WO2010134380A1 - Method for manufacturing electrochemical display device - Google Patents

Abstract

Provided is a method for manufacturing an electrochemical display device having excellent display properties. To this end, in the electrochemical display device manufacturing method in which an electrolyte solution containing a polymer binder and metal oxide fine particles is applied to one of opposed substrates and the other substrate is adhered thereto under a decompression atmosphere to form a display portion, a dispersion solvent in which spherical spacers (19) are dispersed is applied onto a substrate (14) at a predetermined position to form a dispersion liquid-applied portion (62)before the electrolyte solution is applied, and the electrolyte solution is applied to form an electrolyte solution-applied portion (72) after the dispersion solvent is dried.

Description

Method for manufacturing electrochemical display device

The present invention relates to a method of manufacturing an electrochemical display device capable of rewriting display using an electrochemical reaction.

Conventionally, the display function is realized by modulating the light of self-luminous display devices such as CRT (Cathode Ray Tube) and PDP (Plasma Display Panel) and LCD (Liquid Crystal Display). Display devices are known.

These display devices have an advantage of being bright and easy to see, but have a problem of high power consumption. Therefore, from the viewpoint of low power consumption, a display device that has memory characteristics that keeps an image once displayed in a non-powered state and operates at a low driving voltage is desired.

As a display device having such memory characteristics and operation characteristics, an electrochromic display device (Electro-Chromic Display: hereinafter simply referred to as “ECD”), an electrodeposition display device (Electrodeposition Display: hereinafter simply referred to as “ECD”). Called "ED"). ECD and ED have a thin display portion formed by sealing an electrolyte between upper and lower substrates, and as electronic paper with the advantages of paper (lightness and flexibility) Can be used.

The display principle of ECD and EC is as follows. That is, ECD utilizes a phenomenon in which an oxidation-reduction reaction occurs at an electrode on a substrate and a light absorption state of an electrochromic layer formed on the electrode reversibly changes, so that a desired character or image is displayed on the display unit. Is displayed.

On the other hand, ED is a display device that uses an electrolytic solution containing silver or a compound having silver in a chemical structure. ED utilizes the fact that the light absorption state of the electrode reversibly changes due to the reaction in which silver is deposited on the electrode from the electrolytic solution and the reaction in which silver deposited on the electrode is dissolved in the electrolytic solution. Then, a desired character or image is displayed on the display unit.

Thus, electrochemical display devices such as ECD and ED use the fact that the light absorption state changes due to the oxidation-reduction reaction at the electrodes. That is, the electrochemical display device can display an image on the display unit without an additional member such as a polarizing plate or a backlight, and the number of parts of the electrochemical display device is reduced. Therefore, the electrochemical display device is very excellent in terms of cost reduction and process saving at the time of manufacture as compared with other display devices.

However, the conventional ECD and ED technologies have the following problems. That is, in the conventional ECD and ED, an electrolyte solution having a relatively low viscosity is used. Therefore, when ECD and ED are used for a long time, the electrolytic solution flows in the display portion, and the concentration of the electrolytic solution in the display portion becomes non-uniform. As a result, in some cases, display unevenness occurs in the display unit due to changes over time, and this display unevenness becomes a problem.

As one of the techniques for solving the display unevenness caused by the change with time, for example, there is a technique of using an electrolytic solution containing a polymer binder and increasing the viscosity of the electrolytic solution. In this method, the electrolytic solution sealed in the display unit hardly moves in the display unit due to its viscosity.

Further, the electrolyte solution having a high viscosity is sealed in the display unit by a liquid crystal dropping method, for example. Here, the liquid crystal dropping method is a technique widely used as a manufacturing method for a large LCD. In the liquid crystal dropping method, first, a desired amount of electrolytic solution is dropped and supplied to either the upper or lower substrate. And an upper side and a lower side board | substrate are bonded together in a pressure-reduced atmosphere, and electrolyte solution is satisfy | filled between both board | substrates by an electrolyte solution being spread between both board | substrates.

However, even if a high-viscosity electrolyte is used as a conventional ECD and ED electrolyte, if the gap between the upper and lower substrates (hereinafter, also simply referred to as “cell gap”) varies, The amount of the electrolytic solution in each part of fluctuates. As a result, display unevenness corresponding to the variation in cell gap occurs in the display unit, and this display unevenness becomes a problem.

