JP2012093385A - Display sheet, display device and electronic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a display sheet with high reliability capable of exhibiting excellent display characteristics and a display device provided therewith, and further to provide an electronic apparatus with high reliability.SOLUTION: A display device 20 comprises: a substrate 12 disposed at a side of a display surface 121; a counter substrate 11 disposed opposite to the substrate 12; a display layer 400 interposed between the substrate 12 and the counter substrate 11 and filled with dispersion liquid 100 containing at least one kind of particles charged to either positive or negative polarity and dispersed in a dispersion medium; and partition members 6 disposed inside the display layer 400 and dividing the display layer 400 into a plurality of regions in a plan view of the display layer 400. In addition, a separation distance between the substrate 12 and the counter substrate 11 is equal to (H+R) or more, where the height of the partition members 6 is denoted H and an average particle diameter of the particles is denoted R.

Description

  The present invention relates to a display sheet, a display device, and an electronic apparatus.

For example, an electrophoretic display using particle electrophoresis is known as an image display unit of electronic paper (see, for example, Patent Document 1). The electrophoretic display has excellent portability and power saving, and is particularly suitable as an image display unit for electronic paper.
The electrophoretic display has a pair of electrodes arranged opposite to each other and a display layer provided between them, and the display layer includes, for example, positively charged white particles and negatively charged black particles. Are dispersed in a liquid phase dispersion medium. Such an electrophoretic display is configured to display a desired image by applying a voltage between a pair of electrodes and causing white particles and black particles to migrate in a desired direction.

  Here, the configuration of the display layer is roughly divided into a “partition wall type” in which the display layer is divided into a plurality of cells by partition walls as in Patent Document 1, and a dispersion liquid is filled in each cell, as in Patent Document 2. A “microcapsule type” in which a plurality of microcapsules filled with a dispersion liquid are arranged and fixed by a binder, and the display layer is formed as one space (that is, not divided by a partition wall or the like) as in Patent Document 3. The liquid crystal type is filled with the dispersion liquid.

  However, the “partition wall type” has a problem in that the effective display area (area in which the display color can be changed) in the display surface is reduced by the partition wall, and the display characteristics are deteriorated. Further, in the “microcapsule type”, a gap is generated between adjacent microcapsules, so that an effective display area in the display surface is reduced and display characteristics are deteriorated, or when a voltage is applied between a pair of electrodes, There is a problem that display characteristics deteriorate due to the occurrence of leakage current. In the “liquid crystal type”, almost the entire display area can be used as an effective display area. For example, when the display is set up like a book, white particles and black particles move downward in the vertical direction due to their own weight. (Sedimentation), the display image cannot be maintained, and the reliability is lowered.

JP 2010-44114 A JP 2003-140202 A Japanese National Patent Publication No. 8-510790

  An object of the present invention is to provide a display sheet that has high reliability and can exhibit excellent display characteristics, a display device including the display sheet, and a highly reliable electronic device.

Such an object is achieved by the present invention described below.
The display sheet of the present invention includes a first substrate provided on the display surface side,
A second substrate disposed opposite the first substrate;
A display layer provided between the first substrate and the second substrate and filled with a dispersion liquid in which at least one kind of positively or negatively charged particles is dispersed in a dispersion medium;
A partition member provided in the display layer and dividing the display layer into a plurality of regions in plan view of the display layer;
When the height of the partition member is H and the average particle diameter of the particles is R, the separation distance between the first substrate and the second substrate is (H + R) or more.
Thereby, it is possible to provide a display sheet that is highly reliable and can exhibit excellent display characteristics.

In the display sheet of the present invention, the separation distance between the first substrate and the second substrate is preferably (H + 10R) or less.
Thereby, the reliability and display characteristics of the display sheet are further improved.
In the display sheet of this invention, it is preferable that the said partition member is floating in the said dispersion medium.
Thereby, a gap can also be formed between the partition member and the second substrate. This improves the convenience of the apparatus.

In the display sheet of the present invention, it is preferable that a spacer is provided between the partition member and the first substrate to maintain a separation state between the partition member and the first substrate.
Thereby, particles can be more surely introduced between the partition wall member and the first substrate.
In the display sheet of the present invention, it is preferable that the partition member is fixedly provided in the display layer.
As a result, it is possible to maintain a state in which the partition member is separated from the first substrate by a predetermined distance.

In the display sheet of the present invention, it is preferable that the partition member is provided in contact with the second substrate.
Thereby, when the display sheet is erected, the particles gathered on the second substrate side can be prevented from moving downward in the vertical direction.
In the display sheet of the present invention, it is preferable that a cross-sectional area of each of the plurality of regions on the first substrate side gradually increases from the second substrate toward the first substrate.
This makes it easier for particles to enter between the partition wall member and the first substrate.

In the display sheet of the present invention, the partition member includes a first partition member and a second partition member provided on the first substrate side with respect to the first partition member,
Preferably, the region divided by the second partition member is smaller than the cross-sectional area of the region divided by the first partition member.
Thereby, the sedimentation of particles when standing the display sheet can be more effectively prevented or suppressed without inhibiting the migration of particles.

In the display sheet of the present invention, the dispersion contains first particles that are positively or negatively charged, and second particles that are charged to the opposite pole to the first particles.
It is preferable that the average particle diameters of the first particles and the second particles are substantially equal.
Thereby, the same effect can be exhibited by the first particles and the second particles.
The display device of the present invention includes the display sheet of the present invention.
Thereby, a highly reliable display device is obtained.
An electronic apparatus according to the present invention includes the display device according to the present invention.
As a result, a highly reliable electronic device can be obtained.

It is sectional drawing which shows 1st Embodiment of the display apparatus of this invention. It is a figure which shows the problem of the conventional display apparatus. It is a figure which shows the problem of the conventional display apparatus. It is a top view of the display apparatus shown in FIG. It is sectional drawing explaining the drive and effect of the display apparatus shown in FIG. It is sectional drawing explaining the drive and effect of the display apparatus shown in FIG. It is a partial expanded sectional view which shows 2nd Embodiment of the display apparatus of this invention. It is a partial expanded sectional view which shows 3rd Embodiment of the display apparatus of this invention. It is a partial expanded sectional view which shows 4th Embodiment of the display apparatus of this invention. It is a partial expanded sectional view which shows 5th Embodiment of the display apparatus of this invention. It is a top view of the display apparatus shown in FIG. It is a schematic perspective view which shows 6th Embodiment of the display apparatus of this invention. It is sectional drawing of the display sheet shown in FIG. It is a perspective view which shows embodiment at the time of applying the electronic device of this invention to electronic paper. It is a figure which shows embodiment at the time of applying the electronic device of this invention to a display.

Hereinafter, a display sheet, a display device, and an electronic device of the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings.
1. Display Device First, a display device incorporating the display sheet of the present invention will be described.
<First Embodiment>
1 is a cross-sectional view showing a first embodiment of a display device of the present invention, FIGS. 2 and 3 are diagrams showing problems of a conventional display device, and FIG. FIGS. 5 and 6 are cross-sectional views illustrating the driving and effects of the display device shown in FIG. In the following description, for convenience of explanation, the upper side in FIGS. 1 to 3, 5, and 6 will be described as “upper” and the lower side as “lower”.

