JP2014032285A - Reflective display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reflective display device which requires no high pressure upon adhering a substrate to a partition wall, suppresses generation of bubbles in cells and suppresses bleed-out of an adhesive into cells.SOLUTION: The reflective display device includes a display medium containing at least one kind of electrophoretic material sealed between two substrates opposing to each other, at least one of which is transparent, and displays predetermined information by the display medium when a predetermined electric field is given between the two substrates. A partition wall is formed into a predetermined pattern on one of the substrates; and the display medium is disposed in each region as a cell segmented by the partition wall. A hole is formed at a top part in a branching region of the partition wall; an adhesive is disposed on the top part of the partition wall; and the other substrate is adhered to the adhesive.

Description

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

  Recently, electrophoretic display devices have been widely used as reflective display devices. 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 or a pixel. In each cell, ink or gas (display medium) containing an electrophoretic body is enclosed. For example, Japanese Unexamined Patent Application Publication No. 2005-202245 discloses a conventional example of such an electrophoretic display device.

  Further, Patent Document 2 (Japanese Patent Laid-Open No. 2012-013790) filed by the present applicant discloses a method of forming an adhesive only on a partition wall that divides cells and ensuring adhesion between the partition wall and the substrate. Yes. Patent Document 3 (Japanese Patent Laid-Open No. 2011-154202) discloses a method in which an adhesive layer is formed on the side of a substrate instead of a partition wall.

  Further, in Patent Document 4 (Japanese Patent Laid-Open No. 2006-154655), in order to prevent the adhesive applied to the upper surface of the partition wall from seeping out into the cell, the substrate is bonded to the adhesive (layer). A method for slightly curing the adhesive is disclosed.

JP-A-2005-202245 JP 2012-013790 A JP 2011-154202 A JP 2006-154655 A

  The present inventor has obtained the following knowledge while earnestly researching the state of adhesion between the adhesive layer provided on the partition wall and the substrate.

  When the adhesion between the adhesive layer provided on the partition and the substrate is insufficient, the display medium moves between the cells when local pressure is applied from the outside, and so-called display unevenness (pressure) Scratches) will occur. Therefore, the adhesion between the adhesive layer provided on the partition and the substrate needs to be performed to a desired level or more.

  However, according to the knowledge obtained by the present inventor, when an adhesive layer is formed on the partition wall with an adhesive, the adhesive tends to be accumulated in an amount more than necessary in the branch region of the partition wall. Here, the branch region of the partition wall means a branch portion of the partition wall and a region in the vicinity thereof that can be recognized as an intersection or a branch point of the partition wall in a plan view. In addition, a center line extending in the vertical direction of the branch portion of the partition wall that can be recognized as an intersection or a branch point of the partition wall in plan view is referred to as a branch center of the partition wall.

  If more than the required amount of adhesive is placed on the partition wall, more pressure is required when the substrate is bonded to the adhesive on the partition wall, bubbles are generated in the cell, and adhesion The agent may spread in the surface direction of the substrate and ooze out into the cell. If the adhesive is so large that it oozes out into the cell, the aperture ratio will decrease and the contrast will decrease.

  In addition, the bonding method described in Patent Document 4 is disadvantageous in terms of cost because it requires a complicated process.

  The present invention has been made based on such circumstances, the purpose is not to require a large pressure when bonding the substrate to the partition wall, it is also possible to suppress the generation of bubbles in the cell, It is an object of the present invention to provide a reflective display device in which the adhesive is prevented from leaking into a cell.

  In the present invention, when a display medium including at least one kind of electrophoretic body is sealed between two opposing substrates, at least one of which is transparent, and a predetermined electric field is applied between the two substrates. A reflective display device in which the display medium displays predetermined information, wherein a partition including a branch region in a predetermined pattern is formed on one substrate, and each region partitioned by the partition is a cell. As described above, the display medium is arranged in the cell, a hole is formed at the top of the branch region of the partition, and an adhesive is arranged at the top of the partition. The reflective display device is characterized in that the other substrate is bonded. The hole in the present invention may be a dent that does not penetrate or a through hole.

