JP2004093897A - Sheet type display device and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sheet type display device which has superior contrast and high visibility. <P>SOLUTION: In the device, in which display is conducted by rotating rotary particles, the packing ratio of the rotary particles under a prescribed condition is set to 40 volume % to less than 65 volume % and the ratio between the rotary particles located up to a prescribed depth and the total rotary particles is set to a prescribed ratio. <P>COPYRIGHT: (C)2004,JPO

Description

【００７４】
これらの結果より本発明に係るシート型表示装置ではコントラスト１０：１以上の表示が行え、高い視認性を得られるようになることが理解できる。
【００７５】
［実施例２］
表１の番号１のケースにおいて、樹脂中に磁性材料を混合し、磁性材料を含有した回転粒子を作製すれば、さらに容易に２色粒子をうまくシートの下面に沈ませることができる。すなわち、図７に示すように、硬化前のシートの下に磁石を設置する等により、回転粒子を磁力で整列させるとともに、うまく下面に沈ませることができる。上記希釈方法と併用してもよい。
【００７６】
［実施例３］
予めシリコーンゴムＫＥ１０９よりなる平均４μｍ厚のシートを作製し、この上に１２０μｍ厚のブレードを用いて塗布し、シート状に成形した以外は、表１の番号１のケースと同様にした。
【００７７】
表１の番号１のケースでは、シートの下面に接してしまったため、透光性液体を充填した空隙をその周囲に形成できなかった回転粒子が、１ｃｍ^２当たり１０００個以上見出されたが、実施例３ではこのようなケースは完全に防止できた。この方法は、実施例２の場合にも適用できる。
【００７８】
なお、上記に開示した内容から、下記の付記に示した発明が導き出せる。
【００７９】
（付記１）　色の異なる少なくとも２つの表面領域を有する回転粒子とそのまわりにある透光性液体を充填した空隙とこの空隙を分散させた基材とを含んだシート中で、回転粒子を回転させることにより表示を行うシート型表示装置において、
シートの表示面から回転粒子の平均粒子直径の１．５倍の深さまでの領域において、その全体が当該領域に含まれる回転粒子の当該領域における充填率が、透光性液体を充填した空隙を考慮しない場合に、４０体積％以上６５体積％未満であり、
シートの表示面から回転粒子の平均粒子直径の２倍の深さまでにその全体が含まれる回転粒子が、全回転粒子の７０体積％以上である、
シート型表示装置。
【００８０】
（付記２）　シートの表示面から回転粒子の平均粒子直径の３倍の深さまでにその全体が含まれる回転粒子が、全回転粒子の９０体積％以上である、付記１に記載のシート型表示装置。
【００８１】
（付記３）　前記シートの表示面に回転粒子および透光性液体を充填した空隙を含まない基材の層が存在する、付記１または２に記載のシート型表示装置。
【００８２】
（付記４）　前記シートの表示面に、回転粒子および透光性液体を充填した空隙を含まない、厚さが１〜２０μｍの範囲にある基材の層が存在する、付記１または２に記載のシート型表示装置。
【００８３】
（付記５）　色の異なる少なくとも２つの表面領域を有する回転粒子を硬化性の基材中に分散した分散体を成形してシートとなす第１のステップと、
その後当該基材を硬化させる第２のステップと、
その後、当該シートを透光性液体で膨潤し、当該回転粒子とそのまわりにある透光性液体を充填した空隙とこの空隙を分散させた硬化済み基材とを含んだシートを形成する第３のステップと
を含むシート型表示装置の製造方法において、
第１のステップで、当該硬化性の基材に希釈用溶媒を加えて当該粒子の体積割合を５０体積％以下にした分散体を成形してシートとなし、
第１のステップと第２のステップとの間に、当該シートを所定時間放置し、ついで当該希釈用溶媒を除去する
シート型表示装置の製造方法。
【００８４】
（付記６）　色の異なる少なくとも２つの表面領域を有する回転粒子を硬化性の基材中に分散した分散体を成形してシートとなす第１のステップと、
その後当該基材を硬化させる第２のステップと、
その後、当該シートを透光性液体で膨潤し、当該回転粒子とそのまわりにある透光性液体を充填した空隙とこの空隙を分散させた硬化済み基材とを含んだシートを形成する第３のステップと
を含むシート型表示装置の製造方法において、
第１のステップで、当該硬化性の基材に希釈用溶媒を加えて、当該基材と当該希釈用溶媒とよりなる分散媒の比重が当該回転粒子の比重よりも小さく、当該分散媒中における当該粒子の体積割合が５０体積％以下になるようにし、
第１のステップと第２のステップとの間に、当該シートを所定時間放置し、ついで当該希釈用溶媒を除去する
シート型表示装置の製造方法。
【００８５】
（付記７）　前記希釈用溶媒として、常圧において、回転粒子の軟化点温度以下で蒸発する溶媒を使用する、付記５または６に記載のシート型表示装置の製造方法。
【００８６】
（付記８）　前記回転粒子に磁性材料を含有させ、
前記第１のステップと第２のステップとの間に、当該回転粒子を磁力で整列させる、付記５〜７のいずれかに記載のシート型表示装置の製造方法。
【００８７】
（付記９）　回転粒子および透光性液体を充填した空隙を含まない基材よりなる層の上に前記シートを成形する付記５〜８のいずれかに記載のシート型表示装置の製造方法。
【００８８】
（付記１０）　前記回転粒子および透光性液体を充填した空隙を含まない基材よりなる層の厚さが１〜２０μｍの範囲にあるようにする付記９に記載のシート型表示装置の製造方法。
【００８９】
【発明の効果】
本発明により、コントラストに優れ、高い視認性を与えるシート型表示装置が提供できる。
【図面の簡単な説明】
【図１】２色粒子を用いたシート型表示媒体の模式断面図である。
【図２】電界の印加により回転する粒子の様子を示すモデル図である。（ａ）は電界印加前、（ｂ）は電界印加中、（ｃ）は電圧印加後である。
【図３】充填率測定のためのサンプルシートを表すモデル図である。
【図４】図３のＡ方向断面図である。
【図５】回転粒子が、基材と希釈用溶媒との混合物中で分散している様子を示すモデル図である。
【図６】シート中で回転粒子が底部に沈積する様子を表すモデル図である。
【図７】シートの表示面に回転粒子および透光性液体を充填した空隙を含まない基材の層を持つシート型表示装置において、回転粒子が、磁力の作用で配列させられる様子を示すモデル図である。
【符号の説明】
１　　２色粒子
２　　透光性液体（空隙）
３　　シート用基材
４　　電極
４’　透明電極
５　　電源
６　　面状磁石
