JP5884336B2 - Electrophoretic display device - Google Patents

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. Once the electrophoretic particles move spatially, even if the voltage is removed, diffusion is suppressed by the cohesive force between the particles. For this reason, the electrophoretic display device has a property of maintaining an image even when power is not supplied, and thus is adapted to an electronic book or the like with low power consumption. Conventionally, in order to manufacture such an electrophoretic display device, as described in Patent Document 1, a plurality of cells are formed on a substrate, and an electrophoretic material is filled in these cells by an ink jet method. It was.

JP 2001-343672 A

  However, since the electrophoretic display device has a strong cohesion force between particles, it is not easy to fill the electrophoretic material by the ink jet method. As a result, a defective product may occur in the filling operation. However, in the conventional electrophoretic display device and its manufacturing method, there is a problem that it is difficult to select a good product and a defective product after filling. . In addition, after various filling processes such as a sealing process and a mounting process after filling, the electrophoretic material may change depending on heat or pressure. Conventionally, whether such deterioration has occurred, or There was a problem that it was impossible to grasp what caused the problem when it occurred. That is, the conventional electrophoretic display device and the manufacturing method thereof have problems that it is difficult to determine the quality of the product during the manufacturing process and it is difficult to identify the cause of the defective product.

  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 inspection area provided outside the display area, the display area includes a display cell, and the inspection area includes an inspection area. A cell is provided, the display cell is filled with a first dispersion containing first particles and second particles, and the inspection 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 second particles and the weight of the second particles is different between the first dispersion and the second dispersion.
According to this configuration, the first dispersion liquid and the second dispersion liquid have different compositions, and the second dispersion liquid can be made a dispersion liquid suitable for inspection, so various inspections and cause analysis using the inspection cell. Can be done. That is, the quality of the product can be determined during the manufacturing process, and if a defect occurs, the cause can be specified. Therefore, a good electrophoretic display device can be efficiently manufactured without waste. Moreover, since the cause of the defect can be specified, product improvement and process reform can be promoted.

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、ある検査セルをほぼ第一粒子の分散液、或いはほぼ第二粒子の分散液とする事ができる。従って、各分散液充填の良否を判断する事ができる。又、不良が発生した際には、第一粒子の分散液と第二粒子の分散液とを独立に解析する事ができ、不良原因の特定を容易にする事ができる。

According to this configuration, it is possible to make a certain inspection cell substantially a dispersion of the first particles or a dispersion of the second particles. Therefore, the quality of each dispersion filling can be judged. In addition, when a failure occurs, the dispersion of the first particles and the dispersion of the second particles can be analyzed independently, and the cause of the failure can be easily identified.

Application Example 3 An electrophoretic display device according to this application example includes a display area and an inspection area provided outside the display area. The display area includes a display cell, and the inspection area includes an inspection area. A cell is provided, the display cell is filled with a first dispersion containing first particles and second particles, and the inspection cell contains a third dispersion containing first particles and not containing second particles. It is characterized by being filled.
According to this configuration, a certain inspection cell becomes a dispersion of the first particles. Therefore, it can be judged whether the dispersion liquid containing the first particles is filled. Further, when a defect occurs, only the dispersion of the first particles can be analyzed, and the cause of the defect can be easily identified.

Application Example 4 An electrophoretic display device according to this application example includes a display area and an inspection area provided outside the display area, the display area includes a display cell, and the inspection area includes an inspection area. A cell is provided, and the display cell is filled with a dispersion in which the first particles are dispersed in the solution at the first composition ratio, and the first particles are dissolved in the solution at the second composition ratio in the inspection cell. The dispersion liquid is filled, and the first composition ratio and the second composition ratio are different.
According to this configuration, since the second composition ratio can be a composition ratio suitable for inspection, various inspections and cause analysis can be performed using the inspection cell. That is, the quality of the product can be determined during the manufacturing process, and if a defect occurs, the cause can be specified. Therefore, a good electrophoretic display device can be efficiently manufactured without waste. Moreover, since the cause of the defect can be specified, product improvement and process reform can be promoted.

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、ある検査セルをほぼ第一粒子の分散液、或いは第一粒子を殆ど含まない分散液とする事ができる。従って、分散液の各成分充填の良否を判断する事ができる。又、不良が発生した際には、第一粒子の分散液と第一粒子を殆ど含まぬ分散液とを独立に解析する事ができ、不良原因の特定を容易にする事ができる。

According to this configuration, it is possible to make a certain inspection cell a dispersion of almost the first particles or a dispersion containing almost no first particles. Therefore, it can be judged whether each component of the dispersion is filled. In addition, when a failure occurs, the dispersion of the first particles and the dispersion containing almost no first particles can be analyzed independently, and the cause of the failure can be easily identified.

