JP2014010342A - Reflection type display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reflection type display device that prevents nonuniform display and display failure when partial pressure is applied from outside, and to provide a manufacturing method for it.SOLUTION: A reflection type display device is such that at least a display medium including at least one or more types of electrophoresis is sealed between two opposite substrates, one of which is transparent, and when a predetermined electric field is applied between the two substrates, the display medium displays given information. In the reflection type display device, a partition is formed on one of the substrates by using a first pattern. The display medium is arranged having, as a cell, each of areas separated by the partition. A first adhesive layer is formed on the partition and a second adhesive layer is formed on the other substrate by using a predetermined second pattern. The pattern of cells separated by the partition of the first pattern differs from that of the second pattern.

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) by the applicant of the present application discloses a method in which an adhesive is applied only on the partition walls that partition the cells to ensure adhesion between the partition walls and the substrate. ing. 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.

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

  The present inventor has obtained the following knowledge while earnestly researching the state of adhesion between the adhesive layer provided on the partition and the substrate, or the state of adhesion between the adhesive layer provided on the substrate and the partition. It came to.

  When the adhesion between the adhesive layer provided on the partition wall and the substrate is insufficient, the display medium moves between cells when local pressure is applied from the outside, resulting in so-called display unevenness. Pressure marks are generated. 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, for example, the adhesion between the adhesive layer provided on the top surface of the partition wall in which the ink (display medium) containing the electrophoretic material is arranged and the substrate is the electrophoresis. Since the ink containing the body is in a wet state, the ink may enter between the top surface of the adhesive layer provided on the partition wall and the substrate, thereby reducing the adhesive strength between the two. Such an influence may not be negligible because the area of the top surface of the partition wall, that is, the area of the adhesive layer is small. In particular, when the ink containing the electrophoretic body contains solid particles, the solid particles enter between the top surface of the adhesive layer provided on the partition wall and the substrate, and adhesion between the two. Strength may be significantly reduced.

  The present invention has been made based on such circumstances, and an object of the present invention is to provide a reflective display device in which display unevenness and display failure do not occur when local pressure is applied from the outside. is there.

  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. In the electrophoretic display device in which the display medium displays predetermined information, a partition is formed with a predetermined first pattern on one substrate, and each region partitioned by the partition is defined as a cell. The display medium is disposed, a first adhesive layer is formed on the partition, a second adhesive layer is formed in a predetermined second pattern on the other substrate, and the first pattern partition The reflection type display device is characterized in that the pattern of the cells partitioned by the second pattern is different from the second pattern.

  According to the present invention, the second adhesive layer is also provided on the other substrate, and the second adhesive layer on the other substrate is bonded to the first adhesive layer on the partition wall, whereby the electrophoretic body In particular, when the display medium includes solid particles or solid powder, both the solid particles and the solid powder may enter between the first adhesive layer and the second adhesive layer. Since the adhesive layer adheres such that the display medium, in particular, solid particles or solid powder is sandwiched, pushed away, or encased, the adhesive strength between the two is remarkably suppressed.

  On the other hand, since the cell pattern and the second pattern defined by the partition walls of the first pattern are different and generally the second adhesive layer having a high resistance value does not cover the entire surface of the cell, The problem that the drive voltage increases excessively does not occur.

  The first adhesive layer and the second adhesive layer are not necessarily made of the same material, but extremely high adhesive strength can be realized if they are made of the same material.

  The second pattern of the second adhesive layer is preferably a dot array pattern, and each dot constituting the dot array pattern has a size that fits within a circle having a diameter of 20 μm. Here, the shape of each dot constituting the dot arrangement pattern is generally square or circular, but is not limited thereto and is arbitrary. In addition, the arrangement mode of each dot is generally a matrix arrangement, but is not limited thereto and is arbitrary. When such a dot array pattern is adopted, according to actual verification by the present inventors, for example, when the occupied area ratio by the dot array pattern is 40% to 60%, the reduction and driving of the adhesive strength is reduced. Good balance with suppression of voltage increase.