７　　回転粒子および透光性液体を充填した空隙を含まない基材の層[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a rotating particle having at least two different color surface areas, and a sheet-type display device that performs display by rotating the rotating particle.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a sheet-shaped display medium and a sheet-type display device, which are called an electronic paper, a paper-like display, a digital paper, or the like, and perform image display by changing optical absorption or optical reflection by an electric field, have been proposed.
[0003]
As an element for changing optical absorption or optical reflection by an electric field, a solvent in which electrophoretic particles are dispersed as described in JP-A-01-086116 is colored, and a microcapsule containing the solvent is disclosed in JP-A-8-08116. As disclosed in Japanese Patent No. 234686, there is a liquid crystal / polymer composite film containing a dichroic dye and a smectic liquid crystal, including a microcapsule containing a rotating body composed of hemispheres having different colors and electric characteristics.
[0004]
In these methods, since the reflective display device has a memory property and can hold image information without a power supply, it is expected as a substitute for paper. In addition, since it is only necessary to apply the element on a PET film having electrodes, the element can be thin, light, and bendable.
[0005]
In particular, the display media described in U.S. Pat. Nos. 4,126,854 and 4,143,103 which use hemispheres of rotating particles divided into different colors and charging characteristics are disclosed. , Is known as a display exhibiting excellent contrast characteristics as compared with other methods.
[0006]
FIG. 1 shows a state in which two-color particles as rotating particles 1 in such a display medium are held in gaps 2 in a sheet substrate 3. Two regions on the two-color particles represent different colors from each other. FIG. 1 can also be used to modelly describe the display function of a sheet-type display device as a display medium according to the present invention.
[0007]
FIG. 2 shows a state in which the rotating particles 1 of FIG. 1 rotate while migrating upward in the gap 2. (A) shows before rotation, (b) shows during rotation, and (c) shows when rotation is completed.
[0008]
In addition, there has been proposed a particle corresponding to multicoloring in which particles are applied in four colors or three colors.
[0009]
In the present invention, the term “rotation” includes the case where there is an electrophoretic operation accompanying such rotation.
[0010]
The method and material for producing such rotating particles include (1) two kinds of melted wax particles having different colors using carnauba wax, carbon black, and titanium oxide as described in US Pat. No. 5,262,908. (2) a method of forming a sphere by surface tension and then solidifying; (2) a method of forming a metal on the surface of glass or resin light-transmitting particles described in JP-A-11-85067 and JP-A-11-85068. , Carbon black, antimony sulfide and the like, and (3) a photosensitive material described in JP-A-11-85069 and JP-A-11-161206, wherein zinc oxide is used as a material and toner is used as a color former. Using exposure / development / fixing treatment using particles consisting of, for example, silver halide as a color former on a hydrophilic polymer Such as those that were added have been proposed.
[0011]
The sheet holding the rotating particles in the gap can be produced, for example, as follows.