Application Example 6 An electrophoretic display device according to this application example includes a display area and an inspection area provided outside the display area, the display area includes a display cell, and the inspection area includes an inspection area. A cell is provided, and 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 inspection cell is filled with the solution.
According to this configuration, a certain inspection cell becomes a solution that does not contain the first particles. Therefore, it can be judged whether the solution is filled or not. In addition, when a defect occurs, only the solution can be analyzed, and the cause of the defect can be easily identified.

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 an inspection electrode is provided in the region to be the region.
According to this configuration, various measurements such as electrophoretic measurement, resistance measurement, and impedance measurement can be performed using the inspection electrode, and quality inspection can be performed during each manufacturing process.

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 inspection region provided outside the display region. Using a discharge device having a cell forming step of providing a display cell in a region to be a display region on one substrate and providing a test cell in a region to be an inspection region, and a first discharge portion and a second discharge portion, A first injection step of injecting the first component containing particles into the display cell and the inspection cell from the first discharge unit, and at least the display cell containing the second component including the second particles from the second discharge unit using the discharge device; And a second injecting step of injecting into the substrate.
According to this configuration, the ratio between the first component and the second component can be easily changed between the display cell and the inspection 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 discharged separately, aggregation in the discharge device hardly occurs, and discharge failure can be remarkably reduced.

Application Example 9 In the method of manufacturing an electrophoretic display device according to the application example, in the second injection step, the second component is further fed from the second discharge unit to the inspection cell, and the weight of the first particle and the second particle. It is preferable to inject so that the weight ratio of the first particles to the sum of the weights of the display cell and the inspection cell is different.
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 inspection cell. Therefore, it is possible to easily manufacture an electrophoretic display device that enables various inspections and analysis.

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 inspection cell.
According to this configuration, the weight ratio of the first particles can be easily changed by changing the introduction amount of the first particles between the display cell and the inspection cell. Therefore, it is possible to easily manufacture an electrophoretic display device that enables various inspections and analysis.

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 ′. 2A and 2B are circuit diagrams of the electrophoretic display device according to the first embodiment, in which FIG. 1A is a diagram illustrating an entire configuration, FIG. 2B is a diagram illustrating a pixel circuit, and FIG. FIG. 3 is a diagram illustrating a method for manufacturing an electrophoretic display device according to the first embodiment. 4A and 4B are diagrams illustrating a test element according to Embodiment 1, where FIG. 5A is a fourth test element, and FIG. 5B is a fifth test element. 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 a method for manufacturing an electrophoretic display device according to Modification Example 2.

  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 the first embodiment. 2A and 2B are diagrams illustrating the electrophoretic display device according to the first 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 inspection 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 inspection area 60 is provided outside the display area 10, but the inspection area 60 is hidden by the casing and is not recognized by the user. The inspection area 60 is provided with a single or a plurality of inspection cells.

  As shown in FIG. 2, a display cell 271 partitioned by the partition wall 26 is provided in the display area 10, and an inspection cell 276 partitioned by the partition wall 26 is provided in the inspection 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 one of several inspection cells 276 is filled with a second dispersion containing at least first particles. Yes. 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 set to facilitate various inspections and analysis. By doing so, it is possible to determine whether the product is good or bad during the manufacturing process, and if a defect occurs, the cause can be specified. The inspection cell 276 may be filled with a third dispersion liquid that contains the first particles and does not contain 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.

  As shown in FIG. 2A, an inspection area 60 is provided outside the display area 10 together with the scanning line driving circuit 72 and the data line driving circuit 73. An inspection element is provided in the inspection region 60. In the present embodiment, five test elements including a first test element group 61, a second test element group 62, a third test element group 63, a fourth test element group 64, and a fifth test element group 65 are provided. A group is provided (hereinafter, when there is no need to distinguish each test element group, it is simply referred to as a test element group), and each test element group has one or a plurality of test elements. Of course, the number of inspection element groups is not limited to five, and is a number according to the purpose of inspection, and may be one or plural. The inspection that belongs to the scanning line driving circuit 72, the data line driving circuit 73, and several inspection element groups (in this embodiment, the first inspection element group 61, the second inspection element group 62, and the third inspection element group 63). Wirings connected to an external controller 71 (see FIG. 3) are drawn on the element, and these wirings are collected at one end of the first substrate 80 to form connection terminals 75. In FIG. 2A, a plurality of types of wiring are also drawn as a single black line as a symbol. Further, in these inspection elements, the inspection electrode 28 is formed so as to spread on a plane like the pixel electrode 22, and between the inspection electrode 28 and the common electrode 23, in the vertical direction of the cross-sectional view of FIG. An electric field is applied (between the first substrate 80 and the second substrate 90). The inspection elements belonging to some inspection element groups (in this embodiment, the fourth inspection element group 64 and the fifth inspection element group 65) that are not connected to the external controller 71 are provided with wirings that continue to the inspection terminal 66. ing. Similarly to the above, in FIG. 2A, a plurality of types of wirings connected to a plurality of inspection terminals are also drawn with a single black line as a symbol.