A display device 20 (display device of the present invention) shown in FIG. 1 is an electrophoretic display device that displays a desired image using particle migration. The display device 20 includes a display sheet (front plane) 21 and a circuit board (back plane) 22.
As shown in FIG. 1, the display sheet 21 is provided on a substrate (first substrate) 12 including a flat base 2 and a second electrode 4 provided on the lower surface of the base 2, and the substrate 12. And a display layer 400 filled with the dispersion liquid 100. In such a display sheet 21, the upper surface of the substrate 12 constitutes the display surface 121. Hereinafter, the display surface 121 refers to a region overlapping the display layer 400 on the upper surface of the substrate 12 in a plan view of the display device 20, and other regions (for example, a region overlapping a sealing portion 9 described later). Shall be excluded.

On the other hand, the circuit board 22 has a counter substrate 11 having a flat base 1 and a plurality of first electrodes 3 provided on the upper surface of the base 1 and a circuit (not shown) provided on the counter substrate 11. is doing. The circuit includes, for example, TFTs (switching elements) arranged in a matrix, gate lines and data lines formed corresponding to the TFTs, a gate driver that applies a desired voltage to the gate lines, and a desired data line. A data driver for applying the voltage of the gate driver, and a control unit for controlling the driving of the gate driver and the data driver.
In such a display device 20, the counter substrate 11 also serves as the second substrate of the display sheet 21.

Hereinafter, the structure of each part is demonstrated sequentially.
The base 1 and the base 2 are each composed of a sheet-like (flat plate) member, and have a function of supporting and protecting each member disposed therebetween. Each of the base portions 1 and 2 may be either flexible or hard, but is preferably flexible. By using the bases 1 and 2 having flexibility, it is possible to obtain a display device 20 having flexibility, that is, for example, a display device 20 useful in constructing electronic paper.

  When each base part (base material layer) 1 and 2 is flexible, the constituent materials thereof are, for example, polyesters such as PET (polyethylene terephthalate) and PEN (polyethylene naphthalate), polyethylene, etc. Polyolefins, modified polyolefins, polyamides, thermoplastic polyimides, polyethers, polyether ether ketones, various thermoplastic elastomers such as polyurethanes and chlorinated polyethylenes, or their main copolymers, blends, polymer alloys, etc. 1 type or 2 types or more of these can be mixed and used.

  The average thicknesses of the bases 1 and 2 are appropriately set depending on the constituent material, application, and the like, and are not particularly limited. More preferably, it is about 25 μm or more and 250 μm or less. Thereby, size reduction (especially thickness reduction) of the display apparatus 20 can be achieved, aiming at harmony with the softness | flexibility and intensity | strength of the display apparatus 20. FIG.

  The first electrode 3 and the second electrode 4 that form a layer (film shape) are provided on the surfaces of the bases 1 and 2 on the display layer 400 side, that is, on the upper surface of the base 1 and the lower surface of the base 2, respectively. ing. In the present embodiment, the second electrode 4 is a common electrode, and the first electrode 3 is an individual electrode (pixel electrode connected to a TFT) divided in a matrix (matrix). In such a display device 20, a region where one first electrode 3 and the second electrode 4 overlap constitute one pixel Pix.

The constituent materials of the electrodes 3 and 4 are not particularly limited as long as they are substantially conductive, for example, metal materials such as gold, silver, copper, aluminum or alloys containing these, carbon black, etc. An ionic substance such as NaCl, Cu (CF ₃ SO ₃ ) ₂ is dispersed in a carbon-based material, an electroconductive polymer material such as polyacetylene, polyfluorene or a derivative thereof, or a matrix resin such as polyvinyl alcohol or polycarbonate. Various conductive materials such as ion conductive polymer materials, conductive oxide materials such as indium oxide (IO), indium tin oxide (ITO), fluorine-doped tin oxide (FTO), etc. 1 type or 2 types or more can be used in combination.

Further, the average thickness of the electrodes 3 and 4 is appropriately set depending on the constituent material and application, and is not particularly limited, but is preferably about 0.01 μm or more and 10 μm or less, preferably 0.02 μm or more and 5 μm or less. More preferred is the degree.
Here, among the bases 1 and 2 and the electrodes 3 and 4, the base and the electrode disposed on the display surface 121 side are each transparent, that is, substantially transparent (colorless and transparent, colored Transparent or translucent). In the present embodiment, since the upper surface of the substrate 12 constitutes the display surface 121, at least the base 2 and the second electrode 4 are substantially transparent. Thereby, the state of the white particles A and the black particles B in the dispersion 100, that is, the information (image) displayed on the display device 20 can be easily recognized visually from the display surface 121 side.

A sealing portion 9 is provided between the substrate 12 and the counter substrate 11 along the edges. The display layer 400 is hermetically sealed by the sealing portion 9. Thereby, it is possible to prevent moisture from entering the display device 20 and more reliably prevent display performance deterioration of the display device 20.
The constituent material of the sealing portion 9 is not particularly limited. For example, a thermoplastic resin such as an acrylic resin, a urethane resin, or an olefin resin, an epoxy resin, a melamine resin, or a heat such as a phenol resin. Various resin materials such as a curable resin can be used, and one or more of these can be used in combination.

The display layer 400 is filled with the dispersion liquid 100. Further, a partition wall member 6 is provided in the display layer 400.
Dispersion liquid 100 is obtained by dispersing white particles (first particles) A and black particles (second particles) B, which are charged to opposite poles, in dispersion medium 7.
As the dispersion medium 7, a medium having a relatively high insulating property is preferably used. Examples of the dispersion medium 7 include various types of water (for example, distilled water, pure water, etc.), alcohols such as methanol, cellosolves such as methyl cellosolve, esters such as methyl acetate, ketones such as acetone, pentane and the like. Aliphatic hydrocarbons (liquid paraffin), cyclohexane and other alicyclic hydrocarbons, benzene and other aromatic hydrocarbons, methylene chloride and other halogenated hydrocarbons, pyridine and other aromatic heterocycles and acetonitrile Nitriles such as amides, amides such as N, N-dimethylformamide, carboxylates, silicone oils or other various oils, and the like, and these can be used alone or as a mixture.

  Among these, as the dispersion medium 7, an aliphatic hydrocarbon (liquid paraffin) or a material mainly composed of silicone oil is preferable. The dispersion medium 7 containing liquid paraffin or silicone oil as the main component is preferable because it has a high aggregation suppressing effect on the white particles A and the black particles B. Thereby, it can prevent or suppress more reliably that the display performance of the display apparatus 20 deteriorates with time. In addition, liquid paraffin or silicone oil is preferable from the viewpoint of excellent weather resistance and high safety because it does not have an unsaturated bond.

  Further, in the dispersion medium 7, for example, an electrolyte, a surfactant such as an alkenyl succinate (anionic or cationic), a metal soap, a resin material, a rubber material, an oil, a varnish, a compound, as necessary. Various additives such as a charge control agent composed of particles such as a dispersant, a dispersant such as a silane coupling agent, a lubricant, and a stabilizer may be added. When the dispersion medium 7 is colored, various dyes such as anthraquinone dyes, azo dyes, and indigoid dyes may be dissolved in the dispersion medium 7 as necessary.