  Alternatively, the second pattern of the second adhesive layer is preferably a mesh pattern, and each linear element constituting the mesh pattern has a width of 20 μm or less. Here, the shape of each linear element constituting the mesh pattern is generally a linear shape, but is not limited thereto and is arbitrary. For example, each linear element may have a wavy line shape, need not have a uniform thickness, and may not have the same shape. The arrangement of the linear elements is also generally a lattice arrangement, but is not limited thereto and is arbitrary. Even in the case where such a mesh pattern is adopted, according to actual verification by the present inventor, for example, when the occupied area ratio by the mesh pattern is 40% to 60%, it is possible to suppress and drive down the adhesive strength. Good balance with suppression of voltage increase.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the reflection type display apparatus which reduces that a display nonuniformity and a display defect generate | occur | produce when a local pressure is applied from the outside.

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 illustrating an example of the second pattern of the first adhesive layer. FIG. 4 is a diagram illustrating another example of the second pattern of the first adhesive layer. FIG. 5 is an explanatory diagram of suitable numerical conditions for the second adhesive layer. FIG. 6 is a diagram schematically showing an example of the display medium arranging step. FIG. 7 is a diagram schematically showing an example of the other substrate bonding step.

  In FIG. 1 to FIG. 8, 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 photolithographic method (by ultraviolet (UV) irradiation) is performed on the upper surface of one substrate 11 (a substrate on the viewing side: the substrate must be transparent) generally placed in the horizontal direction. The partition walls 12 having a predetermined first 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. For example, the pattern of the partition walls 12 is a lattice shape. The thickness of a partition 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.

  Next, the first adhesive layer 22 is formed on the partition wall 12 (first adhesive layer forming step). In the first adhesive layer forming step, a heat seal agent such as a polyester-based thermoplastic adhesive is formed by, for example, a transfer method or a printing method. To supplement a specific description of an example of a typical thermal transfer method as a transfer method, for example, a transfer sheet in which a heat sealant such as a polyester-based thermoplastic adhesive is formed on a PET film with a thickness of 30 μm is prepared. The surface of the heat sealant of this 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 a temperature higher than the softening point of the heat sealant, and then the transfer sheet is peeled off. As a result, an adhesive of 6 μm, for example, is formed on the partition wall.

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

  In addition, the range of the thickness of the preferable 1st contact bonding layer 22 of 1-10 micrometers is the range of the thickness after the said contact bonding 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. On the other hand, when the first adhesive layer 22 is not on the viewing side as in the present embodiment, the first adhesive layer 22 is allowed to protrude from the partition wall 12 within a predetermined range. This predetermined range is obtained by the same principle as described later with reference to FIG. 5 and is, for example, ± 10 μm. For example, when the partition wall width is 10 μm, the first adhesive layer 22 is allowed to be formed to a total width of 30 μm in consideration of both the left and right protrusions. At this time, if the particle diameter is assumed to be 5 μm, the cross-sectional area is 30 μm × 5 μm = 150 μm ² , and when this is stacked on a 10 μm wide partition wall, the height of the adhesive layer having a substantially triangular cross section is set to 30 μm. The On the other hand, the second adhesive layer forming step is performed on the other substrate 16 (substrate on the non-viewing side: it may not be transparent). Also in this process, a heat sealant such as a polyester-based thermoplastic adhesive is formed with a thickness of 1 to 100 μm by, for example, a transfer method or an offset printing method. Preferably, it is formed with a thickness of 1 to 50 μm, and particularly preferably with a thickness of 1 to 10 μm. Here, the second adhesive layer 122 is formed according to a second pattern different from the pattern of the partition wall 12, for example, as a dot arrangement pattern as shown in FIG. 3 or as a mesh pattern as shown in FIG. 4. It is formed.

  The dot arrangement pattern is not particularly limited, and may be a pattern in which square dots are arranged in a matrix as shown in FIG. 3 (a), or a circular shape as shown in FIG. 3 (b). A pattern in which dots are arranged in a matrix may be used, or a pattern in which circular dots and square dots are mixedly arranged in a matrix as shown in FIG. As shown in FIG. 3D, a pattern arranged in a matrix form in which square dots are partially missing may be used. However, according to the verification by the present inventor, it is preferable to satisfy the condition that each dot constituting the dot arrangement pattern has a size that fits within a circle having a diameter of 20 μm.

  The mesh pattern is not particularly limited, and may be a pattern in which linear linear elements are arranged in a grid pattern as shown in FIG. 4A, or a wavy line pattern as shown in FIG. May be a pattern in which the linear elements are arranged in a substantially lattice pattern, or may be a pattern in which wavy linear elements are arranged in substantially parallel as shown in FIG. A pattern in which wavy line-shaped linear elements are randomly arranged as shown in FIG. However, according to the verification by the present inventors, it is preferable to satisfy the condition that the width of each linear element constituting the mesh pattern is 20 μm or less.

