JP2013044904A - Electrophoretic display device and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophoretic display device that performs high quality display.SOLUTION: An electrophoretic display device 150 includes a display area 10 and an outer frame area 60 provided outside the display area 10. The display area 10 includes a display cell 271. The outer frame area 60 includes an outer frame cell 276. The display cell 271 is filled with a first dispersion liquid containing first particles and second particles. The outer frame cell 276 is filled with a second dispersion liquid containing at least the first particles. The first dispersion liquid and the second dispersion liquid are different with regard to a weight ratio of the first particles to a sum of a weight of the first particles and a weight of the second particles. Accordingly, in the outer frame area 60, there can be formed an architrave having a sense of unity with the display area 10 and giving a natural impression to a user and an architrave making the display area 10 stood out. Namely, the electrophoretic display device 150 with high display quality can be realized.

Description

  The present invention relates to a technical field of an electrophoretic display device and a manufacturing method thereof.

  In an electrophoretic display device, a voltage is applied between a pixel electrode and a common electrode facing each other with an electrophoretic material interposed therebetween, and the electrophoretic particles such as charged black particles and white particles are moved spatially to display a display area. An image is formed. Pixel electrodes are arranged in a matrix in the display area, and a scanning line driving circuit, a data line driving circuit (both are referred to as a driving circuit) and various wirings are provided on the outer periphery of the display area. A signal suitable for display is supplied. In the conventional electrophoretic display device, as described in Patent Document 1, dummy electrodes are provided in a frame shape so as to cover these drive circuits and wirings formed on the outer periphery of the display area in a plane. . As a result, the leakage electric field from the drive circuit and wiring is shielded to improve the display quality, and the area where the dummy electrode is provided is used as a frame for the display area.

JP 2006-227053 A

  However, the conventional electrophoretic display device has a problem that since the parasitic capacitance is formed between the dummy electrode and the drive circuit or wiring, the drive circuit is liable to malfunction, and further, high-speed operation is hindered. On the other hand, when the dummy electrode is removed, an uncontrolled region of the electrophoretic material is generated on the outer periphery of the display region due to a leakage electric field from the drive circuit or the wiring, and there is a problem that display quality is deteriorated. In other words, the conventional electrophoretic display device has a problem that it is difficult to achieve both high display quality and high-speed and accurate display driving operation.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

Application Example 1 An electrophoretic display device according to this application example includes a display area and an outer frame area provided so as to surround the display area, and the display area includes a display cell. Is provided with an outer frame cell, the display cell is filled with a first dispersion containing first particles and second particles, and the outer frame cell is filled with a second dispersion containing at least first particles. The weight ratio of the first particles to the sum of the weight of the first particles and the weight of the second particles is different between the first dispersion and the second dispersion.
According to this configuration, since the outer frame area is formed using the same material as that used in the display area, the frame and the display area that have a sense of unity with the display area and bring a natural feeling to the user are displayed. A frame to be emphasized can be formed in the outer frame region. That is, an electrophoretic display device having high display quality is realized.

Application Example 2 In the electrophoretic display device according to the application example, when the weight ratio in the first dispersion is denoted as R ₁ and the weight ratio in the second dispersion is denoted as R ₂ , R ₁ and R ₂ preferably satisfies the relational expression (1).

この構成によれば、外枠領域の色相を第一粒子の色相又は第一粒子の色相に近い色相、或いは第二粒子の色相又は第二粒子の色相に近い色相とする事ができる。従って、表示領域における第二粒子の色相や第一粒子の色相を際立たせる事や、使用者に表示領域における第一粒子の色相と第二粒子の色相とのコントラスト比が高い様に感じさせる事ができる。

According to this configuration, the hue of the outer frame region can be the hue of the first particle or the hue of the first particle, or the hue of the second particle or the hue of the second particle. Therefore, the hue of the second particles and the hue of the first particles in the display area are emphasized, and the user feels that the contrast ratio between the hue of the first particles and the second particles in the display area is high. Can do.

Application Example 3 An electrophoretic display device according to this application example includes a display area and an outer frame area provided so as to surround the display area, and the display area includes a display cell. Is provided with an outer frame cell, the display cell is filled with a first dispersion containing first particles and second particles, and the outer frame cell contains first particles and does not contain second particles. The third dispersion is filled.
According to this configuration, the hue of the outer frame region can be the hue of the first particle. Therefore, the hue of the second particles in the display area can be made to stand out.

Application Example 4 An electrophoretic display device according to this application example includes a display area and an outer frame area provided so as to surround the display area, and the display area includes a display cell. Is provided with an outer frame cell, the display cell is filled with a dispersion liquid in which the first particles are dispersed in the solution at the first composition ratio, and the first particle is contained in the second cell in the outer frame cell. A dispersion liquid dispersed in a solution at a composition ratio is filled, and the first composition ratio and the second composition ratio are different.
According to this configuration, since the outer frame area is formed using the same material as that used in the display area, the frame and the display area that have a sense of unity with the display area and bring a natural feeling to the user are displayed. A frame to be emphasized can be formed in the outer frame region. That is, an electrophoretic display device having high display quality is realized.

Application Example 5 In the electrophoretic display device according to the application example, when the first composition ratio is expressed as C ₁ and the second composition ratio is expressed as C ₂ , C ₁ and C ₂ are: It is preferable that the relational expression 2 is satisfied.

この構成によれば、外枠領域の色相を第一粒子の色相又は第一粒子の色相に近い色相、或いは溶液の色相又は溶液の色相に近い色相とする事ができる。従って、表示領域における溶液の色相や第一粒子の色相を際立たせる事や、使用者に表示領域のコントラスト比が高い様に感じさせる事ができる。

According to this configuration, the hue of the outer frame region can be the hue of the first particles, the hue close to the hue of the first particles, or the hue of the solution or the hue of the solution. Therefore, the hue of the solution and the hue of the first particles in the display area can be made to stand out, and the user can feel that the contrast ratio of the display area is high.

Application Example 6 An electrophoretic display device according to this application example includes a display area and an outer frame area provided so as to surround the display area, and the display area includes a display cell. The outer cell is provided with an outer frame cell, the display cell is filled with a dispersion liquid in which the first particles are dispersed in the first composition ratio, and the outer frame cell is filled with the solution. It is characterized by.
According to this configuration, the hue of the outer frame region can be set as the hue of the solution. Therefore, the hue of the first particles in the display area can be made to stand out.

Application Example 7 In the electrophoretic display device according to the application example described above, the first substrate and the second substrate are provided, and a pixel electrode is provided in a region serving as a display region of the first substrate. It is preferable that no pixel electrode is provided in the region to be the frame region.
According to this configuration, even if a drive circuit or wiring is formed in the outer frame region, there is no pixel electrode in the outer frame region, and the electrophoretic material does not perform electrophoresis, so the hue of the outer frame region is disturbed. There is no. Further, the drive circuit does not malfunction, and further high speed operation is possible. In addition, signal delay in the wiring hardly occurs. In other words, an electrophoretic display device that achieves both high display quality and high-speed and accurate display driving operation can be realized.

Application Example 8 A method for manufacturing an electrophoretic display device according to this application example is a method for manufacturing an electrophoretic display device including a display region and an outer frame region provided so as to surround the display region. A cell forming step of providing a display cell in a region to be a display region on the first substrate and providing an outer frame cell in a region to be an outer frame region, and a discharge device having a first discharge unit and a second discharge unit A first injection step of injecting the first component containing the first particles into the display cell and the outer frame cell from the first discharge unit, and a second discharge of the second component containing the second particles using the discharge device. And a second injection step of injecting at least the display cell from the portion.
According to this configuration, the ratio between the first component and the second component can be easily changed between the display cell and the outer frame cell. In general, if a solution in which a first component and a second component are mixed is to be accurately discharged in a very small amount, the first particles and the second particles are aggregated in the discharge device, which tends to cause a discharge failure. According to this configuration, since the first component and the second component are ejected separately, agglomeration in the ejection device is unlikely to occur, and application defects can be significantly reduced.