  As shown in FIG. 2B and FIG. 2C, in the display region 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.

The partition wall 26 is also provided on the first substrate 80 so as to form the inspection cell 276 in the inspection element. The test element includes one or more test cells 276. In principle, the planar shape of the inspection cell 276 is a quadrangle having the same size as the display cell 271, but the size and shape of the inspection cell 276 can be changed according to the inspection purpose. In the inspection cell 276 that performs electrical measurement, the inspection electrode 28 is provided on the first substrate 80. An inspection cell 276 that does not have the inspection electrode 28 may be provided depending on the inspection purpose, such as the dispersion liquid discharge inspection. The inspection electrode 28 may be a single electrode spreading in a plane like the pixel electrode 22 inside the inspection cell 276 or a plurality of thin electrodes in a linear shape. In the case where the inspection electrode 28 is a single electrode spread in a plane, an appropriate electric field is applied between the inspection electrode 28 and the common electrode 23 to cross-section the electrophoretic display device 150 (FIG. 2C). Then, the vertical electrical measurement is performed. In the case where the inspection electrode 28 is a plurality of thin electrodes, a suitable electric field is applied between the plurality of inspection electrodes 28, and the cross section of the electrophoretic display device 150 (FIG. 2C) Take an electrical measurement of direction. These will be described later. At least one of the bowl-shaped inspection cells 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 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 cell depth 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.

The inspection element that performs optical measurement such as color tone and reflectance is sized according to the measurement area of the optical measuring instrument, and is preferably a polygon having a diameter in the range of 20 μm to 10 mm. The length of the diameter is the square root of the area of the test element. Further, the polygon is formed by combining one or a plurality of inspection cells 276. If the length of the diameter is larger than 20 μm, a general-purpose microspectrophotometer can be used. If the diameter is smaller than 10 mm, the peripheral area is expanded even if a test element is provided in the peripheral area outside the display area 10. There is nothing. That is, it is possible to provide a test element in the peripheral region where the wiring and the drive circuit 70 are formed. In this embodiment, one inspection cell 276 is used as it is as an inspection element for optical measurement. The inspection cell 276 is a square having the same size as the pixel 20 and a side of 71 μm. On the other hand, an inspection element that performs electrical measurement such as DC resistance measurement or impedance measurement is a rectangle or square having a diameter of about 100 μm to about 10 mm, or a polygon formed by combining a plurality of inspection cells 276. The specific resistance of the electrophoretic material 24 is about 10 giga Ωcm (10 ¹⁰ Ωcm) to 10 tera Ωcm (10 ¹³ Ωcm). When the cell 27 has the deepest depth of 100 μm and the specific resistance of the solvent is 10 giga Ωcm, the area of the test element for electrical measurement is 10 ⁴ μm ² (for example, a square whose one side (diameter length) is 100 μm) Then, the resistance value between the inspection electrode 28 and the common electrode 23 is 1 teraΩ (10 ¹² Ω). When the voltage amplitude in the impedance measurement is 0.1 V, the current to be measured is 100 femto A (10 ⁻¹³ A). Generally, a current value of 1 femto A or more can be measured. Therefore, if the area of the test element for electrical measurement is 10 ⁴ μm ² or more, various electrical measurements can be made relatively easily. Even if the inspection cell 276 has the deepest depth of 100 μm and the specific resistance of the solvent is 10 tera Ωcm, the area of the inspection element for electrical measurement is 10 ² mm ² (for example, one side (diameter length ) Is a 10 mm square), the resistance value between the inspection electrode 28 and the common electrode 23 is 0.1 tera ohms, and various electrical measurements can be performed very easily. A total of 20 test cells 276 of 5 rows and 4 columns were arranged in the test element for performing electrical measurement in this embodiment, and the area was 10 ⁵ μm ² . In this case, the length of the diameter of the test element that performs electrical measurement is 318 μm.

