JP2012063630A - Microcapsule type electrophoresis display device and manufacturing method thereof - Google Patents

Abstract

Disclosed is a microcapsule electrophoretic display device and a method for manufacturing the same, which can effectively prevent a color development defect in image display by adjusting the water content of the microcapsule electrophoretic display device.
A microcapsule-type electrophoretic display device according to the present invention includes an electrophoretic display layer containing microcapsules laminated on a transparent electrode layer of a transparent substrate, and conductive adhesion so as to cover the electrophoretic display layer. It is characterized by laminating an agent layer and a conductive release substrate.
[Selection] Figure 1

Description

  The present invention relates to a microcapsule type electrophoretic display device using an electrophoretic phenomenon and a method for manufacturing the same.

  In recent years, with the development of information equipment, information display has been made in various forms. As the variable information display, a CRT (cathode ray tube), a liquid crystal display (LCD), and the like are mainly used. A light emitting display such as a liquid crystal display of the type using a CRT or a backlight makes the eyes look tired when used for a long time, and does not drop to read a document or the like.

  Also, as a flat panel display device, the liquid crystal display is currently thin and can be miniaturized, so it is widely used in various applications. However, a light-emitting display such as a transmissive LCD is There are problems that the eyes are easily fatigued and that the optical characteristics vary greatly depending on the viewing angle.

  On the other hand, a liquid crystal display of a type that does not use a backlight has a problem that the darkness of the screen due to the use of a polarizing plate appears and the visibility is poor. Furthermore, the display images of these displays have no memory property and have the disadvantage that they disappear as soon as the electrical energy supply is stopped.

  In the replacement of displays in portable information devices such as e-books and portable information terminal devices that are expected to become more widespread in the future, eye fatigue is less likely to occur even when used for a long time, visibility is good, and power consumption is low. In addition, it is considered necessary to have image memory properties.

  Among them, so-called electronic paper is one of the display devices particularly attracting attention. This has the advantages of both paper and an electronic display, and has the feature that image information is retained even in a non-powered state and can be rewritten. Because of the reflective display, there is an advantage that the contrast ratio does not change and the viewing angle is wide.

  As such electronic paper, a microcapsule-type electrophoretic display device has attracted attention. Since the microcapsule type electrophoretic display device displays characters and images by reflected light, similarly to the printed paper surface, the load on the eyes is small, and it is also suitable for work that keeps watching the screen for a long time. This is based on the principle that by applying an electric field, the charged particles in the microcapsule move and display an image.

  Also, the microcapsule type electrophoretic display device puts white and black particles positively and negatively charged in a microcapsule filled with a dispersion medium, and pulls up the respective particles to the display surface by applying an external voltage, thereby displaying an image. Is formed. Since the size of the microcapsules is as small as several tens of μm to several hundreds of μm, when the microcapsules are dispersed in a transparent binder material, they can be coated like ink. Since this ink can be displayed in black and white by applying a voltage, it is also called “electronic ink”.

  When this ink is coated on a transparent resin on which a transparent electrode is formed and a conductive adhesive layer is formed thereon, the substrate is bonded to a substrate on which an electrode circuit for active matrix driving represented by TFT is formed. An active matrix display can be obtained (for example, Patent Document 1).

  Usually, a component in which a transparent resin film on which a transparent electrode is formed is coated with electronic ink is called a “front plate”, and a substrate on which an electrode circuit for driving an active matrix is formed is called a “back plate”.

  In the production of the front plate, first, an ink including an electrophoretic display layer in which an additive is arbitrarily blended is formed on a transparent resin on which a transparent electrode is formed using a predetermined coating method. On the other hand, a conductive adhesive layer is separately formed on the resin using the same coating method. A front plate is formed by bonding the ink layer and the conductive adhesive layer by applying heat.

JP 2000-221546 A JP 2003-186064 A

  However, each of the front plates formed of a transparent resin that is the base material of the electrophoretic display layer, an electrophoretic display layer, a conductive adhesive layer, and a resin that is the base material of the conductive adhesive layer The moisture content of each constituent layer varies. For this reason, when a voltage is applied to each front plate, the electric resistance values of these layers change, and there is a problem that a difference occurs in the response of the pigment particles of the electrophoretic display layer to the voltage applied to the electrodes.

  If the moisture content is high, leakage current flows between the front and back plates, the voltage applied between the electrodes drops, and a sufficient potential difference is not given to the electrophoretic display layer, resulting in a decrease in ink color. A malfunction occurs. In addition, when the moisture content is low, the electrophoretic display layer and the conductive adhesive layer behave like an insulator layer of a capacitor, charges accumulate in the electrodes and their correlation, and the bias is opposite to the applied voltage. This causes a problem called kickback phenomenon in which the color development is reduced due to the application of the pressure.