As one of the techniques for solving the display unevenness caused by the cell gap variation, for example, there is a technique of arranging spherical spacers (beads) between the upper and lower substrates. Here, in the electrochemical display device using the high-viscosity electrolytic solution, the cell gap needs to be about 20 to 50 μm. By arranging spacers of an appropriate size (diameter) at an appropriate density between the upper and lower substrates, the cell gap in each part of the display unit becomes a desired range, and display unevenness due to variations in the cell gap. Can be suppressed.

Further, as one method for supplying the spacer to the substrate, for example, a wet spraying method using spraying or a dry spraying method using a gas flow can be cited. Furthermore, a method of supplying spacers to a substrate by applying an electrolytic solution in which the spacers are dispersed to the substrate has also been conventionally known (for example, Patent Document 1).

JP-A-62-247335

However, in the wet spraying method and the dry spraying method, the spacer distribution becomes non-uniform as the spacer diameter increases, resulting in a problem that the cell gap becomes non-uniform in each part of the display unit.

In addition, as in Patent Document 1, when supplying an electrolytic solution in which spacers are dispersed to a substrate by a dispenser, when the specific gravity of the electrolytic solution with respect to the spacer is very large, the spacer is located above the electrolytic solution reservoir. Will be levitating. As a result, the number of spacers contained in the electrolyte in the reservoir is larger at the upper portion of the reservoir and lower at the lower portion of the reservoir. For this reason, the number of spaces included in the electrolyte solution varies at each discharge timing for the electrolyte solution discharged from the dispenser. This variation in the number of spacers also occurs when the specific gravity of the electrolyte with respect to the spacers is very small.

As described above, in the technique of Patent Document 1, when the specific gravity of the electrolyte with respect to the spacer is greatly different, the spacer cannot be uniformly supplied on the substrate. As a result, there arises a problem that the cell gap becomes nonuniform in each part of the display unit.

Therefore, an object of the present invention is to provide a method for manufacturing an electrochemical display device with good display characteristics.

In order to solve the above-described problem, the manufacturing method according to the first aspect is such that the electrolytic solution includes a polymer binder and metal oxide fine particles, and the electrolytic solution is applied onto one of the opposing substrates. In the method of manufacturing an electrochemically operated display device in which the other substrate is bonded in a reduced pressure atmosphere to form a display portion, a dispersion solvent in which spherical spacers are dispersed is applied on the substrate before the electrolytic solution is applied. It is applied to the first application position, and the electrolytic solution is applied after the dispersion solvent is dried.

According to the manufacturing method according to the first aspect, the spherical spacers contained in the dispersion solvent are supplied onto one substrate by the first stage coating process, and then the spherical spacers are formed by the second stage coating process. The electrolytic solution is supplied onto the supplied one substrate.

Thus, in consideration of the position of the electrolytic solution applied in the second-stage coating process and the movement state of the electrolyte solution that is pushed and moved when the two substrates are bonded together, By determining the position of the dispersion solvent to be applied, the distribution of the spherical spacers dispersed between the two substrates after being bonded can be made uniform.

Therefore, in the manufacturing method according to the first aspect, the gap between the opposing substrates can be within a desired range for the electrochemical display device manufactured by this manufacturing method, and the gap is caused by the variation in the gap between the opposing substrates. Display unevenness can be suppressed.

FIG. 1 is a plan view showing an example of the configuration of a display system according to an embodiment of the present invention. FIG. 2 is a front sectional view taken along line VV of FIG. FIG. 3 is a front view showing an example of the manufacturing process of the display panel. FIG. 4 is a perspective view showing an example of a seal portion formed on the upper substrate in the first embodiment. FIG. 5 is a front view showing an example of the manufacturing process of the display panel. FIG. 6 is a perspective view showing an example of a dispersion liquid application part applied to the lower substrate. FIG. 7 is a perspective view showing an example of the arrangement state of the spacers supplied to the lower substrate. FIG. 8 is a front view showing an example of the manufacturing process of the display panel. FIG. 9 is a perspective view illustrating an example of an electrolytic solution application unit applied to the lower substrate. FIG. 10 is a front view showing an example of the manufacturing process of the display panel. FIG. 11 is a perspective view showing an example of a seal portion formed on the upper substrate in the second embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

<1. First Embodiment>
<1.1. Display system configuration>
FIG. 1 is a plan view showing an example of the configuration of the display system 1 according to the first embodiment of the present invention. FIG. 2 is a front sectional view taken along line VV in FIG.

Here, the display system 1 is a display device that displays characters, images, and the like on a non-volatile display unit that keeps display content even in a non-powered state. As shown in FIG. 1, the display system 1 mainly includes an information processing device 5, a power supply 8, and a display panel 10. In addition, in FIG. 1 and the subsequent drawings, an XYZ orthogonal coordinate system in which the Z-axis direction is a vertical direction and the XY plane is a horizontal plane is appropriately attached as necessary to clarify the directional relationship. Yes.