  The white particles A and the black particles B are particles that are charged and can be electrophoresed in the dispersion medium 7 by the action of an electric field. As the white particles A and the black particles B, any particles can be used as long as they have electric charges. Although not particularly limited, at least one of pigment particles, resin particles, or composite particles thereof is used. Preferably used. These particles have the advantage that they are easy to manufacture and the charge can be controlled relatively easily.

  Examples of the pigment constituting the pigment particles include black pigments such as aniline black, carbon black, titanium black and copper chromite, white pigments such as titanium oxide and antimony oxide, azo pigments such as monoazo, isoindolinone, Yellow pigments such as yellow lead, red pigments such as quinacridone red and chrome vermilion, blue pigments such as phthalocyanine blue and indanthrene blue, green pigments such as phthalocyanine green, etc. They can be used in combination.

Examples of the resin material constituting the resin particles include acrylic resin, urethane resin, urea resin, epoxy resin, polystyrene, polyester, and the like, and one or more of these are combined. Can be used.
The composite particles include, for example, those in which the surface of the pigment particles is coated with a resin material or other pigment, those in which the surface of the resin particles is coated with a pigment, or a mixture in which the pigment and the resin material are mixed at an appropriate composition ratio. The particle | grains comprised by these, etc. are mentioned.

Examples of particles obtained by coating the surface of pigment particles with other pigments include those obtained by coating the surface of titanium oxide particles with silicon oxide or aluminum oxide. Such particles are suitable as white particles A. Used. Carbon black particles or particles covering the surface thereof are preferably used as the black particles B.
The shapes of the white particles A and the black particles B are not particularly limited, but are preferably spherical. Further, the average particle diameters of the white particles A and the black particles B are not particularly limited, but are preferably 10 nm or more and 500 nm or less, more preferably 20 nm or more and 300 nm or less. If the average particle diameter of the white particles A and the black particles B is less than 10 nm, sufficient chromaticity cannot be obtained, and the contrast may be lowered and the display may become unclear. Conversely, when the average particle diameter of the white particles A and the black particles B exceeds 300 nm, it is necessary to increase the coloring degree of the particles themselves more than necessary, increasing the amount of pigments used and increasing the voltage for display. It is difficult to move the particles quickly at the portion where is applied, and the response speed may decrease.

In addition, the average particle diameter of the white particle A and the black particle B means the volume average particle diameter measured with a dynamic light scattering type particle size distribution measuring device (for example, product name: LB-500, manufactured by Horiba, Ltd.). To do.
In the present embodiment, the average particle diameters of the white particles A and the black particles B are set substantially equal to each other.

Next, the partition member 6 will be described. Prior to that, problems that occur when the partition member 6 is omitted will be described.
When a predetermined voltage is applied between the electrodes 3 and 4, as shown in FIG. 2, the white particles A are collected on the second electrode 4 (substrate 12) side of the display layer 400, and the black particles B are collected on the display layer 400. They can be collected on the first electrode 3 (counter substrate 11) side. As a result, white is displayed on the entire display surface 121.

  Here, it is assumed that the display device 20 is visually recognized in a state where the display device 20 is held like a book. Therefore, as shown in FIG. 3, when the display device 20 is held up like a book, the white particles A are positioned in the vicinity of the particles in contact with the second electrode 4 or in the vicinity of the second electrode 4. The position of the particles is maintained by the adsorption force with the second electrode 4, but the particles that are relatively separated from the second electrode 4 do not have the adsorption force with the second electrode 4. Therefore, it moves (sinks) downward in the vertical direction due to its own weight. The same applies to the black particles B.

When such a phenomenon occurs, the white particles A and the black particles B are biased in the display layer 400, and the image displayed on the display surface 121 is an uneven image. Further, in a pixel in which the number of white particles A is reduced due to the movement (sedimentation) of the white particles A, a high reflectance cannot be obtained, and the contrast is lowered.
Thus, the conventional type without the partition member 6 cannot exhibit excellent display characteristics.

Further, once the white particles A and the black particles B are settled, it is difficult to uniformly disperse the white particles A and the black particles B in the display layer 400 again. For example, it is necessary to reset the display once. Etc. Therefore, when the reset cannot be performed, the display is continued with the display characteristics deteriorated, or when the display is reset to restore the display characteristics, the display is temporarily stopped, and the convenience of the display device 20 is deteriorated. .
The partition member 6 solves such a problem, that is, prevents or suppresses the movement (sedimentation) of the white particles A and the black particles B downward in the vertical direction, thereby exhibiting excellent display characteristics in the display device 20. Let

Hereinafter, the partition member 6 will be described in detail.
As shown in FIG. 1, the partition wall member 6 is provided in the display layer 400 and floats in the dispersion liquid 100. That is, the partition wall member 6 exists in the display layer 400 in a state where it is not fixed to the substrates 11 and 12.
The partition member 6 has a function of dividing the display layer 400 into a plurality of regions in a plan view of the display device 20. As shown in FIG. 4, the partition wall member 6 extends in the vertical direction (first direction) on the paper surface and is spaced apart in the horizontal direction (second direction) on the paper surface in the plan view of the display device 20. And a plurality of second wall portions 62 extending in the horizontal direction of the paper and spaced apart in the vertical direction of the paper surface and intersecting with the first wall portions 61. The partition wall member 6 forms a plurality of regions S surrounded by a pair of adjacent first wall portions 61 and a pair of adjacent second wall portions 62 in a matrix.

  The partition member 6 is configured such that each region S corresponds to one pixel Pix. That is, the partition wall member 6 is configured such that one first electrode 3 is disposed in one region S in a plan view of the display device 20. Accordingly, one pixel can be partitioned from adjacent pixels to some extent by the partition member 6, and the number of white particles A and black particles B present in each pixel can be maintained to some extent. Therefore, the display device 20 can display white or black having substantially the same reflectance in each pixel, and as a result, can exhibit excellent display characteristics.

  The separation distance between a pair of adjacent first wall portions 61 is not particularly limited, and varies depending on the size and shape of the first electrode 3, but is preferably about 1 μm or more and 1 cm or less, and is 5 μm or more and 5 mm or less. More preferred is the degree. The separation distance between the pair of adjacent second wall portions 62 is preferably the same as this. By setting it as such a numerical value range, sedimentation of the white particle A and the black particle B when standing up the display apparatus 20 more effectively can be prevented or suppressed.

The height of the partition wall member 6 (the length in the thickness direction of the display layer 400) is set to be smaller than the thickness of the display layer 400. Specifically, when the height of the partition wall member 6 is H and the average particle diameter of the white particles A (black particles B) is R, the height of the display layer 400 (the separation distance between the substrate 12 and the counter substrate 11). ) Satisfies a numerical range of (H + R) or more.
In other words, in the display device 20, the thickness of the display layer 400 is such that a gap of R or more can be formed between the partition wall member 6 and the substrate 12 when the partition wall member 6 is separated from the substrate 12 side. Alternatively, the height of the partition wall member 6 is set.