Application Example 9 In the method for manufacturing an electrophoretic display device according to the application example described above, in the second injection step, the second component is further transferred from the second discharge portion to the outer frame cell, and the weight of the first particles and the second It is preferable to inject so that the weight ratio of the first particle to the sum of the particle weight is different between the display cell and the outer frame cell.
According to this configuration, the weight ratio of the first particles can be easily changed by changing the introduction amount of the second particles between the display cell and the outer frame cell. Therefore, an electrophoretic display device having high display quality can be easily manufactured.

Application Example 10 In the method for manufacturing an electrophoretic display device according to the application example described above, it is preferable that the injection amount of the first component in the first injection step is different between the display cell and the outer frame cell.
According to this configuration, the weight ratio of the first particles can be easily changed by changing the weight of the first particles between the display cell and the outer frame cell. Therefore, an electrophoretic display device having high display quality can be easily manufactured.

FIG. 3 is a perspective view of the electronic device according to the first embodiment. 1A and 1B are diagrams illustrating an electrophoretic display device according to Embodiment 1, wherein FIG. 1A is a plan view illustrating a configuration of the electrophoretic display device, FIG. 2B is an enlarged plan view taken along line AA ′ in FIG. ) Is a cross-sectional view taken along line AA ′. FIG. 3 is an equivalent circuit diagram of the electrophoretic display device according to the first embodiment. FIG. 3 is a diagram illustrating a method for manufacturing an electrophoretic display device according to the first embodiment. The figure explaining the influence which an outer frame area | region has on a display area. The perspective view which shows the structure of electronic paper. The perspective view which shows the structure of an electronic notebook. FIG. 6 illustrates an example of an electrophoretic display device according to a second embodiment. FIG. 6 illustrates an example of an electrophoretic display device according to a third embodiment. FIG. 10 is a diagram illustrating an example of an electrophoretic display device according to Modification 2. FIG. 10 is a diagram illustrating an example of an electrophoretic display device according to Modification 3.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following drawings, the scale of each layer and each member is made different from the actual scale so that each layer and each member can be recognized.

(Embodiment 1)
"Outline of electronic equipment"
First, an outline of the electronic apparatus and the electrophoretic display device according to the first embodiment will be described with reference to FIGS. 1 and 2.

  FIG. 1 is a perspective view of an electronic apparatus according to this embodiment. 2A and 2B are diagrams illustrating the electrophoretic display device according to this embodiment. FIG. 2A is a plan view illustrating the configuration of the electrophoretic display device, and FIG. 2B is a plan view taken along line AA ′ in FIG. An enlarged view and (c) are cross-sectional views along AA ′.

  As shown in FIG. 1, an electronic device 100 according to the present invention includes an electrophoretic display device 150 and an interface for operating the electronic device 100. Specifically, the interface is the operation unit 120 and includes a switch and the like. The electrophoretic display device 150 is a display module having a display area 10 and an outer frame area 60. The display area 10 includes a plurality of pixels, and an image is displayed on the display area 10 by electrically controlling these pixels. An outer frame area 60 is provided outside the display area 10 so as to surround the display area 10 and forms a frame.

  As shown in FIG. 2, a display cell 271 partitioned by the partition wall 26 is provided in the display area 10, and an outer frame cell 276 partitioned by the partition wall 26 is provided in the outer frame area 60. In the electrophoretic display device 150, these cells 27 are filled with a dispersion liquid having two kinds of particles between a pair of substrates. The two types of particles are a first particle and a second particle, and among these, at least one type is a charged particle that is positively or negatively charged. The first particles have a first color, and the second particles have a second color different from the first color. The first particles and the second particles are dispersed in a liquid to form a dispersion. This dispersion is also called electrophoretic material 24. Here, the two types of charged particles include a first particle charged to a first polarity and a second particle charged to a second polarity opposite to the first polarity. If the first particles charged to the first polarity are positively charged, the second particles charged to the second polarity are negatively charged. In each pixel, the display state is controlled for each pixel by applying an appropriate electric field to such a dispersion to cause electrophoresis of the first particles and the second particles, and a desired image is displayed in the display region 10. Is done.

  The display cell 271 is filled with a first dispersion containing first particles and second particles, and the outer frame cell 276 is filled with a second dispersion containing at least first particles. The second dispersion may further contain second particles. In this case, the ratio of the weight of the first particles to the sum of the weight of the first particles and the weight of the second particles (weight ratio R) is different between the first dispersion and the second dispersion. That is, in the first dispersion, the weight ratio is such that the contrast ratio between the first color and the second color increases when an electric field having a reverse polarity is applied to the display cell 271. On the other hand, in the second dispersion liquid, the weight ratio is such that the display area 10 is enhanced as a frame, or the display content is easy to read or read. By doing so, a frame that has a sense of unity with the display area 10 and brings a natural feeling to the user, or a frame that makes the display area 10 stand out, can be formed in the outer frame area 60, and it has high display quality. The electrophoretic display device 150 is realized. The outer frame cell 276 may be filled with a third dispersion liquid containing the first particles and not containing the second particles. The composition of the dispersion will be described later.

"Structure of electrophoretic display device"
Next, the structure of the electrophoretic display device according to this embodiment will be described with reference to FIG.
The electrophoretic display device 150 includes a first substrate 80 and a second substrate 90. A plurality of pixels 20 are arranged in a matrix in the display area 10. A pixel electrode 22 and a pixel circuit (see FIG. 3B) are formed for each pixel 20 in a region to be the display region 10 on the first substrate 80, and a common electrode 23 is formed on the second substrate 90 on almost the entire surface. Has been. A cell 27 partitioned by a partition wall 26 is provided between both substrates, and the electrophoretic material 24 is filled in the cell 27. A sealing material 110 is disposed outside the cell 27 to bond the first substrate 80 and the second substrate 90 and to isolate and protect the electrophoretic material 24 from the external environment. Thus, the electrophoretic material 24 can be electrophoresed between the pixel electrode 22 and the common electrode 23. The second substrate 90 is transparent, and the user views the electrophoretic display device 150 from the second substrate 90 side. In the present embodiment, as an example, the first color is white, the white first particles are charged to the first polarity (positive, positive), the second color is black, and the black second It is assumed that the particles are charged to the second polarity (negative, negative). Therefore, for example, to display white, white particles are brought closer to the common electrode 23 and black particles are brought closer to the pixel electrode 22 as shown in the leftmost column of FIG. As a result, as shown in the leftmost column of FIG. 2B, white display is obtained when viewed from the second substrate 90 side.

  Regarding the color of the particles, the combination of the first color and the second color is not limited to black and white, and may be a combination of colors (complementary colors) in the opposite positions in the color circle. For example, a combination of red particles and green particles, a combination of yellow particles and purple particles, a combination of blue particles and orange particles, or the like may be used. In addition, an appropriate two colors may be combined from the three primary colors of additive color mixture of red, green and blue, or an appropriate two colors may be combined from the three primary colors of subtractive color mixture of cyan, magenta and yellow. It is also possible to combine two colors from these six colors. Also, if one type of two types of particles is positively or negatively charged, the other type of particles may not necessarily be charged (the other particle is electrically neutral). It does not matter.) This is because if either particle is charged, it functions as the electrophoretic material 24. However, as in the present embodiment, when the first particles and the second particles are charged with opposite polarities, the first particles and the second particles are quickly and surely made according to the electric field applied to each pixel. Can be separated. That is, a high-contrast high-quality image can be quickly formed. In contrast to the above example, the first particles may be negatively charged and the second particles may be positively charged. Further, it may be a three-particle system including first positively charged particles, second negatively charged particles, and neutral third particles that are not charged.

  In the display area 10, the partition wall 26 is provided on the first substrate 80 so as to partition each pixel. As a result, one display cell 271 becomes one pixel 20, and the pixel electrode 22 is formed for each display cell 271. The shape of the display cell 271 is quadrangular in plan view, and is almost square. This is because the electronic device 100 of this embodiment is used for an electronic book and is displayed in black and white. In the case of color display, the shape of the display cell 271 may be a rectangle whose short side is one third of the long side. Note that the size of the display cell 271 and the size of the pixel 20 do not necessarily match. A plurality of display cells 271 may be contained in one pixel 20, and conversely, a plurality of pixels 20 may be contained in one display cell 271. The inside of the bowl-shaped display cell 271 is filled with the first dispersion.