  In addition, in an electrophoretic display device using display particles, a method of adjusting the water content of ink has been proposed in order to improve color contrast (for example, Patent Document 2). However, the moisture content fluctuates during processing of the electrophoretic display device, and there is a problem that high contrast cannot be obtained in the display body.

  In addition, there is an aging jig that does not warp the entire sheet, has high work efficiency, and that air containing moisture easily reaches the film substrate in the aging process, so that the moisture content of the entire sheet is uniform. Proposed. However, in this system, for example, when the apparatus is left in an environment where the temperature is 20 ° C. and the humidity is 50% and the temperature is 45 ° C. to 55 ° C. and the relative humidity is 40% to 60%, the edge of the sheet There is a problem that condensation occurs on the jig.

  The generated dew condensation causes moisture above the specified level to enter the transparent resin that is the base material of the electrophoretic display layer, the electrophoretic display layer, the conductive adhesive layer, and the resin that is the base material of the conductive adhesive layer. In particular, there is a problem that a large amount of moisture permeates from the edge of the sheet or the cut surface, a sufficient potential difference is not given to the electrophoretic display layer, and the color development of the ink is lowered.

  Accordingly, the present invention provides a front plate composed of a transparent resin that is a base material of an electrophoretic display layer, an electrophoretic display layer, a conductive adhesive layer, and a resin that is a base material of a conductive adhesive layer. An object of the present invention is to provide a microcapsule type electrophoretic display device and a method for manufacturing the same that are effective for eliminating the coloring defects of the electrophoretic layer caused by the large amount of the electrophoretic layer.

  The microcapsule-type electrophoretic display device according to claim 1 of the present invention is formed by laminating an electrophoretic display layer containing microcapsules on a transparent electrode layer of a transparent substrate, and conductive adhesion so as to cover the electrophoretic display layer. It is characterized by laminating an agent layer and a conductive release substrate.

  In the microcapsule type electrophoretic display device according to claim 2 of the present invention, the microcapsules in the electrophoretic display layer are constituted by encapsulating charged particles and a dispersion medium for dispersing the charged particles in a resin film. It is characterized by.

Moreover, the manufacturing method of the microcapsule type electrophoretic display device according to claim 3 of the present invention includes an electrophoretic display layer containing a microcapsule on a transparent electrode layer of a transparent substrate, a conductive adhesive layer, and a conductive release substrate. A sealing agent having a melting point of 40 ° C. to 50 ° C. is provided on a jig in which a microcapsule-type electrophoretic display device and a slip sheet are alternately formed in a sheet-like shape, and is cured. Moisture content of the sheet-like microcapsule electrophoretic display device by placing the tool in an aging environment of 45 ° C. to 55 ° C., a temperature of 45 ° C. to 55 ° C., and a relative humidity of 40% to 60%. Is characterized in that the humidity is adjusted to be 1.0 g / m ² or more and 3.0 g / m ² or less.

  Further, in the method of manufacturing a microcapsule type electrophoretic display device according to claim 4 of the present invention, the jig is configured by alternately laminating microcapsule type electrophoretic display devices and slip sheets formed in a sheet shape, It is characterized by being able to stand upright while being sandwiched.

  According to the present invention, a front plate composed of a transparent resin that is a base material of an electrophoretic display layer, an electrophoretic display layer, a conductive adhesive layer, and a resin that is a base material of a conductive adhesive layer, It is possible to provide a microcapsule type electrophoretic display device and a method for manufacturing the same that are effective for eliminating the coloring defects of the electrophoretic layer caused by the large amount.

1 is a vertical side view schematically showing a configuration of a microcapsule type electrophoretic display device according to an embodiment of the present invention. The schematic diagram which shows an example of the manufacturing line of the microcapsule-type electrophoretic display device which concerns on embodiment of this invention. The schematic diagram which shows an example of the aging jig | tool in the loading part of the manufacturing line of the microcapsule-type electrophoretic display device which concerns on embodiment of this invention. The schematic diagram which shows an example at the time of stacking | stacking multiple aging jig | tool in the loading part of the manufacturing line of the microcapsule-type electrophoretic display device which concerns on embodiment of this invention. The schematic diagram which shows an example of the aging process in the aging chamber of the manufacturing line of the microcapsule-type electrophoretic display device which concerns on embodiment of this invention. The schematic diagram which shows an example of the aging process in the aging chamber of the manufacturing line of the microcapsule-type electrophoretic display device which concerns on embodiment of this invention. The schematic diagram which shows the structural example of the microcapsule contained in the electrophoretic display layer of the microcapsule-type electrophoretic display device which concerns on embodiment of this invention.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 schematically shows a configuration of a microcapsule electrophoretic display device according to the present embodiment. As shown in FIG. 1, the front plate 9 of the microcapsule type electrophoretic display device 1 according to the present embodiment includes a transparent substrate 2 made of a transparent resin substrate on which a transparent electrode (transparent electrode layer) 3 is formed, The electrophoretic display layer 6 is composed of a microcapsule 4 containing colored particles and white particles, a conductive adhesive layer 7, and a conductive release substrate 8 having a release layer.