The upper limit of the height of the display layer 400 is not particularly limited, but is preferably 10R or less, and more preferably 5R or less. Thereby, sedimentation of the white particles A and the black particles B can be prevented or suppressed more effectively.
Since the partition wall member 6 can be separated from the substrate 11 by such a distance, the following effects can be exhibited. First, sedimentation of the white particles A and the black particles B when the display device 20 is erected can be prevented or suppressed, and excellent display characteristics can be exhibited. Second, since the white particles A or the black particles B can enter between the substrate 12 and the partition wall member 6, substantially the entire area of the display surface 121 can be made an effective display area, and excellent display characteristics can be obtained. Can be demonstrated. Thirdly, the partition member 6 is obscured by particles entering between the substrate 12 and the partition member 6, and the partition member 6 is not visually recognized from the display surface 121. Therefore, the partition member 6 adversely affects the display. Can be prevented, and excellent display characteristics can be exhibited. Such an effect will be described later in detail.

Further, it is preferable that the specific gravity of the partition wall member 6 is set to be substantially equal to the specific gravity of the dispersion medium 7. Thereby, the partition member 6 can be in a suspended state in the dispersion liquid 100 (a state where the partition member 6 is not in contact with either the substrate 12 or the counter substrate 11), and particles are separated between the partition member 6 and the substrate 12. It becomes easy to enter.
Moreover, the partition member 6 may be substantially colorless and transparent, or may be colored. When it is colored, the color is not particularly limited, but is preferably white.

The partition member 6 has a relatively high insulating property. Thereby, generation | occurrence | production of leak current can be suppressed and the power saving of the drive of the display apparatus 20 can be achieved. Moreover, it is preferable that the partition member 6 has flexibility. Thereby, when the display device 20 is deformed, the partition wall member 6 is also deformed accordingly, so that damage or the like of the display device 20 can be effectively prevented or suppressed.
Moreover, the partition member 6 is uncharged.

  The constituent material of the partition member 6 is not particularly limited. For example, polyolefin such as polyethylene, polypropylene, ethylene-vinyl acetate copolymer, modified polyolefin, polyamide (eg nylon 6, nylon 66), styrene, polychlorinated Various thermoplastic elastomers such as vinyl-based, polyurethane-based, polyester-based, fluororubber-based, chlorinated polyethylene, etc., or copolymers, blends, polymer alloys, etc. mainly composed of these are listed. A seed or a mixture of two or more can be used.

2. Method for Driving Display Device Such a display device 20 is driven as follows.
When a voltage is applied between the electrodes 3 and 4, an electric field is generated between them. The white particles A and the black particles B move (electrophoresis) toward one of the electrodes 3 and 4 in accordance with this electric field. Below, the case where the white particle A which has a positive charge is used, and the negative particle is used as the black particle B will be representatively described. Hereinafter, for convenience of explanation, one pixel will be described as a representative.

-White display state-
When a voltage is applied between the first electrode 3 and the second electrode 4 so that the first electrode 3 has a positive potential and the second electrode 4 has a negative potential, the electric field generated by the voltage application is displayed on the display layer. Acts on white particles A and black particles B in 400. Then, as shown in FIG. 5A, the white particles A migrate to the second electrode 4 side and gather on the second electrode 4, and the black particles B migrate to the first electrode 3 side. Gather on the first electrode 3. As a result, a white display state in which white is displayed on the display surface 121 is achieved.

  At this time, since the white particles A migrated to the display surface 121 side enter between the partition wall member 6 and the second electrode 4, the partition wall member 6 is covered with the white particles A when viewed from the display surface 121 side. It is. In particular, in this embodiment, since the partition member 6 is suspended in the dispersion liquid 100, the white particles A enter between the partition member 6 and the second electrode 4, so that the partition member 6 is opposed to the counter substrate 11. The above effect becomes more remarkable because it sinks to the side.

  Thus, in the display device 20, almost the entire display surface 121 can be used as an effective display area, and excellent display characteristics can be exhibited. Further, since the partition wall member 6 is not visually recognized from the display surface 121, the partition wall member 6 does not adversely affect the display image, and excellent display characteristics can be exhibited from this point. The electric field acts so as to spread from the first electrode 3 to the second electrode 4, and acts in an inclined direction at the edge of the pixel. Therefore, the white particles A easily enter between the partition wall member 6 and the first electrode 3. The white particles A move in the direction of the electrode 3 by application of electrolysis, and the white particles A repel each other and are dispersed when the electric field is released, so that the white particles A enter between the partition wall member 6 and the first electrode 3. .

  Further, when the display device 20 is erected in this state, the second electrode is used for the particles in contact with the second electrode 4 and the particles positioned in the vicinity of the second electrode 4 in the white particles A. The position can be maintained by the adsorption force with 4. Furthermore, since these particles are moving irregularly and minutely (Brownian motion) in the dispersion medium 7, the positions can be maintained macroscopically.

On the other hand, among the white particles A, the particles that are relatively separated from the second electrode 4 do not act (or work only slightly) as described above, and move downward (sedimentation) due to their own weight. However, as shown in FIG. 5B, this movement is prevented or suppressed by the partition member 6.
According to such a display device 20, since the increase or decrease in the number of white particles A used for white display can be prevented or suppressed in each pixel, a white display state having a high reflectance can be maintained. High contrast can be exhibited. In addition, since deviation of particles in the display layer 400 can be effectively prevented or suppressed, a clear image without unevenness can be displayed on the display surface 121.

−Black display state−
When a voltage is applied between the first electrode 3 and the second electrode 4 so that the first electrode 3 has a positive potential and the second electrode 4 has a negative potential, the electric field generated by the voltage application is displayed on the display layer. Acts on white particles A and black particles B in 400. Then, as shown in FIG. 6A, the white particles A migrate to the first electrode 3 side and gather on the first electrode 3, and the black particles B migrate to the second electrode 4 side. Collect on the second electrode 4. As a result, a black display state in which black is displayed on the display surface 121 is achieved.

  At this time, since the black particles B migrated to the display surface 121 side enter between the partition wall member 6 and the second electrode 4, the partition wall member 6 is covered by the black particles B when viewed from the display surface 121 side. It is. In particular, in this embodiment, since the partition member 6 is suspended in the dispersion liquid 100, the black particles B enter between the partition member 6 and the second electrode 4, so that the partition member 6 is opposed to the counter substrate 11. The above effect becomes more remarkable because it sinks to the side.

As described above, in the display device 20, almost the entire area of the display surface 121 can be used as an effective display area, and excellent display characteristics can be exhibited. Further, since the partition wall member 6 is not visually recognized from the display surface 121, the partition wall member 6 does not adversely affect the display image, and excellent display characteristics can be exhibited from this point.
Further, when the display device 20 is erected in this state, the second electrode is used for the particles that are in contact with the second electrode 4 and the particles that are located in the vicinity of the second electrode 4 among the black particles B. The position is maintained by the adsorption force with 4. Furthermore, since these particles are moving irregularly and minutely (Brownian motion) in the dispersion medium 7, the positions can be maintained macroscopically.

On the other hand, among the black particles B, particles that are relatively far from the second electrode 4 do not have an adsorption force between the second electrode 4 and try to move (sediment) downward in the vertical direction by their own weight. However, as shown in FIG. 6B, the sedimentation is prevented or suppressed by the partition wall member 6.
According to such a display device 20, since the increase or decrease in the number of black particles B used for black display can be prevented or suppressed in each pixel, a black display state having a low reflectance can be maintained. High contrast can be exhibited. Further, a clear image without unevenness can be displayed on the display surface 121.