  According to the present invention, since the hole is formed at the top of the branch region of the partition wall, a part of the adhesive accumulated in the branch region is accommodated in the hole, and the adhesive is required in the branch region. It is suppressed that more than the amount is accumulated. Thereby, when bonding a board | substrate to a partition, a big pressure is not required, it is suppressed that a bubble generate | occur | produces in a cell and an adhesive oozes out in a cell. On the other hand, since the width of the top part of the partition wall other than the branch region is not narrow, the top part of the partition wall and the substrate can be sufficiently satisfactorily bonded, and there is no fear of the partition wall falling down.

  According to the knowledge of the present inventors, the hole is preferably larger than a circle having a diameter of 1 μm in a plan view and is not open to two or more cells, and the depth is 0.1 μm or more. As a result, it is possible to effectively prevent the adhesive from being accumulated more than necessary in the branch region, and display defects do not occur due to the display medium moving between the cells through the holes. .

  The adhesive is, for example, a thermoplastic resin that is transferred from another substrate to the top of the partition wall.

  Alternatively, in the present invention, a display medium including at least one kind of electrophoretic body is sealed between two opposing substrates, at least one of which is transparent, and a predetermined electric field is applied between the two substrates. A method of manufacturing a reflective display device in which the display medium displays predetermined information when the barrier rib is formed, and forming a barrier rib including a branch region in a predetermined pattern on one substrate, An adhesive layer forming step of forming an adhesive layer on the top of the partition; a display medium disposing step of disposing the display medium in the cell with each region partitioned by the partition as a cell; and disposing the display medium And a second substrate bonding step of bonding the other substrate to the adhesive layer, and a hole is formed at the top of the branch region of the partition wall. Is the method.

  According to the present invention, since the hole is formed at the top of the branch region of the partition wall, it is possible to prevent the adhesive from being deposited more than necessary in the branch region. Thereby, when bonding a board | substrate to a partition, a big pressure is not required, it is suppressed that a bubble generate | occur | produces in a cell and an adhesive oozes out in a cell.

FIG. 1 is a flowchart schematically showing a manufacturing method of a reflective display device according to an embodiment of the present invention. FIG. 2 is a diagram schematically showing an example of the partition wall forming step. FIG. 3 is a diagram schematically showing an example of the shape of a partition wall according to an embodiment of the present invention and a heat sealant transferred thereon. Specifically, FIG. 3 (a) is a plan view of the partition, FIG. 3 (b) is a cross-sectional view taken along the line bb of the partition, and FIG. 3 (c) transfers the heat sealant onto the partition. FIG. 3D and FIG. 3E are a sectional view taken along the line dd and a sectional view taken along the line ee of FIG. 3C, respectively. FIG. 4 is a diagram for explaining the definition of the width of the top of the partition wall. FIG. 5 is a view showing an example of an exposure mask used in forming the partition walls. FIG. 6 is a diagram illustrating a mechanism in which the hole is formed as a through hole. FIG. 7 is a diagram illustrating a mechanism in which the hole is formed as a recess that does not penetrate. FIG. 8 is a diagram schematically showing an example of the adhesive layer forming step. FIG. 9 is a diagram schematically showing an example of the display medium arranging step. FIG. 10 is a schematic diagram for explaining the function of the conductive paste. FIG. 11 is a diagram schematically showing an example of the other substrate bonding step. FIG. 12 is a diagram for explaining a mechanism by which the amount of adhesive deposited on the top of the partition wall is reduced by providing the hole. FIG. 13 is a diagram illustrating an example of the shape of the hole portion in which the amount of adhesive deposited on the top of the partition wall is not reduced. FIG. 14 is a diagram for explaining the condition that the hole is not open to two or more cells. FIG. 15 is a diagram schematically showing an example of the shape of a partition wall according to another embodiment of the present invention and a heat sealant transferred thereon. Specifically, FIG. 15A is a plan view of the partition wall, FIG. 15B is a cross-sectional view taken along the line bb of the partition wall, and FIG. 15C shows the heat sealant transferred onto the partition wall. FIG. 15D is a cross-sectional view taken along the line dd of FIG. 15C.

  In FIG. 1 and FIG. 2 and FIGS. 3 to 15, electrode patterns are provided on the upper surface of one substrate 11 and the upper surface of the other substrate 16, respectively, but these electrode patterns are not shown. .

