JP2014228701A - Reflective display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reflective display device, in which particles in a display medium are prevented from moving among cells even when a through-hole of a counter electrode is disposed below a partition wall.SOLUTION: The reflective display device displays a desired image by a display medium when a predetermined electric field is applied between two substrates. The device includes partition walls which are disposed between the two substrates and segment a plurality of regions. A transparent electrode is formed on one substrate; and a counter electrode is formed on the other substrate. A through-hole is formed in the counter electrode. The width of a top part of the partition wall on a side close to the counter electrode is larger than the width of an opening of the through-hole on a side close to the partition wall.

Description

  The present invention relates to a reflective display device applied to electronic paper and the like.

  Recently, as a reflective display device, an electrophoretic display device using an electrophoretic material as an electroresponsive material contained in a display medium has been widely used. An electrophoretic display device is a device that displays information by using electrophoretic migration, that is, particle movement, of an electrophoretic body (usually electrophoretic particles) in air or in a solvent. In general, an electrophoretic state is controlled by applying an electric field between two substrates, thereby realizing a desired display. As the electrophoretic body, charged powder as well as charged particles can be used. In that case, the charged powder electrophoreses in the gas.

  In recent years, the electrophoretic display device has attracted attention especially as an electronic paper. When applied as an electronic paper, it is possible to enjoy advantages such as visibility at the printed matter level (easy for eyes), ease of information rewriting, low power consumption, and light weight.

  However, in an electrophoretic display device, display defects, particularly a decrease in contrast, may occur due to sedimentation or uneven distribution of particles or powder. In order to prevent this phenomenon, it is used to form partition walls between the upper and lower electrode substrates and divide the migration space of the particles and powder to be electrophoresed, that is, the movement space into minute spaces. This minute space is called a cell. In each cell, ink or gas (display medium) containing an electrophoretic body is enclosed. For example, Patent Literature 1 (Japanese Patent Laid-Open No. 2011-170019) and Patent Literature 2 (International Publication No. 2005/015892) disclose a conventional example of such an electrophoretic display device.

JP 2011-170019 A International Publication No. 2005/015892 Japanese Patent No. 4516481 Japanese Patent No. 4579768

  The present inventor has obtained the following knowledge while earnestly researching the arrangement method of the partition wall on the pixel electrode.

  When an electrode having an island shape on the upper layer is used on one of the upper and lower electrode substrates, such as a pixel electrode on which a TFT electrode structure is arranged, the arrangement relationship between the pixel electrode and the partition wall becomes a problem. . That is, since the through-hole for electrically connecting the upper layer electrode and the lower layer electrode is formed in the electrode having an island-like upper layer portion, as shown in FIG. If it is arranged below, there will be a passage communicating between the cells through the through hole under the partition. When the voltage for driving the electroresponsive material is applied between the substrates, the electroresponsive material included in the display medium may move to another cell through the passage. As described above, when the electrically responsive material moves between cells, the component ratio of the display material in the cell fluctuates and the charge balance is lost, resulting in display characteristics defects such as a decrease in reflectance and display unevenness. End up.

  In order to avoid such a problem, the partition and the pixel electrode are precisely aligned so that the pattern misalignment between them does not occur, and the partition is placed on the pixel electrode so that the through hole is not disposed under the partition. Arrangement is also possible. However, for example, when the partition wall and the pixel electrode are arranged on different substrates, they are not required for precise alignment between the partition wall and the pixel electrode in terms of manufacturing ease and manufacturing cost. It is preferable that these substrates are bonded together. In addition, when a plastic film is used as the electrode substrate, the dimensional stability of the substrate itself cannot be ensured in the first place, so the upper and lower electrode substrates are bonded together while performing precise alignment between the partition walls and the pixel electrodes. It is impossible. Furthermore, even when the partition walls are formed in an aperiodic pattern, it is difficult to perform precise alignment between the partition walls and the pixel electrodes.

  The present invention has been made based on such circumstances, and the object thereof is to suppress the movement of particles in the display medium between cells even when the through-hole of the counter electrode is disposed under the partition. Another object is to provide a reflective display device.

  In the present invention, a display medium including at least one kind of electrically responsive material is sealed between two opposing substrates on which at least one has translucency and each has electrodes formed thereon, A reflective display device in which the display medium performs a desired display when a predetermined electric field is applied between two substrates, and a partition that partitions a plurality of regions disposed between the two substrates; Each of the regions partitioned by the partition walls as a cell, and the display medium disposed in each cell, wherein a transparent electrode is formed on one substrate, and the other substrate is opposed to the other substrate. An electrode is formed, the transparent electrode and the counter electrode are arranged to face each other, and the counter electrode has a through hole formed on the top of the partition on the counter electrode side. The width of the opening on the partition side of the through hole A reflective display device and greater than.

  According to the present invention, the width of the top portion of the partition wall on the counter electrode side is larger than the width of the opening of the through hole on the partition wall side. In this case, even if the partition wall is arranged so as to overlap the through hole, the through hole is blocked by the partition wall, so that a passage communicating between the cells is suppressed under the partition wall. The Therefore, it is suppressed that the particle | grains in a display medium move between cells through a through hole.