  First, on the transparent substrate 2 having the transparent electrode 3, the electronic ink in which the microcapsules 4 and the binder material 5 are dispersed is applied by a predetermined coating method such as screen printing, microgravure, die coater, dip coater, etc. The electrophoretic display layer 6 is formed. Moreover, the conductive adhesive layer 7 is applied on the conductive release substrate 8 in which a silicon layer is provided as a release layer on the conductive layer and the surface layer, thereby forming a conductive adhesive substrate.

  By attaching the electrophoretic display layer 6 and the conductive adhesive layer 7 together, the front plate 9 of the microcapsule type electrophoretic display device 1 having the layer configuration of FIG. 1 is formed.

  By using the conductive adhesive layer 7 having the same components as the binder material 5 used in the electronic ink, the affinity of the resin interface is increased and the separation is less likely to occur, and the dielectric constant is similar. There is an advantage that the voltage applied to the microcapsule 4 tends to be constant on the surface.

  For the transparent substrate 2, a material that can visually recognize the color of the display medium from the outside of the display device 1 and has a high visible light transmittance is optimal. As the transparent substrate 2, an organic polymer substrate such as polyethylene terephthalate (PET) can be used. The substrate on the back electrode side may be a transparent substrate or an opaque substrate.

  For the transparent electrode 3 on the transparent substrate 2, a conductive material having high light transmittance such as indium tin oxide (ITO) or indium zinc oxide (IZO) is used. Moreover, you may use the transparent resin material which has electroconductivity for the transparent electrode 3 other than the said metal material. Such a transparent electrode 3 can be formed using a sputtering method, a vapor deposition method, or the like.

  Since the conductive layer of the conductive release substrate 8 does not require transparency, it may be a metal film such as copper or aluminum, a thin film formed by electrodeposition, or a film formed of a conductive polymer.

  FIG. 2 schematically shows an example of a production line of the microcapsule type electrophoretic display device 1 according to the present embodiment. In this production line, an electrophoretic display layer 6 laminated on a transparent substrate 2 and a conductive adhesive layer 7 laminated on a conductive release substrate 8 are bonded together, and a front plate 9 wound in a roll shape is attached. Unwinding unit 10 to be attached, cutting unit 11 for cutting the front plate 9 wound up in a roll shape into a predetermined size, transport unit 12 in which a conveyor for transporting the cut front plate sheet 16 is installed, front plate aging A loading section 13 on which an aging jig 14 is mounted and an aging chamber 15 for aging the front plate are provided.

  FIG. 3 schematically shows an example of the aging jig 14 in the stacking unit 13 of the production line of the microcapsule type electrophoretic display device 1 according to the present embodiment.

  As shown in FIG. 3, the water content of the transparent substrate 2, the electrophoretic display layer 6, the conductive adhesive layer 7, and the conductive release substrate 8 that are constituent members of the front plate 9 prepared by the above steps is the There are variations between the face plates 9 and in the front plate 9. When the front plate sheet 16 cut to a predetermined size is assembled to the aging jig 14 from the front plate 9 in which the electrophoretic display layer 6 and the conductive adhesive layer 7 are bonded together in order to make the entire moisture uniform. In addition, by cutting the cut front plate sheet 16 and the interleaf paper 17 alternately, the moisture containing air can easily reach the entire front plate sheet 16 during the aging process. .

  Further, as shown in FIG. 3, fixing bolt holes (through holes) 21 are provided in the periphery of the jig body 18 so that a predetermined number of bundles 16 a of the front plate sheets 16 can be stacked on the plate-like jig body 18. A stacking block (short) 19 and a stacking block (long) 20 are respectively arranged.

  The interleaf paper 17 alternately laminated on each front plate sheet 16 makes it easy for moisture-containing air to easily reach the front plate sheet 16 during the aging process, and the laminated front plate sheets 16 are attached to each other. It also has the effect of preventing.

