JP5304065B2 - Manufacturing method of display member - Google Patents

Description

The present invention relates to a method for manufacturing a display member that develops a structural color and can be used as a sensor, a display, a panel, a sheet, a label, and the like.

  Conventionally, various display members that express a structural color by a periodic structure formed of spheres have been proposed (see, for example, Patent Document 1 and Patent Document 2).

However, these have a low degree of periodic arrangement, that is, a high degree of displacement of the position from the regular periodic structure state, or a high ratio of hollow regions (internal void ratio) where neither a sphere nor a matrix exists Therefore, the wavelength peak of expression of the structural color in the reflection spectrum is broad or the reflected light intensity is low, and the color purity and the high color of the display color required for use as a display member are high. The color density was not sufficiently satisfied.
That is, conventionally, there has been no display member having both a high periodic arrangement degree and a low internal porosity.

JP 2004-27195 A JP 2006-28202 A

The present invention has been made in consideration of the circumstances as described above, and its purpose is that the wavelength peak of the expression of the structural color in the reflection spectrum is sharp, the color purity of the display color is high, and An object of the present invention is to provide a method of manufacturing a display member having a high reflected light intensity at a wavelength peak and a high color density of display color.

In the method for producing a display member of the present invention, a layer is formed by a dispersion liquid in which spheres are dispersed in a liquid, and the layer is allowed to stand or be dried, and when the liquid content in the layer becomes 5 to 20%. By adding a liquid filler to the layer and solidifying the filler to form a matrix,
A display member having a display layer made of a sphere and a matrix and having a regular periodic structure state in which a periodic arrangement degree is 90% or more and which expresses a structural color is obtained.

  In the method for producing a display member of the present invention, the layer formed by dispersing the spheres in a liquid may be a coating layer formed by applying the dispersion on a substrate. A layer formed by introducing the dispersion into a cell having a small gap may be used.

According to the manufacturing method of the display member of the present invention, the periodic arrangement degree indicating the degree of displacement of the position from the regular periodic structure state is extremely high, and the ratio of the hollow region in which neither the sphere nor the matrix is present. Since the porosity is extremely low, the wavelength peak of the appearance of structural colors in the reflection spectrum is sharp, the display color has no color turbidity, and a sufficiently high color purity can be obtained while obtaining a large reflected light intensity, which is sufficient for the display color. In addition, it is possible to reliably manufacture a display member capable of obtaining a high color density.

  Hereinafter, the present invention will be specifically described.

  As shown in FIG. 1, the display member of the present invention has a display layer 10 composed of a sphere 12 and a matrix M that expresses a structural color. From the regular periodic structure state of the sphere 12 in the display layer 10. The ratio of the hollow regions in which the periodic arrangement degree indicating the degree of displacement of the position of the display layer 10 is 90% or more and neither the sphere 12 nor the matrix M analyzed in the image in an arbitrary cross section of the display layer 10 exists. The internal porosity is 10% or less. In addition, the cavity area | region which neither the spherical body 12 nor the matrix M in the display layer 10 exists normally is formed unintentionally.

[Display layer]
Specifically, the display layer 10 of the display member of the present invention is formed by forming a periodic structure 16 of spheres 12 made of solid particles in a matrix M, and more specifically, in the matrix M. The spherical layer 15 that is regularly formed by contacting the spheres 12 in the plane direction has a configuration that is regularly arranged in a state where the spheres 12 are in contact with each other also in the thickness direction.
Further, for example, a sphere layer 15 spheres 12 to each other are formed by regularly arranged in a non-contact state in the surface direction in the matrix M is, spheres 12 together even in the thickness direction was regularly arranged in a non-contact state You may have a structure.
The sphere layer 15 has a configuration in which spheres 12 are regularly arranged in one direction with respect to the direction in which light is incident. In particular, the periodic structure has a cubic close-packed structure such as a face-centered cubic structure, It is preferable that the spheres 12 are arranged so as to exhibit a close-packed structure such as a hexagonal close-packed structure.
The display layer 10 has a structure capable of reflecting light by the display layer 10, and light of a wavelength defined based on the observation angle is selectively reflected, whereby the structural color is expressed. Visible.