"Circuit configuration"
3A and 3B are circuit diagrams of the electrophoretic display device according to the first embodiment. FIG. 3A is a diagram for explaining the overall configuration, FIG. 3B is a diagram for explaining a pixel circuit, and FIG. FIG. Next, the drive circuit of the electrophoretic display device 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, the common potential supply circuit 74, and a part or all of the inspection elements included in the inspection region 60, such as a clock signal and a timing signal. Various signals are supplied to each circuit.

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 electrode 22 rewritten to the first display (white display), and the second display (black display). image signal of low potential V _L is supplied to the pixel electrode 22 are 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. 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.

  As shown in the circuit diagram of FIG. 3C, the test elements belonging to the first test element group 61, the second test element group 62, and the third test element group 63 include the test electrode 28, the common electrode 23, and the test electrode 28. And the inspection electrode 28 is controlled by the controller 71. The common electrode 23 is connected to the common potential line 50. A switching transistor may be provided between the inspection electrode 28 and the controller. On the other hand, the inspection electrodes 28 are also provided in the inspection elements belonging to the fourth inspection element group 64 and the fifth inspection element group 65, and these are connected to the inspection terminal 66.

“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 in the pixel 20, and the inspection electrode 28 is disposed in the inspection cell 276 that requires the inspection electrode 28. Next, the partition wall 26 is formed. The partition wall 26 is made of a material that does not dissolve in the solvent used for the electrophoretic material 24, and it does not matter whether the material is organic or inorganic. 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 inspection cell 276 is provided in the area to be the inspection area 60. After this cell formation step is completed, the display cell 271 is filled with the first dispersion liquid, and the inspection cell 276 is filled with the second dispersion liquid and the like. This filling operation is performed using a discharge device having a first discharge portion 131 and a second discharge portion 132. A preferred 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 particle or the second particle and forms 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 an injection inspection process and an injection process. The injection inspection process includes a first injection inspection process for injecting the first component 241 from the first discharge part 131 into the inspection cell 276 and a second injection inspection for injecting the second component 242 from the second discharge part 132 into the inspection cell 276. And a third injection inspection step of injecting the third component 243 from the third discharge portion 133 into the inspection cell 276. The injection step includes a first injection step of injecting the first component 241 from the first discharge portion 131 into the display cell 271 and the inspection cell 276, and a second component 242 from the second discharge portion 132 to at least the display cell 271. A second injection step of injecting, and a third injection step of injecting the third component 243 from the third discharge portion 133 into the display cell 271 and the inspection cell 276. First, an injection inspection process is performed to inspect whether or not the discharge device is normal. If there is no abnormality in this inspection, an injection process is performed. On the other hand, if an abnormality is found in the ejection device in the inspection, the ejection device is readjusted and the injection inspection process is performed again. In the first injection process, the injection amount of the first component 241 may be different between the display cell 271 and the inspection cell 276. In the second injection step, the second component 242 may be injected into the inspection 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 inspection 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 amount of application at one time is about 0.1 picoliter to about 100 picoliter It can be changed within a wide range. Here, it adjusted so that the coating 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. Moreover, an 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 into the inspection 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 in which the particles are stored 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. Further, in order to fill the second dispersion liquid in the test cell 276 as an example, first, the third component 243 is first discharged six times, then the first component 241 is discharged once, and then the second component 242 is discharged. Was discharged twice, and 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 is A4 size (height 297 mm × width 210 mm) and the definition is 360 dpi, the number of cells 27 is 4209 vertically and 2976 horizontally, so the total number is 125259854. Since 10 discharges are performed in one cell 27, the total number of discharges is 125,259,840. 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 10,000. . In the ejection device of this embodiment, the drive frequency was 10 kHz and the total number of ejection units was 1000 nozzles. Accordingly, 10 million discharges are made per second, and the filling of the electrophoretic material 24 into the A4 size display region 10 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. After the sealing film is formed, a discharge inspection process is performed. This is an inspection for checking whether or not each discharged component has a quality abnormality. If there is no quality abnormality, the process proceeds to the next step. If an abnormality is found, the charged electrophoretic material 24 is washed away and normal electrophoresis is performed. Refill material 24. 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 cell formation process, the injection inspection process, the injection process, the sealing process, the discharge inspection process, and the like are performed on the second substrate 90 as described above, and the first substrate 80 on which the pixel electrode 22 is formed in the bonding process is bonded. Also good. 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.

  When the first substrate 80 and the second substrate 90 are bonded together, thermocompression bonding, ultraviolet curing, or the like is used. In addition, after the two substrates are bonded together, various processes such as a flexible printed circuit mounting process on the connection terminal 75, a protective film laminating process for protecting the electrophoretic display device 150, or an electronic apparatus mounting process are performed. A process is performed. During these steps, the electrophoretic material 24 is subjected to various external stimuli such as heat, pressure, light, vibration, and impact, and as a result, the electrophoretic material 24 may be altered. Accordingly, an inspection process (collectively referred to as a post-inspection process) is provided in the middle of these processes, and quality inspection of the electrophoretic material 24 and its components (first component 241 and the like) is performed using the inspection element. Is preferred.