[0012]
That is, the rotating particles are thoroughly mixed and dispersed with the curable liquid silicone rubber. The dispersion is formed into a sheet and then the silicone rubber is cured and cross-linked. When this sheet of rotating particle-dispersed silicone rubber is immersed in a translucent dielectric liquid and left for an appropriate time, the translucent liquid penetrates into the silicone rubber and the silicone rubber swells. On the other hand, the rotating particles do not absorb the light-transmitting liquid or absorb very slowly, so that voids are formed around the rotating particles, and the voids are filled with the light-transmitting liquid.
[0013]
It is to be noted that a gap can be formed in advance by another method such as mechanical processing of an optically transparent base material, and a method of enclosing the rotating particles and the translucent liquid can be used. The optically transparent substrate need not be an elastomer such as silicone rubber, but may be a hard resin such as polyethylene or polystyrene, or silicate glass.
[0014]
[Problems to be solved by the invention]
When display is performed using the sheet-like device manufactured by the above-described method, there remains a problem that it is difficult to express colors showing desired reflectance and absorptivity and high contrast. This is because not all portions of the display surface can be used for the display by the rotating particles because there is a gap filled with the base material or the translucent liquid in the gap between the spheres.
[0015]
Therefore, in order to obtain high contrast, it is conceivable to increase the abundance ratio of the rotating particles on the display surface by performing the closest packing of the rotating particles for one layer and arranging them. However, when such a filling of the rotating particles is performed, the dispersion in which the rotating particles are dispersed in the base material has a high viscosity, and it is difficult to form a sheet. Problems such as the inability to exhibit the function of
[0016]
An object of the present invention is to provide a technique capable of expressing a color showing a desired reflectance or absorptance and expressing a high contrast without causing such a problem.
[0017]
Still other objects and advantages of the present invention will become apparent from the following description.
[0018]
[Means for Solving the Problems]
According to one embodiment of the present invention, in a sheet including a rotating particle having at least two surface regions of different colors, a void surrounding the rotating particle, and a base material having the void dispersed therein, In a sheet-type display device that performs display by rotating the rotating particles, in a region from the display surface of the sheet to a depth of 1.5 times the average particle diameter of the rotating particles, the entire rotating particles are included in the region. Is not less than 40% by volume and less than 65% by volume when the gap filled with the translucent liquid is not taken into account, and from the display surface of the sheet to a depth of twice the average particle diameter of the rotating particles. In addition, the present invention provides a sheet-type display device in which the total amount of the rotating particles is 70% by volume or more of the total rotating particles.
[0019]
According to another aspect of the present invention, a first step of forming a sheet by forming a dispersion in which rotating particles having at least two different surface regions of different colors are dispersed in a curable substrate, Then, a second step of curing the base material, and thereafter, the sheet is swollen with a translucent liquid, and the rotating particles and the surrounding space filled with the translucent liquid and the curing in which the voids are dispersed. And a third step of forming a sheet containing a finished substrate. In the first step, a diluting solvent is added to the curable substrate to form a sheet. And the specific gravity of the dispersion medium composed of the solvent for dilution is smaller than the specific gravity of the rotating particles, and the volume ratio of the particles in the dispersion medium is 50% by volume or less. Between the steps It was left for a predetermined time, and then the production method of the sheet-type display device for removing the diluting solvent is provided.
[0020]
The rotating particles including the entire rotating particles from the display surface of the sheet to the depth of three times the average particle diameter of the rotating particles account for 90% by volume or more of the total rotating particles, It is preferable that a layer of the base material having a thickness in the range of 1 to 20 μm, which does not include voids filled with the particles and the translucent liquid, be present.
[0021]
Further, it is preferable that the rotating particles contain a magnetic material, and the rotating particles are aligned by magnetic force between the first step and the second step.
[0022]
According to these aspects, it is possible to realize a sheet-type display device which is excellent in contrast and provides high visibility.
[0023]
In addition, further features of the present invention will be clarified in the embodiments and drawings of the invention described below.
[0024]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to drawings, tables, examples, and the like, focusing on the case where black and white two-color particles are used as rotating particles and held in a sheet-like base material. However, these drawings, tables, examples, and the like, and the description are only illustrative of the present invention, and do not limit the scope of the present invention. It goes without saying that other embodiments can also belong to the category of the present invention as long as they conform to the gist of the present invention.
[0025]
The display medium of the present invention using the rotating particles having at least two surface regions having different colors (also simply referred to as two-color particles) is a particle 1 having a colored layer formed as shown in FIG. The display medium is composed of a sheet substrate 3 rotatably supporting the color particles, and a gap 2 dispersed in the sheet substrate 3 so that the two-color particles can rotate freely. And a driving unit including a power supply 5 and electrodes 4 and 4 ′ for rotating the device based on a difference in electrical characteristics such as charging characteristics between regions of different colors to display a desired colored layer side. Constitutes a sheet-type display device. Although only one layer of rotating particles is shown in FIG. 1, this is merely a simplified illustration of the detailed state and does not limit the scope of the invention in any way.