[Periodic arrangement degree]
When the periodic arrangement degree of the spheres 12 in the display layer 10 according to the present invention is 90% or more, the obtained display member has a sharp wavelength peak in the appearance of structural colors in the reflection spectrum. The periodic arrangement degree of the spheres 12 in the display layer 10 is more preferably 95% or more.

The periodic arrangement degree of the spheres 12 in the display layer 10 is obtained by quantifying an actual filling state with respect to an ideal regular periodic structure state [formula: periodic arrangement degree (%) = (actual periodic arrangement degree / ideal Periodic periodicity) × 100]. Specifically, the periodicity is measured as follows.
That is, the display layer 10 is cut in the perpendicular direction of the display layer 10 while passing through the center position of an appropriate sphere 12 using a cryomicrotome to produce a cross section, and a scanning electron microscope “JSM-7410” ( Two pieces of a 50,000 times photograph of the cross section are taken using JEOL Ltd., and the deviation from the ideal position is measured for each of 100 spheres 12 in the two photographic images. It is calculated using the following formula (1) based on the total deviation.
Here, “deviation from the ideal position” refers to the displacement distance of the sphere 12 from the position of the theoretically regular periodic structure state.
Formula (1): Periodic arrangement degree (%) = [1 − {(total deviation) / (a × 200)}] × 100
In the above formula (1), a is the center-to-center distance between adjacent spheres 12 in a theoretically regular periodic structure state (see FIG. 2 (a) or FIG. 3 (a)). As shown in FIG. 2 (b) or FIG. 3 (b), the displacement amount z1, which represents the displacement distance from the ideal position of each sphere 121, 122, 123, 124, 125. This is the total amount of z2, z3, z4, z5... (z1 + z2 + z3 + z4 + z5...). In FIG. 2B, z1, z3 and z5 are 0, and in FIG. 3B, z2, z4 and z5 are 0.
In the measurement of the periodic arrangement degree, when all the 200 spheres 12 to be measured for the deviation are in the positions of the theoretical regular periodic structure state, the periodic arrangement degree is 100%.

[Internal porosity]
Moreover, when the internal porosity of the sphere 12 in the display layer 10 according to the present invention is 10% or less, the obtained display member has a large reflected light intensity. The internal porosity of the sphere 12 in the display layer 10 is more preferably 5% or less.

The internal porosity of the display layer 10 is measured as follows.
That is, the display layer 10 is made of a cross section using a cryomicrotome, and two 50,000 times photographs of the cross section are taken using a scanning electron microscope “JSM-7410” (manufactured by JEOL Ltd.). Then, the area of the hollow portion other than the matrix M such as the spherical body 12 and the hollow portions x1 and x2 is calculated for each arbitrary 10 cm × 10 cm region in the two photographic images, and the following equation (2) is used. Calculated.
Formula (2): Internal porosity (%) = (Cavity area (cm ² ) / 100 (cm ² )) × 100

In the display layer 10, the absolute value of the difference between the refractive index of the sphere 12 and the refractive index of the matrix M (hereinafter referred to as “refractive index difference”) is preferably 0.02 to 2.0. Preferably it is 0.1-1.6.
If this difference in refractive index is less than 0.02, the structural color is difficult to develop, and if this difference in refractive index is greater than 2.0, the structural color may become cloudy due to large light scattering. There is.

[Structural color]
The structural color obtained in the display member of the present invention is not a color due to light absorption of a pigment or the like but a color expressed by selective light reflection due to a periodic structure or the like.

The light selectively reflected in the display layer 10 is light having a wavelength represented by the following formula (3) based on Bragg's law and Snell's law.
In addition, the following formula (3) and the following formula (4) are approximate formulas, and in practice, these calculated values may not completely match.
Formula (3): λ = 2 nD (cos θ)
In this formula (3), λ is the peak wavelength of the structural color, n is the refractive index of the display layer 10 represented by the following formula (4), D is the layer spacing of the sphere layer 15 (perpendicular direction of the display member of the sphere 12) ), Θ is an observation angle with respect to the normal of the display member.
Formula (4): n = {na · c} + {nb · (1-c)}
In this formula (4), na is the refractive index of the sphere 12, nb is the refractive index of the matrix M, and c is the volume ratio of the sphere 12 in the display layer 10.
Here, the peak wavelength λ of the structural color can be measured using “MCPD-3700” (manufactured by Otsuka Electronics Co., Ltd.) that can confirm the relationship between the reflection light source and the observation angle using a fiber.