  Preferably, a top portion of the partition wall on the counter electrode side is disposed so as to partially overlap the through hole when viewed from the one substrate toward the other substrate. In this case, it is possible to suppress the formation of a passage communicating between the cells under the partition wall arranged so as to overlap the through hole. Therefore, it is suppressed that the particle | grains in a display medium move between cells through a through hole.

  Alternatively, in the present invention, a display medium containing at least one or more kinds of electrically responsive materials is sealed between two opposing substrates on which at least one has translucency and each electrode is formed. A reflective display device in which the display medium displays a desired display when a predetermined electric field is applied between the two substrates, and divides a plurality of regions arranged between the two substrates. A partition, and the display medium disposed in each cell with each region partitioned by the partition as a cell, a transparent electrode is formed on one substrate, and the other substrate is A counter electrode is formed, the transparent electrode and the counter electrode are arranged to face each other, a through hole is formed in the counter electrode, and the counter electrode side of the partition wall is formed on the counter electrode side. The top portion extends from the one substrate to the other substrate. The partition wall is arranged so as to partially overlap the through hole when viewed in the direction toward the first substrate, and overlaps the through hole when viewed from the one substrate toward the other substrate. The reflective display device is characterized in that the width of the top portion on the counter electrode side is larger than the width of the opening on the partition wall side of the through hole.

  According to the present invention, the width of the top portion on the counter electrode side of the partition arranged so as to overlap the through hole is larger than the width of the opening on the partition side of the through hole. In this case, since the partition arranged so as to overlap the through hole blocks the through hole, formation of a passage communicating between the cells is suppressed under the partition arranged so as to overlap the through hole. The Therefore, it is suppressed that the particle | grains in a display medium move between cells through a through hole.

  For example, the counter electrode is a pixel electrode having a TFT electrode structure.

  For example, the counter electrode is a segment electrode.

  Alternatively, in the present invention, a display medium containing at least one or more kinds of electrically responsive materials is sealed between two opposing substrates on which at least one has translucency and each electrode is formed. A method of manufacturing a reflective display device in which the display medium displays a desired display when a predetermined electric field is applied between the two substrates, and a plurality of regions are partitioned on one substrate. A partition forming step for forming a partition, a display medium disposing step for disposing the display medium on the one substrate or the other substrate, and a region partitioned by the partition after the display medium is disposed As described above, the one substrate and the other substrate are arranged so that the top surface of the partition wall of the one substrate faces the other substrate so that the display medium is sealed in each cell. An opposing substrate placement step A transparent electrode is formed in advance on the one substrate, and a counter electrode having a through hole is formed in advance on the other substrate. In the counter substrate arranging step, the transparent electrode and the A reflective display device manufacturing method, wherein the reflective electrode device is disposed so as to face a counter electrode, and a width of a top portion of the partition wall on the counter electrode side is larger than a width of an opening of the through hole on the partition wall side. It is.

  According to the present invention, the width of the top portion of the partition wall on the counter electrode side is larger than the width of the opening of the through hole on the partition wall side. In this case, even if the partition wall is arranged so as to overlap the through hole, the through hole is blocked by the partition wall, so that a passage communicating between the cells is suppressed from being formed under the partition wall. Therefore, it is suppressed that the particle | grains in a display medium move between cells through a through hole.

  Preferably, in the counter substrate arrangement step, the top of the partition on the counter electrode side is arranged so as to partially overlap the through hole when viewed in the direction from the one substrate to the other substrate. . In this case, it is possible to suppress the formation of a passage communicating between the cells under the partition wall arranged so as to overlap the through hole. Therefore, it is suppressed that the particle | grains in a display medium move between cells through a through hole.

  Alternatively, in the present invention, a display medium containing at least one or more kinds of electrically responsive materials is sealed between two opposing substrates on which at least one has translucency and each electrode is formed. A method of manufacturing a reflective display device in which the display medium displays a desired display when a predetermined electric field is applied between the two substrates, and a plurality of regions are partitioned on one substrate. A partition forming step for forming a partition, a display medium disposing step for disposing the display medium on the one substrate or the other substrate, and a region partitioned by the partition after the display medium is disposed As described above, the one substrate and the other substrate are arranged so that the top surface of the partition wall of the one substrate faces the other substrate so that the display medium is sealed in each cell. An opposing substrate placement step A transparent electrode is formed in advance on the one substrate, and a counter electrode having a through hole is formed in advance on the other substrate. In the counter substrate arranging step, the transparent electrode and the The counter electrode is disposed so as to oppose the counter electrode, and the top of the partition on the counter electrode side is partially overlapped with the through hole when viewed from the one substrate toward the other substrate. The width of the top portion on the counter electrode side of the partition wall disposed so as to overlap the through hole when viewed in the direction from the one substrate toward the other substrate is the opening on the partition side of the through hole. It is a manufacturing method of a reflection type display device characterized by being larger than the width of the reflection type display device.

  According to the present invention, the width of the top portion on the counter electrode side of the partition arranged so as to overlap the through hole is larger than the width of the opening on the partition side of the through hole. In this case, since the partition arranged so as to overlap the through hole closes the through hole, a passage communicating between the cells may be formed under the partition arranged so as to overlap the through hole. It is suppressed. Therefore, it is suppressed that the particle | grains in a display medium move between cells through a through hole.

  According to the present invention, it is possible to provide a reflective display device in which the movement of particles in a display medium between cells is suppressed even when a through-hole of a counter electrode is disposed under a partition.