In such a display device 20, by selecting a white display state or a black display state for each pixel, that is, by combining a pixel in the white display state and a pixel in the black display state, a desired display surface 121 is displayed on the display surface 121. An image can be displayed.
In particular, in the present embodiment, since the average particle diameters of the white particles A and the black particles B are equal, the same effect can be exhibited by the pixels in the white display state and the pixels in the black display state. Therefore, the display characteristics of the display device 20 are further improved.

  In this embodiment, since the partition wall member 6 is suspended in the dispersion liquid 100, not only between the partition wall member 6 and the substrate 12 but also between the partition wall member 6 and the counter substrate 11 (gap). ) Can be formed. Thus, the following effects can be exhibited by forming gaps between the partition member 6 and the substrate 12 and between the partition member 6 and the counter substrate 11.

In addition, when the display device 20 is kept standing for a long time or when a strong impact or vibration is applied to the display device 20, the white particles A and the black particles B may be biased in the display layer 400. is there. In that case, a refresh voltage is applied so that the white particles A and the black particles B are uniformly dispersed in the display layer 400, and the white particles A and the black particles B are arranged in the horizontal direction (the thickness of the display layer 400). It is necessary to move in the direction orthogonal to the vertical direction. As the refresh voltage, for example, a state in which a positive voltage is applied to a predetermined first electrode 3 and a negative voltage is applied to the remaining first electrode 3 and a state opposite thereto are alternately repeated. Voltage.
If a gap is formed not only between the partition wall member 6 and the substrate 12 but also between the partition wall member 6 and the counter substrate 11, the white particles A and the black particles B as described above move in the lateral direction. Can be done more smoothly.

<Second Embodiment>
FIG. 7 is a partially enlarged sectional view showing a second embodiment of the display device of the present invention.
Hereinafter, the second embodiment will be described with a focus on differences from the above-described embodiment, and description of similar matters will be omitted.
The display device according to the second embodiment of the present invention is the same as the display device of the first embodiment except that the partition wall member is fixed to the counter substrate. In addition, the same code | symbol is attached | subjected to the structure similar to 1st Embodiment mentioned above.

In the display device 20 </ b> A shown in FIG. 7, the partition wall member 6 is fixed to the counter substrate 11. That is, the partition member 6 is fixedly provided with respect to the display layer 400. Thereby, the state in which the partition member 6 is separated from the substrate 12 by a predetermined distance can be maintained. Therefore, the display device 20 can exhibit the effects described in the first embodiment more reliably.
In particular, by fixing the partition wall member 6 to the counter substrate 11, the partition wall member 6 and the counter substrate are in contact with each other, so that the precipitation of the white particles A and the black particles A as described above can be more effectively prevented or Can be suppressed. Specifically, the black particles B in the white display state for a given pixel are gathered on the counter substrate 11 (first electrode 3) side, but there are gaps between the partition wall member 6 and the counter substrate 11. Therefore, even if the display device 20 is set up, the black particles B cannot move downward in the vertical direction. The same applies to the white particles A in the black display state. In this manner, by fixing the partition wall member 6 to the counter substrate 11, sedimentation of particles on the counter substrate 11 side when the display device 20 is erected can be effectively prevented.
The method for fixing the partition wall member 6 to the counter substrate 11 is not particularly limited, but can be fixed using, for example, an adhesive. In this embodiment, the case where the partition member 6 is fixed to the counter substrate 11 has been described. However, the partition member 6 is not limited to this as long as the partition member 6 is fixed to the display layer 400. For example, the partition member 6 May be fixed to the sealing portion 9.

<Third Embodiment>
FIG. 8 is a partially enlarged sectional view showing a third embodiment of the display device of the present invention.
Hereinafter, the third embodiment will be described with a focus on differences from the above-described embodiment, and description of similar matters will be omitted.
The display device according to the third embodiment of the present invention is the same as the display device of the first embodiment except that the configuration of the partition member is different. In addition, the same code | symbol is attached | subjected to the structure similar to 1st Embodiment mentioned above.

  In the display device 20A shown in FIG. 8, each first wall portion 61 of the partition wall member 6 has a tapered shape in which the thickness W gradually decreases from the counter substrate 11 side toward the substrate 12 side. Each of the second wall portions 62 that intersect with the first wall portion 61 is similarly tapered. In other words, in the display device 20A, the cross-sectional area of each pixel gradually increases from the counter substrate 11 side toward the substrate 12 side. If the partition wall member 6 has such a shape, the white particles A or the black particles B move along the wall surfaces of the first wall portion 61 or the second wall portion 62 as indicated by arrows in FIG. This makes it easier to enter between the partition wall member 6 and the substrate 12. Therefore, the display characteristics of the display device 20B are further improved.

<Fourth embodiment>
FIG. 9 is a partially enlarged sectional view showing a fourth embodiment of the display device of the present invention.
Hereinafter, the fourth embodiment will be described with a focus on differences from the above-described embodiment, and description of similar matters will be omitted.
The display device according to the fourth embodiment of the present invention is the same as the display device of the first embodiment except that a spacer is provided between the substrate and the partition member. In addition, the same code | symbol is attached | subjected to the structure similar to 1st Embodiment mentioned above.

In the display device 20 </ b> C shown in FIG. 9, the spacer 5 is provided between the partition wall member 6 and the substrate 12. The spacer 5 has a function of preventing the partition member 6 floating in the dispersion 100 from getting too close to the substrate 12, that is, a function of maintaining a state where the partition member 6 and the substrate 12 are separated from each other. . Thereby, the white particles A or the black particles B can be more surely entered between the partition wall member 6 and the substrate 12.
The height of the spacer 5 is preferably 1R or more and 5R or less, where R is the average particle diameter of the white particles A and the black particles B. Thereby, the clearance gap which can exhibit the effect of this invention more reliably can be formed between the board | substrate 12 and the partition member 6. FIG.

In the present embodiment, the spacer 5 is formed integrally with the partition wall member 6. Specifically, the spacer 5 is formed by extending a part of the first wall portion 61 and the second wall portion 62 toward the substrate 12 side. Thereby, the structure of the spacer 5 becomes simple. The spacer 5 is preferably as thin as possible (having a small cross-sectional area). Thereby, the spacer 5 can be made inconspicuous. Further, the number of the spacers 5 is preferably small as long as the function can be exhibited. For example, it is preferable that the spacers 5 are arranged at a rate of about one per 1 cm ^{2 of the} display surface 121.

<Fifth Embodiment>
FIG. 10 is a partially enlarged sectional view showing a fifth embodiment of the display device of the present invention, and FIG. 11 is a plan view of the display device shown in FIG.
Hereinafter, the fifth embodiment will be described with a focus on differences from the above-described embodiments, and description of similar matters will be omitted.

The display device according to the fifth embodiment of the present invention is the same as the display device of the first embodiment except that the configuration of the partition member is different. In addition, the same code | symbol is attached | subjected to the structure similar to 1st Embodiment mentioned above.
The partition member 6 of the display device 20D shown in FIG. 10 includes a first partition member 6a and a second partition member 6b. The first partition member 6a and the second partition member 6b are provided so as to overlap in the thickness direction of the display layer 400, the first partition member 6a is located on the counter substrate 11 side, and the second partition member 6b is Located on the substrate 12 side. The first partition member 6a and the second partition member 6b are each suspended in the dispersion liquid 100.