  Although the thickness of the display layer 10 changes with uses, it can be 0.1-100 micrometers, for example.

The number of cycles of the spherical layer 15 in the display layer 10 needs to be at least 1 or more, preferably 5 to 500.
When the number of periods is less than 1, the display layer cannot exhibit a structural color.

  In the display member of the present invention, the display color based on the structural color is not limited to a color having a peak wavelength in the visible region, but may be a color having a peak wavelength in the ultraviolet region or the infrared region.

〔sphere〕
In the present invention, a sphere is a solid substance having a sphere shape in three dimensions, and is not limited to a true sphere, but may be approximately a sphere shape.
As a material for forming the sphere 12 constituting the display layer 10, a material having a refractive index different from that of the matrix M and a material incompatible with the filler forming the matrix M are appropriately used. Can be selected.
Moreover, it is preferable that the sphere 12 constituting the display layer 10 is made of a material having high affinity with the filler for forming the matrix M.

Various things can be mentioned as the spherical body 12 constituting the display layer 10.
Specifically, for example, styrene monomers such as styrene, methylstyrene, methoxystyrene, butylstyrene, phenylstyrene, chlorostyrene; methyl acrylate, ethyl acrylate, (iso) propyl acrylate, butyl acrylate, acrylic Acrylic acid ester or methacrylic acid ester monomer such as hexyl acid, octyl acrylate, ethyl hexyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, ethyl hexyl methacrylate; acrylic acid, methacrylic acid, itaconic acid, fumarate The particle | grains which superposed | polymerized 1 type in polymerizable monomers, such as carboxylic acid monomers, such as an acid, or the organic particle which copolymerized 2 or more types can be mentioned.
Alternatively, organic particles obtained by adding a crosslinkable monomer to a polymerizable monomer and polymerizing may be used. Examples of the crosslinkable monomer include divinylbenzene, ethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, and trimethylol. Examples thereof include propane trimethacrylate.
Examples thereof include inorganic oxides and composite oxides such as silica, titanium oxide, aluminum oxide, copper oxide, barium sulfate, and ferric oxide, and inorganic particles formed of glass, ceramics, and the like.
Further, for example, core-shell type particles in which the above organic particles or inorganic particles are used as core particles, and a shell layer made of a material different from the material constituting the core particles is formed on the surface thereof. The shell layer can be formed using metal fine particles, metal oxide fine particles made of titania, metal oxide nanosheets made of titania, or the like.
Further examples include hollow particles obtained by removing the core particles from the core-shell particles by a method such as firing or extraction.

The average particle diameter of the sphere 12 needs to be set in relation to the refractive index of the sphere 12 and the refractive index of the matrix M, and at least preferably has a size that makes the dispersion into a stable colloidal solution. For example, it is preferable that it is 50-500 nm.
When the average particle diameter of the spheres 12 is in the above range, the dispersion liquid can be made into a stable colloid solution, and the structural color expressed in the obtained display member is in the near ultraviolet to visible to near infrared region. The color has a peak wavelength.
On the other hand, when the average particle size of the sphere is less than 50 nm, the visible structural color may be light, and when the average particle size of the sphere is larger than 500 nm, light scattering is greatly generated. As a result, the degree of expression of the structural color is small, and as a result, it may become white turbid and difficult to recognize the structural color.

The CV value representing the particle size distribution is preferably 20 or less, more preferably 10 or less, and particularly preferably 5 or less.
When the CV value is larger than 20, the display member obtained as a result of the large disturbance of the spherical layers to be regularly arranged has a small degree of expression of the structural color. May be difficult to recognize.
The average particle size was obtained by taking two 50,000 times photographs of the sphere 12 using a scanning electron microscope “JSM-7410” (manufactured by JEOL Ltd.), and 100 spheres 12 in the two photographic images. For each, the maximum length is measured and the number average value is calculated. Here, the “maximum length” refers to the maximum distance between two points by any two points on the circumference of the sphere 12.
When the sphere 12 is photographed as an aggregate, the maximum length of primary particles (sphere) forming the aggregate is measured.
The CV value is calculated from the following formula (CV) using the standard deviation in the number-based particle size distribution and the above average particle size value.
Formula (CV): CV value = ((standard deviation) / (average particle diameter)) × 100