The information processing apparatus 5 is configured by a so-called personal computer or workstation, and is electrically connected to the display panel 10 through a signal line 6. As shown in FIG. 1, the information processing apparatus 5 mainly includes a memory 5a and a CPU 5b. The memory 5a is a volatile or non-volatile storage unit, and stores programs, data, and the like. The CPU 5b executes desired processing at desired timing according to the program. For example, the information processing apparatus 5 displays desired characters and images on the display panel 10 by transmitting an image signal to the display panel 10 via the signal line 6.

The power supply 8 applies a drive voltage to the display panel 10 through the power supply line 9. The display panel 10 executes rewriting processing and erasing processing of characters and images displayed on the display panel 10 with power supplied from the power supply 8.

The display panel 10 is a display device that realizes a display function by an electrochemical operation, such as ECD or ED. As shown in FIGS. 1 and 2, the display panel 10 has a thin display portion 12 in which an electrolytic solution 18 is sealed, and is used as electronic paper having the advantages of paper (lightness and flexibility). it can. The detailed configuration of the display panel 10 will be described later.

<1.2. Configuration of display panel>
Here, a detailed configuration of the display panel 10 will be described. As shown in FIG. 1, the display panel 10 mainly includes a display unit 12, an upper electrode driver 20, a lower electrode driver 30, and a controller board 40.

The display unit 12 is a thin display area, and each pixel (display element) operates by a so-called simple matrix driving method. As shown in FIG. 2, the display unit 12 mainly includes an upper substrate 13, a lower substrate 14, a seal unit 17, an electrolytic solution 18, and a spherical spacer 19. As a driving method for each pixel, an active matrix driving method in which each pixel is operated by an active element (transistor) may be employed.

Each of the upper substrate 13 and the lower substrate 14 is a sheet body made of, for example, a resin film. As shown in FIGS. 1 and 2, the upper substrate 13 has a plurality of upper electrodes 13 a extending substantially along the Y-axis direction (horizontal first direction), and the lower substrate 14 has a substantially X-axis direction (horizontal second direction). A plurality of lower electrodes 14a extending along (direction) are provided. The positions where the upper electrode 13a and the lower electrode 14a intersect each function as a pixel (display element).

As shown in FIG. 2, the seal portion 17 is used as a partition wall that separates the enclosed space 12a formed between the upper substrate 13 and the lower substrate 14 from the space outside the enclosed space 12a. The seal part 17 is formed by, for example, a UV curable sealant applied to the lower substrate 14.

The electrolytic solution 18 contains an electrolyte in a solvent and is enclosed in an enclosed space 12 a surrounded by the upper and lower substrates 13 and 14 and the seal portion 17. The electrolytic solution 18 of the present embodiment includes a polymer binder and metal oxide fine particles as an electrolyte.

Here, in the present embodiment, “electrolyte” means (1) a substance that dissolves in a solvent such as water or alcohol, and whose solution (electrolytic solution) exhibits ion conductivity (hereinafter, simply “narrow electrolyte”). (2) a mixture in which a narrowly defined electrolyte and another metal or compound (which may be either a narrowly defined electrolyte or a non-electrolyte) are mixed (hereinafter simply referred to as “broadly defined electrolyte”). ")".

In the present embodiment, as the electrolyte, a mixture in which an organic solvent, an ionic liquid, a redox active substance, a supporting electrolyte, a complexing agent, a polymer binder, a white scattering material, and the like are selected as necessary is used. The

Hereinafter, each component of the electrolyte of the present embodiment will be further described.

As an organic solvent applicable in the electrolyte layer (electrolytic solution 18 in a state of being enclosed in the enclosed space 12a), a boiling point of 120 to 300 ° C. that can remain in the electrolyte layer without causing volatilization after the electrolyte layer is formed. A range of organic solvents can be used, for example, propylene carbonate, ethylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, butylene carbonate, γ-butyl lactone, tetramethyl urea, sulfolane, dimethyl sulfoxide, 1,3- Dimethyl-2-imidazolidinone, 2- (N-methyl) -2-pyrrolidinone, hexamethylphosphortriamide, N-methylpropionamide, N, N-dimethylacetamide, N-methylacetamide, N, N-dimethylformamide N-methylform Amide, butyronitrile, propionitrile, acetonitrile, acetylacetone, 4-methyl-2-pentanone, 2-butanol, 1-butanol, 2-propanol, 1-propanol, acetic anhydride, ethyl acetate, ethyl propionate, dimethoxyethane, di Examples thereof include ethoxyfuran, tetrahydrofuran, ethylene glycol, diethylene glycol, triethylene glycol monobutyl ether and the like.