The first partition member 6a and the second partition member 6b may be joined (fixed) to each other or may not be fixed. When fixed, the first partition member 6a and the second partition member 6b may be integrally formed.
As shown in FIG. 11, the first partition wall member 6 a includes a plurality of first wall portions 61 a that extend in the vertical direction (first direction) in the drawing and are spaced apart in the horizontal direction (second direction) in the drawing. And a plurality of second wall portions 62a that extend in the horizontal direction of the paper surface and are spaced apart from each other in the vertical direction of the paper surface and intersect with the first wall portions 61a. And the 1st partition member 6a forms many area | region S1 enclosed with a pair of adjacent 1st wall part 61a and a pair of adjacent 2nd wall part 62a in matrix form.

In such a first partition member 6a, one first electrode 3 is arranged in one region S1 so that each region S1 corresponds to one pixel Pix, that is, in a plan view of the display device 20D. It is configured to be.
On the other hand, the second partition wall member 6b includes a plurality of first wall portions 61b extending in the vertical direction (first direction) and spaced apart in the horizontal direction (second direction), and in the horizontal direction of the paper. The plurality of second wall portions 62b that extend and are spaced apart from each other in the vertical direction of the drawing and intersect with the first wall portions 61b. And the 2nd partition member 6b forms many area | regions S2 enclosed with a pair of adjacent 1st wall part 61b and a pair of adjacent 2nd wall part 62b in matrix form.

  Such a 2nd partition member 6b is comprised so that several area | region S2 may be included in one area | region S1 by planar view of display apparatus 20D. That is, the second partition member 6b is configured such that the cross-sectional area of the region S2 is smaller than the cross-sectional area of the region S1. In the present embodiment, four regions S2 are included in one region S1, but the number of regions S2 included in one region S1 is not particularly limited.

  By configuring the partition member 6 in such a configuration, the sedimentation of the particles when the display device 20D is set up can be more effectively prevented or suppressed without inhibiting the migration of the particles (white particles A, black particles B). can do. More specifically, since the region S1 (cross-sectional area of the region S1) formed by the first partition member 6a is relatively wide, particles can migrate smoothly in the region S1. On the other hand, since the region S2 (cross-sectional area of the region S2) formed by the second partition member 6b is narrower than the region S2, the display surface 121 (second electrode 4) when the display device 20 is erected. ) Sideward movement of particles gathered on the side can be more effectively prevented or suppressed. Therefore, the display device 20 </ b> D having such a partition member 6 can exhibit more excellent display characteristics.

  In addition, when the height of the 1st partition member 6a is set to H6a and the height of the 2nd partition member 6b is set to H6b, it is preferable that H6b is 0.1H6a or more and about 0.5H6a or less. Thereby, since the area S1 in which the particles can move smoothly can be secured widely, the above-described effect becomes more remarkable. The height H6b of the second partition wall member 6b is not particularly limited, but is preferably about 20 nm or more and 1000 nm or less, for example.

<Sixth Embodiment>
FIG. 12 is a schematic perspective view showing a sixth embodiment of the display device of the present invention, and FIG. 13 is a sectional view of the display sheet shown in FIG.
Hereinafter, the fifth embodiment will be described with a focus on differences from the above-described embodiments, and description of similar matters will be omitted.

The display device according to the sixth embodiment of the present invention is the same as the first embodiment except that the display sheet is configured as a separate body.
As shown in FIG. 12, the display device 20E of the present embodiment includes a display sheet 21E and a writing device 22E.
As shown in FIG. 13, the display sheet 21E includes a substrate (first substrate) 12E, a substrate (second substrate) 11E disposed opposite to the substrate 12E, and a display layer 400 provided between the substrates 12E and 11E. And the partition member 6 provided in the display layer 400 and the sealing portion 9 that seals the display layer 400. Since the substrates 12E and 11E have the same configuration as the base 2 of the substrate 12 of the first embodiment described above, description thereof is omitted.

The writing device 22E is a device used when writing a desired image (pattern, color, character, picture, or a combination thereof) on the display sheet 21E. As shown in FIG. 12, the writing device 22E is common to a pedestal 221E, a sheet-like common electrode 222E provided on the pedestal 221E, and a writing pen (input tool) 224E provided with a partial electrode 223E at the tip. Voltage application means 225E for applying a voltage between the electrode 222E and the partial electrode 223E.
Such a display device 20E is used as follows, for example.

First, the display sheet 21E in which the entire display surface 121 is in a white display state is placed on the common electrode 222E of the writing device 22E with the display surface 121 facing upward. Next, a voltage at which the partial electrode 223E side is at a low potential is applied between the common electrode 222E and the partial electrode 223E by the voltage applying means 225E. In this state, by moving the writing pen 224E along a desired locus while being in contact with the display surface 121, particles migrate in an area corresponding to the locus, and the display color changes from white to black.
According to such a generating device 20E, it is possible to draw a desired character or the like on the display surface 121 of the display sheet 21E with the same feeling as drawing a character or the like on a paper with a pencil. Therefore, the operability (operation feeling) of the display device 20E is improved.

  Each of the display devices 20 described above can be incorporated into various electronic devices. As an electronic apparatus of the present invention provided with an electrophoretic display device, for example, an electronic paper, an electronic book, a television, a viewfinder type, a monitor direct view type video tape recorder, a car navigation device, a pager, an electronic notebook, a calculator, an electronic newspaper, Examples include a word processor, a personal computer, a workstation, a videophone, a POS terminal, and a device equipped with a touch panel.

Of these electronic devices, an electronic paper will be described as an example for specific description.
FIG. 14 is a perspective view showing an embodiment when the electronic apparatus of the present invention is applied to electronic paper.
An electronic paper 600 shown in FIG. 14 includes a main body 601 composed of a rewritable sheet having the same texture and flexibility as paper, and a display unit 602. In such electronic paper 600, the display unit 602 includes the display device 20 as described above.

Next, an embodiment when the electronic apparatus of the present invention is applied to a display will be described.
FIG. 15 is a diagram showing an embodiment when the electronic apparatus of the present invention is applied to a display. Among these, (a) in FIG. 15 is a sectional view and (b) is a plan view.
A display (display device) 800 shown in FIG. 15 includes a main body 801 and an electronic paper 600 that is detachably attached to the main body 801. The electronic paper 600 has the same configuration as described above, that is, the configuration shown in FIG.

  The main body 801 has an insertion port 805 into which the electronic paper 600 can be inserted on its side (right side in FIG. 15A), and two pairs of conveying rollers 802a and 802b are provided inside. Yes. When the electronic paper 600 is inserted into the main body 801 through the insertion port 805, the electronic paper 600 is installed in the main body 801 in a state of being sandwiched between the pair of conveyance rollers 802a and 802b.

  A rectangular hole 803 is formed on the display surface side of the main body 801 (the front side in FIG. 15B), and a transparent glass plate 804 is fitted in the hole 803. . Thereby, the electronic paper 600 installed in the main body 801 can be viewed from the outside of the main body 801. That is, in the display 800, the display surface is configured by visually recognizing the electronic paper 600 installed in the main body 801 on the transparent glass plate 804.