The refractive index of the sphere 12 can be measured by various known methods, and the refractive index of the sphere 12 in the present invention is a value measured by an immersion method.
Specific examples of the refractive index of the sphere 12 include, for example, 1.59 for polystyrene, 1.49 for polymethyl methacrylate, 1.60 for polyester, 1.40 for fluorine-modified polymethyl methacrylate, and polystyrene / butadiene. Polymerization 1.56, polymethyl acrylate 1.48, polybutyl acrylate 1.47, silica 1.45, titanium oxide (anatase type) 2.52, titanium oxide (rutile type) 2. 76, copper oxide is 2.71, aluminum oxide is 1.76, barium sulfate is 1.64, and ferric oxide is 3.08.

  The spheres 12 constituting the sphere layer 15 may be a single composition or a single composition, but may have a substance that adheres the spheres to the surface of the spheres, or In addition, a substance for bonding spheres may be introduced into the sphere. By using such an adhesive substance, the spheres can be bonded to each other even if the spheres are made of a substance that hardly causes self-alignment when the sphere layer 15 is formed. Further, when the sphere is formed of a material having a high refractive index, a low refractive index substance may be internally added.

The spheres 12 constituting the display layer 10 are preferably highly monodispersed because they are easily arranged regularly when the display layer 10 is formed.
In order to obtain a highly monodispersed sphere, when the sphere 12 is a particle made of an organic substance, the sphere 12 is a polymerization method such as a commonly used soap-free emulsion polymerization method, suspension polymerization method, emulsion polymerization method or the like. It is preferable to obtain by.

  The particles 12 may be subjected to various surface treatments in order to increase the affinity with the matrix M.

〔matrix〕
The matrix M constituting the display layer 10 is solid, and the filler to form the matrix M is liquid in the process of adding to the periodic structure 16 in the manufacturing process, such as heat and light. Those that can be solidified by applying the energy of are used.
As the matrix M constituting the display layer 10, a material having a refractive index different from that of the sphere 12 and incompatible with the material constituting the sphere 12 can be appropriately selected.
Moreover, as a filler which should form the matrix M, a material with high affinity with the spherical body 12 is preferable.

Examples of the filler to form the matrix M include a solution in which a resin soluble in an organic solvent is dissolved in the organic solvent, an aqueous solution in which a resin soluble in water is dissolved in water, hydrogel, oil gel, light Examples thereof include a curing agent, a heat curing agent, and a moisture curing agent.
Specific examples of resins that are soluble in organic solvents include polystyrene resins, acrylic resins, and polyester resins. Examples of resins that are soluble in water include polyacrylic acid, polyvinyl alcohol, and polyvinyl chloride. Is mentioned.
Specific examples of hydrogels include gels obtained by mixing gelatin, carrageenan, polyacrylic acid, sodium polyacrylate and other gelling agents with water, and oil gels include silicone gels and fluorine-based silicone gels. And gels obtained by mixing gelling agents such as amino acid derivatives, cyclohexane derivatives and polysiloxane derivatives with silicone oil and organic solvents.

The refractive index of the matrix M can be measured by various known methods. The refractive index of the matrix M in the present invention is a thin film made of only the matrix M, and this thin film is used as an Abbe refractometer. Measured value.
Specific examples of the refractive index of the matrix include 1.41 for silicone gel, 1.53 for gelatin / gum arabic, 1.51 for polyvinyl alcohol, 1.51 for sodium polyacrylate, and fluorine-modified acrylic resin. 1.34, N-isopropylamide is 1.51, and foamed acrylic resin is 1.43.

[Method for producing display layer]
Such a display layer 10 forms a layer of a dispersion liquid (sphere dispersion liquid) in which the sphere 12 is dispersed in a liquid incompatible with the material constituting the sphere 12, and the layer is allowed to stand or be dried. The spherical bodies 12 are self-aligned to form the periodic structure 16, and when the liquid content in the layer containing the periodic structure 16 becomes 5 to 20%, the liquid filler is added to the periodic structure 16. Is added to the spheres 12 without gaps, and the filler M is solidified to form a matrix M.
As the liquid for obtaining the sphere dispersion liquid, an aqueous solvent having low solubility is preferable.
Here, the “aqueous medium” refers to a medium composed of 50 to 100% by mass of water and 0 to 50% by mass of a water-soluble organic solvent. Examples of the water-soluble organic solvent include methanol, ethanol, isopropanol, butanol, acetone, methyl ethyl ketone, and tetrahydrofuran, and alcohol-based organic solvents are preferable because they do not dissolve the resin.