Also in the outer frame region 60, the partition wall 26 is provided on the first substrate 80 so as to form the outer frame cell 276. The outer frame cell 276 is also a quadrangle having the same size as the display cell 271. However, the pixel electrode 22 is not provided on the first substrate 80 in the outer frame region 60. Therefore, in the outer frame region 60, the electrophoretic material 24 does not undergo electrophoresis and always has a constant color. The weight ratio R of the second dispersion is determined so that this color becomes a color that makes the display area 10 stand out or looks high in the contrast ratio of the display area 10. After all, the cell 27 provided so as to cover the plurality of pixel electrodes 22 forming the display area 10 is the display cell 271, and the cell 27 provided in the area where the pixel electrode 22 is not formed outside the display area 10. Outer frame cell 276. The inside of the bowl-shaped outer frame cell 276 is filled with the second dispersion. Incidentally, the weight ratio of the first dispersion denoted as R _1, the weight ratio of the second dispersion upon denoted as R _2, R ₁ and R _2, it is preferable to satisfy the relationship of Equation 3 .

  One side of the cell 27 is in the range of 10 μm to 1 cm, and the depth is preferably in the range of 20 μm to 100 μm. As a preferred example, one side of the cell 27 is 71 μm (360 dpi), which is the same as one side of the pixel 20, and its depth is 50 μm. The thickness of the partition wall 26 is preferably in the range of 2 μm to 100 μm, optimally in the range of 3 μm to 30 μm, and preferably 5 μm. The region provided with the partition walls 26 does not contribute to display. However, if one side of the cell 27 is 10 μm or more, the ratio of the partition walls 26 can be reduced to less than 20%, and the electrophoretic display device 150 having a high contrast ratio can be obtained. Can do. Since the distance between the first substrate 80 and the second substrate 90 (the depth of the cell 27) is 100 μm or less, if one side of the cell 27 is 1 cm or less, the electrophoretic display device 150 can be set up vertically even if it stands upright. It can suppress that the electrophoretic material 24 precipitates below by gravity. That is, there is no problem even if the electronic device 100 is used upright. If the depth of the cell 27 is 20 μm or more, the first particles and the second particles can be separated in the vertical direction, so that a sufficiently high contrast ratio can be obtained. If the depth of the cell 27 is 100 μm or less, the electrophoretic distance of the charged particles is shortened, so that the image can be rewritten in a short time of 1 second or less. If the thickness of the partition wall 26 is 2 μm or more, the partition wall 26 can be easily formed by a traditional method using photolithography and etching, and the partition wall 26 can withstand the manufacturing process. If the partition wall 26 has a thickness of 100 μm or less, it is difficult for the human eye to visually recognize it. Note that the volume of the cell 27 in the preferred example is 218 picoliters.

"Circuit configuration"
FIG. 3A is a circuit block diagram showing the configuration of the display area and the drive circuit of the electrophoretic display device according to this embodiment, and FIG. 3B is an equivalent circuit diagram showing the electrical configuration of the pixel. . Next, the drive circuit of the electrophoretic display device 150 according to this embodiment will be described with reference to FIG.

  As shown in FIG. 3A, m rows × n columns of pixels 20 are arranged in a matrix (two-dimensional planar) in the display area 10. In the display area 10, there are m scanning lines 30 (that is, scanning lines Y1, Y2,..., Ym) and n data lines 40 (that is, data lines X1, X2,..., Xn). It is provided so as to cross each other. Specifically, m scanning lines 30 extend in the row direction (that is, the X direction), and n data lines 40 extend in the column direction (that is, the Y direction). Pixels 20 are arranged corresponding to the intersections of m scanning lines 30 and n data lines 40.

  A drive circuit 70 is provided outside the display area 10. The drive circuit 70 includes a controller 71, a scanning line drive circuit 72, a data line drive circuit 73, a common potential supply circuit 74, and the like. The controller 71 controls the operation of the scanning line driving circuit 72, the data line driving circuit 73, and the common potential supply circuit 74, and supplies various signals such as a clock signal and a timing signal to each circuit. A part or all of the drive circuit 70 becomes an outer frame region 60, and an outer frame cell 276 is formed so as to cover these circuits.

Based on the timing signal supplied from the controller 71, the scanning line driving circuit 72 sequentially supplies a scanning signal in a pulse manner to each of the scanning lines Y1, Y2,. The data line driving circuit 73 supplies image signals to the data lines X1, X2,..., Xn based on the timing signal supplied from the controller 71. The image signal takes a multilevel potential between a high potential V _H (for example, 15 V) and a low potential V _L (for example, −15 V). In the present embodiment, the image signal is binary, and the image signal of the high potential V _H is supplied to the pixel 20 rewritten to the first display (white display), and the second display (black display). An image signal having a low potential V _L is supplied to the pixel 20 to be rewritten.

The common potential supply circuit 74 supplies the common potential V _com to the common potential line 50. Note that the common potential V _com may be a constant potential, or may be changed according to, for example, a gradation to be written or a frame. In the present embodiment, the common potential V _com is a reference potential for all potentials, and the common potential is 0V. Therefore, the previous high potential V _H (for example, 15 V) and low potential V _L (for example, −15 V) are directly used as a potential difference with respect to the common potential V _com . Various signals are input / output to / from the controller 71, the scanning line driving circuit 72, the data line driving circuit 73, and the common potential supply circuit 74, but the description of those not particularly related to the present embodiment is omitted. ing.

  As shown in the circuit diagram of FIG. 3B, the pixel 20 includes a pixel switching transistor 21, a pixel electrode 22, a common electrode 23, an electrophoretic material 24, and a storage capacitor 25.

  The pixel switching transistor 21 is composed of, for example, an N-type transistor. Although an upper gate type thin film transistor is employed here, a lower gate type thin film transistor may be used. The pixel switching transistor 21 has a gate electrically connected to the scanning line 30, a source electrically connected to the data line 40, and a drain connected to one end of the pixel electrode 22 and the storage capacitor 25. Electrically connected. The storage capacitor 25 is composed of a pair of electrodes that are arranged to face each other with a dielectric film therebetween, and one electrode (one end) is electrically connected to the pixel electrode 22 and the pixel switching transistor 21 and the other electrode (others). End) is electrically connected to the common potential line 50. The holding capacitor 25 can maintain the image signal for a certain period. The pixel switching transistor 21 receives the image signal supplied from the data line driving circuit 73 via the data line 40 and the timing according to the scanning signal supplied in a pulse form from the scanning line driving circuit 72 via the scanning line 30. Thus, the data is output to the pixel electrode 22 and the storage capacitor 25.

An image signal is supplied to the pixel electrode 22 from the data line driving circuit 73 through the data line 40 and the pixel switching transistor 21. The pixel electrode 22 is disposed so as to face the common electrode 23 with the electrophoretic material 24 interposed therebetween. The common electrode 23 is electrically connected to a common potential line 50 to which a common potential V _com is supplied. The common electrode 23 is provided on the second substrate 90 facing the first substrate 80 on which the pixel electrode 22 is formed, and the electrophoretic particles are electrophoresed in the vertical direction of the cross-sectional view shown in FIG. In addition, the common electrode 23 is provided on the first substrate 80 on which the pixel electrode 22 is formed, and the electrophoretic particles are electrophoresed in the horizontal direction of the cross-sectional view of FIG. 2C (the left-right direction of FIG. 2C). It is good also as a structure.

“Method of manufacturing an electrophoretic display device”
FIG. 4 is a diagram illustrating a method for manufacturing an electrophoretic display device according to this embodiment. Next, a manufacturing method is demonstrated using FIG.
First, the pixel switching transistor 21 and the drive circuit 70 are formed on the first substrate 80 using a thin film element such as a thin film transistor or a thin film capacitor. At that time, the pixel electrode 22 is disposed on the pixel 20. Next, the partition wall 26 is formed. The partition wall 26 is a material that does not dissolve in the solvent used for the electrophoretic material 24, and it does not matter whether it is an organic material or an inorganic material. Specifically, examples of organic materials include urethane resin, urea resin, acrylic resin, polyester resin, silicone resin, acrylic silicone resin, epoxy resin, polystyrene resin, styrene acrylic resin, polyolefin resin, butyral resin, vinylidene chloride resin, Examples include melamine resin, phenol resin, fluororesin, polycarbonate resin, polysulfone resin, polyether resin, polyamide resin, polyimide resin, and the like. These resin simple substance or 2 or more types of composite agents are used. A method for manufacturing the partition wall 26 is not particularly limited. As a preferable example, the film formed on the first substrate 80 is processed using photolithography and chemical etching. In addition, a mold having a concavo-convex shape may be pressed against a heated thermoplastic resin, or a sheet on which cells are formed may be bonded to the first substrate 80. Alternatively, the partition wall 26 may be formed by disposing a resin having fluidity with a solvent or the like by a wet process such as a screen printing method or a gravure printing method.