  Here, the grounds for the numerical limiting conditions “inside a circle having a diameter of 20 μm” or “a width of 20 μm or less” will be described. As shown in FIG. 5, when the thickness of the second adhesive layer 122 is T, the diameter or width of the second adhesive layer 122 is 2 L, the distance between the electrodes is G, and the potential difference between the electrodes is ΔV, the charged particles adhere to the second adhesive layer. When it is possible to move from the position A above the center point of the layer 122 beyond the edge position B of the second adhesive layer 122, the following equation is established.

Distance between A and B: (L ² + (GT) ² ) ^1/2
Potential difference between A and B: ΔV × (GT) / G
The electric field (E) between A and B is the potential difference between A and B / the distance between A and B, and this (QE) multiplied by the charge (Q) of the charged particle is applied to the charged particle. The working electrophoretic force (F). If this overcomes the electrophoretic resistance force (resistance force in the display medium) acting on the charged particles, the charged particles move from the position A above the center point of the second adhesive layer 122 to the edge position of the second adhesive layer 122. You can move beyond B.

The resistance in the display medium (T (for example, 10 μm), G (for example, 20 μm), ΔV (for example, 40 V), and Q (for example, 5 × 10 ⁻¹¹ C) widely used in the embodiment of the reflective display device For example, when the value of L (μm) is actually obtained by further considering 7 × 10 ⁻⁵ N), for example.
Distance between A and B: (L ² + (GT) ² ) ^{1/2
= (L 2 + (20-10)} 2) 1/2
= (L ² +100 ) ^1/2 (μm)
Potential difference between A and B: ΔV × (GT) / G
= 40 * (20-10) / 20
= 20 (V)
Because
QE = 5 × 10 ⁻¹¹ × 20 / (L ² +100 ) ^1/2 (C ・ V / μm)
= 10 ⁻³ / (L ² +100 ) ^1/2 (C · V / m = N)
And if this solves the inequality that the resistance 7 × 10 ⁻⁵ N is overcome,
10 ⁻³ / (L ² +100 ) ^1/2> 7 × 10 ⁻⁵
From this, L = 10 (μm) is obtained. 2L = 20 (μm).

  Here, an example of a method for measuring the diameter of the second adhesive layer 122 will be described. An image of the diameter of the second adhesive layer 122 is taken with a lens of 20 times or more with an optical microscope. At this time, for example, it is assumed that the pixel resolution is 10,000 or more. Then, how many μm the distance of 100 pixels corresponds to is obtained in advance by observing a pattern with a certain size such as a photomask. For example, if the pattern having a width of 10 μm is 20 pixels, the pattern is 50 μm per 100 pixels. Then, one pixel is selected from the photographed image of the diameter of the second adhesive layer 122, and whether or not all the pixels within the circle having a radius of 10 μm centering on the pixel are in the image of the diameter of the second adhesive layer 122. Is determined. As for the pixel, if all pixels within a circle having a radius of 10 μm from the pixel are within the image of the diameter of the second adhesive layer 122, one of the pixels within a circle having a radius of 10 μm from the pixel is the second adhesive layer. If it is outside the image having a diameter of 122, it is determined as NG. Such a discrimination process is performed for all the pixels in the image having the diameter of the second adhesive layer 122, and if any one of the selected pixels is the result OK, the diameter of the image can be discriminated to be within 20 μm. .

  Returning to FIG. 1, after the first adhesive layer 22 is formed, the ink 13 as a display medium is disposed in each partition 12 or each region partitioned by the partition 12 and the first adhesive layer 22 (display medium arrangement). Process). FIG. 6 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.

  Thereafter, the second adhesive layer 122 of the other substrate 16 facing the one substrate 11 is bonded onto the first adhesive layer 22 on the partition wall 12 (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. 7, the heat sealing agent 22 applied as the first adhesive layer and the heat sealing agent 122 applied as the second adhesive layer are heated to obtain an adhesive force. It has become. Specifically, while applying a predetermined thermocompression bonding pressure (laminating pressure) by the laminator 91, both the heat sealants 22 and 122 are heated from the periphery to a temperature exceeding the softening temperature to soften the ink. The partition wall 12 filled with 13 is bonded to the other substrate 16. However, other thermocompression bonding modes may be employed.