FIG. 1 is a cross-sectional view schematically showing a configuration of a reflective display device according to an embodiment of the present invention. FIG. 2 is a plan view schematically showing a pixel electrode formed on the other substrate of the reflective display device shown in FIG. 1 and a through hole formed in the pixel electrode. FIG. 3 is a diagram schematically showing a pixel electrode, a TFT electrode structure disposed on the pixel electrode, and a through hole for electrically connecting the pixel electrode and the TFT electrode structure. Specifically, FIG. 3A is a plan view showing a pixel electrode, a TFT electrode structure, and a through hole, and FIG. 3B is a cross-sectional view taken along line 3b-3b of FIG. FIG. 4 is a diagram schematically showing a display pattern electrode of a segment electrode, a wiring electrode arranged on the display pattern electrode, and a through hole for electrically connecting the display pattern electrode and the wiring electrode. It is. Specifically, FIG. 4A is a plan view showing a segment electrode, a wiring electrode, and a through hole, and FIG. 4B is a cross-sectional view taken along line 4b-4b of FIG. FIG. 5 is a diagram for explaining the definition of the width of the through hole. FIG. 6 is a flowchart schematically showing a manufacturing method of the reflective display device according to the embodiment of the present invention. FIG. 7 is a diagram schematically showing an example of the partition wall forming step. FIG. 8 is a diagram for explaining the definition of the width of the top surface of the partition wall. FIG. 9 is a diagram schematically showing an example of the adhesive layer forming step. FIG. 10 is a diagram for explaining the definition of the width of the top of the partition wall on the counter electrode side when an adhesive layer is formed on the partition wall. FIG. 11 is a diagram for explaining the definition of the width of the top portion of the partition wall on the counter electrode side when the adhesive layer is not formed on the partition wall. FIG. 12 is a diagram schematically showing an example of the display medium arranging step. FIG. 13 is a cross-sectional view schematically showing a state where the other substrate is bonded onto one substrate in the counter substrate arranging step. FIG. 14 is a cross-sectional view schematically showing the relationship between the width of the top portion of the partition wall on the counter substrate side and the width of the opening of the through hole on the partition wall side in the display device according to the comparative example of the present invention.

  FIG. 1 is a cross-sectional view schematically showing a configuration of a reflective display device according to an embodiment of the present invention. In the reflective display device according to the present embodiment, at least one of the electrical responses is provided between the two opposing substrates 11 and 16 on which at least one of them has translucency and the electrodes 111 and 161 are respectively formed. A display medium 13 containing a conductive material is enclosed, and the display medium 13 performs a desired display when a predetermined electric field is applied between the two substrates 11 and 16. Here, in the specification and claims of the present application, “translucent” means a property of transmitting light. In the present embodiment, the substrate (one substrate 11) arranged on the viewing side has a light-transmitting property such that the total light transmittance is 50% or more, preferably 80% or more, more preferably 90% or more. have.

  2 to 14, an electrode 111 is provided on the surface of one substrate 11, but the illustration of the electrode 111 is omitted. In the present embodiment, one substrate 11 is disposed on the viewing side, and the other substrate 16 is disposed on the non-viewing side.

  One substrate 11 includes a light-transmitting film such as polyethylene (PE), polyethylene terephthalate (PET), polyethersulfone (PES), polyethylene naphthalate (PEN), or light-transmitting glass, and indium tin oxide (ITO). ), Zinc oxide (ZnO), tin oxide (SnO), or the like, to which a transparent electrode (transparent electrode) 111 is attached can be typically used.

  The transparent electrode 111 can be formed by a coating method, sputtering, a vacuum deposition method, a CVD method, or the like. Since the transparent electrode 111 is used as a common electrode in the case of active matrix driving and segment driving, it is not always necessary to form a pattern, and the entire surface of the substrate may be an electrode.

  The thickness of one substrate 11 is preferably 10 μm to 1 mm. If it is thinner than 10 μm, the strength as a panel cannot be obtained and the risk of breakage increases. On the other hand, if it is thicker than 1 mm, the panel weight becomes too heavy and the handling becomes inconvenient and the cost also increases. Because. A suitable thickness range that is difficult to break and easy to handle is about 50 μm to 300 μm.

  A barrier layer may be provided on one substrate 11. The function of the barrier layer is to prevent display deterioration due to moisture entering the cells. The barrier layer may be disposed on the surface of one substrate 11 on which the display medium 13 is disposed (the surface on the display medium side), or provided on the surface opposite to the surface on the display medium side. Also good. Further, the barrier layer may be provided between the one substrate 11 and the electrode 111. In this embodiment, since one substrate is disposed on the viewing side, the barrier layer needs to be light-transmitting. The barrier layer may be obtained by depositing an inorganic film on one substrate 11, or may be obtained by pasting a film on which a barrier layer has been previously formed on one substrate 11. .

  Further, an ultraviolet cut film or an ultraviolet absorption layer may be provided on the surface of one substrate 11 opposite to the display medium side surface. Alternatively, one substrate 11 itself may have an ultraviolet absorbing function.

  In addition, on the surface opposite to the display medium side surface of one of the substrates 11, as other surface coating layers, an antiglare layer (AG layer), a scratch prevention layer (HC layer), and an antireflection layer (AR layer). Etc. may be added.

  One substrate 11 can be applied in either a roll shape or a sheet shape.