<Method for manufacturing reflective display device>
FIG. 1 is a flowchart schematically showing a manufacturing method of a reflective display device according to an embodiment of the present invention. FIG. 2 is a diagram schematically showing an example of the partition wall forming step. As shown in FIG. 2, first, for example, a photolithography method (ultraviolet (UV) irradiation) is performed on the upper surface of one substrate 11 (substrate on the non-viewing side: not necessarily transparent) generally placed in the horizontal direction. The barrier ribs 12 having a predetermined pattern are formed by (exposure → development → firing). The partition wall 12 is a member that defines lower surfaces and side surfaces of a plurality of cells to be described later.

  In the present embodiment, the pattern of the partition walls 12 has a lattice shape as a whole, but as shown in FIG. It is provided to be aligned. The depth of the hole 124 is 5 μm.

  The width of the top 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 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 or peels off, and the separated partition wall 12 moves on the substrate. To do. 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 | variety of the top part of the partition 12 is shown in FIG. If the top corner is not rounded, the width of the top is defined as it is, as shown in FIGS. 4 (a) and 4 (b). On the other hand, when the top corner is rounded, as shown in FIG. 4C and FIG. 4D, it is understood as the width between the intersecting lines of the top extension surface and the wall extension surface. . 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).

  Moreover, the thickness of the partition 12 is 5-50 micrometers, Preferably it is 10-50 micrometers. The cell size depends on the size of the display panel, but is 0.05 to 1 mm pitch, preferably 0.1 to 0.5 mm pitch.

  In the present embodiment, the partition wall 12 is formed by a photolithography method using an exposure mask 60 corresponding to the pattern of the partition wall 12 as shown in FIG. In this case, a partition material layer 125, which is a layer of a negative photosensitive resin material, is formed on the substrate 11, and the partition material layer 125 is covered with the exposure mask 60 and exposed.

  The exposure mask 60 includes a hole mask portion 61 corresponding to the hole portion 124 and a cell mask portion 62 corresponding to the inside of the cell. In this case, if the size of the hole mask portion 61 is made sufficiently large, the hole portion 124 can be formed as a through hole, while if the size of the hole mask portion 61 is made sufficiently small, the hole portion 124 is penetrated. It can be formed as a recess rather than a hole. This is because if the hole mask portion 61 is sufficiently small, the portion 126 of the partition wall material layer 125 that has not been exposed by the hole mask portion 61 becomes very narrow, and the reaction component in the developer at the time of development in the portion 126 is reduced. This is because the diffusion speed becomes slow and a difference occurs in the developing speed between the portion 126 not exposed by the hole mask portion 61 and the portion 127 not exposed by the cell mask portion 62 (see FIGS. 6 and 7).

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

  The adhesive layer 22 is formed corresponding to the pattern of the partition wall 12. In particular, in the present embodiment, as shown in FIGS. 3A and 3B, a hole 124 is provided at the top of the partition wall 12 on the branch center 121, as shown in FIG. As described above, since a part of the adhesive accumulated in the branch region 122 is accommodated in the hole portion 124, it is effectively prevented that the adhesive layer 22 is excessively deposited on the top of the partition wall 12 in the branch region 122. Is done.

  If a specific description is supplemented with reference to FIG. 8 about an example of a typical thermal transfer method as a transfer method, for example, a heat seal agent such as a polyester-based thermoplastic adhesive is formed on a PET film with a thickness of 30 μm. A transfer sheet is prepared, and the surface of the heat sealant of the transfer sheet is laminated on the partition wall at a normal temperature and a pressure of 0.1 MPa. This is heated for 1 minute on a hot plate maintained at, for example, 120 ° C., which is equal to or higher than the softening temperature of the heat sealant, and then the transfer sheet is peeled off. As a result, an adhesive of about 6 μm, for example, is formed on the partition wall.