Among the above organic solvents, carboxylic acid esters are preferable. Examples thereof include propylene carbonate, ethylene carbonate, ethyl methyl carbonate, diethyl carbonate, and γ-butyrolactone.

In the electrolyte layer of the present embodiment, a polymer binder is used from the viewpoint of increasing the viscosity of the electrolyte layer. The polymer binder is not particularly limited. For example, the polymer binder may be selected from various polymer compounds such as butyral resin, polyvinyl alcohol, polyethylene glycol, and polyvinylidene fluoride from the viewpoint of display characteristics and electrolyte viscosity. it can.

In the electrolyte layer of the present embodiment, inorganic metal oxide fine particles are preferably used as a white scatterer that achieves white display by scattering. For example, titanium dioxide (anatase type or rutile type), sulfuric acid Barium, calcium carbonate, aluminum oxide, zinc oxide, magnesium oxide and zinc hydroxide, magnesium hydroxide, magnesium phosphate, magnesium hydrogen phosphate, alkaline earth metal salts, talc, kaolin, zeolite, acid clay, glass, etc. be able to.

The spherical spacer 19 is a fine particle for controlling the gap G between the upper and lower substrates 13 and 14 facing each other. As the spherical spacer 19, for example, micro true spheres such as acrylic resin, styrene resin, and vinyl resin that are used in liquid crystal displays and the like can be used. The average particle diameter is preferably in the range of 10 μm or more and 50 μm or less in order to ensure the dispersion stability in the electrolytic solution and to ensure white color due to the scattering effect of the metal fine particles dispersed in the electrolytic solution layer.

Here, in the case where the electrochemical display device is an electrodeposition display device (ED), the observation surface (in order to observe the displayed characters and images) of the upper and lower electrodes 13a and 14a of the display unit 12, One electrode close to the surface (observed by the user of the electrochemical display device) is provided with a transparent electrode such as an ITO (Indium Tin Oxide) electrode, and the other electrode is provided with a metal electrode such as a silver electrode. Yes. An electrolyte layer having silver or a compound containing silver in the chemical structure is sandwiched between the upper and lower electrodes 13a and 14a facing each other.

Thus, when positive and negative voltages are applied between the upper and lower electrodes 13a and 14a, a silver oxidation-reduction reaction is performed on both the electrodes 13a and 14a. Therefore, on the transparent electrode, the black silver image in the reduced state and the transparent silver state in the oxidized state are switched reversibly.

The “compound containing silver or silver in the chemical structure” in the present embodiment is, for example, a compound such as silver oxide, silver sulfide, metallic silver, silver colloidal particles, silver halide, silver complex compound, and silver ion. There are no particular restrictions on the phase state species such as the solid state, the solubilized state in liquid, and the gas state, and the charged state species such as neutral, anionic, and cationic.

The concentration of silver ions contained in the electrolytic solution 18 is preferably 0.2 (mol / kg) ≦ [Ag] ≦ 2.0 (mol / kg). When the silver ion concentration is less than 0.2 (mol / kg), a dilute silver solution is formed and the driving speed is delayed. On the other hand, when the silver ion concentration is higher than 2 (mol / kg), the solubility is deteriorated and precipitation tends to occur during low-temperature storage, which is disadvantageous.

Further, a polymer material is added to the electrolytic solution 18 as a binder for increasing the viscosity, and metal oxide fine particles such as TiO ₂ and ZnO are dispersed as a white scattering material. Therefore, when each display element of the display unit 12 is in a transparent state, high-quality white is displayed on the display unit 12.

On the other hand, when the electrochemical display device is an electrochromic display device (ECD), a transparent electrode such as an ITO electrode is provided on one of the upper and lower electrodes 13a and 14a of the display unit 12 that is close to the observation surface. The other electrode is provided with an electrode having a tin oxide layer doped with antimony on the ITO electrode. An electrolyte layer having an electrochromic dye is provided between the upper and lower electrodes 13a and 14a facing each other.

Thereby, when a positive and negative voltage is applied between the upper and lower electrodes 13a and 14a, an electrochromic dye oxidation-reduction reaction is performed on the electrode on the observation surface side. Therefore, the electrochromic coloring state is reversibly switched on the transparent electrode.