[0026]
The space 2 is filled with a translucent liquid. The two-color particles may be produced by uniting colored resins or waxes to form a sphere, or may be produced by providing spherical core particles with semi-circular coat layers of different colors. In such a configuration, different hues are realized by using the difference between the color of reflected light and the reflection intensity in the colored layer.
[0027]
For the colored resin or wax, as the resin, use polystyrene, polyacryl, polyethylene, polypropylene, polyester, etc., as the wax, stearic acid, palmitic acid, myristic acid, higher fatty acids such as lauric acid, aluminum stearate, Metal salts of higher fatty acids such as potassium stearate and zinc palmitate, derivatives of higher fatty acids such as hydrogenated castor oil, cocoa butter, methylhydroxystearate, glycerol monohydroxystearate, wood wax, beeswax, carnauba wax, micro Using waxes such as crystallin wax and paraffin wax, low molecular weight olefin polymers and copolymers such as polyethylene, polypropylene, ethylene-vinyl acetate copolymer and ethylene-vinyl alkyl ether It is possible.
[0028]
These are heated to, for example, the vicinity of the melting point, and a coloring agent necessary for displaying two colors there (for example, white pigments such as titanium oxide, mica and calcium carbonate for white, carbon black for black) Spherical two-color particles can be produced by using a necessary amount of kneading black pigments or black dyes such as magnetite and additives (charge control agent, surfactant, etc.).
[0029]
As a specific manufacturing method, for example, a method of laminating a thermoplastic white resin sheet and a black resin sheet, cutting into a chip shape, and spheroidizing by heat treatment may be used, or a molten white resin and a black resin may be used. A method may be used in which the fibers are bonded together to form a fibrous shape, which is cut into a cylindrical shape and then formed into a sphere by heat treatment.
[0030]
Alternatively, a method may be used in which the white wax and the black wax are heated to be in a liquid state, a small amount of particles are blown into the air while bonding them, and the wax is made spherical by the surface tension of the wax itself. Further, a two-color particle may be produced by applying a material of another color (paint or vapor-deposited film) to a half surface of a sphere such as colored glass particles.
[0031]
The spherical black-and-white two-color particles thus produced are mixed and dispersed in silicone rubber to form a sheet, cured, and swelled with silicone oil to produce a sheet-type display device, which is sandwiched between electrodes, for example. By applying an electric field of 1 V / 50 V / mm, monochrome display can be performed.
[0032]
In the present invention, in the region from the display surface of the sheet to a depth of 1.5 times the average particle diameter of the rotating particles, the filling rate of the rotating particles in the entire region included in the region is the translucent liquid. When the void filled with is not considered, the content is 40% by volume or more and less than 65% by volume.
[0033]
Ideally, if the rotating particles all have the same particle diameter and are closely arranged along the display surface as shown in FIG. 1, all the incident light will be reflected or absorbed by these rotating particles. It is thought that we can do it.
[0034]
However, it is actually difficult to achieve such an arrangement, and it is physically difficult to hold the rotating particles in the sheet. Further, voids filled with the translucent liquid are required around the rotating particles, and it is preferable that these voids are independent of each other. Therefore, it is essential that some space exists between the voids. In addition, when such rotating particles are completely in contact with the display surface of the sheet, the translucent liquid flows out of the gap filled with the translucent liquid, causing a problem. Further, it is difficult to realize that all the rotating particles have the same particle diameter.
[0035]
In such a situation, as a result of studying the optimization of the filling of the rotating particles in the vicinity of the display surface, as a result, in the region from the display surface of the sheet to a depth of 1.5 times the average particle diameter of the rotating particles, It has been found that the filling rate of the rotating particles contained in the region in the region is preferably 40% by volume or more and less than 65% by volume with respect to the sheet before the void filled with the translucent liquid.
[0036]
The reason why the filling rate is determined in a region from the display surface of the sheet to a depth of 1.5 times the average particle diameter of the rotating particles is in consideration of a variation in the particle diameter of the rotating particles. In the case of rotating particles with a very uniform particle diameter, it is possible that similar conditions can be found even with a value smaller than 1.5 times the average particle diameter.
[0037]
When the filling rate is less than 40% by volume, the rate at which incident light reaches the rotating particles at the rear becomes remarkable, which is often disadvantageous. This is because the light reflected by the rotating particles at the rear is scattered or absorbed by the rotating particles at the front thereof, so that the overall light reflection efficiency is reduced. When the content is 65% by volume or more, the gaps filled with the translucent liquid are stuck together or the chance of exposure to the display surface increases, which is not preferable in many cases.