  Here, the description of the thickness of the adhesive layer 22 will be supplemented. When the ink 13 to be described later includes solid particles, when the solid particles get on the partition walls 12 and the thickness of the adhesive layer 22 is smaller than the particle diameter of the solid particles, the other adhesive layer 22 on the partition walls 12 is described later. Does not reach the substrate 16. Therefore, the particle diameter of the solid particles has a meaning as the lower limit of the thickness of the adhesive layer 22. On the other hand, when the thickness of the adhesive layer 22 is larger than the particle diameter of the solid particles, the thickness of the adhesive layer 22 may be non-uniform depending on the pressure and temperature at the time of forming the adhesive layer. On the other hand, if the thickness of the adhesive layer 22 is set to be equal to the particle diameter of the solid particles, the particles actually define the thickness of the adhesive layer 22, so that the thickness of the adhesive layer 22 becomes uniform. Can be expected. Therefore, after all, it is preferable to set the thickness of the adhesive layer 22 equal to the particle diameter of the solid particles. Since the particle diameter of the solid particles is 1 to 10 μm, the preferable range of the thickness of the adhesive layer 22 is also 1 to 10 μm.

  In addition, the range of the thickness of the preferable adhesive layer 22 of 1-10 micrometers is the range of the thickness after the said adhesive layer formation. In a state before the so-called bonding in a state where the heat sealing agent is transferred, the adhesive is deposited on the partition wall 12 in a substantially triangular cross section, and therefore the height at that time is a value of 1 to 10 μm, that is, 2 ˜20 μm. For example, if the particle diameter is 5 μm, the height of the adhesive deposited on the partition wall 12 is preferably 10 μm, which is twice that height. The preferable range of the adhesive height of 2 to 20 μm applies as it is when the first adhesive layer 22 is on the viewing side as in the present embodiment.

  Returning to FIG. 1, after the adhesive layer 22 is formed, the ink 13 as a display medium is arranged in each partition 12 or each region partitioned by the partition 12 and the adhesive layer 22 (display medium arranging step). FIG. 9 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 the ink jet or die coat, (2) the ink 13 is applied by the central squeegee 32, the doctor blade, or the doctor knife so as to be in-plane uniform, and (3) Excess ink that protrudes is scraped off by the squeegees 33a and 33b at both ends, or by a doctor blade or doctor knife. (4) Finally, the excess ink collected on one side is wiped off by the wiper 34.

  Returning to FIG. 1, after the display medium arranging step, a conductive paste applying step is performed. FIG. 10 is a schematic diagram for explaining the function of the conductive paste. The conductive paste 14 is a metal paste such as a silver paste, and is applied to a predetermined position by, for example, a dispenser 41 or ink jet, tampo printing, pad printing, or stacking printing. As shown in FIG. 10, the conductive paste 14 functions as a wiring for applying a voltage to the other substrate 16. When a predetermined electric field (voltage) is applied between the electrode pattern on one substrate 11 and the electrode pattern on the other substrate 16, the electrophoretic particles in the ink 13 which is a display medium are driven, and a predetermined pattern such as a character pattern is driven. Information is displayed. Thereafter, even if the electric field is no longer applied, the information display state is maintained until a new electric field is applied between the two substrates.

  Thereafter, on the adhesive layer 22 on the partition wall 12, the other substrate 16 (viewing side substrate: needs to be transparent) facing the one substrate 11 is bonded (the other substrate bonding step). Thereby, each upper surface of a some cell is prescribed | regulated and a display medium (ink 13) is sealed in each cell.

  In the other substrate bonding step, as shown in FIG. 11, the heat sealing agent 22 formed as an adhesive layer is heated to obtain an adhesive force. Specifically, the ink 13 is filled by heating and softening the heat sealant 22 from the periphery to a temperature exceeding the softening temperature while applying a predetermined thermocompression bonding pressure (laminating pressure) by the laminator 91. The partition wall 12 and the other substrate 16 are bonded. However, other thermocompression bonding modes may be employed.

  Here, in the present embodiment, the hole 124 is provided at the top of the partition wall 12 in the branch region 122, and at least a part of the adhesive accumulated in the branch region 122 is accommodated in the hole 124. In the branch region 122, the heat seal agent 22 is prevented from being deposited more than necessary. Thereby, when bonding the other board | substrate 16 to the partition 12, large pressure is not required, it is suppressed that a bubble generate | occur | produces in a cell and the heat-seal agent 22 oozes out in a cell. . On the other hand, since the width of the top of the partition 12 in the region 123 other than the branch region is not narrow, the top of the partition 12 and the other substrate 16 can be sufficiently satisfactorily bonded, and there is no fear that the partition 12 falls down.