Further, the “electrochromic dye” in the present embodiment is a compound that changes a light absorption state by accepting electrons, and an organic compound or a metal complex can be used.

As the organic compound, a pyridine compound, a conductive polymer, and a styryl compound can be used. Various viologen compounds described in JP-A No. 2002-328401, dyes described in JP-T-2004-537743, and others are known. A dye can be used. When a leuco dye is used, a developer or a color erasing agent may be used in combination as necessary.

An organic compound or metal complex that can be used as an electroclock dye may be applied directly on the electrode. In addition, after an oxide semiconductor nanostructure typified by TiO ₂ is formed on an electrode, an electrochromic material may be applied and impregnated on the oxide by a method such as an inkjet method.

Further, as in the case of ED, a polymer material is added to the electrolytic solution 18 as a binder to increase the viscosity, and fine metal oxide particles such as TiO ₂ and ZnO are dispersed as a white scattering material. ing. Therefore, when each display element of the display unit 12 is in a transparent state, high-quality white is displayed on the display unit 12.

The upper electrode driver 20 gives an electric signal to each upper electrode 13a at a predetermined timing. As shown in FIG. 1, the upper electrode driver 20 includes an FPC 21, a PCB substrate 22, and a driver IC 23, and is electrically connected to the controller board 40 via a signal / power line 25.

The FPC (Flexible Printed Circuits) 21 is formed by bonding a conductive foil (for example, copper foil) on a film-like insulator (for example, polyimide), and the upper electrode 13a and the PCB substrate. 22 is electrically connected. The driver IC 23 is directly mounted on the FPC 21, and controls the voltage applied to the corresponding upper electrode 13a.

The lower electrode driver 30 gives an electric signal to each lower electrode 14a at a predetermined timing. As shown in FIG. 1, the lower electrode driver 30 includes an FPC 31, a PCB substrate 32, and a driver IC 33, and is electrically connected to the controller board 40 via a signal / power line 35.

The FPC 31, like the FPC 21, is formed by bonding a conductive foil on a film-like insulator, and electrically connects the lower electrode 14a and the PCB substrate 32. The driver IC 33 is directly mounted on the FPC 31, and controls the voltage applied to the corresponding lower electrode 14a.

The controller board 40 generates an electric signal to be given to the driver IC 23 of the upper electrode driver 20 and the driver IC 33 of the lower electrode driver 30 based on the image signal transmitted from the information processing apparatus 5. That is, the controller board 40 converts the image signal transmitted from the information processing device 5 into an electrical signal that can be used by the upper and lower electrode drivers 20 and 30.

<1.3. Manufacturing method of display panel>
3 to 10 are views for explaining a method of manufacturing the display panel 10 (electrochemical display device) in the present embodiment.

In the method for manufacturing the display panel 10, first, a UV curable sealant 51 is applied to the surface of the upper substrate 13 on which the upper electrode 13 a is formed by the seal dispenser 50. Thereby, the seal portion 17 is formed on the upper substrate 13 (see FIGS. 3 and 4).

Here, the seal dispenser 50 has a storage portion 50a for storing the sealant 51. Further, the seal dispenser 50 moves relative to the upper substrate 13 (at least one of the holders (not shown) of the seal dispenser 50 and the upper substrate 13 may be movable), and the sealant. 51 can be continuously discharged. As a result, a substantially rectangular annular seal portion 17 is formed on the upper substrate 13, for example, as shown in FIG. 4.

In addition, the shape of the seal part 17 is appropriately selected according to the shape of the display part 12. For example, when the disk-shaped display part 12 is created, the shape of the seal part 17 is substantially annular. Further, the seal portion 17 may be formed on the lower substrate 14 instead of the upper substrate 13.

Next, the dispersion liquid 61 is applied by the dispersion liquid dispenser 60 to the main surface of the lower substrate 14 on which the lower electrode 14a is formed (hereinafter also simply referred to as “application surface”) 14b. . That is, the first-stage coating process is executed. As a result, a substantially upper hemispherical (dome-shaped) dispersion applying unit 62 is formed on the lower substrate 14 (see FIGS. 5 and 6).

Here, the position of each dispersion liquid coating part 62 formed on the lower substrate 14 (that is, the dispersion solvent application position (first application position)) is, for example, as shown in FIGS. It is set in a lattice shape along the axial direction and the Y-axis direction so that the distances between the adjacent dispersion liquid application portions 62 are substantially the same.