  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 unit) to cause discharge failure. 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 discharge defects can be significantly reduced. In addition, 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 coating surface such as the display region 10 and the inspection region 60 is covered. Thus, a uniform dispersion (the first component 241 and the second component 242) can be discharged. 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. 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, the electrophoretic material 24 is used, so that the first component 241 and the second component 242 are dispersions excellent in applicability and dischargeability. The electrophoretic material 24 can be a dispersion having excellent electrophoretic properties.

"First dispersion composition"
Here, the composition of the first dispersion 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.

When the depth of the cell 27 is represented by d, white particles and black particles are put into the cell 27, and the specific gravity of the solvent is ρ _S , the weight of the solvent filling the cell 27 is determined from the volume of the cell 27 to the white particle. 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%.

"Inspection contents"
Next, the contents of inspection performed in the injection inspection process, the discharge inspection process, the post-inspection process, or the defect analysis will be described.

  In the injection inspection process, the ejection state of each component from the ejection device is inspected. That is, the coating amount is inspected by microscopic observation and optical measurement. In the microscopic observation, each component is discharged for each inspection cell 276 so that each component fills the inspection cell 276 (in the case of the present embodiment, 10 times), and whether or not the inspection cell 276 is full for each component is provided in the discharge device. Observe with a microscope. For example, one test cell 276 is discharged to be filled with the first component 241, another test cell 276 is discharged to be filled with the second component 242, and another test cell 276 is filled with the third component 243. After being discharged in this manner, it is observed whether or not these inspection cells 276 are actually filled with the respective components.

  In the optical measurement, some of the inspection cells 276 are filled with the second dispersion liquid that satisfies Equation 19, and the coating amount of each component is inspected by measuring optical characteristics such as reflectance and hue.

Here, R ₁ is a weight ratio in the first dispersion, and R ₂ is a weight ratio in the second dispersion. First, the weight of the first particles in the first dispersion liquid in a predetermined volume and a _1, the weight of the second particles and b _1. Similarly, the weight of the first particles in the second dispersion in the same volume is a ₂ and the weight of the second particles is 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. By doing so, the inspection cell 276 is filled with a dispersion liquid in which the first particles are mainly added and the second particles are slightly added thereto. Various second dispersion liquids such as those filled with the dispersion liquid to which the particles are added are stored. Further, the inspection cell 276 may be filled with a third dispersion liquid that includes the first particles and does not include the second particles, or a third dispersion liquid that includes the second particles and does not include the first particles. Eventually, one inspection cell 276 is filled with a dispersion liquid (third dispersion liquid) that does not contain the second particles and contains the first particles, and another inspection cell 276 contains the second particles slightly, mainly the first particles. Filled with the dispersion liquid (second dispersion liquid), another inspection cell 276 is filled with the same first dispersion liquid as the display cell 271, and the other inspection cell 276 is composed of the second particles as a main component and the first particles slightly. (Second dispersion, white particles 2.1 wt% as described above and black particles 5.3 wt%, example of R ₂ = 0.285), and yet another inspection cell 276 contains the first particles. It becomes the situation where it is filled with the dispersion liquid (third dispersion liquid) that does not contain and contains the second particles. This is because the accuracy of inspection and analysis is improved, and pass / fail judgment and cause analysis are facilitated. For example, in a preferred example of R ₁ = 0.667, in an example of R ₂ = 0.285 (β / α = 5), the inspection cell 276 is slightly grayish with a reflectance of about 14% if normal. Should be black. However, if this is, for example, a reflectance of 10%, this means that ejection failure has occurred in the first component 241 containing white particles. In this manner, by preparing the inspection cell 276 having dispersion liquids having various compositions, the inspection accuracy can be improved, and the cause can be easily identified when a defect occurs.