  Thereafter, as shown in FIG. 1, 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, a laser cutter, etc., and is further subjected to outer periphery sealing processing to obtain a desired reflection. The production of the mold display device is completed.

  As described above, according to the present embodiment, by using the heat sealant 22 as an adhesive layer, the partition 12 for cell formation and the other substrate 16 are preferably bonded while being a simple process. it can.

  Further, when the heat sealant 22 of the adhesive layer is made of a thermoplastic material, it does not have tack or stickiness at room temperature, so that it is very easy to handle. Further, since there is no tack, that is, stickiness, the subsequent display medium arranging step is easy. Specifically, even when the display medium is arranged using a squeegee, a doctor blade, a doctor knife, or the like, the display medium (ink 13) does not adhere to the heat sealant 22.

  Further, in the adhesive layer forming step, the hole 124 is provided at the top of the partition wall 12 on the branch center 121, and a part of the adhesive accumulated in the branch region 122 is accommodated in the hole 124. In the branch area 122, it is suppressed that the heat seal agent 22 is accumulated more than a necessary amount. Thereby, when bonding the other board | substrate 16 to the partition 12, large pressure is not required, it is suppressed that a bubble generate | occur | produces in a cell and the heat-seal agent 22 oozes out in a cell. . Therefore, the possibility that the aperture ratio is lowered is also reduced, that is, the possibility that the contrast is lowered is also reduced.

  On the other hand, since the width of the top of the partition 12 in the region 123 other than the branch region is not narrow, the top of the partition 12 and the other substrate 16 can be sufficiently satisfactorily bonded, and there is no fear that the partition 12 falls down.

  In addition, when a predetermined electric field (voltage) is applied between an electrode pattern (not shown) on one substrate 11 and an electrode pattern (not shown) on the other substrate 16, electrophoresis in ink 13 as a display medium is performed. The particles are driven and predetermined information such as a character pattern is displayed. Thereafter, even if the electric field is no longer applied, the information display state is maintained until a new electric field is applied between the two substrates.

  Further, the above embodiments can be applied in principle when the electrophoretic body is a charged powder and the display medium is a gas.

  In the above-described embodiment, the pattern of the partition walls 12 has a lattice shape as a whole. However, the present invention is not limited to such a shape, and for example, a circle, a honeycomb shape (hexagon), and other polygons Etc. are basically arbitrary.

  In the above-described embodiment, the shape of the hole 124 at the top of the partition wall 12 is square, but the present invention is not limited to such a mode. For example, the shape of the hole portion 124 in a plan view may be a circular shape, a cross shape, a “human” character shape, or any other shape as long as it can accommodate a part of the adhesive accumulated in the branch region 122. May be.

  The size of the hole 124 in plan view, that is, the size of the branch region where the hole 124 can be provided is, for example, a region within 30 μm from the branch center 121 of the partition wall 12. Further, the hole 124 may penetrate the partition wall 12 completely or partially.

  Furthermore, the hole 124 does not necessarily need to be provided on the branch center 121, and is provided at a position away from the branch center 121 as long as a part of the adhesive accumulated in the branch region 122 can be accommodated. May be.

  In addition, according to the verification by the present inventors, it is preferable that the hole 124 satisfies the condition that it is larger than a circle having a diameter of 1 μm and the depth is 0.1 μm or more in plan view. This condition will be described with reference to FIGS.

  In the adhesive layer forming step shown in FIG. 8, when the surface of the heat sealant of the transfer sheet is laminated on the partition wall at room temperature, the heat sealant enters the hole 124 by about 0.1 μm. When this is heated at a temperature equal to or higher than the softening temperature of the heat sealant and then the transfer sheet is peeled off, an adhesive layer is formed on the partition walls. Here, even if the adhesive is transferred onto the hole 124, the adhesive flows into the gap portion of the hole 124, and the amount of the adhesive deposited on the top of the partition wall on the hole 124 is reduced (see FIG. 12). Further, when the transfer sheet is laminated and thermally transferred onto the partition wall, the heat sealant cannot come into contact with the partition wall on the hole portion 124, and this also reduces the amount of adhesive transferred itself.