  As the other substrate 16, a substrate in which a counter electrode 161 is formed of a conductive material such as a metal on a display medium side surface such as a resin film, a resin plate, glass, epoxy glass (glass epoxy), or the like can be used. As the counter electrode 161, a pattern electrode is used in the case of segment driving, and a pixel electrode in which a TFT (Thin Film Transistor) is arranged in the case of active matrix driving is used.

  The other substrate 16 may be a translucent base material. Furthermore, it may be an opaque base material that is translucent, but an opaque glass base material, resin film, resin plate, glass, epoxy glass with the other surface different from the electrode surface roughened. (Garaepo) or the like can be used. In the present embodiment, since the other substrate 16 is disposed at a position opposite to the viewing side, there is no necessity of having translucency. However, when the same physical properties as the one substrate 11 such as thermal expansion characteristics are required, a light-transmitting member similar to the one substrate 11 can be used.

  The thickness of the other substrate 16 is preferably 10 μm to 1 mm, similarly to the thickness of the one substrate 11. If it is thinner than 10 μm, the strength as a panel cannot be obtained and the risk of breakage increases. On the other hand, if it is thicker than 1 mm, the panel weight becomes too heavy and the handling becomes inconvenient and the cost also increases. Because. A suitable thickness range that is difficult to break and easy to handle is about 50 μm to 300 μm.

  The thickness of the other substrate 16 is preferably 10 μm to 1 mm, similarly to the thickness of the one substrate 11. If it is thinner than 10 μm, the strength as a panel cannot be obtained and the risk of breakage increases. On the other hand, if it is thicker than 1 mm, the panel weight becomes too heavy and the handling becomes inconvenient and the cost also increases. Because. A suitable thickness range that is difficult to break and easy to handle is about 50 μm to 300 μm.

  Further functional layers can be added to the other substrate 16. For example, a barrier film can be attached on the other substrate 16. Even if a transparent film in which a transparent inorganic film barrier layer is formed in advance by vapor deposition or the like, or a transparent film in which a non-transparent barrier layer such as a metal film is formed as the other substrate 16, is the same as this. The function of can be demonstrated. The barrier film or barrier layer may be provided on the display medium side surface of the other substrate 16 (on the pixel electrode 161), or may be provided on the surface opposite to the display medium side surface.

  Further, an ultraviolet cut film or an ultraviolet absorption layer may be provided on the surface of the other substrate 16 opposite to the surface on the display medium side. Alternatively, the other substrate 16 itself may have an ultraviolet absorbing function.

  The other substrate 16 can be applied in either a roll shape or a sheet shape.

  Here, the counter electrode 161 formed on the other substrate 16 will be described in more detail with reference to FIGS.

  In the present embodiment, the counter electrode 161 is a pixel electrode having a TFT (Thin Film Transistor) electrode structure 163 as shown in FIG. 3, and the pixel electrode 161 is used for a desired display in a reflective display device. They are arranged in a matrix so as to cover the area (display area) (see FIG. 2). As shown in FIG. 3, each pixel electrode 161 is electrically connected to the pixel electrode 161 and a TFT electrode structure 163 provided between the pixel electrode 161 and the other substrate 16. A through hole 162 is formed.

  When the segment electrode as shown in FIG. 4 is formed on the other substrate 16, the counter electrode 161 is a display pattern electrode, and the display pattern electrode 161 includes the display pattern electrode 161 and the display pattern. A through hole 162 for electrically connecting the electrode 161 and the wiring electrode 164 provided between the other substrate 16 is formed.

  The width of the opening on the partition wall 12 side of the through hole 162 is 10 μm to 100 μm, preferably 10 μm to 50 μm.

  Here, the definition of the width of the opening of the through hole 162 on the partition wall 12 side is shown in FIG. In the present embodiment, the opening is circular as shown in FIG. 5A, and the width of the opening is defined as the length of the diameter. However, if the opening has a shape other than a circle, the width of the opening is defined as its maximum width. For example, when the opening is a rectangle as shown in FIG. 5B, it is understood as the length of the diagonal line, and when the opening is an ellipse as shown in FIG. Is understood as the length of.

  The width of the opening on the partition wall 12 side of the through hole 162 can be measured using, for example, a non-contact three-dimensional surface shape / roughness measuring instrument (NewView 7100 manufactured by Zygo Corporation).

<Method for manufacturing reflective display device>
FIG. 6 is a flowchart schematically showing a manufacturing method of the reflective display device according to the embodiment of the present invention.

  FIG. 7 is a diagram schematically showing an example of the partition wall forming step. As shown in FIG. 7, first, partition walls 12 are formed on the upper surface of one substrate 11 generally placed in the horizontal direction by, for example, photolithography (exposure by ultraviolet (UV) irradiation → development → firing). The The partition wall 12 is a member that defines a plurality of cells to be described later.

  In the specification and claims of the present application, the “cell” means the upper and lower electrode substrates 11, 11 to prevent display defects due to sedimentation or uneven distribution of particles or powder, in particular, reduction in contrast. This means a minute migration space of particles or powder to be electrophoresed, that is, a movement space, divided by partition walls 12 formed between 16.