In the manufacturing process of the display layer 10, the periodic arrangement degree of the spheres 12 is 90% or more by adding a filler when the liquid content in the layer containing the periodic structure 16 becomes 5 to 20%. And the display layer 10 whose internal porosity is 10% or less can be obtained.
The reason is estimated as follows.

That is, in the process of forming a layer of the sphere 12 by the sphere dispersion liquid, and then allowing it to stand or dry, first, the sphere 12 in the sphere dispersion liquid self-aligns to an electrostatically stable position, and further moisture evaporates. As the water content between the spheres 12 rearranges to a more stable position by liquid-crosslinking between the spheres 12 as the liquid content increases, the liquid content in the layer containing the periodic structure 16 becomes 5 to 20%. That is, the time when this liquid crosslinking force is acting. At this time, the filler is added, so that the state of introduction between the spheres 12 is good, but the filler is removed from the spheres 12 without causing a large disturbance in the arrangement of the spheres 12 due to the action of the liquid crosslinking force. It can be introduced in between.
On the other hand, when the filler is added at the time when the drying is not progressing so much and the liquid content in the layer containing the periodic structure 16 is excessive, the action of the liquid crosslinking force between the spheres 12 is weak, The addition of the agent disturbs the arrangement of the spheres 12 and the desired periodic arrangement degree cannot be obtained, and as a result, the obtained display member has a broad wavelength peak for the expression of the structural color in the reflection spectrum. .
Further, when the filler is added when the drying progresses and the liquid content in the layer containing the periodic structure 16 is too low or the water is completely evaporated, the state of introduction of the filler between the spheres 12 is As a result, the desired internal porosity cannot be obtained, and as a result, the obtained display member does not have a large reflected light intensity.

  The liquid content in the layer containing the periodic structure 16 can be obtained from the initial concentration of the sphere dispersion of the sphere 12, the area where the sphere dispersion is applied, and the mass change. In addition, because it is easy to manage the manufacturing process, it is easy to obtain the correlation between the liquid content in the layer and the optical properties such as visible absorption and reflection intensity, and to determine the addition point of the filler while performing the optical measurement. ,preferable.

The layer made of the spherical dispersion can be formed as a coating layer by applying the dispersion on an appropriate substrate, for example. Alternatively, the spherical dispersion liquid can be introduced into a cell having a planar narrow gap.
In addition, the planar narrow gap | interval should just be a gap | interval which has the distance with which a spherical dispersion is filled by capillary action, for example, it is preferable that the distance is 0.1-100 micrometers.

In the case of forming the sphere dispersion layer by coating on the substrate, the sphere 12 sphere dispersion may be applied by a bar coating method, screen coating method, dip coating method, spin coating coating method, curtain coating method, LB ( For example, a Langmuir-Blodgett film forming method can be used.
Moreover, as a material of a board | substrate, what was mentioned as a material of the following board | substrate 13 can be mentioned.

In the case of forming a layer of sphere dispersion using a cell, the cell may be one in which the left side and the right side are closed and the upper side and the lower side are opened in a state where two opposing substrates are stacked. The sphere dispersion liquid can be introduced by such a cell by utilizing capillary action, for example, by immersing the lower side of the cell in a container containing the sphere dispersion liquid.
Moreover, as a material of a cell, what was mentioned as a material of the following board | substrate 13 can be mentioned.

[Display material]
The display member of the present invention has a configuration in which the display layer 10 as described above is laminated on a layer or substrate of a color that absorbs light as desired, such as black or gray, in order to obtain more color display effects. It is preferable. Specifically, for example, as shown in FIG. 1, it can be configured as a sheet having a display layer 10 laminated on a substrate 13. For example, in the case where a layer made of a sphere dispersion according to the method for manufacturing the display layer 10 is formed by coating, the substrate 13 on which the coating layer is formed may be used as it is as a substrate in the display member.

As the substrate 13, for example, glass, ceramics, polyethylene terephthalate (PET), polyethylene naphthalate (PEN) film or sheet can be used.
In addition, since the display layer 10 is manufactured using the sphere dispersion liquid of the spheres 12, the substrate 13 preferably has a surface contact angle with water that is somewhat low. Moreover, since the thing with high surface smoothness is preferable, you may perform an appropriate surface treatment about the board | substrate 13. FIG. Moreover, it can be used in a state where the spheres are easily attached by performing blasting or the like.