  However, when the hole portion 124 has a size that fits in a circle having a diameter of 1 μm in plan view, the opening portion of the hole portion 124 is too small, so that the effect of reducing the amount of adhesive transferred onto the hole portion 124 can be obtained. In addition, the adhesive transferred onto the hole 124 in a bridge shape cannot flow into the gap portion of the hole 124 (see FIGS. 13A and 13B).

  Also, if the depth of the hole 124 is less than 0.1 μm, the heat sealant will come into contact with the bottom of the hole 124 when the heat sealant is laminated and thermally transferred onto the partition wall. The amount of adhesive transferred cannot be reduced (see FIGS. 13C and 13D).

  Moreover, it is preferable that the hole part 124 is not open | released with respect to two or more cells. As shown in FIG. 14 (a), when the hole 124 is open to one cell, the display medium 13 does not move between the cells, but as shown in FIG. 14 (b), When the hole 124 is open to two or more cells, the display medium 13 moves between the cells through the hole 124, the cell particle concentration fluctuates, and the cell color overlaps driving. Because it will change every time.

  Next, actual examples and comparative examples will be described.

<Example>
As one substrate 11, an indium tin oxide (ITO) vapor deposition film (thickness 0.2 μm) as a transparent electrode on one surface of 300 mm × 400 mm × 0.5 mm non-alkali glass (OA-10G manufactured by Nippon Electric Glass) ) Was prepared. The transparent electrode 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). obtain.

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, followed by baking at 200 ° C. for 60 minutes, so that the cell pitch is 175 μm. A grid-like pattern of partition walls 12 was formed.

  The width of the top of the partition wall 12 was about 20 μm, the shape of the hole 124 in a plan view was square, the length of one side was about 10 μm, and the depth was 5 μm. In the present embodiment, the hole 124 is formed on the branch center 121.

  A polyethylene terephthalate (PET) film (manufactured by Teijin DuPont) having a thickness of 50 μm is used as the transfer film substrate 21, and a heat sealant 22 (Byron 630 manufactured by Toyobo Co., Ltd.) having a thickness of 10 μm is applied by a die coder. And dried. Thus, a roll-shaped transfer film 20 having a 10 μm adhesive layer 22 was produced. The softening temperature of the heat sealing agent 22 was about 110 ° C.

  Then, with the transfer film 20 placed on the upper surface of the partition wall 12, the periphery of the heat seal agent 22 is heated to a temperature exceeding its softening temperature, for example, about 120 ° C. while further applying a pressing force of about 1 kPa. As a result, the heat sealant 22 was thermally transferred to the entire top surface of the partition wall 12. The height from the top of the partition wall 12 to the top of the heat sealant 22 was about 10 μm at the branch center 121 and about 7 μm in the region 123 other than the branch region (see FIG. 3).

  Subsequently, an ink 13 having the following components is used as a display medium, dropped from the dispenser 31, and squeezed with a central squeegee 32 (Neurong squeegee 1: made of urethane resin), and then in each cell. Filled. Excess ink that protruded in the substrate width direction was scraped off by another squeegee 33a, 33b (Nelogue Squeegee 2: made of urethane resin), and further wiped off by a roll wiper 34.

<Ink component>
・ Electrophoretic particles (titanium dioxide): 60 parts by weight ・ Dispersion liquid: 40 parts by weight Subsequently, silver paste (manufactured by Fujikura Kasei) is formed on a part of the outer periphery of the partition wall pattern (square area of 2 mm × 2 mm). Spot application was performed by the dispenser 41.

  Next, as the other substrate 16, a non-alkali glass (OA-10G manufactured by Nippon Electric Glass Co., Ltd.) having a size of 300 mm × 400 mm × thickness 0.5 mm and various electrodes such as Cu electrodes formed in a pattern were used. . Various electrode patterns were formed by a general etching method.

  Then, in the atmosphere, the other substrate 16 is disposed on the adhesive layer 22 on the partition wall 12 of the one substrate 11, and the cell volume in the partition wall 12 is applied while further applying a constant thermocompression pressure. While extruding excess ink exceeding 1, the partition 12 of one substrate 11 and the other substrate 16 were brought into close contact with each other (see FIG. 11). The temperature at the time of thermocompression bonding was 80 ° C. to 150 ° C., preferably 80 ° C. to 90 ° C., and in this example, it was 80 ° C. The thermocompression bonding pressure is preferably 0.01 MPa to 0.7 MPa, more preferably 0.1 MPa to 0.4 MPa, and 0.3 MPa in this example.