  The partition wall 12 can be composed of an ultraviolet curable resin, a thermosetting resin, a room temperature curable resin, or the like. As a method for forming the partition wall 12, a mold transfer method such as embossing can be adopted in addition to the photolithography method. Further, a method of manufacturing a structure having a desired pattern as a partition and sticking the structure to one substrate 11 may be employed. The aperture ratio is preferably 70% or more, and particularly preferably 90% or more. The higher the aperture ratio, the wider the displayable area, so that high contrast can be obtained.

  The shape of the unit pattern of the partition wall 12 is basically arbitrary, such as a circle, a lattice, a hexagon, and other polygons. The cell size (pitch) is 0.05 mm to 1 mm, preferably 0.1 mm to 0.5 mm, although it depends on the size of the display panel. Here, the pitch means the distance between the center points of adjacent cells.

  The width of the top surface of the partition wall 12 is 9 μm to 50 μm, preferably 9 μm to 20 μm. 9 μm is the lower limit of the line width at which the partition wall 12 can be patterned without falling down. When the width of the top surface of the partition wall 12 is less than 9 μm, in a pattern in which the length of the partition wall 12 is 60 μm or more, at least a part of the partition wall 12 falls, peels off, or the separated partition wall 12 moves over the substrate. Or move. In that case, the function of preventing the movement of particles by the partition wall 12 is lost, and the display quality is deteriorated. On the other hand, the upper limit of 50 μm, which is the upper limit of the preferred range, is an upper limit at which the partition wall 12 is not too conspicuous when visually observed.

  Here, the definition of the width of the top surface of the partition 12 is shown in FIG. If the corners of the top surface are not rounded, the width of the top surface is defined as it is, as shown in FIGS. 8 (a) and 8 (b). On the other hand, when the corner of the top surface is rounded, it is understood as the width between the intersecting lines of the extended surface of the top surface and the extended surface of the wall surface as shown in FIG. 8 (c) and FIG. 8 (d). The As a measuring method for evaluation, one substrate 11 on which the partition wall 12 was formed was embedded in a curable resin, and a cross section of the partition wall 12 was cut out by a microtome (Daiwa Kogyo Kogyo Co., Ltd .: FX-801). Each width can be measured based on an image taken by a scanning electron microscope (SEM).

  The thickness of the partition wall 12 is 5 to 50 μm, preferably 10 to 50 μm. If the thickness is 5 μm or less, the amount of ink to be filled is small and sufficient display characteristics, particularly contrast, cannot be obtained. From the viewpoint that good display characteristics can be obtained at a low driving voltage, a thickness in the range of 10 to 50 μm is preferable.

  Next, the adhesive layer 22 is formed on the partition wall 12 (adhesive layer forming step: step (2) in FIG. 6). In this adhesive layer forming step, a thermoplastic resin such as a polyester-based thermoplastic adhesive is formed with a thickness of 1 μm to 100 μm by, for example, a transfer method or a printing method. Preferably, it is formed with a thickness of 1 μm to 50 μm, particularly preferably with a thickness of 1 μm to 20 μm.

  Supplementing a specific description of an example of a typical thermal transfer method as a transfer method, as shown in FIG. 9, for example, a polyester-based thermoplastic adhesive having a thickness of 20 μm on a PET film as a substrate 21. A transfer sheet 20 on which an adhesive 221 is formed is prepared. Next, the transfer sheet 20 is arranged to face the one substrate 11 so that the surface of the adhesive 221 is arranged on the top surface of the partition wall 12 of the one substrate 11. In this state, one substrate 11 and the transfer sheet 20 are laminated at a normal temperature and a pressure of 1 kPa. After lamination, this is heated for 1 minute on a hot plate maintained at 120 ° C., which is a temperature higher than the softening temperature of the adhesive 221, and then the transfer sheet 20 is peeled off. As a result, an adhesive layer 22 of about 10 μm, for example, is formed on the partition wall 12.

  As the adhesive 221 for forming the adhesive layer 22, an adhesive using a thermoplastic material is preferable. It has a property of softening by heating and solidifying when cooled, and is plastic when repeated cooling and heating. Is a material that is reversibly maintained.

  When an adhesive made of a thermoplastic material is used as the adhesive layer, the adhesive solidified on the transfer sheet substrate is softened by heating to a temperature exceeding the softening temperature, and only on the upper surface of the partition wall. The adhesive can be reliably thermally transferred. Moreover, since the adhesive after thermal transfer is cooled to room temperature and solidified again, tackiness, that is, stickiness, is eliminated. Further, since there is no tack or stickiness, the display medium filled in the cell does not adhere to the adhesive. Then, the adhesive on the top surface of the partition wall is heated again to a temperature exceeding the softening temperature to be softened, so that it has tackiness, that is, stickiness, so that it is securely bonded to the other substrate. Since the adhesive after being bonded to the other substrate does not have tack or stickiness at normal temperature again, the display medium will not adhere to the adhesive and display quality may not be deteriorated.

  Specifically, thermoplastic base polymers such as ethylene-vinyl acetate copolymer, polyester, polyamide, polyolefin, polyurethane, natural rubber, styrene-butadiene block copolymer, styrene-isoprene block copolymer, styrene-ethylene. A resin mainly composed of a thermoplastic elastomer such as a butylene-styrene block copolymer or a styrene-ethylene-propylene-styrene copolymer, and a tackifier resin or a plasticizer is mainly used.