[0038]
The above describes the sheet before the gap filled with the translucent liquid exists, but after the gap filled with the translucent liquid is present, the gap filled with the translucent liquid is referred to as It should be considered as not considering. That is, the gap may be subtracted from the volume of the sheet. This can be determined as follows.
[0039]
First, the average particle diameter of the rotating particles is determined by an appropriate method. For example, any known method such as microscopic observation may be used. In the step of forming a sheet, the value can be determined from the rotating particles before being dispersed in the sheet.
[0040]
Then, if the sheet loses elasticity and there are voids filled with the translucent liquid, cool the translucent liquid until it solidifies, and then, for a predetermined area of the sheet, from the display surface of the display surface sheet. A region up to a depth of 1.5 times the average particle diameter of the rotating particles is cut out to obtain a sample sheet as shown in FIG. In FIG. 3, the rotating particles are omitted.
[0041]
First, rotating particles that are not entirely included in the region are excluded. The particles indicated by oblique lines X in FIG. 4, which is a sectional view in the direction A in FIG. 3, correspond to this. In addition, the description of the two-color area is omitted for the rotating particles in FIG. Further, also for the side surface portion of the cross section, similarly, the rotating particles that are not entirely included in the region are excluded. The particles hatched in FIG. 4 correspond to this.
[0042]
The number of rotating particles remaining in this way is counted, and a sphere-converted particle volume is determined from this and the average particle diameter. The sphere-converted particle volume is divided by L1 × L2 × L3 in FIG. 3 and multiplied by 100 is the filling rate according to the present invention.
[0043]
Although the predetermined area can be arbitrarily determined, it is preferable that the total number of the rotating particles included in the entire area is about 100 or more. In the present invention, if the above condition is satisfied even for a part of the sheet, the requirements of the present invention are satisfied. In practice, however, it is preferable to appropriately evaluate several places on the display surface.
[0044]
Furthermore, it is desirable that there be rotating particles behind the rotating particles near the display surface for reflecting or absorbing the light rays that have passed through these rotating particles, but the more particles behind the rotating particles, the better. It turned out not. If the amount is too large, it is necessary to apply a higher voltage to rotate the rotating particles, and further, the rotation speed of the rotating particles decreases and the display responsiveness deteriorates.
[0045]
As a result of the study, it has been found that it is preferable that the rotating particles including the entire rotating particles from the display surface of the sheet to a depth twice as large as the average particle diameter of the rotating particles is 70% by volume or more of all the rotating particles. If the number is less than this, the above-mentioned problems of the voltage and display responsiveness are likely to appear.
[0046]
It is more preferable that the rotating particles including the entire rotating particles from the display surface of the sheet to a depth three times the average particle diameter of the rotating particles is 90% by volume or more of all the rotating particles. This is such an overlap that the particles appear to form two to three layers when using rotating particles having a substantially uniform particle diameter.
[0047]
Note that the “rotated particles that are entirely contained from the display surface of the sheet to a depth of twice or three times the average particle diameter of the rotated particles” and the “all-rotated particles” are the above “display surface of the display surface sheet”. In a region from to a depth of 1.5 times the average particle diameter of the rotating particles, the entirety can be determined in the same manner as the "rotating particles included in the region". However, in the case of “all rotating particles”, no particles are excluded as shown by X in FIG.
[0048]
In the sheet-type display device according to the present invention, it is preferable that the display surface of the sheet has a base material layer that does not include voids filled with the rotating particles and the translucent liquid. This is because the space filled with the translucent liquid can be reliably prevented from being exposed on the display surface. The thickness of this layer is preferably in the range from 1 to 20 μm. If the thickness is too small, it is not preferable because the thickness is partially reduced, but if uniformity of the thickness can be ensured, it is more preferably in the range of 1 to 10 μm, and further preferably in the range of 1 to 5 μm. Such a base material layer can be realized by preparing in advance and then forming the above-mentioned sheet thereon.
[0049]
It is also an aspect of the present invention to manufacture a sheet-type display device by including the above-described first step, second step, and third step.
[0050]
In this case, in the first step, a diluting solvent is added to the curable base material to form a dispersion in which the volume ratio of the particles is reduced to 50% by volume or less to form a sheet. If the sheet is left for a predetermined time between steps 2 and 3, and then the diluting solvent is removed, the space in which the rotating particles are dispersed once increases, which facilitates the dispersion, which is preferable. This is schematically shown in FIG. This predetermined time can be determined experimentally.
[0051]
At this time, if the type of the diluting solvent is selected so that the specific gravity of the dispersion medium composed of the base material and the diluting solvent is smaller than the specific gravity of the rotating particles, the first step and the second step are performed. If the sheet is left for a predetermined period of time, the rotating particles are deposited on the bottom. This is shown in FIG.