  Thereafter, the substrate is cut into a predetermined size, and a UV curable resin (LCB-610, manufactured by EACH Sea Co., Ltd.) is applied and sealed around both the substrates 11 and 16 using a dispenser (not shown). Then, UV light was exposed (exposure amount (700 mJ / cm 2)) and cured (peripheral sealing treatment).

  Although the quality of the display panel obtained as described above was evaluated, the degree of the seepage into the cell of the heat sealant 22 in the branch region 122 was very small, and the “seepage” shown in FIG. The distance “D” remained at 10 μm and the display contrast was good. Further, no great force was required for bonding in the other substrate bonding step, and the bonding between the heat sealant 22 on the partition wall and the other substrate 16 was good. Furthermore, no bubbles were generated in the cell.

  As a modified example, when the hole 124 at the top of the partition wall 12 is a square having a side of 15 μm in plan view, the “seeding distance D” shown in FIG. 3C is only 8 μm, and the display contrast is also good. Met.

  Further, as a modified example, when the hole 124 at the top of the partition wall 12 is formed into a square having a side of 1 μm in a plan view, the “seeding distance D” shown in FIG. 3C is only 12 μm, and the display contrast is also good. Met.

<Comparative example>
In contrast to the above example, a display panel was manufactured in the same process except that the hole 124 was not provided at the top of the partition wall 12 in the branch region 122 when the partition wall was formed. The width of the top of the partition wall 12 was uniformly about 20 μm, and the height of the adhesive layer on the partition wall 12 was about 14 μm in the branch region 122 and about 7 μm in the region 123 other than the branch region.

  The quality of the display panel thus obtained was evaluated, but the degree of the seepage into the cell of the heat sealant 22 in the branch region 122 was large, and “seeding distance D” shown in FIG. Was 15 μm, and the display contrast was not good. In the other substrate bonding step, in order to crush the crest of the heat sealant 22 in the branch region 122, a large force was required for bonding, and in this comparative example, a thermocompression pressure of 0.6 MPa or more was required. Furthermore, generation | occurrence | production of the bubble was seen in the cell.

<Other embodiments>
Next, as another embodiment of the present invention, a case where the pattern of the partition walls 12 is a honeycomb as a whole will be briefly described.

  When the pattern of the partition walls 12 has a honeycomb shape, the top width of the partition walls 12 is 9 μm to 50 μm, preferably 9 μm to 20 μm. The thickness of the partition wall 12 is 5 to 50 μm, preferably 10 to 50 μm. The cell size depends on the size of the display panel, but is 0.05 to 1 mm pitch, preferably 0.1 to 0.5 mm pitch.

  In the case of manufacturing a display panel using such a partition 12, it is effectively prevented that the adhesive layer 22 is overlaid on the top of the partition in the branch region 122 in the adhesive layer forming step (FIG. 15 ( d)), and the extent of the leakage of the heat sealant 22 in the branch region 122 into the cell in the obtained display panel is very small as shown in FIG.

<Materials and characteristics of each member>
Finally, materials and characteristics of the reflection type display device as a manufacturing object of the present invention will be supplemented in more detail.

  As the substrate 11, a substrate in which an electrode is formed of a conductive material such as a metal on the surface of a resin film, a resin plate, glass, epoxy glass (glass epoxy) or the like can be used. The one substrate 11 may be a light transmissive base material. Furthermore, it may be a light-transmitting and opaque substrate, such as an opaque glass substrate, resin film, resin plate, glass, epoxy glass (glass epoxy) with the other surface different from the electrode surface roughened. Can be used.

  The thickness of one substrate 11 is preferably 10 μm to 2 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 2 mm, the panel weight becomes too heavy and 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 800 μm.