  Here, in the present embodiment, the second adhesive layer 122 is also provided on the other substrate 16, and the second adhesive layer 122 on the other substrate 16 with respect to the first adhesive layer 22 on the partition wall 12. Is adhered to the display medium including the electrophoretic body, and in particular, when the display medium includes solid particles, the solid particles enter between the first adhesive layer 22 and the second adhesive layer 122. However, since the adhesive layers 22 and 122 are bonded by softening or flowing so that the display medium, in particular, solid particles are sandwiched, pushed away, or wrapped, the adhesive strength between the two is significantly reduced. Is suppressed.

  Further, for example, the cell pattern defined by the partition 12 of the first pattern which is a grid pattern is different from the second pattern which is a dot arrangement pattern or a mesh pattern of the second adhesive layer 122 and generally has a resistance value. Since the high second adhesive layer 122 does not cover the entire surface of the cell, there is no problem that the driving voltage of the reflective display device increases excessively.

  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 sealing agent 22 as the first adhesive layer, it is preferable to bond the partition wall 12 and the other substrate 16 for cell formation with a simple process. Can be implemented.

  Further, when the heat sealing agent 22 of the first adhesive layer is made of a thermoplastic material, it is very easy to handle because there is no tack or stickiness at room temperature. 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.

  According to the present embodiment, the second adhesive layer 122 is also formed on the other substrate 16 in the second adhesive layer forming step (FIG. 1), and in the other substrate adhesive step (FIGS. 1 and 5), By bonding the second adhesive layer 122 on the other substrate 16 to the first adhesive layer 22 on the partition wall 12, a display medium containing an electrophoretic body, particularly when it contains solid particles. Even if the solid particles enter between the first adhesive layer 22 and the second adhesive layer 122, the two adhesive layers 22 and 122 sandwich the display medium, in particular, the solid particles, and push or wrap the solid particles. Glue in this way. For this reason, it is suppressed that the adhesive strength between both falls notably. Therefore, when local pressure is applied from the outside, display unevenness and display failure do not occur.

  However, the cell pattern defined by the partition 12 of the first pattern which is a lattice pattern, for example, is different from the second pattern which is a dot arrangement pattern or a mesh pattern of the second adhesive layer 122 and generally has a resistance value. Since the high second adhesive layer 122 does not cover the entire surface of the cell, there is no problem that the driving voltage of the reflective display device increases excessively.

  The first adhesive layer 22 and the second adhesive layer 122 are not necessarily made of the same material as long as they have sealing properties with respect to the display medium (ink 13), but the same material, in particular, the same resin material. If so, extremely high adhesive strength can be realized. This is due to the fact that the resins have compatibility and have the same softening point. The adhesive strength between the first adhesive layer 22 and the second adhesive layer 122 can also be adjusted by adjusting the thickness of each adhesive layer. In general, the adhesive force is proportional to the thickness of the adhesive layer.

  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.

  Next, practical examples actually performed will be described.

<Example of Reflective Display Device>
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 ), followed by development using a 1% KOH aqueous solution for 30 seconds, and baking at 200 ° C. for 60 minutes, so that the top surface line Partition walls 12 having a grid pattern with a width of 10 μm and a cell pitch of 175 μm were formed.

  And the polyester-type thermoplastic adhesive as the 1st contact bonding layer 22 was apply | coated by the printing method with the thickness of 5 micrometers on the partition 12, and was dried.

  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 Next, as the other substrate 16, 300 mm × 400 mm × 0.5 mm thick non-alkali glass (OA made by Nippon Electric Glass) -10G) was used in which various electrodes such as Cu electrodes were formed in a pattern. Various electrode patterns were formed by a general etching method.

  Then, a polyester-based thermoplastic adhesive as the second adhesive layer 122 was applied to the other substrate 16 with a thickness of 5 μm by an offset printing method. Here, the second adhesive layer 122 was formed in a dot matrix arrangement pattern according to a second pattern different from the pattern of the cells partitioned by the partition walls 12. Here, a dot matrix arrangement pattern in which each dot is circular, has a diameter of about 15 μm, and occupies an area of 40% is employed (see FIG. 3B).

  Then, in the atmosphere, the second adhesive layer 122 on the other substrate 16 is disposed on the first adhesive layer 22 on the partition wall 12 of the one substrate 11, and a constant thermocompression pressure is further applied by overlapping them. At the same time, the partition 12 of one substrate 11 and the other substrate 16 were brought into close contact with each other while extruding excess ink exceeding the cell volume in the partition 12 (see FIG. 7). The temperature during thermocompression bonding was 110 ° C. Moreover, the thermocompression bonding pressure was 0.5 MPa.