In addition, the display member can be configured such that the display layer 10 is formed on the substrate 13 and a surface coating layer is provided on the display layer 10 via an adhesive layer.
In such a display member, the substrate 13, the adhesive layer, and the surface coating layer are provided as necessary depending on the use and the like, and a configuration in which a label adhesive layer is provided on the back surface of the substrate 13. Also good.
When providing a surface coating layer, as the surface coating layer, a film made of polyethylene terephthalate (PET), polyethylene naphthalate (PEN), or the like that is highly transparent and does not hinder the visual recognition of the structural color expressed in the display layer 10; A film made of a UV curable resin or the like can be used.
When used as a label, an adhesive pressure-sensitive adhesive such as an acrylic pressure-sensitive adhesive or an acrylic / olefin copolymer pressure-sensitive adhesive can be used as the pressure-sensitive adhesive layer for a label.

  According to the display member as described above, the internal porosity, which is a ratio of the hollow region in which neither the sphere nor the matrix exists, and the degree of periodic arrangement indicating the degree of displacement of the position from the regular periodic structure state is extremely high. Is extremely low, the wavelength peak of expression of the structural color in the reflection spectrum is sharp, the display color has no color turbidity, and a sufficiently high color purity is obtained, while a large reflected light intensity is obtained and the display color is sufficiently high Color density can be obtained.

  Although the embodiments of the present invention have been specifically described above, the embodiments of the present invention are not limited to the above examples, and various modifications can be made.

Hereinafter, specific examples of the present invention will be described, but the present invention is not limited thereto. In the following, the average particle diameter, CV value, and refractive index were measured by the same method as described above.
In the following, the transmission spectrum is measured with a spectrophotometer “U-4100” (manufactured by Hitachi, Ltd.), and the reflection spectrum is measured with a spectrocolorimeter “CM-3600d” (manufactured by Konica Minolta Sensing). The reflectance and ¼ value width were measured from this reflection spectrum. Note that the ¼ value width is the peak width when the reflectance of the base portion other than the peak portion in the reflection spectrum is 0, the highest reflectance of the peak portion is 100, and the reflectance is 25.

[Particle Synthesis Example 1]
A monomer solution was prepared by heating 71 parts by mass of styrene, 20 parts by mass of n-butyl acrylate, and 9 parts by mass of methacrylic acid to 80 ° C. On the other hand, a surfactant solution in which 0.2 parts by mass of sodium dodecyl sulfonate was dissolved in 263 parts by mass of ion-exchanged water was heated to 80 ° C., and this surfactant solution and the above monomer mixture were mixed. Then, an emulsified dispersion was prepared by carrying out a dispersion treatment for 30 minutes using a mechanical disperser “CLEARMIX” (manufactured by M Technique Co., Ltd.).
The emulsified dispersion and 0.1 parts by weight of sodium dodecyl sulfonate were dissolved in 142 parts by weight of ion-exchanged water in a reaction vessel equipped with a stirrer, a heating / cooling device, a nitrogen introduction device, and a raw material / auxiliary charging device. The surfactant solution was charged, and the internal temperature was raised to 80 ° C. while stirring at a stirring speed of 200 rpm under a nitrogen stream. To this solution, 1.4 parts by mass of potassium persulfate and 54 parts by mass of water were added, and a dispersion of fine particles was obtained by performing polymerization for 3 hours, and this was separated into large / small particles by a centrifuge, A dispersion of highly spherical fine sphere particles (hereinafter referred to as “spherical dispersion”) [1] was obtained. The sphere [1] in the sphere dispersion [1] had an average particle size of 250 nm, a CV value of 2.8, and a refractive index of 1.55.