[0052]
Thereafter, the solvent for dilution was removed, and the bottom portion was made to be a display surface, and if the sheet-type display device according to the present invention was manufactured according to a predetermined procedure, the rotating particles were densely filled in the vicinity of the display surface. This is advantageous because it has a structure. Further, the method is excellent as a method for realizing the sheet-type display device according to the present invention having the above-described requirements.
[0053]
As the solvent for dilution, it is preferable to use a solvent that evaporates at a normal pressure or lower than the softening point temperature of the rotating particles. The diluting solvent can be removed at room temperature or by heating, but it is not preferable that the rotating particles are softened or deformed during heating.
[0054]
Further, since the sheet base material according to the present invention is usually produced using a thermosetting resin, it is preferable that the curing does not progress or does not progress so much before the removal of the dilution solvent is completed. This is because if the curing proceeds, it becomes difficult to remove the diluting solvent, and the removal of the diluting solvent may cause problems such as deformation of the sheet.
[0055]
As a method of accelerating the deposition of the rotating particles on the bottom when left unattended, a method of causing the rotating particles to contain a magnetic material and aligning the rotating particles with a magnetic force between the first step and the second step is also useful. It is. This is because in this case, a desired arrangement can often be realized in a short time. Any known magnetic material may be used without departing from the spirit of the present invention. Ferromagnetic materials are often preferred.
[0056]
FIG. 7 shows a state in which the rotating particles are arranged by the action of a magnetic force in a sheet-type display device having a substrate layer that does not include voids filled with the rotating particles and the translucent liquid on the display surface of the sheet. In FIG. 7, reference numeral 7 denotes a layer of a base material which is filled with rotating particles and a translucent liquid and does not include voids, and reference numeral 6 denotes a planar magnet.
[0057]
【Example】
Next, examples and comparative examples of the present invention will be described in detail.
[0058]
[Example 1]
Titanium oxide as a white pigment was heated and kneaded at a ratio of 10% by weight with a thermoplastic polyester resin (manufactured by Kao Corporation) to produce a white resin sheet.
[0059]
Further, a black resin was prepared by heating and kneading carbon black as a black pigment at a ratio of 2% by weight to a polyester resin.
[0060]
Then, the two colored resin sheets are stretched while being laminated under pressure at 130 ° C. to adjust the thickness of the sheets, cut into chips, and heat-treated in oil to form spherical particles having an average particle diameter of 50 μm. Color particles were produced.
[0061]
The two-color particles are dispersed in a dispersion medium in which a room temperature-curable silicone rubber KE109 manufactured by Shin-Etsu Chemical Co., Ltd. is used as a base material for a sheet and low-viscosity silicone oil is used as a diluent. Was 50% by volume.
[0062]
This dispersion was applied using a blade having a thickness of 120 μm, formed into a sheet, and left standing for 60 minutes to remove the solvent for dilution, thereby depositing the rotating particles on the bottom, and then heating at 50 ° C. for 360 minutes. The substrate was cured while removing the dilution solvent was completed. The sufficient removal of the diluting solvent was performed by measuring the weight change of the sheet.
[0063]
The filling ratio of the rotating particles of the sheet before swelling is obtained by cutting a 1 mm long, 1 mm wide plate-like body in a region from the display surface of the sheet to a depth of 1.5 times the average particle diameter of the rotating particles. Was measured according to the method described above.
[0064]
After curing, this sheet is ² / S silicone oil SH200 (manufactured by Toray Dow Corning Silicone Co., Ltd., specific gravity 0.95) for 60 hours to swell, and the gap filled with the silicone oil SH200, which is a translucent liquid, around the rotating particles is formed. A dispersed sample sheet was prepared.
[0065]
As the silicone oil as a diluent, 0.65 cs dimethyl silicone oil was used. Since the silicone oil has high volatility and a boiling point at normal pressure of 100 ° C., which is lower than 120 ° C., which is the softening point of the thermoplastic polyester, the two-color particles are not deformed by removing the diluting solvent. Was.
[0066]
The specific gravity of the silicone rubber KE109 as the base material for the sheet is 1.02, the specific gravity of dimethyl silicone oil as the diluting solvent is 0.76, and the specific gravity of the dispersion medium as a mixture thereof is 0.89. The specific gravity of the two-color particles was 1.25, and there was a sufficient difference in specific gravity. Therefore, it was evident from the observation of the cross section of the cured sheet that the two-color particles were well settled on the lower surface after being left for 60 minutes. Was.
[0067]
The usage ratio between the rotating particles and the base material for the sheet is changed, and the entire area of the sheet before swelling is included in the region from the display surface to a depth of 1.5 times the average particle diameter of the rotating particles. Sheets in which the filling rate of the rotating particles in this region was 63% by volume, 54% by volume, 45% by volume, and 39% by volume were obtained.