In addition, a terminal portion 806 is provided at the leading end of the electronic paper 600 in the insertion direction (left side in FIG. 15A), and the electronic paper 600 is installed in the main body 801 inside the main body 801. A socket 807 to which the terminal portion 806 is connected in the state is provided. A controller 808 and an operation unit 809 are electrically connected to the socket 807.
In such a display 800, the electronic paper 600 is detachably installed on the main body 801, and can be carried and used while being detached from the main body 801. This improves convenience.
As described above, the display sheet, the display device, and the electronic apparatus according to the present invention have been described based on the illustrated embodiment. It can be replaced with that of the configuration. In addition, any other component may be added to the present invention. Moreover, you may combine each embodiment suitably.

  In the above-described embodiment, the white particles A and the black particles B are charged particles that are charged to opposite poles. However, the present invention is not limited to this. For example, one of the white particles A and the black particles B is positive or negative. It is also possible to use charged particles that are electrically charged and non-charged particles that are not substantially charged. In this case, when the height of the partition wall member 6 is H and the average particle diameter of the charged particles of the white particles A and the black particles B is R, the height of the display layer 400 (opposite the substrate 12). It is only necessary to satisfy the numerical range of (H + R) or more and (H + 10R) or less (separation distance from the substrate 11). This is because the uncharged particles are maintained in a dispersed state in the dispersion medium regardless of the presence or absence of an electric field and the orientation of the display device, so that the particles do not easily settle as described above. Therefore, it is sufficient to prevent sedimentation of charged particles.

The average particle diameter of the uncharged particles is preferably larger than the gap between the partition wall member 6 and the substrate 12 (the maximum value of the gap that can be generated). Thereby, the movement of uncharged particles between pixels can be reliably prevented.
In this case, the black particles are preferably charged particles and the white particles are preferably uncharged particles. In this case, when black particles are collected on the first electrode side, a white display state is obtained, and when black particles are collected on the second electrode side, a black display state is obtained. Further, by dispersing the white particles, the light from the display surface 121 can be reflected and diffused more efficiently, and white with higher reflectivity can be displayed.

  Moreover, although embodiment mentioned above demonstrated what the average particle diameter of a white particle and a black particle is mutually equal, it is not limited to this, A mutual average particle diameter may differ. In this case, when the height of the partition wall member 6 is H and the average particle diameter of the particles having the smaller average particle diameter among the white particles A and the black particles B is R, the height of the display layer 400 (with the substrate 12 and It is only necessary to satisfy the numerical range of (H + R) or more and (H + 10R) or less (distance from the counter substrate 11).

  In the above-described embodiment, the configuration in which the partition member has a lattice shape has been described. However, the configuration of the partition member 6 is not limited to this as long as the particles can be prevented from sedimentation when the display sheet is erected. . For example, the partition member may have a configuration in which a plurality of wall portions extending in a direction perpendicular to the vertical direction (horizontal direction) are arranged in parallel along the vertical direction when the display layer is erected. Good.

Next, specific examples of the present invention will be described. However, the present invention is not limited to these examples.
1. Manufacture of display device (Example 1)
<1> First, titanium oxide particles were prepared as white particles, and titanium black particles were prepared as black particles. Then, these particles were dispersed in dimethyl silicone oil (dispersion medium) to prepare a dispersion. The titanium oxide particles and the titanium black particles were each subjected to graft modification so as to be charged with opposite polarities. Both the titanium oxide particles and the titanium black particles had an average particle size of 50 nm.

<2> Moreover, the sheet | seat member comprised by polyethylene was prepared and the lattice-shaped partition member was obtained by forming many through-holes in a sheet | seat member by an etching. The partition wall member had a height (thickness) of 50 μm.
<3> Next, a PET-ITO substrate on which an electrode (second electrode) made of ITO was formed was prepared. Subsequently, the sealing part which consists of an epoxy-type adhesive agent was formed in the edge (outer peripheral part) of a PET-ITO substrate.

Next, the partition member was disposed in the recess formed by the PET-ITO substrate and the sealing portion, and then the dispersion was supplied into the recess to fill the recess with the dispersion. Thereby, a display layer was obtained. Subsequently, the circuit board in which the individual electrode made of ITO was formed on the display layer was disposed, and then the display device was obtained by bonding to the sealing portion using a roll laminator.
The thickness of the display layer of the obtained display device was 50.05 μm. That is, the obtained display sheet was able to form a gap of 50 nm (one time the average particle diameter) between the PET-ITO substrate and the partition member.

(Example 2)
A display device of Example 2 was obtained in the same manner as Example 1 except that the thickness of the display layer of the obtained display sheet was 50.1 μm. That is, the obtained display sheet was able to form a gap of 150 nm (three times the average particle diameter) between the PET-ITO substrate and the partition member.

(Example 3)
A display device of Example 3 was obtained in the same manner as in Example 1 except that the thickness of the display layer of the obtained display sheet was 50.15 μm. That is, the obtained display sheet was able to form a gap of 250 nm (5 times the average particle diameter) between the PET-ITO substrate and the partition member.

Example 4
A display device of Example 4 was obtained in the same manner as in Example 1 except that the thickness of the display layer of the obtained display sheet was 50.2 μm. That is, the obtained display sheet was capable of forming a gap of 300 nm (six times the average particle diameter) between the PET-ITO substrate and the partition member.

(Example 5)
A display device of Example 5 was obtained in the same manner as in Example 1 except that the thickness of the display layer of the obtained display sheet was 50.25 μm. That is, the obtained display sheet was capable of forming a gap of 400 nm (eight times the average particle diameter) between the PET-ITO substrate and the partition member.

(Example 6)
A display device of Example 6 was obtained in the same manner as in Example 1 except that the thickness of the display layer of the obtained display sheet was 50.25 μm. That is, the obtained display sheet was able to form a gap of 500 nm (10 times the average particle diameter) between the PET-ITO substrate and the partition member.

(Example 7)
A display device of Example 7 was obtained in the same manner as in Example 1 except that the thickness of the display layer of the obtained display sheet was 50.25 μm. That is, the obtained display sheet was able to form a gap of 450 nm (11 times the average particle diameter) between the PET-ITO substrate and the partition member.

(Comparative Example 1)
A display device of Comparative Example 1 was obtained in the same manner as Example 1 except that the partition member was omitted.
(Comparative Example 2)
A display device of Comparative Example 2 was obtained in the same manner as in Example 1 except that the thickness of the display layer of the obtained display sheet was 50 μm. That is, the obtained display sheet could not form a gap between the PET-ITO substrate and the partition member.

(Comparative Example 3)
A display device of Comparative Example 3 was obtained in the same manner as in Example 1 except that the thickness of the display layer of the obtained display sheet was 50.02 μm. That is, the obtained display sheet was capable of forming a gap of 20 nm (less than half of the average particle diameter) between the PET-ITO substrate and the partition member.

2. Evaluation (2-1) Whether or not the partition member is visually recognized For each of Examples 1 to 7 and Comparative Examples 1 to 3, the entire display surface is in a white display state, and then the partition member is removed from the display surface. Whether it was visually recognized was observed using a digital microscope (product name: VHX-600, manufactured by Keyence Corporation) and a lens (product name: VH-Z100, manufactured by Keyence Corporation). The measurement results are shown in Table 1 below.