  In the discharge inspection process, the quality inspection of the electrophoretic material 24 immediately after discharge is performed. This is done by the optical measurements described above and the electrical measurements described below. FIGS. 5A and 5B are diagrams for explaining a test element according to the present embodiment. FIG. 5A shows a test cell 276 forming a fourth test element group, and FIG. 5B shows a single test cell 276 forming a fifth test element group. The inspection elements belonging to the fourth inspection element group 64 and the fifth inspection element group 65 are not controlled by the controller 71, and a linear inspection electrode 28 connected to the inspection terminal 66 is provided. Therefore, even if the common electrode 23 is not provided in the inspection cell 276, the electrical measurement of the dispersion filled in the inspection cell 276 can be realized by directly connecting the electrical measuring device to the inspection terminal 66. As shown in FIG. 5A, the test elements belonging to the fourth test element group 64 have a two-terminal test cell 276 that measures electrical characteristics, and the test cell 276 includes a first test electrode 281. And a second inspection electrode 282 parallel to the first inspection electrode 281. Both the first inspection electrode 281 and the second inspection electrode 282 are connected to the inspection terminal 66. The space S between the first inspection electrode 281 and the second inspection electrode 282 is in the range of 3 μm to 15 μm, and in a preferred example is 7 μm. If it is 3 μm or more, the space S is sufficiently larger than the dimensional deviation that occurs when the inspection electrode is formed by photolithography and chemical etching, so that the error due to the dimensional deviation can be sufficiently reduced in the electrical measurement. In addition, if the space S is 15 μm or less, the electrical measurement of the electrophoretic material 24 having a specific resistance of 10 gigaΩcm or more can be easily performed. In FIG. 5A, inspection cells 276 for 3 rows and 2 columns are drawn (3 rows of inspection elements). Actually, the type of dispersion liquid is changed in rows (the type of dispersion liquid is changed for each test element), and the number of columns is 10. Accordingly, in one inspection element, the first inspection electrode 281 and the second inspection electrode 282 both have a width W of 70 μm × 10 rows = 700 μm, and a ratio of space to width S / W = 1/100. is there. Since the depth of the inspection cell 276 was 50 μm, when the resistance of the electrophoretic material 24 having a specific resistance of 10 gigaΩcm was measured with the inspection elements belonging to the fourth inspection element group 64, it was about 20 gigaΩ, which was easily Measurement is performed. In this way, in order to facilitate electrical measurement, the fourth test element is set so that the ratio S / W of the space S to the width W between the first test electrode 281 and the second test electrode 282 is approximately 1/100 or less. Test elements belonging to group 64 are formed.

  On the other hand, as shown in FIG. 5B, the test elements belonging to the fifth test element group 65 have a four-terminal type test cell 276 for measuring electrical characteristics. The cell 276 is provided with four parallel linear inspection electrodes 28. That is, a first inspection electrode 281, a second inspection electrode 282, a third inspection electrode 283, and a fourth inspection electrode 284 are provided, and these are all parallel to each other. The spaces S between the adjacent inspection electrodes 28 are all equal, and are the same as the fourth inspection element group 64 described above. The width W of the test electrode 28 is the same as that of the fourth test element group 64, and one row of test cells 276 is used for one type of dispersion (one row of test elements is used for one type of dispersion). 10) the test cells 276 are provided in one row so that the ratio S / W is approximately 1/100 or less. The first inspection electrode 281, the second inspection electrode 282, the third inspection electrode 283, and the fourth inspection electrode 284 are all connected to the inspection terminal 66.

  The electrical measurement in the discharge inspection process is performed before the common electrode 23 is formed using the fourth inspection element group 64, the fifth inspection element group 65, and the like. In both the two-terminal inspection cell 276 (the inspection element of the fourth inspection element group 64) and the four-terminal inspection cell 276 (the inspection element of the fifth inspection element group 65), resistance measurement using a direct current and alternating current are performed. Measure the impedance used. In the resistance measurement, the time dependency of the resistance value is examined, and the quality of the dispersion filled in the inspection cell 276 is inspected. In the impedance measurement, the quality inspection of the dispersion liquid is performed using the frequency region of the reciprocal of the response time of the electrophoretic material 24 as the main inspection range. Since the response time is approximately in the range of 1 millisecond to 10 seconds, the frequency region that is the main inspection range is in the range of 0.1 Hz to 1 kHz. A more important frequency range is 1 Hz to 100 Hz. In addition to this, impedance measurement in a high frequency region of 10 kHz or more is also important, and measurement may be performed. This is because the charged particles do not respond in this frequency region, so that the electrical characteristics of the solvent and ions that are one component of the electrophoretic material 24 can be measured.

  In the two-terminal type test cell 276 (the test element of the fourth test element group 64), a current is passed between the first test electrode 281 and the second test electrode 282, and the voltage between both electrodes is measured to determine the resistance value or the like. Obtain the impedance value. On the other hand, in the four-terminal type inspection cell 276 (the inspection element of the fifth inspection element group 65), the third inspection electrode 283 and the second inspection electrode 283 when a current is passed between the first inspection electrode 281 and the second inspection electrode 282. The voltage between the four test electrodes 284 is measured to determine the resistance value and the impedance value. By providing two types of inspection cells 276 of two-terminal type and four-terminal type, the quality inspection of the dispersion becomes more accurate. In the ejection inspection process, similarly to the injection inspection process, an inspection element filled with the first dispersion, various second dispersions, third dispersion, and the like is prepared and inspected.

