In the intermediate layer 6, the absorption wavelength is changed from ultraviolet to blue, and from the transparent to yellow, the lower layer. 7 displays magenta to transparent by setting the absorption wavelength to green to infrared. Black is displayed by simultaneously absorbing red in the upper layer 5, blue in the intermediate layer 6, and green in the lower layer 7, and white is displayed in the color of the underlying reflector by making all three layers transparent. In this embodiment, the refractive index of the medium is changed by electrowetting.

  In the upper layer 5, the upper plate 3 is subjected to water repellent treatment by the organic film 351, and gold nanoparticles 354 are fixed on the organic film 351. The gold nanoparticles 354 are fixed by physical adsorption by naturally drying the dispersion after coating. The upper layer 5 is filled with an aqueous solvent 352 and an oil-based solvent 353. When no voltage is supplied, the upper substrate 3 is hydrophobic, so that the oil-based solvent 353 becomes a surrounding medium for the gold nanoparticles 354, and the gold nano The absorption wavelength by the particles 354 is infrared. When a voltage is applied to the organic film 351, the upper substrate 3 is switched to hydrophilicity, the aqueous solvent 352 becomes a medium around the gold nanoparticles 354, and the absorption wavelength by the gold nanoparticles 354 becomes red. At this time, the oil-based solvent 353 is hidden under the black matrix 4. The oil-based solvent 353 preferably has a large refractive index, and examples thereof include paraffin oil, benzene, and silicone oil. The aqueous solvent 352 desirably has a small refractive index, and examples thereof include water and air.

  In the intermediate layer 6, the intermediate substrate 2 is subjected to water repellent treatment by the organic film 251, and the silver nanoparticles 254 are fixed on the organic film 251. The silver nanoparticles 254 are fixed by physical adsorption by naturally drying the dispersion after coating. The intermediate layer 6 is filled with an aqueous solvent 252 and an oil-based solvent 253, and in a state where no voltage is supplied, the intermediate substrate 2 is hydrophobic, so that the oil-based solvent 253 becomes a surrounding medium of the silver nanoparticles 254, and silver The absorption wavelength of the nanoparticles 254 is blue. When a voltage is applied to the organic film 251, the intermediate substrate 2 is switched to hydrophilicity, the aqueous solvent 252 becomes a surrounding medium of the silver nanoparticles 254, and the absorption wavelength by the silver nanoparticles 254 becomes ultraviolet. At this time, the oil-based solvent 253 is hidden under the black matrix 4. The oil-based solvent 253 desirably has a high refractive index, and examples thereof include paraffin oil, benzene, and silicone oil. The aqueous solvent 252 preferably has a low refractive index, and examples thereof include water and air.

  In the lower layer 7, the lower substrate 1 is subjected to water repellent treatment with the organic film 151, and gold nanoparticles 154 are fixed on the organic film 151. The fixation of the gold nanoparticles 154 is physical adsorption by naturally drying the dispersion after coating. The lower layer 7 is filled with an aqueous solvent 152 and an oil-based solvent 153. When no voltage is supplied, the lower substrate 1 is hydrophobic, so that the oil-based solvent 153 serves as a surrounding medium for the gold nanoparticles 154, and the gold nano The absorption wavelength by the particles 154 is infrared. When a voltage is applied to the organic film 151, the lower substrate 1 is switched to hydrophilicity, the aqueous solvent 152 becomes a medium around the gold nanoparticles 154, and the absorption wavelength by the gold nanoparticles 154 becomes green. At this time, the oil-based solvent 153 is hidden under the black matrix 4. The oil-based solvent 153 preferably has a high refractive index, and examples thereof include paraffin oil, benzene, and silicone oil. The aqueous solvent 152 preferably has a small refractive index, and examples thereof include water and air.

  Further, the layers 5, 6, and 7 may have a juxtaposed structure. In this case, one pixel is composed of three subpixels 5, 6, and 7. The driving method for displaying each color is the same as in the case of the laminated structure.

The figure explaining the method of changing a display color using the shift of the plasmon resonance wavelength of the 1st and 2nd metal nanostructure. 2A and 2B are a cross-sectional view and a plan view of a display device in Embodiment 1. Sectional drawing of the display apparatus in Example 2. FIG. Sectional drawing and the top view of the display apparatus in Example 3. FIG. Sectional drawing of the display apparatus in Example 4. FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Lower substrate, 2 ... Intermediate substrate, 3 ... Upper substrate, 11 ... Medium, 12 ... Comb electrode, 13 ... Silver nanostructure, 21 ... Medium, 22 ... Comb electrode, 23 ... Gold nanostructure, 121 ... Thin film electrode, 122 ... Thin film electrode, 221 ... Thin film electrode, 222 ... Thin film electrode, 32 ... Comb electrode, 33 ... Gold nanostructure, 4 ... Black matrix, 151 ... Organic film, 152 ... Aqueous solvent, 153 ... Oil-based solvent, 154 ... Gold Nanoparticles, 251 ... organic film, 252 ... aqueous solvent, 253 ... oil-based solvent, 254 ... gold nanoparticle, 351 ... organic film, 352 ... aqueous solvent, 353 ... oil-based solvent, 354 ... gold nanoparticle.

Claims (10)

A pair of substrates;
A nanostructure sandwiched between the pair of substrates;
A medium provided around the nanostructure while being sandwiched between the pair of substrates;
An electrode for changing the refractive index of the medium;
Having one or more cells containing
The nanostructure includes two types of nanostructures, and the nanostructure has a plasmon resonance wavelength that changes in accordance with a change in a refractive index of the medium provided around the nanostructure, and a plasmon resonance wavelength region is different for each type. Display device. 2. The display device according to claim 1, wherein the plasmon resonance wavelengths of the two kinds of nanostructures are independently controlled in a short wavelength region of ultraviolet to visible light and a long wavelength region of visible light to infrared. First nano was made form a first medium refractive index is varied by an electric field is sandwiched between the lower substrate and the intermediate substrate, on said lower substrate or the intermediate substrate wherein the lower substrate facing the on the surface of A lower layer comprising a structure and electrodes ;
Wherein the second medium refractive index is varied by an electric field is held between the intermediate substrate and the upper substrate, the intermediate substrate or the upper substrate and the second was made form the intermediate substrate opposed to the surface The display device according to claim 1, further comprising an upper layer portion including a nanostructure and an electrode . A medium sandwiched between the lower substrate and the upper substrate and having a refractive index variable by an electric field;
A first nanostructure and electrode formed on the lower substrate;
The display device according to claim 1, characterized in that it comprises a second nano structures and electrodes formed on the lower substrate facing the on the surface of the upper substrate. Metal electrode for changing the refractive index of the medium, on the lower substrate, the lower substrate and the opposing surfaces of the intermediate substrate, the medium between the substrate and which is formed in the intermediate substrate and the opposing surfaces of the upper substrate The display device according to claim 3 , wherein the display device is a thin film and changes a refractive index of the medium by an electric field in a vertical direction. The display device according to claim 1, wherein the nanostructure is a metal nanoparticle, a semiconductor nanoparticle or metal nano patterns. The display device according to claim 1, wherein a volume average particle diameter of the nanostructure is in a range of 10 to 100 nm.   The display device according to claim 1, wherein the closest distance of the nanostructure is at least twice the volume average particle diameter. The medium has a hydrophobic medium and a hydrophilic medium,
The display device according to claim 1, wherein a film whose hydrophilicity is changed by an applied voltage is formed between the substrate and the medium . The display device according to claim 1, wherein the medium is a liquid crystal.

Images