  The cells 27 are formed on the first substrate 80 by forming the partition walls 26. That is, the display cell 271 is provided in the area to be the display area 10, and the outer frame cell 276 is provided in the area to be the outer frame area 60. After the cell formation step is completed, the display cell 271 is filled with the first dispersion liquid, and the outer frame cell 276 is filled with the second dispersion liquid. This filling operation is performed using a discharge device having a first discharge portion 131 and a second discharge portion 132. An optimal example of the discharge device is an ink jet type discharge device, but a dispenser type discharge device or a screen printing type discharge device may also be applied. Here, an ink jet type ejection device capable of drawing a minute region with high accuracy was used. A first component 241 containing first particles is discharged from the first discharge part 131. Similarly, the second component 242 including the second particles is discharged from the second discharge unit 132. Further, the discharge device preferably includes a third discharge portion 133, and the third component 243 is discharged from the third discharge portion 133. The third component 243 is a solution that does not include the first particles or the second particles and has one composition of the electrophoretic material 24.

  The first particles are titanium oxide as a white pigment, and the first component 241 contains 21.2 wt% of titanium oxide as a white pigment using silicone oil as a solvent. The second particles are black pigment titanium black, and the second component 242 contains 26.5 wt% of black pigment titanium black using silicone oil as a solvent. The third component 243 is a solvent for silicone oil. The filling operation includes a first injection step of injecting the first component 241 from the first discharge part 131 into the display cell 271 and the outer frame cell 276, and injecting the second component 242 from the second discharge part 132 into at least the display cell 271. And a third injection step of injecting the third component 243 from the third discharge part 133 into the display cell 271 and the outer frame cell 276. In the first injection step, the injection amount of the first component 241 may be different between the display cell 271 and the outer frame cell 276. In the second injection step, the second component 242 may be injected into the outer frame cell 276. At this time, the injection is performed such that the weight ratio of the first particle to the sum of the weight of the first particle and the weight of the second particle is different between the display cell 271 and the outer frame cell 276.

In an ink jet type ejection device, by changing the diameter of the ejection part (nozzle), the voltage value supplied to the ejection part, the waveform thereof, etc., the ejection amount per time is about 0.1 picoliter to about 100 picoliter. It can be changed in a wide range. Here, it adjusted so that the discharge amount of one time might be set to 22 picoliters. Since the volume of the cell 27 in the preferred example is 218 picoliters, in the preferred example, one cell 27 is discharged a total of 10 times. As will be described in detail later, a preferred example of the weight percentage of white particles in the first dispersion is 10.6 wt%, and a preferred example of the weight percentage of black particles is 5.3 wt%. In order to achieve such a composition, the first component 241 may be discharged to the display cell 271 five times, the second component 242 may be discharged twice, and the third component 243 may be discharged three times. A preferred example of the weight percent of white particles in the second dispersion is 2.1 wt%, and a preferred example of the weight percent of black particles is 5.3 wt%. In order to achieve such a composition, the first component 241 may be discharged once to the outer frame cell 276, the second component 242 may be discharged twice, and the third component 243 may be discharged seven times. The weight ratio in the preferred example is R ₁ = 0.667, R ₂ = 0.285, and (1 / R ₂ −1) / (1 / R ₁ −1) = 5.

The viscosity range in which a liquid or dispersion having thixotropy such as ink or electrophoretic material 24 can be easily and stably discharged by an ink jet type discharge device is approximately 3 mPas to 30 mPas. If the liquid to be discharged is a non-dispersed solution such as a solvent and its thixotropy is small, the lower limit of the dischargeable viscosity range is lowered to about 0.8 mPas. On the other hand, the kinematic viscosity at which the electrophoretic material 24 is electrophoresed at a high speed is about 4 mm ² / s or less, and the kinematic viscosity in the preferred example of the first dispersion is about 2.5 mm ² / s. The kinematic viscosity is a value obtained by dividing the viscosity by the specific gravity. The specific gravity of the electrophoretic material 24 was about 0.8 g / cm ³ to 1.2 g / cm ³ , and 0.92 g / cm ³ in the preferred example of the first dispersion. Accordingly, the viscosity at which the electrophoretic material 24 is electrophoresed at a high speed is 4.8 mPas or less for most materials, and usually 3 mPas or less. Actually, the viscosity of the preferred example of the first dispersion was 2.3 mPas. It is not easy to discharge such a material with an inkjet discharge device because it is out of the above-described viscosity range, and discharge failure is likely to occur. On the other hand, the viscosities of the first component 241 and the second component 242 are adjusted to about 3 mPas or more by increasing the weight percent of the particles compared to the first dispersion. Therefore, the first component 241 and the second component 242 are easily and stably ejected by an ink jet type ejection device. Since the third component 243 is a solvent and has a viscosity of about 2 mPas, the third component 243 is easily and stably discharged. As described above, according to the present embodiment, the electrophoretic material 24 that is difficult to be discharged by an ink jet type discharge device can be discharged easily and stably.

  When discharging the third component 243 and other components to the cell 27, it is preferable to discharge the third component 243 first. Since the third component 243 does not contain particles, nozzle clogging does not occur and stable ejection can be achieved. By discharging the third component 243 first, the discharge region becomes a solvent atmosphere. In this way, when other components including particles are subsequently discharged, the evaporation of the solvent is suppressed, so that aggregation of particles at the nozzle is difficult to occur, and other components can be discharged relatively stably. It is. In addition, since other components including particles are discharged in a state where the third component 243 is accumulated in the cell 27, the solvent evaporates in the cell 27 and the particles are aggregated as solid matter on the partition wall 26 and the bottom surface of the cell 27. There is almost no fear of doing so. That is, the first dispersion and the second dispersion can be kept stable in the cell 27 over the filling operation period.

  When the third component 243 is discharged to the cell 27 together with the components other than the third component 243 such as the first component 241 and the second component 242, the first discharge and the last discharge are performed. It is preferable to discharge the third component 243 and discharge components other than the third component 243 therebetween. The effect of using the first discharge as the third component 243 is as described above. The reason why the last discharge is the third component 243 is to cover the cell 27 containing the particles with the solvent of the third component 243. By doing so, the electrophoretic material 24 can be kept stable inside the cell 27 until the next sealing step is performed, and the surface state of the electrophoretic material 24 for each cell 27 can be made uniform. Moreover, it is difficult for particles to adhere to the upper surface of the partition wall 26 (the bonding surface with the second substrate 90), and defects in the subsequent sealing process and adhesion process can be reduced. In this embodiment, in order to fill one display cell 271 with the first dispersion liquid, the third component 243 is first discharged twice, then the first component 241 is discharged five times, and then the second component 242 is discharged. Was discharged twice, and finally the third component 243 was discharged once again. In order to fill the second dispersion liquid in one outer frame cell 276, the third component 243 is first discharged six times, then the first component 241 is discharged once, and the second component 242 is then discharged 2 times. Finally, the third component 243 was discharged once again. The order of ejection is not limited to this, and any other permutation is possible. For example, when one discharge of the first component 241 is expressed by F, one discharge of the second component 242 is expressed by S, and one discharge of the third component 243 is expressed by T, FFFFFSSTTT Alternatively, it may be an FSFTFFTFT or an FSTFSFTFF.