  One substrate 11 can be provided with further functional layers. For example, a barrier film can be attached to the surface of one substrate 11. Even if a transparent film in which a barrier layer of a transparent inorganic film is previously formed by vapor deposition or the like is employed as one substrate 11, the same function can be exhibited. Alternatively, an ultraviolet cut film can be attached to the surface of one substrate 11. Even if the surface of one of the substrates 11 is subjected to another ultraviolet ray cut treatment, the same function can be exhibited. As other surface coat layers, an AG layer (antiglare layer), an HC layer (scratch prevention layer), an AR layer (antireflection layer) and the like can be added.

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

  The partition wall 12 can be composed of an ultraviolet curable resin, a thermosetting resin, a room temperature curable resin, or the like, and is preferably formed to a thickness of 5 to 50 μm as described above. If the thickness is 5 μm or less, the amount of ink to be filled is small, and sufficient display characteristics, in particular, contrast cannot be obtained. On the other hand, if the thickness is 50 μm or more, the panel is too thick and the drive voltage increases excessively. 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.

  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.

  As a method for forming the partition wall 12, a mold transfer method such as embossing as well as a photolithography method may be employed. Furthermore, a method of manufacturing a mesh-processed structure as a partition and sticking the structure to one substrate 11 may be employed.

  The adhesive layer (heat sealant) 22 is preferably a material using a thermoplastic material, and has a property of softening by heating and solidifying when cooled, and the plasticity is reversibly when cooling and heating are repeated. It is a material that is kept. When a heat seal agent made of a thermoplastic material is used as an adhesive layer, the heat seal agent solidified on the transfer film substrate is softened by heating to a temperature exceeding its softening temperature, and the partition upper surface It is also possible to reliably heat transfer the heat sealant only. Moreover, since the heat sealant after heat 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 heat sealant. Then, the heat sealing agent on the upper 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 the other substrate is securely bonded. Since the heat sealant after bonding the other substrate does not have tack or stickiness at normal temperature again, the display medium is not bonded to the heat sealant, and there is no possibility of deterioration of display quality. 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 increase the adhesion between the partition wall 12 and the heat sealant 22, 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 heat sealing agent 22.

  As the other substrate 16, a transparent film such as PE, PET, PES, or PEN or a transparent glass provided with a transparent electrode such as ITO or ZnO can be typically used. The transparent electrode can be formed by a coating method, a vapor deposition method, or the like.

  The thickness of the other substrate 16 is preferably 10 μm to 2 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 2 mm, the panel weight becomes too heavy and 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 800 μm.

  The surface of the other substrate 16 may be subjected to an oxidation preventing process by a plating process. A barrier layer may be provided on the back surface (outside) of the other substrate 16. The function of the barrier layer is to prevent display deterioration caused by the ink adsorbing moisture. The barrier layer may be transparent on the upper substrate, transparent or opaque on the lower substrate, and obtained by depositing an inorganic film. Or the film in which the barrier layer was previously formed may be bonded together. The formation of the electrode pattern on one substrate 11 can be performed by a photolithography method, a laser drawing method, an ink jet method, a screen printing method, a flexographic printing method, or the like.

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

  The peripheral sealant 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. They are applied to the periphery of both substrates 11, 16 by a dispenser, by various printing methods, or by thermocompression.

11 One substrate 12 Partition 13 Ink (display medium)
16 Other substrate 22 Heat seal agent 31 Dispenser 32 Central squeegee (squeegee 1)
33a, 33b Both-end squeegee (squeegee 2)
34 Roll wiper 41 Dispenser 51 Cutting device 91 Laminator 92 Hot plate 93 Metal piece

Claims (3)

A display medium including at least one kind of electrophoretic body is sealed between two opposing substrates, at least one of which is transparent, and the display medium is applied when a predetermined electric field is applied between the two substrates. Is a reflective display device that displays predetermined information,
A partition including a branch region in a predetermined pattern is formed on one substrate,
Each area defined by the partition walls is a cell, and the display medium is disposed in the cell.
A hole is formed at the top of the branch region of the partition wall,
An adhesive is disposed on the top of the partition;
A reflective display device, wherein the other substrate is bonded to the adhesive. 2. The reflection according to claim 1, wherein the hole is larger than a circle having a diameter of 1 μm in a plan view and is not open to two or more cells and has a depth of 0.1 μm or more. Type display device. The reflective display device according to claim 1, wherein the adhesive is a thermoplastic resin.

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