  As shown in Table 1, in each of the display devices of Examples 1 to 7, white particles (titanium oxide particles) entered between the PET-ITO substrate and the partition member, so that the partition member was covered with the white particles. It was hidden. In other words, white particles were present in almost the entire area of the display surface 121. From the above, in each of Examples 1 to 3, it was confirmed that the entire display surface could be used as an effective display area. s

  On the other hand, in Comparative Examples 2 and 3, white particles (titanium oxide particles) cannot enter between the PET-ITO substrate and the partition member, and the partition member is not covered with the white particles. The member was visible. That is, in Comparative Examples 2 and 3, it was confirmed that the entire display surface cannot be used as an effective display area. In addition, about the comparative example 1, since the partition member was abbreviate | omitted, evaluation was abbreviate | omitted.

(2-2) Measurement of reflectance For each of Examples 1 to 7 and Comparative Examples 1 to 3, the reflectance was measured when the entire display surface was in a white display state. The reflectance was measured 3 seconds after the switch to the white display state was completed. The reflectance of the display color of each display device indicates the ratio of the reflection amount of the display color of the display device when the reference white (standard sample) reflection amount is 100. In addition, the reflectance was measured using a color luminance meter ("BM-5A" manufactured by Topcon Corporation).

Further, for each of Examples 1 to 7 and Comparative Examples 1 to 3, the reflectance was measured when the entire display surface was in a black display state. This measurement was performed in the same manner as the measurement of the reflectance in the white display state.
Table 2 shows the reflectivity in each of Examples 1 to 7 and Comparative Examples 1 to 3 obtained as described above.

As shown in Table 2, the white reflectance measured by the display devices of Examples 1 to 7 is not inferior to the reflectance measured by the display device of Comparative Example 1. Met. That is, in Examples 1-7, it was confirmed that the partition member is effectively prevented (suppressed) from adversely affecting the white display.
On the other hand, the white reflectance measured by the display devices of Comparative Examples 2 and 3 is lower than the reflectance measured by the display device of Comparative Example 1, and the partition member adversely affects the white display. It was confirmed that

Moreover, all the black reflectance measured with the display apparatus of each Example 1-7 was a thing inferior compared with the reflectance measured with the display apparatus of the comparative example 1. FIG. That is, in Examples 1-7, it was confirmed that the partition member is effectively prevented (suppressed) from adversely affecting the black display.
On the other hand, the black reflectance measured by the display devices of Comparative Examples 2 and 3 is higher than the reflectance measured by the display device of Comparative Example 1, and the partition member adversely affects the black display. It was confirmed that

(2-3) Measurement of reflectance For each of Examples 1 to 7 and Comparative Examples 1 to 3, the entire display surface was in a white display state, and voltage application was stopped, and the display surface was in the vertical direction. The reflectance when the display device was stood and left for 10 minutes so as to be parallel was measured. Further, the reflectance was measured in a region on the upper side in the vertical direction in the display surface (that is, a region where the number of particles may decrease due to particle settling).

Further, for each of Examples 1 to 7 and Comparative Examples 1 to 3, the entire display surface is displayed in black, and the display surface is parallel to the vertical direction in a state where voltage application is stopped. The reflectance when the apparatus was stood and left for 10 minutes was measured.
The reflectance was measured in the same manner as (2-2) described above.
Table 3 shows the reflectivity in each of Examples 1 to 7 and Comparative Examples 1 to 3 obtained as described above. The numerical values in parentheses in Table 3 indicate the difference from the reflectance shown in Table 2.

As shown in Table 3, the white reflectance measured by the display devices of Examples 1 to 7 was almost the same as the reflectance measured in (2-2) described above. Especially about the display apparatus of Examples 1-3, it was the same as the reflectance measured by (2-2) mentioned above. Thereby, it was confirmed that the movement (sedimentation) of the white particles in the vertical direction is prevented by the partition member.
On the other hand, the white reflectance measured with the display device of Comparative Example 1 in which the partition member was omitted was significantly reduced from the reflectance measured in (2-2) described above. Accordingly, it was confirmed that white particles were precipitated in the display device without the partition member.

Moreover, as shown in Table 3, all the black reflectances measured by the display devices of Examples 1 to 7 were almost the same as the reflectances measured in (2-2) described above. Thereby, it was confirmed that the movement (sedimentation) of the black particles downward in the vertical direction is prevented by the partition member.
On the other hand, the black reflectance measured with the display device of Comparative Example 1 in which the partition wall member was omitted was significantly increased from the reflectance measured in the above (2-2). Accordingly, it was confirmed that black particles were precipitated in a display device without a partition member.

  DESCRIPTION OF SYMBOLS 1 ... Base 2 ... Base 3 ... 1st electrode 4 ... 2nd electrode 5 ... Spacer 6 ... Partition member 6a ... First partition member 6b ... Second partition member 61, 61a, 61b ··· First wall 62, 62a, 62b ··· Second wall 7 ··· Dispersion medium 9 ··· Sealing portion 100 · · · Dispersion liquid 11 and 11E · · · Counter substrate 12 and 12E · · · Substrate 121 ··· Display Surface 20, 20A, 20B, 20C, 20D, 20E ... Display device 21, 21E ... Display sheet 22 ... Circuit board 22E ... Writing device 221E ... Pedestal 222E ... Common electrode 223E ... Partial electrode 224E ... Writing pen 225E ... Voltage application means 400 ... Display layer 600 ... Electronic paper 601 ... Main body 602 ... Display unit 800 ... Display 801 ... Main body 8 2a, 802b ... Pair of conveying rollers 803 ... Hole 804 ... Transparent glass plate 805 ... Insertion port 806 ... Terminal part 807 ... Socket 808 ... Controller 809 ... Operation part A ... White particles B ... Black particles S, S1, S2 ... Area W ... Thickness

Claims (11)

A first substrate provided on the display surface side;
A second substrate disposed opposite the first substrate;
A display layer provided between the first substrate and the second substrate and filled with a dispersion liquid in which at least one kind of positively or negatively charged particles is dispersed in a dispersion medium;
A partition member provided in the display layer and dividing the display layer into a plurality of regions in plan view of the display layer;
A display sheet, wherein the distance between the first substrate and the second substrate is (H + R) or more, where H is the height of the partition member and R is the average particle diameter of the particles.   The display sheet according to claim 1, wherein a separation distance between the first substrate and the second substrate is (H + 10R) or less.   The display sheet according to claim 1, wherein the partition member is suspended in the dispersion medium.   The display sheet according to claim 3, wherein a spacer for maintaining a separation state between the partition member and the first substrate is disposed between the partition member and the first substrate.   The display sheet according to claim 1, wherein the partition member is fixedly provided in the display layer.   The display sheet according to claim 1, wherein the partition member is provided in contact with the second substrate.   The display sheet according to claim 1, wherein a cross-sectional area of each of the plurality of regions on the first substrate side is gradually increased from the second substrate toward the first substrate. The partition member includes a first partition member, and a second partition member provided closer to the first substrate than the first partition member,
The display sheet according to any one of claims 1 to 7, wherein a region divided by the second partition member is smaller than a cross-sectional area of the region divided by the first partition member. The dispersion includes first particles that are positively or negatively charged, and second particles that are charged on the opposite side of the first particles.
The display sheet according to any one of claims 1 to 8, wherein an average particle diameter of the first particles and the second particles is substantially equal.   A display device comprising the display sheet according to claim 1.   An electronic apparatus comprising the display device according to claim 10.

Images