Further, the dispersion liquid dispenser 60 has a storage part 60 a for storing the dispersion liquid 61. In addition, the dispersion 61 is obtained by dispersing the spherical spacer 19 in a dispersion solvent. As the dispersion liquid dispenser 60, for example, a dispenser in which a SUS needle having a nozzle inner diameter of 0.2 mm or more is attached to the tip, preferably a volumetric dispenser is used.

As the dispersion solvent, a solvent that does not dissolve the spherical spacer 19 (spacer particles) and has a boiling point in the range of 300 ° C. or lower and can be easily dried is desirable.

For example, as the dispersion solvent, water, alcohol, and organic solvents applicable to the electrolyte layer, esters such as propylene glycol monomethyl ether acetate and propylene glycol monoethyl ether acetate, 2-methyl-2-propanol, glycerin, Alcohols such as hexylene glycol, cellosolves such as methyl cellosolve, ethyl cellosolve, butyl cellosolve, ethylene glycol monomethyl ether acetate, ketones such as acetone, methyl ethyl ketone, cyclohexanone, methoxybenzene, 1,2-dimethoxybenzene, diethylene glycol dimethyl ether, etc. Ethers, hydrocarbons such as benzene, toluene, xylene, n-butylbenzene, diethylbenzene, tetralin, etc. It can be.

In particular, when a solvent (for example, water or alcohol) contained in the electrolytic solution is used as the dispersion solvent, the affinity between the dispersion 61 and the electrolytic solution 18 is improved, and unnecessary components are mixed into the electrolytic solution 18. Can be prevented. Therefore, the reliability of the electrolytic solution can be improved.

The specific gravity of the spherical spacer 19 is preferably 1.1 to 1.3 (g / cm ³ ), and the specific gravity of the dispersion solvent is preferably 0.75 to 1.5 (g / cm ³ ). is there. More preferably, in consideration of the dispersibility of the spherical spacer 19 with respect to the dispersion solvent, the spherical gravity is reduced so that the difference in specific gravity between the two becomes small (the difference between the two becomes 0.2 (g / cm ³ ) or less). The spacer 19 and the dispersion solvent are selected.

Thereby, it is possible to suppress the spherical spacer 19 from being levitated above the storage portion 60a or sinking below the storage portion 60a. Therefore, it becomes possible to arrange the spherical spacers 19 uniformly in the reservoir 60a. As a result, the number of spherical spacers 19 contained per unit volume of the dispersion 61 discharged from the dispersion dispenser 60 is substantially the same regardless of the discharge timing.

Therefore, when the spherical spacer 19 and the dispersion solvent are selected so that the difference in specific gravity between the dispersion solvent of the dispersion liquid 61 and the spherical spacer 19 is small, and a certain amount of the dispersion liquid 61 is discharged from the dispersion liquid dispenser 60. The number of the spherical spacers 19 included in each dispersion application unit 62 is substantially the same value (within a certain range).

Subsequently, the lower substrate 14 is heated by the hot plate 65, and each dispersion liquid coating part 62 formed on the lower substrate 14 is heated. Thereby, the dispersion solvent of each dispersion liquid application part 62 evaporates, and the spherical spacer 19 is merely placed on the lower substrate 14 (see FIG. 7).

Subsequently, after the dispersion solvent of the dispersion 61 is dried, the electrolyte 18 is applied to the application surface 14 b of the lower substrate 14 by the electrolyte dispenser 70. That is, the second stage coating process is executed. As a result, a substantially upper hemispherical electrolyte application part 72 is formed on the lower substrate 14 (see FIGS. 8 and 9).

Here, the position of each electrolytic solution application part 72 formed on the lower substrate 14 (that is, the application position of the electrolytic solution 18 (second application position)) is, for example, as shown in FIG. Is set so as to cover the spherical spacer 19 placed on the surface. That is, the position of each electrolytic solution application part 72 and the position (first application position) of the corresponding dispersion liquid application part 62 (one-dot chain line) are substantially the same. As a result, each spherical spacer 19, which is just placed on the lower substrate 14 and has a weak fixing force with respect to the lower substrate 14, is fixed on the lower substrate 14 by the electrolytic solution 18.

Further, the electrolytic solution dispenser 70 has a storage part 70a for storing and filling the electrolytic solution 18 prepared in advance prior to application. As the electrolytic solution dispenser 70, for example, a volumetric dispenser is used in the same manner as the dispersion dispenser 60. Then, the electrolytic solution 18 is metered and applied by the electrolytic solution dispenser 70 so that the amount of the electrolytic solution 18 supplied onto the lower substrate 14 is substantially equal to the volume of the enclosed space 12a (FIGS. 8 and 8). 9).