  FIG. 4 schematically shows an example in which a plurality of aging jigs 14 are stacked in the stacking section 13 of the production line of the microcapsule type electrophoretic display device 1 according to the present embodiment.

  As shown in FIG. 4, when the aging jig 14 is stacked in a plurality of stages, the top plate 24 is placed on the uppermost stage, and each jig body 18, the stacking block (short) 19 using the fixing bolts 22. Then, the stacking block (long) 20 is fixed and integrated.

  FIG. 5 schematically shows an example of the aging process in the aging chamber 15 of the production line of the microcapsule type electrophoretic display device 1 according to the present embodiment.

  As shown in FIG. 5, the aging jig 14 stacked and integrated in a plurality of stages as shown in FIG. 4 is brought into an upright state with the stacking block (long) 20 as the bottom surface. In this way, the aging jig 14 is stacked in a plurality of stages, and the aging jig 14 is erected in a state where the aging jig 14 is sandwiched, thereby eliminating the pressure difference due to the weight of the front plate sheet 16 and the interleaf paper 17 generated when the aging jigs 14 are stacked. be able to.

  FIG. 6 schematically shows an example of an aging process in the aging chamber 15 of the production line of the microcapsule type electrophoretic display device 1 according to this embodiment.

  As shown in FIG. 6, a sealing agent 23 that is not impermeable to water and melts outside the dew point is heat-sealed or adhered to the long and short pieces of the outer peripheral portion of the top plate 24 and the lowermost jig body 18. Apply with adhesive.

In a state where the aging jig 14 with the sealant 23 attached is upright, it is allowed to stand for 3 days or more in an environment where the temperature is adjusted to 45 ° C. or higher and 55 ° C. or lower and the relative humidity is adjusted to 40% or higher and 60% or lower, The humidity is adjusted so that the water content is 1.0 g / m ² or more and 3.0 g / m ² or less.

  In this state, when the aging jig 14 is left in an aging environment where the temperature is 45 ° C. or more and 55 ° C. or less and the relative humidity is 40% or more and 60% or less, which is an aging environment, the aging jig 14 may be in an arbitrary temperature and humidity before aging. The front plate sheet 16 and the aging jig 14 gradually start to reach a temperature range of 45 ° C. or higher and 55 ° C. or lower. When the temperature reaches the range of 45 ° C. or higher and 55 ° C. or lower, the sealing agent 23 is melted.

  When the sealing agent 23 melts, the front plate sheet 16 is exposed to the temperature and humidity of the aging environment. Since the front plate sheet 16 in the aging jig 14 does not undergo a rapid temperature change from the environment before aging and is in contact with the aging environment, condensation does not occur, and the front plate sheet 16 is prevented from entering moisture above the specified level. Can do.

Since the material of the sealant 23 is not impermeable to water, there is no problem even if it is attached to the front plate sheet 16. Even when the sealant 23 remains, since the end of the bundle 16a of the front plate sheet 16 is covered, it becomes easy to handle the bundle 16a of the front plate sheet 16.
As the material of the sealing agent 23, a sealing material having a melting point of 40 ° C. to 50 ° C. such as a paraffin film or a wax film may be used.

  The material of the plate-shaped jig body 18 and the stacking block (short) 19 and the stacking block (long) 20 which are constituent members of the aging jig 14 are polycarbonate resin and polystyrene having a glass transition temperature higher than 80 ° C. By using a polymer resin such as a resin or a metal, it can be used without being deformed by use in an aging process in which it is put in a temperature environment up to 60 ° C.

  FIG. 7 schematically shows a configuration example of the microcapsule 4 included in the electrophoretic display layer 6 of the microcapsule type electrophoretic display device 1 according to the present embodiment.

  As shown in FIG. 6, the microcapsule 4 included in the electrophoretic display layer 6 includes a methacrylic acid resin, a urea resin, gum arabic, or the like as a capsule shell 25, and white particles 26 made of titanium oxide and carbon black therein. The black particles 27 are encapsulated in a state of being dispersed in a highly viscous dispersion medium 28 such as silicone oil. Titanium oxide, which is the white particle 26, has a positive charge, while carbon black, which is the black particle 27, has a negative charge.

  The display body of the microcapsule type electrophoretic display device 1 formed as shown in FIG. 1 can be displayed by applying voltage from the transparent electrode layer 3 on the transparent substrate 2 and the TFT substrate side, and the electrode is positive or negative. A color can be expressed by selectively applying a voltage.

  As shown in FIG. 1, the electrophoretic display layer 6 includes a large number of microcapsules 4, and particles in the microcapsules 4 are moved based on the above-described principle by controlling the direction of the electric field of the electrode layer. And can be displayed as white and black.