[Particle Synthesis Example 2]
A monomer solution was prepared by heating 71 parts by mass of styrene, 20 parts by mass of n-butyl acrylate, and 9 parts by mass of methacrylic acid to 80 ° C. On the other hand, a surfactant solution in which 0.4 parts by mass of sodium dodecyl sulfonate was dissolved in 263 parts by mass of ion-exchanged water was heated to 80 ° C., and this surfactant solution and the above monomer mixture were mixed. Then, an emulsified dispersion was prepared by carrying out a dispersion treatment for 30 minutes using a mechanical disperser “CLEARMIX” (manufactured by M Technique Co., Ltd.).
The emulsified dispersion and 0.1 parts by weight of sodium dodecyl sulfonate were dissolved in 142 parts by weight of ion-exchanged water in a reaction vessel equipped with a stirrer, a heating / cooling device, a nitrogen introduction device, and a raw material / auxiliary charging device. The surfactant solution was charged, and the internal temperature was raised to 80 ° C. while stirring at a stirring speed of 200 rpm under a nitrogen stream. To this solution, 1.4 parts by mass of potassium persulfate and 54 parts by mass of water were added, and a dispersion of fine particles was obtained by performing polymerization for 3 hours, and this was separated into large / small particles by a centrifuge, A highly monodispersed spherical dispersion [2] was obtained. The sphere [2] in the sphere dispersion [2] had an average particle size of 205 nm, a CV value of 2.3, and a refractive index of 1.55.

<Example 1>
A double-sided tape having a thickness of 10 μm was applied to the two opposite sides of the cleaned glass plate, and another glass plate having been cleaned was stacked and bonded with the double-sided tape, thereby producing a glass cell having a gap of 10 μm in thickness. The glass cell was placed almost vertically in a beaker containing the sphere dispersion [1], and the sphere dispersion [1] was filled into the glass cell by capillary action. From this state, it was dried from above, and the particles were arranged in a glass cell, and allowed to stand until a red structural color appeared and a periodic structure was formed. The glass cell in which a red structural color appeared was taken out from the beaker containing the spherical dispersion [1], and the liquid content in the glass cell was measured and found to be 28%. When this glass cell was further dried and the liquid content reached 15%, one glass plate was peeled off and the other glass plate was placed horizontally with the surface on which the periodic structure was formed facing upward. The silicone gel “SE1891H” (manufactured by Bundle Dow Corning) was dropped, and after removing the excess silicone gel on the upper part of the periodic structure, it was cured at 55 ° C. for 1 hour, whereby a display layer [ Display member [1] on which 1] was formed was produced.
When the transmittance (transmission spectrum) with respect to the wavelength of the display member [1] was measured, as shown by the line [1] in FIG. 4, the transmittance of the wavelength peak related to the expression of the structural color and the wavelength peak other than the wavelength peak. It was confirmed that the difference from the transmittance in the wavelength range was large and the wavelength peak was sharp, that is, its half width was narrow.
Moreover, when a black polyethylene terephthalate (PET) sheet was covered on the display layer [1] and the reflectance (reflection spectrum) with respect to the wavelength was measured from the glass plate side, as indicated by the line [1] in FIG. It was confirmed that the reflectance of the wavelength peak related to the expression of the structural color is high and the wavelength peak is sharp (its ¼ value width is narrow). The results are shown in Table 1.
If the reflectance is 55% or more, it is determined that the display color has a sufficiently high color density, and if the ¼ value width is 45 nm or less, it is determined that the display color has no color turbidity and high color purity. Is done. The same applies to the following examples and comparative examples.

<Example 2>
Display member [2] was produced in the same manner as in Example 1 except that the silicone gel was dropped when the liquid content in the glass cell reached 7%. For the display member [2], the transmission spectrum and the reflection spectrum were measured in the same manner as in Example 1. The results are shown in FIGS. 4 and 5 and Table 1. In addition, the result which concerns on the said Example 2 was shown by the line [2] in FIG.4 and FIG.5.

<Example 3>
In Example 1, the sphere dispersion [2] was used instead of the sphere dispersion [1], and the silicone gel was further dropped when the liquid content in the glass cell reached 20%. In the same manner, a display member [3] was produced. With respect to this display member [3], the reflection spectrum was measured in the same manner as in Example 1. The results are shown in Table 1.