In the present embodiment, the area S1 (see FIG. 6) in which the dispersion solvent of the applied dispersion 61 (dispersion application unit 62) spreads on the lower substrate 14 is the applied electrolyte 18 (electrolyte). The application portion 72) is set to be smaller than the area S2 that spreads on the lower substrate 14.

Thus, all the spherical spacers 19 supplied to the lower substrate 14 are positioned below any one of the electrolyte application portions 72 before the opposing substrates 13 and 14 are bonded together. For this reason, the spherical spacers 19 are uniformly distributed between the substrates 13 and 14, and as a result, unnecessary spherical spacers 19 are aggregated, resulting in a decrease in visibility of the display unit 12. This can be suppressed.

Subsequently, the upper and lower substrates 13 and 14 are bonded together by the vacuum device 90. Here, the vacuum apparatus 90 is a vacuum bonding apparatus that bonds the upper and lower substrates 13 and 14 in a chamber 91 in a reduced pressure atmosphere. As shown in FIG. 10, the vacuum apparatus 90 mainly includes an upper substrate holding part 93, a lower substrate holding part 94, and a vacuum pump 95.

The upper substrate holding part 93 raises and lowers the upper substrate 13 along the direction of the arrow AR1 while holding the upper substrate 13 in the chamber 91. On the other hand, the lower substrate holding part 94 horizontally moves the lower substrate 14 in the XY plane while holding the lower substrate 14 in the chamber 91.

The vacuum pump 95 is connected to the processing space 91a through a pipe 97. When the vacuum pump 95 is operated, the atmosphere (gas) of the processing space 91a is exhausted, and the processing space 91a is reduced in pressure.

In the bonding process of the substrates 13 and 14 by the vacuum device 90, first, the upper substrate 13 on which the seal portion 17 is formed is the lower substrate in which the spherical spacer 19 and the electrolyte 18 are applied to the upper substrate holding portion 93. 14 are delivered to the lower substrate holding portion 94.

Next, the upper and lower substrates 13 and 14 are aligned by the upper and lower substrate holders 93 and 94, and the upper and lower substrates 13 and 14 are positioned. In parallel with the positioning of the substrates 13 and 14, the processing space 91 a is decompressed by the vacuum pump 95.

Subsequently, the upper substrate 13 is lowered by the upper substrate holder 93. As a result, the seal portion 17 of the upper substrate 13 comes into contact with the application surface 14b of the lower substrate 14, and the electrolyte 18 is pushed and spread between the upper and lower substrates 13 and 14, and the entire surface of the enclosed space 12a. To spread.

Here, as shown in FIG. 8, the position of each electrolytic solution application part 72 on the lower substrate 14 is a distance from the adjacent electrolytic solution application part 72 in a lattice shape along the X-axis direction and the Y-axis direction. Are set to be substantially the same. Further, the position of each electrolytic solution application part 72 of the lower substrate 14 is set so as to cover the spherical spacer 19 placed on the lower substrate 14.

As a result, when the electrolytic solution 18 is uniformly spread between the substrates 13 and 14 when the opposing substrates 13 and 14 are bonded together, the spherical spacer 19 moves between the substrates 13 and 14 together with the electrolytic solution 18. It moves and is uniformly distributed between both substrates 13 and 14. Therefore, the variation in the gap G between the opposing substrates 13 and 14 can be reduced, and display unevenness due to the variation in the gap between the opposing substrates can be suppressed.

Subsequently, after the bonded substrates 13 and 14 are temporarily fixed with a pre-applied UV curable resin or the like at a position away from the display element, and the relative positions of the substrates 13 and 14 are fixed. The processing space 91a is opened to the atmosphere.

Subsequently, both substrates 13 and 14 bonded together are irradiated with ultraviolet rays. As a result, the seal portion 17 is UV-cured, the substrates 13 and 14 are fixed by the seal portion 17, and the present manufacturing method ends.

<1.4. Advantages of Manufacturing Method in First Embodiment>
As described above, in the method for manufacturing the display panel 10 of the present embodiment, the dispersion liquid 61 in which the spherical spacers 19 are dispersed by the first stage coating process is used, and the electrolyte solution 18 is obtained by the second stage coating process. Applied.

Accordingly, the application position of the electrolytic solution 18 to be applied by the second-stage coating process and the movement state of the electrolytic solution 18 that is pushed and moved when the substrates 13 and 14 are bonded to each other are taken into consideration. By determining the application position (that is, the supply position of the spherical space) of the dispersion 61 to be applied by the application process in stages, the distribution of the spherical spacers 19 dispersed between the substrates 13 and 14 after being bonded is determined. It can be made uniform.