  In the post-inspection process, after the first substrate 80 and the second substrate 90 are bonded together, the above-described optical measurement, two-terminal electrical measurement, or electrophoresis measurement is performed. The post-inspection process is performed using inspection elements belonging to the first inspection element group 61, the second inspection element group 62, the third inspection element group 63, and the like. The optical measurement is the same as described above. The electrical measurement is performed by applying an appropriate electric field between the inspection electrode 28 and the common electrode 23, and a measuring instrument that performs the electrical measurement is connected to the controller 71. In the electrophoretic measurement, an appropriate electric field is applied between the inspection electrode 28 and the common electrode 23 to perform optical measurement such as reflectance and hue. In the post-inspection process, similarly to the injection inspection process, an inspection element filled with the first dispersion liquid, various second dispersion liquids, third dispersion liquid, and the like is prepared and inspected.

"Dispersion base material"
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 the present embodiment, and has an inspection region 60 outside the display region 10. However, the inspection area 60 is hidden by the outer frame 402 and is not recognized by the user. 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 the present embodiment, the following effects can be obtained.
Since the first dispersion and the second dispersion have different compositions and the second dispersion can be made a dispersion suitable for inspection, various inspections and cause analyzes can be performed using the inspection cell 276. . That is, the inspection cell 276 can be various dispersions such as a dispersion of the first particles, a dispersion of the first particles, or a dispersion of the second particles, and the quality of each dispersion is determined. I can do it. In addition, when a failure occurs, the dispersion of the first particles and the dispersion of the second particles can be analyzed independently, and the cause of the failure can be easily identified. In this way, the quality of the product can be determined during the manufacturing process, and when a defect occurs, the cause can be specified. Therefore, a good electrophoretic display device can be efficiently manufactured without waste. Moreover, since the cause of the defect can be specified, product improvement and process reform can be promoted.

  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 ejection failure can be remarkably reduced. In addition, 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 coating surface such as the display region 10 and the inspection region 60 is covered. Accordingly, 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 inspection 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 inspection cell 276 are the same size. On the other hand, in the present embodiment (FIG. 8), the sizes of the display cell 271 and the inspection cell 276 are different. That is, the inspection cell 276 is larger than the display cell 271. Of course, the inspection cell 276 may be smaller than the display cell 271 on the contrary. Thus, the size of the inspection cell 276 can be arbitrarily determined so as to be suitable for inspection.

  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 inspection cell 276 is larger than the display cell 271, the filling operation of the second dispersion liquid into the inspection cell 276 is facilitated. Therefore, the manufacturing yield is improved and the price is superior. Furthermore, since the inspection cell 276 has a size suitable for inspection, accurate inspection can be performed.

(Embodiment 3)
"Form without inspection 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 code | symbol is attached | subjected and the overlapping description is abbreviate | omitted.

  The present embodiment (FIG. 9) differs from the first embodiment (FIG. 2) in that the inspection electrode 28 is not provided in the inspection region 60. Other configurations are almost the same as those of the first embodiment. As shown in FIG. 9, the inspection electrode 28 may not be provided in the inspection region 60. If the inspection region 60 must be overlapped with the data line driving circuit 73 or the like that operates at high speed for the sake of layout, it is preferable not to provide the inspection electrode 28. This is because the provision of the inspection electrode 28 may hinder high-speed operation of the circuit, and this is to avoid this. If the test electrode 28 exists so as to overlap the drive circuit 70, a parasitic capacitance is generated between the test electrode 28 and the wiring of the drive circuit 70, which may cause a delay in signal transmission. Therefore, the inspection electrode 28 is not provided in the inspection element provided in a region overlapping with the driving circuit 70 that operates at high speed, and the inspection element provided in the region not overlapping in plane with the driving circuit 70 that operates in high speed. An inspection electrode 28 is preferably provided. In this case, in the inspection cell 276 in which the inspection electrode 28 is not provided, the discharge amount inspection and the optical measurement are performed.

  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 electrophoretic display device 150 having a narrow frame with a limited layout has the inspection region 60. It can be provided, and an effect that a stable high-speed circuit operation is realized can be obtained.

  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 filled in the inspection cell 276. The 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 inspection 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 inspection 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 inspection 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 that fills the cell 27 is obtained by multiplying the volume of the cell 27 by the volume of the white particles and the density of the solvent to obtain Equation 22.