  When the display area 10 and the outer frame area 60 are combined in an A4 size (vertical 297 mm × horizontal 210 mm) and the definition is 360 dpi, 4209 cells 27 are arranged vertically and 2976 cells are arranged horizontally. The total number is 12,525,984. Since 10 discharges are performed in one cell 27, the total number of discharges is 125, 259, and 840. An inkjet type ejection device can eject at a driving frequency of about 1 kHz to 100 kHz. Since about 200 ejection units are provided per head and the number of heads per ejection device is about 1 to 50, the total number of ejection units per ejection device is about 100 to about 10,000. In the ejection device of this embodiment, the drive frequency was 10 kHz, and the total number of ejection units was 1000. Accordingly, 10 million discharges are made per second, and the filling of the electrophoretic material 24 into the A4 size region is completed in about 12.5 seconds.

  After the electrophoretic material 24 is filled in the cell 27, the top of the cell 27 is sealed as a sealing process. In the sealing step, a precursor resin to be a sealing film is floated on the surface of the electrophoretic material 24, and then a polymerization process or a crosslinking process is performed to react the precursor resin to form a sealing film made of a polymer. Finally, as an adhesion step, an adhesive is applied on the sealing film, and the second substrate 90 on which the common electrode 23 is formed is bonded. The second substrate 90 is a polyester film or the like. The partition wall 26 may be formed on the second substrate 90. That is, the first substrate 80 in which the pixel electrode 22 is formed in the bonding process by performing the cell formation process, the first injection process, the second injection process, the third injection process, the sealing process, and the like on the second substrate 90 as described above. May be pasted together. Also, when the electrophoretic material 24 includes three or more types of particles, a dispersion is prepared for each particle and is discharged from a dedicated discharge unit for each particle. In that case, the third component 243 including only the arrow and the solvent is formed, and the first discharge and the last discharge are the discharge of the third component 243.

  Conventionally, a solution in which first particles and second particles are dispersed is applied. In this case, there is a problem that the first particles and the second particles are aggregated in the discharge device (for example, a channel or a nozzle of the discharge portion) to cause poor coating. On the other hand, in the method for manufacturing the electrophoretic display device 150 described in the present embodiment, the first component 241, the second component 242, and the third component 243 are separately ejected and the electrophoretic material 24 in the cell 27. Therefore, aggregation in the discharge device is unlikely to occur, and application defects can be significantly reduced. Further, since the first particles are uniformly dispersed in the first component 241, and the second particles are uniformly dispersed in the second component 242, the entire coated surface area such as the display area 10 and the outer frame area 60 is obtained. In this case, a uniform dispersion (the first component 241 and the second component 242) can be applied, and as a result, the display characteristics of the electrophoretic display device 150 become uniform. Furthermore, since the storage stability of the first component 241 and the second component 242 is high, there is no need to stir them in the discharge device, and the discharge device can be configured simply. Further, since the storage stability of the first component 241, the second component 242, and the third component 243 is high, it is not necessary to add a dispersion stabilizer or the like to the electrophoretic material 24. Since the dispersion stabilizer reduces the retention of the image displayed on the electrophoretic display device 150, the electrophoretic display device 150 of this embodiment exhibits excellent image retention. Furthermore, since the third component 243 is added to the first component 241 and the second component 242 to form the electrophoretic material 24, the first component 241 and the second component 242 are dispersed with excellent coating properties, and electrophoresis is performed. The material 24 can be a dispersion having excellent electrophoretic properties.

"Dispersion composition"
FIG. 5 is a diagram for explaining the influence of the outer frame area on the display area. Hereinafter, the dispersion composition will be described with reference to FIG.
As shown in FIG. 5, since humans have an illusion, even if the same object is present, the user feels that the hue and gradation differ depending on the situation. In both FIG. 5A and FIG. 5B, the display area 10 has the same gray gradation. However, the display area 10 looks different depending on the brightness of the outer frame area 60. In FIG. 5A, the outer frame region 60 is gray near white, and in FIG. 5B, the outer frame region 60 is gray close to black. In this case, the display area 10 in FIG. 5B looks brighter (whiter) than the display area 10 in FIG. By changing the color of the outer frame region 60 in this way, it becomes possible for the user to make the display region 10 easier to see and to make the contrast ratio feel higher. The dispersion composition in which such an effect appears will be described.

First, the composition of the electrophoretic material 24 (composition of the first dispersion liquid) necessary for realizing the electrophoretic display device 150 having a high contrast ratio, where both the first particles and the second particles are spheres, is considered. When the specific gravity of the first particle (white particle) is ρ _W , the radius of the white particle is r _W , the specific gravity of the second particle (black particle) is ρ _B , and the radius of the black particle is r _B , the cross-sectional area of the black particle is It is expressed by Equation 4.

  When the circle is closely packed on the plane, the area ratio of the circle is Equation 5.

  Therefore, the area occupied by the black particles when densely packed is obtained by dividing Formula 4 by Formula 5 and Formula 6.

If the length of one side of the cell 27 is represented by L, the area of the cell 27 is L ² , and therefore, the number of particles necessary to completely cover the cell 27 in a plane is expressed by Equation 7.

Denoting the number of layers of the required black particles N _B, the total number of black particles necessary is the formula 8.

  The weight of one black particle is Equation 9.

  Therefore, the total weight of the black particles in the cell 27 is the product of Equation 8 and Equation 9, and is given by Equation 10.

The depth of the cell 27 is represented by d, white particles and black particles are put in the cell 27, and the specific gravity of the solvent is ρ _S. The volume obtained by subtracting the volume of the black particles and the volume of the black particles is multiplied by the density of the solvent to obtain Equation 11.

  From Equation 10 and Equation 11, the weight of the entire electrophoretic material 24 (solvent + black particles + white particles) is Equation 12.

The ratio W _B of the black particle weight to the total weight of the electrophoretic material 24 is obtained by dividing Expression 10 by Expression 12 to Expression 13.

Similarly, the ratio W _W of the white particle weight with respect to the total weight of the dispersion is expressed by Equation 14.

  Incidentally, the ratio R of the white particle (first particle) weight to the sum of the white particle (first particle) weight and the black particle (second particle) weight is expressed by Equation 15.

If N _B = N _W = 1, there is a gap of 9.31% according to Equation 5, so that even in an ideal system where the reflectance of white particles is 80% and the reflectance of black particles is 0%. The black display reflectivity is 7.4%, and the white display reflectivity is 72.6%. If there is only one layer of white particles and black particles, the contrast ratio is lowered by the gap. If the two layers of particles are densely packed, theoretically, the surface is completely covered. Therefore, in the ideal system, the reflectance for black display is 0% and the reflectance for white display is 80%. Therefore, it is preferable that at least two layers of black particles and white particles are included in the electrophoretic material 24. As for black particles, it is only necessary to absorb incident light, so in principle, black display can be achieved with two black particles. However, with other color particles, incident light is repeatedly reflected multiple times and emitted as reflected light. Must be done. Therefore, in the case of color particles other than black, such as white particles, it is preferable that about 1.5 to 4 times the black particles are contained in the electrophoretic material 24. A preferred example is twice. That is, the minimum necessary number N _B of black particles for the electrophoretic display device 150 and the minimum required number N _W of white particles (particles of colors other than black) are expressed by Equation 16.

Therefore, the minimum amount W _Bmin of black particles for setting the reflectance of black display to 0% in the ideal system is expressed by Equation 17, and the ratio W _B of the black particle weight to the total weight of the electrophoretic material 24 is W _Bmin. That must be done.

Similarly, the minimum necessary amount W _Wmin of white particles for increasing the reflectance of white display in an ideal system is expressed by Equation 18, and the ratio W _W of the white particle weight to the total weight of the electrophoretic material 24 is equal to or _greater than W _Wmin. It must be said.

In this embodiment, r _B = r _W = 0.1 μm, d = 50 μm, ρ _B = ρ _W = 4 g / cm ³ , ρ _S = 0.8 g / cm ³ , so that N _B = 2 and N _W When W = 4, W _Bmin is 2.3 wt%, and W _Wmin is 4.6 wt%. But as described above is an ideal system, in fact, or agglomerated and white particles and black particles in the electrophoretic material 24 as it may be adsorbed, such as the partition wall 26, the value of N _B and N _W Those who larger Is preferred. According to an experiment, the reflectance of a black display is decreased in accordance with increasing N _B with 3,4,5, 5 or more did not change almost. Therefore, the optimum value of N _B is 5, the preferred range is 3 to 7. As described above, N _W is preferably about twice or more than N _B , and in experiments, the reflectivity of white display is improved as N _W is increased, and the increase in reflectivity is moderate at 10 or more. Therefore, the optimum value of N _W is 10, and a preferable range is 6 or more and 21 or less. When N _B = 5 and N _W = 10, W _B is 5.3 wt% and W _W is 10.6 wt%, which are the composition of the first dispersion described above. With this composition, when the pixel electrode 22 was set to a potential of +15 V and the common electrode 23 was set to 0 V, the pixel displayed white and the reflectance was 45%. Further, when the pixel electrode 22 is set to 0V and the common electrode 23 is set to 15V, the pixel is displayed in black and the reflectance is 6%.