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). It was stopped and exposed to ultraviolet rays (exposure amount 700 mJ / cm ² ) and cured (peripheral sealing treatment). Thus, a display panel was produced.

  The display quality of the display panel obtained as described above was evaluated and was very good. In addition, changes in display quality were evaluated by applying local pressure from the outside. Specifically, a metal piece having an area of 10 mm × 10 mm was pressurized at 1 MPa for 10 seconds, then returned to atmospheric pressure, and the change in display quality was evaluated. As a result, display unevenness and display failure did not occur. Furthermore, the driving voltage of the display panel has not increased significantly.

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

  As the one substrate 11, a transparent film such as PE, PET, PES, PEN, or the like that is provided with a transparent electrode such as ITO or ZnO on a transparent glass can be typically used. The transparent electrode can be formed by a coating method, a vapor deposition method, or the like.

  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.

  The surface of one substrate 11 may be subjected to an oxidation preventing process by a plating process. Further, a barrier layer may be provided on the back surface (outside) of one substrate 11. The function of the barrier layer is to prevent display deterioration caused by the ink adsorbing moisture. The barrier layer may be transparent on one substrate (a substrate on the viewing side) and transparent or opaque on the other substrate (a substrate on the non-viewing side), and is 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.

  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 pattern shape of the partition wall 12 is basically arbitrary such as a circle, a lattice, or a polygon. 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 first adhesive layer (heat sealant) 22 is preferably made of a thermoplastic material, has a property of softening by heating and solidifying when cooled, and plasticity is reversible when cooling and heating are repeated. It is a material that is kept in a safe manner. When a heat seal agent made of a thermoplastic material is used as the first adhesive layer, the heat seal agent solidified on the transfer film substrate is softened by heating to a temperature exceeding its softening temperature, The heat sealant can be reliably thermally transferred only to the upper surface of the partition wall. 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 substrate 116 to be the release substrate, an inexpensive film such as PET is usually used, but the material is not particularly limited as long as it has flexibility suitable for the release process. For example, a film provided with an ITO electrode may be used. In the case of such a film, it can function as an “exfoliation substrate with an electrode” from which an ITO electrode can be taken at the time of peeling.

  As the other board | substrate 16, what formed the electrode by electroconductive materials, such as a metal, on the surface, such as a resin film, a resin board, glass, epoxy glass (glass epoxy), may be used. The other substrate 16 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 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 to the surface of the other substrate 16. 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 the other substrate 16, the same function as this can be exhibited. Alternatively, an ultraviolet cut film can be attached to the surface of the other substrate 16. Even if the other substrate 16 is subjected to other ultraviolet cut processing, 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.

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

  Similarly to the first adhesive layer (heat seal agent) 22, the second adhesive layer (heat seal agent) 122 preferably uses a thermoplastic material. Specifically, as described above for the first adhesive layer (heat sealant) 22, thermoplastic base polymers such as ethylene-vinyl acetate copolymer, polyester, polyamide, polyolefin, polyurethane, natural rubber, styrene- A tackifying resin mainly composed of a thermoplastic elastomer such as a butadiene block copolymer, a styrene-isoprene block copolymer, a styrene-ethylene-butylene-styrene block copolymer, or a styrene-ethylene-propylene-styrene copolymer. And resins containing a plasticizer are mainly used.

  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 (first adhesive layer)
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 116 Substrate 122 to be peeled substrate 122 Heat seal agent (second adhesive layer)

Claims (4)

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 wall is formed in a predetermined first pattern on one substrate,
The display medium is arranged with each region partitioned by the partition as a cell,
A first adhesive layer is formed on the partition;
A second adhesive layer is formed in a predetermined second pattern on the other substrate,
The reflection type display device, wherein the pattern of the cells defined by the partition walls of the first pattern is different from the second pattern. The reflective display device according to claim 1, wherein the first adhesive layer and the second adhesive layer are made of the same material. 3. The reflective display according to claim 1, wherein the second pattern is a dot arrangement pattern, and each dot constituting the dot arrangement pattern has a size that fits within a circle having a diameter of 20 μm. apparatus. The reflective display device according to claim 1, wherein the second pattern is a mesh pattern, and each linear element constituting the mesh pattern has a width of 20 μm or less.

Images