  The microcapsule-type electrophoretic display device 1 having the above-described structure is close to the white color of paper in terms of easiness of viewing, has a very large viewing angle, and can be used without problems under direct sunlight outdoors.

  Since each particle in the microcapsule 4 of the electrophoretic display layer 6 is dispersed in a highly viscous dispersion medium, the position of the particle does not change even when the power is turned off once the electric field is applied. As described above, since the display image has a memory property that does not disappear, the electric field only has to be applied at the time of rewriting.

  An ink in which a predetermined amount of microcapsules 4 and a binder material 5 were blended on a roll-like PET resin coated with ITO as the transparent electrode 3 was coated with a die coater to form a film having a thickness of about 23 μm. Further, a urethane resin conductive adhesive 7 having a film thickness of about 25 μm was formed on a roll-shaped conductive release substrate 8 in which an Al layer and a silicon layer were formed on a PET resin by the same coating method.

  The microcapsule 4 and the conductive adhesive 7 were laminated, and the front plate 9 formed in a roll shape was cut into a predetermined size to obtain a front plate sheet 16. On one piece of the jig body 18 of the aging jig 14, 50 sheets of the front plate sheets 16 and the interleaving paper 17 were alternately laminated, and 80 sets were assembled in the jig with one set of three stacked layers. . As the sealing agent 23, a 3 μm thick paraffin sheet having a melting point of 45 ° C. is sealed so as to cover the aging jig 14. The assembled jig was allowed to stand for 5 days in an aging chamber 15 in an environment of a temperature of 50 ° C. and a relative humidity of 50%.

An example of the measurement result of the moisture content measured by the Karl Fischer method after cutting out the front plate sheet 16 subjected to aging for 5 days is shown in Table 1 below.

  It was confirmed that there was no variation between the sheets of each front plate sheet 16 and within the sheets. Further, when the front plate sheet 16 (front plate 9) is driven by applying a voltage of 15 volts to both electrodes, it is confirmed that the electrophoretic display layer 6 of the front plate sheet 16 is driven, and the display performance and display brightness are confirmed. It was confirmed that there was no difference between the sheets of each front plate sheet 16 and within the sheets.

  DESCRIPTION OF SYMBOLS 1 ... Microcapsule type electrophoretic display device, 2 ... Transparent substrate, 3 ... Transparent electrode, 4 ... Microcapsule, 5 ... Binder material, 6 ... Electrophoretic display layer, 7 ... Conductive adhesive, 8 ... Conductive peeling substrate , 9 ... Front plate, 10 ... Unwinding part, 11 ... Cutting part, 12 ... Conveying part, 13 ... Loading part, 14 ... Aging jig, 15 ... Aging chamber, 16 ... Front plate sheet, 17 ... Interleaf, 18 ... Jig body, 19 ... Stacking block (short), 20 ... Stacking block (long), 21 ... Fixing bolt hole, 22 ... Fixing bolt, 23 ... Sealant, 24 ... Top plate, 25 ... Capsule Shell, 26 ... white particles, 27 ... black particles, 28 ... dispersion medium.

Claims (4)

  An electrophoretic display layer containing microcapsules is laminated on a transparent electrode layer of a transparent substrate, and a conductive adhesive layer and a conductive release substrate are laminated so as to cover the electrophoretic display layer. Microcapsule type electrophoretic display device.   2. The microcapsule type electrophoretic display device according to claim 1, wherein the microcapsules in the electrophoretic display layer are constituted by encapsulating charged particles and a dispersion medium for dispersing the charged particles in a resin film. . An electrophoretic display layer containing microcapsules on a transparent electrode layer of a transparent substrate, a conductive adhesive layer, a microcapsule-type electrophoretic display device formed in a sheet shape in which a conductive release substrate is disposed, and a slip sheet A sealing agent having a melting point of 40 ° C. to 50 ° C. is provided on the jig in which the layers are alternately laminated, and the jig in the sandwiched state is 45 ° C. to 55 ° C., the temperature is 45 ° C. to 55 ° C., and the relative humidity is 40 % In the aging environment of not less than 60% and not more than 60% so that the moisture content of the sheet-like microcapsule type electrophoretic display device is 1.0 g / m ² or more and 3.0 g / m ² or less. A method for producing a microcapsule type electrophoretic display device, comprising:   4. The microcapsule type electrophoretic display device according to claim 3, wherein the jig is configured such that a microcapsule type electrophoretic display device formed in a sheet shape and an interleaving paper are alternately laminated and can be erected in a sandwiched state. Manufacturing method.

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