  Next, the composition of the second dispersion and the third dispersion introduced into the outer frame region 60 will be described. In the third dispersion, the outer frame cell 276 is filled with a dispersion containing one kind of particles of the first particles or the second particles. When the outer frame cell 276 is filled with the third dispersion liquid containing only white particles, the outer frame region 60 has a reflectance of 80%, and a slightly grayish black (for example, a black display having a reflectance of about 8% or more). Even if displayed in the display area 10, the user can feel like a deep black with low reflectivity. On the other hand, when the outer frame cell 276 is filled with the third dispersion liquid containing only black particles, the reflectance of the outer frame region 60 is almost 0%, which is slightly grayish white (for example, white having a reflectance of about 40% or less). Even if (display) is displayed in the display area 10, the user can feel it like bright white with high reflectance.

When the outer dispersion cell 276 is filled with the second dispersion, when the weight ratio in the first dispersion is denoted as R ₁ and the weight ratio in the second dispersion is denoted as R ₂ , R ₁ and R ₂ preferably satisfies the relational expression of Expression 19.

The weight of the first particle in the first dispersion is a ₁ and the weight of the second particle is b ₁ . Similarly the weight of the first particles in the second dispersion and a _2, the weight of the second particles and b _2. Also, α and β are defined as a ₂ = αa ₁ and b ₂ = βb ₁ . In this way, β / α is expressed by Equation 20.

Therefore, the formula 1 indicates that the ratio of the first particles to the second particles in the second dispersion is more than twice the ratio of the first particles to the second particles in the first dispersion, or less than half. It makes sense. As a result, the display quality is improved and the display area 10 can be used efficiently. For example, in the preferred example of R ₁ = 0.667, if R ₂ = 0.938, β / α = 0.133, and the outer frame region 60 is white with a reflectance of 45%. This is equal to the reflectance when white display is performed in the display area 10, and the outer frame area 60 can be used as a margin. Conventionally, a margin is provided inside the display area 10, but the electrophoretic display device 150 of the present embodiment can display characters up to the outermost periphery of the display area 10 by the margin of the outer frame area 60. That is, the second dispersion liquid may be determined so that the outer frame area 60 has the same hue as when the display area 10 displays white. The reflectance of the second dispersion can be expressed as white particle ratio (R ₂ ) × white reflectance (80% in a preferred example) × correction coefficient (about 0.6 according to experiments). The correction factor is black particle that absorbs light once and becomes black, while white needs to be reflected by white particle multiple times and reach human eyes. This corrects the point where the reflectance of the bidispersed liquid is smaller than the value of the ratio of white particles × white reflectance.

As another preferred example of R _{2, in} the preferred example of R ₁ = 0.667, if R ₂ = 0.833, β / α = 0.4, and the outer frame region 60 has a reflectance of 40%. A slightly grayish white. In this way, the second dispersion liquid may be determined so that the reflectance of the outer frame region 60 is slightly lower than when the display region 10 displays white. In this way, the white display in the display area 10 seems whiter for the user and the black display in the display area 10 appears black, so that the user can feel that the contrast ratio is high. This effect works only when R ₂ = 0.8, β / α = 0.5, and the reflectance of the outer frame region 60 is about 38%. Therefore, as shown in Equation 1, β / α is 0. Less than 5.

As another preferred example of R _{2, in} the preferred example of R ₁ = 0.667, if R ₂ = 0.125, β / α = 14, and the outer frame region 60 is black with a reflectance of 6%. It becomes. This is equal to the reflectance when black display is performed in the display area 10. Some e-book users prefer to display white text on a black background to avoid eye strain. In such a case, the outer frame area 60 can be used as a black margin (black margin). That is, the second dispersion liquid may be determined so that the outer frame area 60 has the same hue as when the display area 10 displays black.

As another preferred example of R _{2, in} the preferred example of R ₁ = 0.667, if R ₂ = 0.285, β / α = 5, and the outer frame region 60 has a reflectance of 13.7%. It becomes a slightly grayish black. In this way, the second dispersion liquid may be determined so that the reflectance of the outer frame region 60 is slightly higher than when the display region 10 displays black. In this way, the white display in the display area 10 seems whiter and the black display in the display area 10 looks blacker, so that the user can feel that the contrast ratio is high. This effect works when R ₂ = 0.5, β / α = 2, and the reflectance of the outer frame region 60 is about 24%. Therefore, as shown in Equation 1, β / α is 2 or more. Become.

  Next, the base material of the electrophoretic material 24 such as the first dispersion will be described. The electrophoretic material 24 is mainly composed of colored particles such as first particles and second particles, a solvent, and other additives. Colored particles include pigments themselves and those obtained by mixing resin-based fine particles with color materials such as pigments and dyes. Examples of coloring materials such as pigments and dyes include the following. As the black color material, black pigments and black dyes such as aniline black, carbon black and titanium black are used. As the white color material, white pigments such as titanium oxide and antimony oxide are used. As the yellow color material, an azo pigment such as monoazo, a yellow pigment such as isoindolinone or yellow lead, or a yellow dye is used. As the red color material, red pigments and red dyes such as quinacridone red and chrome vermilion are used. As the blue color material, blue pigments and blue dyes such as phthalocyanine blue and indanthrene blue are used. As the green color material, a green pigment such as phthalocyanine green or a green dye is used.

  When the pigment itself is used as colored particles, the pigment may be used as it is, or the surface of the pigment particles may be coated with a resin material or another pigment. 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. These particles are suitable as white particles. Examples of the resin fine particles include acrylic resins, urethane resins, urea resins, epoxy resins, polystyrenes, polyesters, polyethylenes, polypropylenes, and the like, and one or more of these are used in combination. The resin-based fine particles mixed with the coloring material are those in which the surface of the resin fine particles is coated with pigments or dyes in addition to those obtained by mixing pigments and dyes with resin materials at an appropriate composition ratio. Is also included. The surface of these colored particles may be modified with an organic substance such as a polymer. The colored particles are preferably small from the viewpoint of dispersion stability. Specifically, those having an average particle size in the range of about 10 nm to about 3 μm are preferable, and those having an average particle size in the range of about 100 nm to about 1 μm are more preferable. The specific gravity of the particles is preferably close to the specific gravity of the solvent from the viewpoint of dispersion stability.

  As the solvent, a highly insulating organic solvent is preferable. The highly insulating organic solvent is not particularly limited, but o-xylene, m-xylene, p-xylene, toluene, benzene, dodecylbenzene, hexylbenzene, phenylxylylethane, naphthenic hydrocarbons, etc. Aromatic hydrocarbons, aliphatic hydrocarbons such as cyclohexane, n-hexane, kerosene, paraffinic hydrocarbons, various esters such as ethyl acetate and butyl acetate, acetone, methyl ethyl ketone, methyl isobutyl Ketones such as ketones, or alcoholic solvents such as methanol, ethanol, isopropanol, octanol, methyl cellosolve, or chlorobutane, chloroform, trichloroethylene, trichlorofluoroethylene, trichloroethane, carbon tetrachloride, cyclohexyl Ride, chlorobenzene, 1,1,2,2-tetrachloroethylene, ethane trifluoride ethane, ethyl tetrafluoride dibromide, ethane bromide, ethane tetrafluoride difluoride, methylene iodide, triiodosilane, iodide Examples thereof include halogenated hydrocarbons such as methyl, silicone oil such as carbon disulfide, and polydimethylsiloxane. These solvents may be used alone or in combination of two or more.

"Electronics"
Next, electronic devices to which the above-described electrophoretic display device is applied will be described with reference to FIGS. Below, the case where the electrophoretic display device described above is applied to electronic paper and electronic notebook is taken as an example.