  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. Preferred examples of C ₂ is the same as the first embodiment, the easy composition perform various inspection and analysis.

  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)
“A configuration in which the inspection area is not provided in all electrophoretic display devices”
FIG. 10 is a diagram illustrating an example of a method for manufacturing an electrophoretic display device according to this modification. Hereinafter, a method for manufacturing an electrophoretic display device 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.

  As shown in FIG. 10, in this modification, when a plurality of electrophoretic display devices 150 are simultaneously manufactured on a single mother substrate 81, the electrophoretic display device 150 including the inspection region 60 is a single mother substrate. At least one is manufactured. Other configurations are almost the same as those of the first embodiment. In FIG. 10A, nine first substrates 80 are manufactured on one mother substrate 81, but the electrophoretic display device 150 provided with the inspection region 60 and the electricity not provided with the inspection region 60. The electrophoretic display device 150 is manufactured together. In FIG. 10B, the electrophoretic display device 150 provided with the inspection region 60 and the electrophoretic display device 150 provided with the unused inspection region 601 are manufactured together on one mother substrate 81. Has been. The unused inspection area 601 is an area where inspection cells 276 are provided, but these inspection cells 276 are not filled with various dispersion liquids, and the inspection elements are not used there. When the mother substrate 81 is subjected to single wafer processing (sequential processing for each substrate) and the plurality of first substrates 80 are included in the mother substrate, the manufacturing method shown in this modification is effective. When a plurality of first substrates 80 are simultaneously formed on the mother substrate 81, the plurality of first substrates 80 are usually all the same. On the other hand, in FIG. 10A, some (preferably, one) first substrate 80 includes an inspection region 60, and other first substrates 80 manufactured at the same time are in the inspection region. Not equipped. In FIG. 10B, some (preferably, one) first substrate 80 includes an inspection region 60, but other first substrates 80 manufactured at the same time are inspected. The cell 276 is not used, and an unused inspection area 601 is provided. When the cell formation process, the injection inspection process, the injection process, and the like are performed for each mother substrate 81, the injection inspection process is performed as long as at least one inspection region 60 is provided in one mother substrate 81. In addition, a discharge inspection process, a post-inspection process, or defect analysis can be performed.

  As described above, according to the method for manufacturing the electrophoretic display device 150 according to this modification, various inspections can be efficiently performed in addition to the effects of the first embodiment.

  DESCRIPTION OF SYMBOLS 10 ... Display area, 20 ... Pixel, 22 ... Pixel electrode, 23 ... Common electrode, 24 ... Electrophoretic material, 26 ... Partition, 27 ... Cell, 28 ... Inspection electrode, 60 ... Inspection area, 61 ... First inspection element, 62 ... Second inspection element, 63 ... Third inspection element, 64 ... Fourth inspection element, 65 ... Fifth inspection element, 66 ... Inspection terminal, 70 ... Drive circuit, 100 ... Electronic equipment, 131 ... First ejection part, 132: second ejection unit, 133: third ejection unit, 150: electrophoretic display device, 241: first component, 242: second component, 243: third component, 271: display cell, 276: inspection cell.

Claims (7)

A display area, and an inspection area provided outside the display area,
A display cell is provided in the display area, an inspection cell is provided in the inspection area,
The display cell is filled with a first dispersion containing first particles and second particles,
The inspection cell is filled with a second dispersion containing at least the 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 ;
A first substrate and a second substrate;
A pixel electrode is provided in a region to be the display region of the first substrate,
An electrophoretic display device , wherein an inspection electrode is provided in a region to be the inspection region of the first substrate . 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 inspection area provided outside the display area,
A display cell is provided in the display area, an inspection cell is provided in the inspection area,
The display cell is filled with a first dispersion containing first particles and second particles,
The inspection cell is filled with a third dispersion containing the first particles and not containing the second particles ,
A first substrate and a second substrate;
A pixel electrode is provided in a region to be the display region of the first substrate,
An electrophoretic display device , wherein an inspection electrode is provided in a region to be the inspection region of the first substrate . A display area, and an inspection area provided outside the display area,
A display cell is provided in the display area, an inspection cell is provided in the inspection 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 inspection cell is filled with a dispersion liquid 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 first substrate and a second substrate;
A pixel electrode is provided in a region to be the display region of the first substrate,
6. The electrophoretic display device according to claim 4 , wherein a test electrode is provided in a region to be the test region of the first substrate. A display area, and an inspection area provided outside the display area,
A display cell is provided in the display area, an inspection cell is provided in the inspection 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 inspection 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,
An electrophoretic display device , wherein an inspection electrode is provided in a region to be the inspection region of the first substrate .

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