[0068]
Further, these sheets were swollen with silicone oil SH200 so that the particle diameter of the voids was 1.05 times and 1.10 times the average particle diameter of the rotating particles.
[0069]
These sample sheets were sandwiched between electrode films on which upper and lower ITOs were deposited, and a two-color sphere was rotated at 1 Hz and 50 V / mm.
[0070]
In the sheet after swelling, the rotating particles are entirely contained from the display surface of the sheet to a depth twice as large as the average particle diameter of the rotating particles, or are three times the average particle diameter of the rotating particles from the display surface of the sheet. By the way, the ratio of the rotating particles included in the whole was determined by observing the cross section of the sheet with a microscope.
[0071]
As a result, the results shown in Table 1 were obtained. When the filling rate is 63% by volume, 54% by volume, and 45% by volume, in the sheet after swelling, the rotating particles that are entirely contained from the display surface of the sheet to a depth of twice the average particle diameter of the rotating particles Was 70% by volume or more, and the ratio of the rotating particles contained entirely from the display surface of the sheet to a depth three times the average particle diameter of the rotating particles was 90% by volume or more.
[0072]
The reflectance was measured using a colorimeter, Spectroeye manufactured by Macbeth, with a D65 light source in a 2-degree visual field.
[0073]
[Table 1]

[0074]
From these results, it can be understood that the sheet-type display device according to the present invention can perform display with a contrast of 10: 1 or more and obtain high visibility.
[0075]
[Example 2]
In the case of No. 1 in Table 1, if the magnetic material is mixed with the resin to produce the rotating particles containing the magnetic material, the two-color particles can be more easily settled on the lower surface of the sheet. That is, as shown in FIG. 7, by placing a magnet below the sheet before curing, the rotating particles can be aligned with the magnetic force and can be well settled on the lower surface. You may use together with the said dilution method.
[0076]
[Example 3]
A sheet made of silicone rubber KE109 having an average thickness of 4 μm was prepared in advance, and was coated thereon using a 120 μm-thick blade, and was formed into a sheet shape.
[0077]
In the case of No. 1 in Table 1, the rotating particles that could not form a void filled with the translucent liquid around the lower surface of the sheet because of contact with the lower surface of the sheet were 1 cm. ² 1000 or more were found per case, but in Example 3, such a case could be completely prevented. This method is also applicable to the second embodiment.
[0078]
From the contents disclosed above, the inventions shown in the following supplementary notes can be derived.
[0079]
(Supplementary Note 1) The rotating particles are rotated in a sheet including the rotating particles having at least two surface regions of different colors, the voids surrounding the rotating particles, and the base material in which the voids are dispersed. In a sheet-type display device that performs display by causing
In the region from the display surface of the sheet to a depth of 1.5 times the average particle diameter of the rotating particles, the filling rate of the rotating particles included in the entire region in the region is equal to the gap filled with the translucent liquid. When not considered, it is 40% by volume or more and less than 65% by volume,
The rotating particles that are entirely contained from the display surface of the sheet to a depth of twice the average particle diameter of the rotating particles are 70% by volume or more of all the rotating particles.
Sheet type display device.
[0080]
(Supplementary Note 2) The sheet-type display according to Supplementary Note 1, wherein the rotating particles that are entirely contained from the display surface of the sheet to a depth three times the average particle diameter of the rotating particles are 90% by volume or more of all the rotating particles. apparatus.
[0081]
(Supplementary Note 3) The sheet-type display device according to Supplementary Note 1 or 2, wherein a layer of a base material that does not include a void filled with the rotating particles and the translucent liquid is present on a display surface of the sheet.
[0082]
(Supplementary Note 4) The supplementary note 1 or 2, wherein the display surface of the sheet includes a base material layer having a thickness in the range of 1 to 20 µm, which does not include the gap filled with the rotating particles and the translucent liquid. Sheet type display device.
[0083]
(Supplementary Note 5) a first step of forming a sheet by forming a dispersion in which rotating particles having at least two surface regions having different colors are dispersed in a curable substrate;
A second step of subsequently curing the substrate;
Thereafter, the sheet is swollen with the light-transmissive liquid to form a sheet including the rotating particles, the voids filled with the light-transmissive liquid around the rotating particles, and the cured base material in which the voids are dispersed. Steps and
In the method for manufacturing a sheet-type display device including
In a first step, a dispersion in which the volume ratio of the particles is reduced to 50% by volume or less by adding a diluting solvent to the curable substrate is formed into a sheet,
The sheet is left for a predetermined time between the first step and the second step, and then the diluting solvent is removed.
A method for manufacturing a sheet-type display device.