<Example 4>
The spherical dispersion [1] was applied to the cleaned glass plate using a bar coater. Silicone gel “SE1891H” (manufactured by Dow Corning Toray) was dropped when the liquid content of the periodic structure by the coating layer reached 15% while controlling the coating surface so that moisture could be removed uniformly. After removing the excess silicone gel on the upper part of the periodic structure, the display member [4] having the display layer [4] formed on the glass plate was produced by curing at 55 ° C. for 1 hour.
When the transmission spectrum of this display member [4] was measured, the difference between the transmittance of the wavelength peak related to the expression of the structural color and the transmittance in the wavelength range other than the wavelength peak was large, and the wavelength peak was sharp (that It was confirmed that the half width was narrow.
Further, when the reflection spectrum of this display member [4] was measured in the same manner as in Example 1, the reflectance of the wavelength peak related to the expression of the structural color was high and the wavelength peak was sharp (1 / It was confirmed that the quaternary width was narrow. The results are shown in Table 1.

<Example 5>
Display member [5] was produced in the same manner as in Example 4 except that the silicone gel was dropped when the liquid content in the glass cell reached 5%.
When the reflection spectrum of this display member [5] was measured in the same manner as in Example 1, the reflectance of the wavelength peak related to the expression of the structural color was high and the wavelength peak was sharp (the ¼ value width thereof). Is narrow). The results are shown in Table 1.

<Comparative Example 1>
Display member [6] was produced in the same manner as in Example 1 except that the silicone gel was dropped when the liquid content in the glass cell reached 1%.
When the transmission spectrum of this display member [6] was measured, as indicated by the line [6] in FIG. 4, the transmittance of the wavelength peak related to the expression of the structural color and the transmittance in the wavelength range other than the wavelength peak It turned out that the difference of was small.
Further, when the reflection spectrum of this display member [6] was measured in the same manner as in Example 1, the reflectance of the wavelength peak related to the expression of the structural color was as shown by the line [6] in FIG. It turned out to be low. The results are shown in Table 1.
Furthermore, when this display member [6] was observed at an angle, it appeared quite cloudy.

<Comparative example 2>
Display member [7] was produced in the same manner as in Example 1, except that the silicone gel was dropped when the liquid content in the glass cell reached 28%.
When the transmission spectrum of the display member [7] was measured, as shown by the line [7] in FIG. 4, the transmittance of the wavelength peak related to the expression of the structural color and the transmittance in the wavelength range other than the wavelength peak It was found that the wavelength peak is broad, that is, its half width is wide.
Further, when the reflection spectrum of this display member [7] was measured in the same manner as in Example 1, the wavelength peak of the expression of the structural color was broad as shown by the line [7] in FIG. The quarter value range is wide). The results are shown in Table 1.
Further, when the display member [7] was observed at an angle, the color looked quite light.

<Comparative Example 3>
Display member [8] was produced in the same manner as in Example 4 except that the silicone gel was dropped when the liquid content in the glass cell reached 80%.
When the reflection spectrum of this display member [8] was measured in the same manner as in Example 1, it was confirmed that the reflectance of the wavelength peak related to the expression of the structural color was extremely low. The results are shown in Table 1.
Furthermore, when this display member [8] was observed at an angle, it appeared quite cloudy.

  The display member of the present invention can be used as a sensor, display, panel, sheet, label or the like.

It is sectional drawing for description which shows an example of a structure of the display member of this invention typically. It is a schematic diagram for demonstrating the array state of the sphere which concerns on the display member of this invention. It is a schematic diagram for demonstrating the array state of the sphere which concerns on another example of the display member of this invention. It is a graph which shows the transmission spectrum which concerns on the Example and comparative example of this invention. It is a graph which shows the reflection spectrum which concerns on the Example and comparative example of this invention.

Explanation of symbols

10 Display layer 12 Sphere 13 Substrate 15 Sphere layer 16 Periodic structure D Layer spacing M Matrix

Claims (3)

A layer made of a dispersion in which spheres are dispersed in a liquid is formed, the layer is allowed to stand or dry, and when the liquid content in the layer becomes 5 to 20%, a liquid filler is applied to the layer. And through a step of forming a matrix by solidifying the filler,
A display member manufacturing method characterized by obtaining a display member having a display layer made of a sphere and a matrix , which has a regular periodic structure state with a periodic arrangement degree of 90% or more , which expresses a structural color.   The method for manufacturing a display member according to claim 1, wherein the layer formed by dispersing the spheres in a liquid is a coating layer formed by applying the dispersion on a substrate. 2. The display according to claim 1, wherein the layer made of the dispersion liquid in which the spheres are dispersed in a liquid is a layer formed by introducing the dispersion liquid into a cell having a planar narrow gap. Manufacturing method of member.