  In order to improve the adhesion between the partition wall 12 and the adhesive 221, the partition wall 12 may be subjected to a surface treatment by ultraviolet irradiation, plasma treatment, or the like, or a primer may be formed. Alternatively, a silane coupling agent may be added to the adhesive 221.

  In the present embodiment, as shown in FIG. 10, the adhesive layer 22 has a width D of the adhesive layer 22 in the width direction of the top surface of the partition wall 12 on the plane of the counter electrode 161 after the counter substrate placement step described later. The through hole 162 is formed to be larger than the width of the opening on the partition wall 12 side.

  However, as shown in FIG. 11, when the adhesive layer 22 is not formed on the top surface of the partition wall 12, the top surface of the partition wall 22 is larger than the opening width of the through hole 162 on the partition wall 12 side. What is necessary is just to form so that it may become.

  That is, in the specification and claims of the present application, “the width of the top of the partition wall on the counter electrode side” refers to the counter substrate placement step when the adhesive layer 22 is formed on the top surface of the partition wall 12. It means the width of the adhesive layer 22 in the width direction of the top surface of the partition wall 12 on the counter electrode 16 later. On the other hand, when the adhesive layer 22 is not formed on the top surface of the partition wall 12, it is defined as the width of the top surface of the partition wall 12 itself. That is, if the corner of the top surface of the partition wall 12 is not rounded, it means the width of the top surface of the partition wall 12 defined as described above with reference to FIG. 8A and FIG. If the corners of the top surface are rounded, the width of the top surface of the partition wall 12 defined as described above with reference to FIGS. 8C and 8D, that is, the extended surface of the top surface of the partition wall 12 It means the width of the top surface of the partition wall 12 not including the extended surface, not the width between the intersecting lines with the extended surface of the wall surface. However, even when the adhesive layer 22 is formed on the top surface of the partition wall 12, the adhesive layer 22 in the width direction of the top surface of the partition wall 12 on the counter electrode 161 after the counter substrate placement step of the adhesive layer 22. Is narrower than the width of the top surface of the partition wall 12 and the top surface of the partition wall 12 is in contact with the counter electrode 161, the “width of the top of the partition wall on the counter electrode side” It means the width of the top surface itself.

  In the present embodiment, the width of the top portion of the partition wall 12 on the counter electrode 161 side is larger than the width of the opening of the through hole 162 on the partition wall 12 side, but in order to achieve a desirable contrast in the display panel, It is not more than twice the width of the opening.

  Further, not all of the partition walls 12 may be formed so that the width of the top of the partition wall 12 on the counter electrode 161 side is larger than the width of the opening of the through hole 162 on the partition wall 12 side. The partition wall 12 to be disposed to face the through hole 162 may be formed so that the width of the top portion is larger than the width of the opening.

  Next, the ink 13 as a display medium is arranged on one substrate 11 (display medium arranging step: step (3) in FIG. 6). FIG. 12 is a diagram schematically showing an example of the display medium arranging step. Here, (1) the ink 13 is dropped from the dispenser 31 or inkjet or die coat (ink dropping step), and (2) the ink 13 is made uniform in the surface by the applicator 32 or doctor blade, doctor knife, and central squeegee. It is applied (ink application process). The ink 13 may be disposed on the other substrate 16.

  As the display medium 13, a display medium containing at least one or more kinds of electrically responsive materials can be used. Examples of the electroresponsive material include a charged particle material and a liquid crystal material, and the charged particle material includes a so-called electrophoretic material in which colored particles such as white, black, and color move in response to an electric field, or two particles. There are materials typified by twist balls that are color-coded and rotated by an electric field, or nanoparticle materials that move by an electric field. On the other hand, the liquid crystal material includes a material for electrically controlling transmission and scattering known as PDLC (Polymer Dispersed Liquid Crystal), a material in which a liquid crystal is mixed with a dye, a cholesteric liquid crystal material, and the like. These materials that have electrical responsiveness and change optical characteristics need to be isolated into cells regardless of the type, and are subject to application of the present invention.

  In general, the average particle size of the display medium 13 is 0.05 μm or more as described in, for example, Patent Document 3 (Patent No. 4516481) and Patent Document 4 (Patent No. 4579768), and preferably Is 0.08 μm or more, more preferably 0.1 μm or more. Further, the average particle diameter of the display medium 13 is generally 5 μm or less, as described in, for example, Patent Document 3 (Patent No. 45164481) and Patent Document 4 (Patent No. 4579768), and preferably Is 3 μm or less, more preferably 1.5 μm or less.

  Returning to FIG. 6, the outer periphery of the display area on the other substrate 16 prevents moisture and oxygen from entering the display area from the outside of the display area, and the solvent in the display medium 13 from the display area to the outside of the display area Sealing material 62 for preventing leaching is arranged so as to continuously surround the display area (sealing material arranging step: step (4) in FIG. 6). When the other substrate 16 includes a plurality of display areas, the sealing material 62 is disposed on the outer periphery of each of the plurality of display areas.

  If a specific description is supplemented for an example of an arrangement method of the sealing material 62, the sealing material 62 is made of, for example, an adhesive such as an ultraviolet curable resin with a line width of 0.6 mm and a height of 60 μm using a dispenser. It arrange | positions by apply | coating to linear form.