  FIG. 6 is a perspective view illustrating a configuration of electronic paper. As shown in FIG. 6, the electronic paper 400 includes the electrophoretic display device 150 according to this embodiment, and has an outer frame region 60 around the display region 10. The electronic paper 400 has flexibility, and is composed of a rewritable sheet that exhibits the same texture and flexibility as conventional paper.

  FIG. 7 is a perspective view showing the configuration of the electronic notebook. As shown in FIG. 7, an electronic notebook 500 is obtained by bundling a plurality of electronic papers 400 shown in FIG. 6 and sandwiching them between covers 501. The cover 501 includes a display data input unit for inputting display data sent from an external device, for example. Thereby, according to the display data, the display content can be changed or updated while the electronic paper is bundled.

  Since the electronic paper 400 and the electronic notebook 500 described above include the electrophoretic display device 150 according to the present embodiment, high-quality image display can be performed. In addition to these, the electrophoretic display device 150 according to the present embodiment can be applied to electronic devices such as wristwatches, mobile phones, and portable audio devices.

As described above, according to the electrophoretic display device 150 and the manufacturing method thereof according to this embodiment, the following effects can be obtained.
Since the weight ratio of the first particles can be easily changed between the display cell 271 and the outer frame cell 276, and the outer frame region 60 is formed using the same material as that used in the display region 10. A frame that has a sense of unity with the region 10 and brings a natural feeling to the user, and a frame that makes the display region 10 stand out can be formed in the outer frame region 60. That is, the electrophoretic display device 150 having high display quality is realized. Further, the hue of the outer frame region 60 can be set to the hue of the first particle or the hue close to the hue of the first particle. Therefore, it is possible to make the hue of the first particles in the display area 10 stand out and to make the user feel that the contrast ratio of the display area 10 is high.

  Since the first component 241, the second component 242, and the third component 243 are ejected separately, the aggregation of particles in the ejection device hardly occurs, and the application failure can be remarkably reduced. Further, since the first particles are uniformly dispersed in the first component 241, and the second particles are uniformly dispersed in the second component 242, the entire coated surface area such as the display area 10 and the outer frame area 60 is obtained. In this case, uniform application is possible, and as a result, the display characteristics of the electrophoretic display device 150 are also uniform. Furthermore, since the storage stability of the first component 241 and the second component 242 is high, there is no need to stir them in the discharge device, and the discharge device can be configured simply. Further, since the storage stability of the first component 241, the second component 242, and the third component 243 is high, it is not necessary to add a dispersion stabilizer or the like to the electrophoretic material 24, and the electrophoretic display device 150 is an excellent image. Retention will be shown. Furthermore, since the third component 243 is added to the first component 241 and the second component 242 to form the electrophoretic material 24, the first component 241 and the second component 242 are dispersed with excellent coating properties, and electrophoresis is performed. The material 24 can be a dispersion having excellent electrophoretic properties.

  In the present embodiment, the electrophoretic display device 150 has been described using an example in which electrophoresis is performed in the vertical direction of the cross-sectional view shown in FIG. 2C, but the present invention is also applicable to other electrophoretic display devices 150. Is possible. In other words, in the present embodiment, an electric field is applied between the pixel electrode 22 and the common electrode 23 to change the distribution state of the two kinds of particles, and the electrophoresis maintains the display state if no electric field is applied between these electrodes. The present invention can be applied to the display device 150 in general. Specifically, both the pixel electrode 22 and the common electrode 23 are formed on the first substrate 80, and can be applied to an electrophoretic display device 150 that performs electrophoresis in the horizontal direction of the cross-sectional view shown in FIG.

(Embodiment 2)
"Display cell and outer frame cell have different sizes"
FIG. 8 is a diagram illustrating an example of an electrophoretic display device according to the second embodiment. The electrophoretic display device according to this embodiment will be described below. In addition, about the component same as Embodiment 1, the same code | symbol is attached | subjected and the overlapping description is abbreviate | omitted.

  In the present embodiment (FIG. 8), the size of the cell 27 is different from that in the first embodiment (FIG. 2). Other configurations are almost the same as those of the first embodiment. In the first embodiment (FIG. 2), the display cell 271 and the outer frame cell 276 have the same size. On the other hand, in the present embodiment (FIG. 8), the sizes of the display cell 271 and the outer frame cell 276 are different. That is, the outer frame cell 276 is larger than the display cell 271. Of course, the outer frame cell 276 may be smaller than the display cell 271. Thus, the size of the outer frame cell 276 can be arbitrarily determined.

  As described above, according to the electrophoretic display device 150 according to the present embodiment, in addition to the effects of the first embodiment, the following effects can be obtained. Since the outer frame cell 276 is larger than the display cell 271, the filling operation of the second dispersion liquid into the outer frame cell 276 is facilitated. Therefore, the manufacturing yield is improved and the price is superior. Furthermore, since the ratio of the partition walls 26 is reduced in plan view, high display quality can be achieved.

(Embodiment 3)
"Form to provide outer frame electrode"
FIG. 9 is a diagram illustrating an example of an electrophoretic display device according to the third embodiment. The electrophoretic display device according to this embodiment will be described below. In addition, about the component same as Embodiment 1, the same number is attached | subjected and the overlapping description is abbreviate | omitted.

  The present embodiment (FIG. 9) differs from the first embodiment (FIG. 2) in that an outer frame electrode 28 is provided. Other configurations are almost the same as those of the first embodiment. As shown in FIG. 9, the outer frame electrode 28 may be provided in the outer frame region 60, and the second dispersion liquid may be electrophoresed in the outer frame region 60. As described in the first embodiment, when the data line driving circuit 73 that operates at high speed is provided in the outer frame region 60, it is preferable not to provide the outer frame electrode 28. On the other hand, when the driving circuit 70 is mounted as an IC chip outside the first substrate 80, the outer dispersion electrode 28 is not hindered even when the outer frame electrode 28 is provided. Can be electrophoresed. If electrophoresis is possible in the outer frame region 60, subtle changes in hue are possible, and the user can feel a higher quality display.

  The outer frame electrode 28 may be a single electrode provided in the outer frame region 60, or may be an electrode that divides the outer frame region 60 into a plurality of portions. For example, the outer frame electrode 28 may be composed of four electrodes divided for each side outside the display area 10, and the outer frame electrode 28 is provided on the side where the data line driving circuit 73 is formed. Alternatively, the outer frame electrode 28 may be provided on the other three sides. Further, when the outer frame electrode 28 is divided into a plurality of electrodes, each electrode may be controlled independently or collectively. The outer frame electrode 28 is controlled by the controller 71.

  As described above, according to the electrophoretic display device 150 according to the present embodiment, in addition to the effects of the first embodiment, it is possible to control the subtle hue in the outer frame region 60, and to achieve higher quality. It is possible to obtain an effect that the user can feel the display.

  The present invention is not limited to the above-described embodiment, and various changes and improvements can be added to the above-described embodiment. A modification will be described below.

(Modification 1)
"One particle system"
The electrophoretic display device and the manufacturing method thereof according to this modification will be described with reference to FIGS. In addition, about the component same as Embodiment 1, the same code | symbol is attached | subjected and the overlapping description is abbreviate | omitted.

This modified example is different from the first embodiment in the electrophoretic material 24. Other configurations are almost the same as those of the first embodiment. In Embodiment 1, two types of particles are charged with positive and negative polarities, but in this modification, one type of particle is charged positively or negatively in the dye solvent. That is, in this modification, the display cell 271 is filled with a dispersion liquid in which the first particles are dispersed in the solution at the first composition ratio, and the first particles are contained in the outer frame cell 276. A dispersion liquid dispersed in the solution at the second composition ratio is filled, and the first composition ratio and the second composition ratio are different. The composition ratio referred to here is the ratio of the weight of the first particles to the weight of the entire dispersion. Alternatively, the outer frame cell 276 may be filled with a solution that does not contain the first particles. Also, the first composition ratio is expressed as C _1, when the second composition ratio was expressed as C _2, and C ₁ and C _2, it is preferable to satisfy the relational expression of Equation 21.