[0084]
(Supplementary Note 6) a first step of forming a dispersion by dispersing rotating particles having at least two surface regions having different colors in a curable substrate to form a sheet;
A second step of subsequently curing the substrate;
Thereafter, the sheet is swollen with the light-transmissive liquid to form a sheet including the rotating particles, the voids filled with the light-transmissive liquid around the rotating particles, and the cured base material in which the voids are dispersed. Steps and
In the method for manufacturing a sheet-type display device including
In the first step, a diluting solvent is added to the curable base material, and the specific gravity of the dispersion medium including the base material and the diluent solvent is smaller than the specific gravity of the rotating particles. So that the volume ratio of the particles is 50% by volume or less;
The sheet is left for a predetermined time between the first step and the second step, and then the diluting solvent is removed.
A method for manufacturing a sheet-type display device.
[0085]
(Supplementary Note 7) The method for producing a sheet-type display device according to Supplementary Note 5 or 6, wherein a solvent that evaporates at a normal pressure or lower than the softening point temperature of the rotating particles is used as the diluting solvent.
[0086]
(Supplementary Note 8) The rotating particles contain a magnetic material,
8. The method for manufacturing a sheet-type display device according to any one of supplementary notes 5 to 7, wherein the rotating particles are aligned by magnetic force between the first step and the second step.
[0087]
(Supplementary Note 9) The method of manufacturing a sheet-type display device according to any one of Supplementary Notes 5 to 8, wherein the sheet is formed on a layer made of a substrate that does not include a void filled with the rotating particles and the translucent liquid.
[0088]
(Supplementary Note 10) The method for manufacturing a sheet-type display device according to Supplementary Note 9, wherein the thickness of the layer made of the base material that does not include the gap filled with the rotating particles and the translucent liquid is in a range of 1 to 20 μm. .
[0089]
【The invention's effect】
According to the present invention, it is possible to provide a sheet-type display device having excellent contrast and high visibility.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view of a sheet-type display medium using two-color particles.
FIG. 2 is a model diagram showing a state of particles rotating by application of an electric field. (A) before the electric field application, (b) during the electric field application, and (c) after the voltage application.
FIG. 3 is a model diagram showing a sample sheet for filling factor measurement.
FIG. 4 is a sectional view in the direction A of FIG. 3;
FIG. 5 is a model diagram showing a state in which rotating particles are dispersed in a mixture of a substrate and a diluting solvent.
FIG. 6 is a model diagram showing a state in which rotating particles are deposited on the bottom in a sheet.
FIG. 7 is a model showing a state in which rotating particles are arranged by the action of a magnetic force in a sheet-type display device having a layer of a base material without a void filled with rotating particles and a translucent liquid on a display surface of a sheet. FIG.
[Explanation of symbols]
1 Two-color particles
2 translucent liquid (void)
3 Base material for sheet
4 electrodes
4 'transparent electrode
5 Power supply
6 planar magnets
7. Layer of base material without voids filled with rotating particles and translucent liquid

Claims (5)

Display by rotating the rotating particles in a sheet containing rotating particles having at least two surface regions of different colors, a gap surrounding the rotating particles filled with a translucent liquid, and a base material in which the gaps are dispersed. In the sheet type display device that performs
In the region from the display surface of the sheet to a depth of 1.5 times the average particle diameter of the rotating particles, the filling rate of the rotating particles included in the entire region in the region is equal to the gap filled with the translucent liquid. When not considered, it is 40% by volume or more and less than 65% by volume,
The rotating particles that are entirely contained from the display surface of the sheet to a depth of twice the average particle diameter of the rotating particles are 70% by volume or more of all the rotating particles.
Sheet type display device. 2. The sheet-type display device according to claim 1, wherein the rotating particles including the entire rotating particles from the display surface of the sheet to a depth three times the average particle diameter of the rotating particles are 90% by volume or more of the total rotating particles. 3. The sheet mold according to claim 1, wherein the display surface of the sheet has a layer of a base material having a thickness in a range of 1 to 20 μm which does not include a void filled with the rotating particles and the translucent liquid. 4. Display device. A first step of forming a dispersion into a sheet by dispersing rotating particles having at least two different color surface areas in a curable substrate;
A second step of subsequently curing the substrate;
Thereafter, the sheet is swollen with the light-transmissive liquid to form a sheet including the rotating particles, the voids filled with the light-transmissive liquid around the rotating particles, and the cured base material in which the voids are dispersed. And a method of manufacturing a sheet-type display device comprising the steps of:
In the first step, a diluting solvent is added to the curable base material, and the specific gravity of the dispersion medium including the base material and the diluent solvent is smaller than the specific gravity of the rotating particles. So that the volume ratio of the particles is 50% by volume or less;
A method of manufacturing a sheet-type display device, in which the sheet is left for a predetermined time between the first step and the second step, and then the diluting solvent is removed. The rotating particles contain a magnetic material,
The method of manufacturing a sheet-type display device according to claim 4, wherein the rotating particles are aligned by magnetic force between the first step and the second step.

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