  Here, after being cured with ultraviolet rays, the ultraviolet curable resin is polymerized and becomes chemically stable. Therefore, when an ultraviolet curable resin is used as the sealing material 62 and cured with ultraviolet rays, there is no possibility that display performance is deteriorated due to contact between the cured resin and the display medium. The ultraviolet curable resin used for the sealing material 62 is preferably a monomer or oligomer of urethane acrylate, polyester acrylate, or epoxy acrylate. , 3034, 3057, 3052, 3054, 3056B, 3170D, LCB-610 manufactured by EACH Sea, etc. are applicable.

  Furthermore, the sealing material 62 preferably has adhesiveness. In this case, even if it is difficult to keep the posture of one of the substrates or the other substrate flat due to distortion of one of the substrates or the other substrate, it is later on the substrate of one of the substrates or the other substrate 16. When the two substrates are bonded together in a state where the display medium is disposed on the display medium, no gap is formed between the sealing material 62 and the two substrates 11 and 16, and the display medium 13 disposed in the display region 60 is sealed. It moves outside the area surrounded by 62, and display unevenness and generation of bubbles in the cell do not occur. As the sealing material 62 having adhesiveness, a material having a functional group such as a hydroxyl group, an alkoxy group, a urethane group, or an epoxy group capable of reacting with a substrate surface such as a film or glass is preferable.

  The sealing material 62 can be constituted by a thermosetting resin, a room temperature curable resin, a heat seal resin or the like in addition to the ultraviolet curable resin. In addition to the dispenser, the sealing material 62 can be arranged by various printing methods or thermocompression bonding, and may be arranged on one substrate 11.

  Next, the adhesive layer 22 on the partition wall 12 and the other substrate 16 facing the one substrate 11 are bonded while extruding excess ink exceeding the cell volume in the partition wall 12 (opposing substrate placement step: Step (5) in FIG. Thereby, the display medium (ink 13) is sealed in each cell.

  In the counter substrate placement process of the present embodiment, the one substrate 11 and the other substrate 16 do not need to be precisely aligned using a microscope or the like, for example, for alignment provided on the one substrate 11. You may align, aligning a mark and the mark for alignment provided in the other board | substrate 16 by observing with the naked eye. In the present embodiment, the alignment between one substrate 11 and the other substrate 16 is such that the top of the partition wall 12 on the counter electrode 161 side is partially viewed from the one substrate 11 toward the other substrate 16. It was made to overlap with the through hole 162, that is, partially overlap with the through hole 162.

  Furthermore, in the counter substrate placement step of the present embodiment, as shown in FIG. 13, the adhesive 221 transferred as the adhesive layer 22 is heated to obtain an adhesive force. Specifically, while applying a predetermined thermocompression bonding pressure (laminating pressure) by the laminator 91, the adhesive 221 is heated from the periphery to a temperature exceeding its softening point or melting point to soften the partition wall 12 and the other. The substrate 16 is bonded. However, other thermocompression bonding modes may be employed. The pressing force applied by the laminator 91 is preferably 0.01 MPa to 0.7 MPa, particularly preferably 0.1 MPa to 0.4 MPa.

  Thereafter, as shown in FIG. 4, the sheet is cut into a predetermined size by a cutting device 51 such as a guillotine, an upper blade slide device, a laser cutting device, or a laser cutter (cutting step: step (6) in FIG. 6) and desired reflection. The production of the mold display device is completed.

  According to the present embodiment, the width of the top portion of the partition wall 12 on the counter electrode 161 side is larger than the width of the opening of the through hole 162 on the partition wall 12 side. As a result, even if the through hole 162 is disposed under the partition wall 12, the through hole 162 is blocked by the partition wall 12, and therefore, a passage communicating between the cells is formed under the partition wall 12. It is suppressed. Therefore, the particles in the display medium 13 are prevented from moving between cells through the through holes 162.

  Next, practical examples actually performed will be described.

<Example of Reflective Display Device>
<Example>
One substrate 11 is a 300 mm × 400 mm × 0.1 mm thick polyethylene terephthalate (PET) film (A4100, manufactured by Toyobo Co.). .. 2 μm) was prepared. The transparent electrode 111 is formed by a general film formation method such as sputtering, vacuum evaporation, or CVD, and is also formed by zinc oxide (ZnO), tin oxide (SnO), etc. in addition to indium tin oxide (ITO). Can be done.

Next, a negative photosensitive resin material (DuPont MRC Dry Film Resistry Dry Film Resist) is laminated on the one substrate 11 to a thickness of 30 μm and heated at 100 ° C. for 1 minute. Then, exposure is performed using an exposure mask (exposure amount: 500 mJ / cm ² ), and thereafter development using a 1% KOH aqueous solution is performed for 30 seconds, and baking is performed at 120 ° C. for 60 minutes. A 20 μm partition wall 12 was formed.

  Then, a 50 μm-thick PET film 21 (manufactured by Teijin DuPont) is used as the transfer film substrate 21, and a polyester-based thermoplastic adhesive 221 (Toyobo's Byron 630) is applied by a die coder and dried. It was. Thereby, a roll-shaped transfer sheet 20 having an adhesive layer of 20 μm was produced. The softening temperature of the polyester thermoplastic adhesive 221 was about 110 ° C.