As a specific example, the solution is a dye solvent obtained by dissolving an oil-soluble black disazo dye synthesized from aniline in an organic solvent such as benzene. The black disazo dye is a 2,2′-dimethyl-2,3-3-diazolate obtained by diazotizing a monoazo intermediate containing aniline as a diazo component and naphthylamine as a coupling component, and reacting 1,8-diaminonaphthalene with acetone. Synthesized by coupling to dihydroperimidine. Black disazo dye is a mixture containing this composition. In this solution, white pigment titanium oxide is dispersed as first particles. In a preferred example, the first composition ratio of the dispersion filled in the display cell 271 is white pigment C ₁ = 11 wt%, black disazo dye 5 wt%, and benzene 84 wt%. In a preferred example, the second composition ratio of the dispersion filled in the outer frame cell 276 is white pigment C ₂ = 2 wt%, black disazo dye 5 wt%, and benzene 93 wt%. Therefore, in the preferred example, (1 / C ₂ −1) / (1 / C ₁ −1) = 6.1.

  The manufacturing method is substantially the same as that of the first embodiment, and the first component 241 includes first particles and is discharged from the first discharge unit 131 to the display cell 271 and the outer frame cell 276. The second component 242 is a black disazo dye and is discharged from the second discharge portion 132, and the third component 243 is an organic solvent and is discharged from the third discharge portion 133. The discharge order and the like are the same as in the first embodiment.

  In the case of a one-particle system as in this modification, the weight of the organic solvent filling the cell 27 is expressed by Equation 22 by multiplying the volume of the cell 27 by subtracting the volume of white particles and the density of the solvent.

  Therefore, the weight of the entire dispersion (solvent + white particles) is expressed by Equation 23.

  The ratio C of the white particle weight with respect to the total weight of the dispersion is obtained by dividing Formula 10 by Formula 23 and Formula 24.

  Further, the minimum necessary white particle is represented by Equation 25 from Equation 16.

As in Embodiment 1, assuming that r _W = 0.1 μm, d = 50 μm, ρ _W = 4 g / cm ³ , ρ _S = 0.8 g / cm ³ , and N _W = 10, C ₁ is 11%. Become. A suitable example regarding C ₂ is the same as R _{2 in the} first embodiment.

  As described above, according to the present modification, even if the electrophoretic material 24 is a one-particle system, the same effect as in the first embodiment can be obtained.

(Modification 2)
"Forms with different outer frame shapes"
FIG. 10 is a diagram illustrating an example of an electrophoretic display device according to this modification. Hereinafter, an electrophoretic display device according to this modification will be described with reference to FIG. In addition, about the component same as Embodiment 1, the same code | symbol is attached | subjected and the overlapping description is abbreviate | omitted.

  The present modification (FIG. 10) differs from the first embodiment (FIG. 2) in the shape of the outer frame region 60. Other configurations are almost the same as those of the first embodiment. In the first embodiment (FIG. 2), the outer frame region 60 forms a single frame, but the shape of the outer frame region 60 is not limited to this, and any shape is possible. For example, as shown in FIG. 10A, a plurality of continuous frames may be provided along the outer periphery of the display area 10 to form a striped frame. Or as shown in FIG.10 (b), the discontinuous frame in which the cut | interruption was provided in some places along outer periphery may be sufficient. Any shape that improves the user's sense is possible.

  As described above, according to the electrophoretic display device 150 according to this modification, in addition to the effects of the first embodiment, various shapes of outer frames can be provided, and the user can have a more comfortable feeling of use. The effect can be obtained.

(Modification 3)
"Forms with different cell shapes"
FIG. 11 is a diagram illustrating an example of an electrophoretic display device according to this modification. Hereinafter, an electrophoretic display device according to this modification will be described with reference to FIG. In addition, about the component same as Embodiment 1, the same code | symbol is attached | subjected and the overlapping description is abbreviate | omitted.

  The present modification (FIG. 11) differs from the first embodiment (FIG. 2) in the shape of the cell 27. Other configurations are almost the same as those in the first and second embodiments. In the first embodiment (FIG. 2), the shape of the cell 27 is a right-angled quadrangle, but the shape of the cell 27 can be various other shapes. For example, as shown in FIG. 11A, the shape of the cell 27 may be a triangle, or as shown in FIG. 11B, it may be a parallelogram or a rhombus. In addition, a hexagonal honeycomb may be used. Any shape is possible as long as the shape covers the plane.

As described above, according to the electrophoretic display device 150 according to this modification, in addition to the effects of the first embodiment, the shape of the cell 27 can be freely set.
I can do things.

  DESCRIPTION OF SYMBOLS 10 ... Display area | region, 20 ... Pixel, 22 ... Pixel electrode, 23 ... Common electrode, 24 ... Electrophoretic material, 26 ... Partition, 27 ... Cell, 28 ... Outer frame electrode, 60 ... Outer frame region, 70 ... Drive circuit, DESCRIPTION OF SYMBOLS 100 ... Electronic device 131 ... 1st discharge part, 132 ... 2nd discharge part, 133 ... 3rd discharge part, 150 ... Electrophoretic display device, 241 ... 1st component, 242 ... 2nd component, 243 ... 3rd component 271 ... display cells, 276 ... outer frame cells.

Claims (10)

A display area, and an outer frame area provided so as to surround the display area,
Display cells are provided in the display area, outer frame cells are provided in the outer frame area,
The display cell is filled with a first dispersion containing first particles and second particles,
The outer frame cell is filled with a second dispersion containing at least the first particles,
An electrophoretic display characterized in that the weight ratio of the first particles to the sum of the weight of the first particles and the weight of the second particles is different between the first dispersion and the second dispersion. apparatus. The weight ratio of the first dispersion denoted as R _1, the weight ratio of the second dispersion liquid upon denoted as R _2, said R ₁ and said R _2, a relational expression Equation 1 The electrophoretic display device according to claim 1, wherein the electrophoretic display device is satisfied.

A display area, and an outer frame area provided so as to surround the display area,
Display cells are provided in the display area, outer frame cells are provided in the outer frame area,
The display cell is filled with a first dispersion containing first particles and second particles,
The electrophoretic display device, wherein the outer frame cell is filled with a third dispersion liquid containing the first particles and not containing the second particles. A display area, and an outer frame area provided so as to surround the display area,
Display cells are provided in the display area, outer frame cells are provided in the outer frame area,
The display cell is filled with a dispersion liquid in which first particles are dispersed in a solution at a first composition ratio,
The outer frame cell is filled with a dispersion in which the first particles are dispersed in the solution at a second composition ratio,
An electrophoretic display device, wherein the first composition ratio is different from the second composition ratio. When the first composition ratio is expressed as C ₁ and the second composition ratio is expressed as C ₂ , the C ₁ and the C ₂ satisfy the relational expression of Expression 2. The electrophoretic display device according to claim 4.

A display area, and an outer frame area provided so as to surround the display area,
Display cells are provided in the display area, outer frame cells are provided in the outer frame area,
The display cell is filled with a dispersion liquid in which first particles are dispersed in a solution at a first composition ratio,
The electrophoretic display device, wherein the outer frame cell is filled with the solution. A first substrate and a second substrate;
A pixel electrode is provided in a region to be the display region of the first substrate,
7. The electrophoretic display device according to claim 1, wherein a pixel electrode is not provided in a region to be the outer frame region of the first substrate. 8. A method for manufacturing an electrophoretic display device comprising: a display region; and an outer frame region provided so as to surround the display region,
A cell forming step of providing a display cell in a region to be the display region on the first substrate and providing an outer frame cell in the region to be the outer frame region;
A first injection step of injecting a first component containing first particles into the display cell and the outer frame cell from the first discharge portion using a discharge device having a first discharge portion and a second discharge portion; ,
A second injection step of injecting a second component containing second particles into at least the display cell from the second discharge unit using the discharge device;
A method for producing an electrophoretic display device, comprising:   In the second injection step, the weight of the first particles with respect to the sum of the weight of the first particles and the weight of the second particles is further transferred from the second discharge unit to the outer frame cell. 9. The method of manufacturing an electrophoretic display device according to claim 8, wherein the injection is performed so that the ratio is different between the display cell and the outer frame cell.   10. The method for manufacturing an electrophoretic display device according to claim 8, wherein the injection amount of the first component in the first injection step is different between the display cell and the outer frame cell.

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