  Then, with the transfer sheet 20 placed on the top surface of the partition wall 12, the pressure around the thermoplastic adhesive 221 exceeds the softening temperature, for example, about 120 ° C., while further applying a pressing force of about 1 kPa. As a result, the thermoplastic adhesive 221 was thermally transferred to the entire top surface of the partition wall 12. The height from the top surface of the partition wall 12 to the top of the thermoplastic adhesive 221 was about 10 μm.

Subsequently, an ink 13 having the following components is used as a display medium, dropped from the dispenser 31, and the ink 13 is deposited on one substrate 11 by an applicator 32 (manufactured by Tester Sangyo Co., Ltd.). It was applied at 35 μm.
<Ink component>
・ Electrophoretic particles (titanium dioxide): 60 parts by weight ・ Dispersion liquid: 40 parts by weight

  Next, as the other substrate 16, a PEN substrate having a size of 300 mm × 400 mm × thickness 0.1 mm, on which the counter electrode 161 was formed, was used. The electrodes 161 in this embodiment are active matrix drive pixel electrodes, and each pixel electrode 161 has a TFT. The width of the opening on the partition wall 12 side of the through hole 162 formed in the pixel electrode 161 was 15 μm.

  Subsequently, an acrylic sealing material (manufactured by ThreeBond Co .: 3052D) is applied to the outer periphery of the region where the pixel electrode 161 is formed using a dispenser, so that the sealing material 62 has a line width of 0.6 mm and a thickness of A thickness of 60 μm was formed.

  Then, in the atmosphere, one substrate 11 is overlaid on the other substrate 16 and heated to 90 ° C. while further applying a certain pressing force by a laminator 91, and on the partition wall 12 of one substrate 11. The adhesive layer 22 and the other substrate 16 were in close contact (see FIG. 13). At this time, one of the substrates 11 is curled so that no air bubbles remain between the two substrates, and the partition wall is directed from one side of the one substrate 11 and the other substrate 16 to the opposite side. The excess ink 13 exceeding the cell volume in 12 was pasted while being pushed out of the display area. As a result, only a specified amount of ink was filled in the cell.

Then, the ultraviolet-ray was exposed from the one board | substrate 11 side (exposure amount 3000mJ / cm < ² >), and the sealing material 62 was hardened (periphery sealing process). Thus, a display panel was produced.

  About the display panel obtained as described above, a checkered pattern negative image was alternately written 30,000 times, and then the display quality was evaluated. However, pixel burn-in due to particle movement between cells was not observed, and extremely high It was good.

<Comparative example>
A display panel was fabricated in the same process as in the above example, except that the width of the opening on the partition wall 12 side of the through hole was 30 μm.

  The display panel obtained as described above was alternately written with checkered positive / negative images 30,000 times, and the display quality was evaluated. As a result, pixel burn-in caused by particle movement between cells was observed. This is because the width of the top portion of the partition wall 12 on the counter electrode 161 side is smaller than the width of the opening of the through hole 162 on the partition wall 12 side, and therefore, as shown in FIG. In this case, it is considered that a passage communicating between the cells through the through hole was formed under the partition wall 12 and particles in the ink 13 moved to another cell through the passage.

11 One substrate 111 Transparent electrode 12 Partition wall 13 Ink (display medium)
16 Other substrate 161 Counter electrode 162 Through hole 163 TFT
22 Adhesive layer 221 Adhesive 31 Dispenser 32 Applicator 51 Cutting device 62 Sealing material 91 Laminator

Claims (5)

A display medium containing at least one or more kinds of electrically responsive materials is sealed between two opposing substrates, at least one of which has a light-transmitting property and on which electrodes are respectively formed, and the two substrates A reflective display device in which the display medium displays a desired display when a predetermined electric field is applied between the display medium,
A partition partitioning a plurality of regions disposed between the two substrates;
Each region partitioned by the partition as a cell, the display medium disposed in each cell,
With
On one substrate, a transparent electrode is formed,
On the other substrate, a counter electrode is formed,
The transparent electrode and the counter electrode are arranged to face each other,
A through hole is formed in the counter electrode,
The reflective display device, wherein a width of a top portion of the partition wall on the counter electrode side is larger than a width of an opening of the through hole on the partition wall side. The top of the partition on the counter electrode side is disposed so as to partially overlap the through hole when viewed from the one substrate toward the other substrate. The reflective display device described. A display medium containing at least one or more kinds of electrically responsive materials is sealed between two opposing substrates, at least one of which has a light-transmitting property and on which electrodes are respectively formed, and the two substrates A reflective display device in which the display medium displays a desired display when a predetermined electric field is applied between the display medium,
A partition partitioning a plurality of regions disposed between the two substrates;
Each region partitioned by the partition as a cell, the display medium disposed in each cell,
With
On one substrate, a transparent electrode is formed,
On the other substrate, a counter electrode is formed,
The transparent electrode and the counter electrode are arranged to face each other,
A through hole is formed in the counter electrode,
The top of the partition on the counter electrode side is arranged so as to partially overlap the through hole when viewed in the direction from the one substrate to the other substrate,
The width of the top portion on the counter electrode side of the partition arranged so as to overlap the through hole when viewed from the one substrate toward the other substrate is larger than the width of the opening on the partition side of the through hole. A reflective display device characterized by being large. 4. The reflective display device according to claim 1, wherein the counter electrode is a pixel electrode having a TFT electrode structure. The reflective display device according to claim 1, wherein the counter electrode is a segment electrode.