Therefore, in the display panel 10 manufactured by the manufacturing method of the present embodiment, the gap G between the opposing substrates 13 and 14 is set to a desired range, and the display unevenness due to the variation in the gap G between the substrates 13 and 14 is displayed. Is suppressed.

<2. Second Embodiment>
Next, a second embodiment of the present invention will be described. The display system 100 according to the second embodiment is compared with the display system 1 according to the first embodiment.
(1) The structure of the seal portion 117 formed on the upper substrate is different,
(2) The process of bonding the upper and lower substrates 113 and 14 is different,
Is the same as in the first embodiment. Therefore, in the following, this difference will be mainly described.

In addition, in the following description, the same code | symbol is attached | subjected about the component similar to the component in the display system 1 of 1st Embodiment. Since the components with the same reference numerals have already been described in the first embodiment, description thereof will be omitted in the present embodiment.

<2.1. Manufacturing method of display panel>
FIG. 11 is a perspective view showing an example of the seal portion 117 (117a, 117b) formed on the upper substrate 113 in the present embodiment. The inner seal portion 117a is used as a partition wall that separates a space formed between the upper substrate 113 and the lower substrate 14 and a space outside the enclosed space. Then, a space surrounded by the inner seal portion 117 a, the upper substrate 13, and the lower substrate 14 is filled with the electrolytic solution 18.

In the manufacturing method of the present embodiment, first, the sealing agent 51 (see FIG. 3) is discharged from the seal dispenser 50, and the substantially rectangular annular inner seal portion 117a is formed on the upper substrate 113. Next, the sealing agent 51 is discharged along the periphery of the inner seal portion 117a, and the outer seal portion 117b is formed around the inner seal portion 117a (see FIG. 11).

Subsequently, the application process of the dispersion liquid 61, the drying process of the dispersion solvent, and the application process of the electrolytic solution 18 are executed by the same method as in the first embodiment.

Subsequently, the upper substrate 113 in which the inner and outer seal portions 117a and 117b are formed is the upper substrate holding portion 93, and the lower substrate 14 in which the spherical spacer 19 and the electrolytic solution 18 are applied is the lower substrate holding portion 94. To each.

Subsequently, the upper and lower substrates 113 and 14 are aligned by the upper and lower substrate holders 93 and 94, and the upper and lower substrates 113 and 14 are positioned. In parallel with the positioning of the substrates 113 and 14, the processing space 91a is decompressed by the vacuum pump 95.

Subsequently, the upper substrate 113 is lowered by the upper substrate holder 93. As a result, the inner and outer seal portions 117a and 117b of the upper substrate 113 are in contact with the application surface 14b of the lower substrate 14, and the electrolyte 18 is added to the upper and lower substrates 113 and 14 and the inner seal portion 117a. It is pushed out in the space surrounded by.

Subsequently, when the processing space 91a is opened to the atmosphere, the space between the inner and outer seal portions 117a and 117b remains in a reduced pressure state, while the space outside the outer seal portion 117b is at atmospheric pressure. Due to this pressure difference, a force for pressing the upper and lower substrates 113 and 14 is generated. Therefore, unlike the first embodiment, a step of temporarily fixing both substrates and a temporary fixing jig are not required.

Subsequently, both substrates 113 and 14 bonded together are irradiated with ultraviolet rays. As a result, the seal portions 117a and 117b are UV-cured, the both substrates 113 and 14 are fixed by the seal portions 117a and 117b, and the present manufacturing method ends.

<2.2. Advantages of the manufacturing method of the present embodiment>
As described above, in the method for manufacturing the display panel 110 of the present embodiment, the same application process of the dispersion liquid 61, the drying process of the dispersion solvent, and the application process of the electrolytic solution 18 are performed as in the first embodiment. A two-stage coating process is performed.

Thereby, as in the case of the first embodiment, the distribution of the spherical spacers 19 dispersed between the substrates 113 and 14 after being bonded can be made uniform. Therefore, in the display panel 10 manufactured by the manufacturing method of the present embodiment, the gap G between the opposing substrates 113 and 14 is set to a desired range, and the display unevenness due to the variation in the gap G between the substrates 113 and 14 is displayed. Is suppressed.

Also, in the process of bonding the upper and lower substrates 113 and 14, when the processing space 91a is released from the decompressed state to the atmosphere, a force for pressing the upper and lower substrates 113 and 14 is generated due to this atmospheric pressure difference. Thereby, the step of temporarily fixing both substrates and the jig for temporary fixing as in the first embodiment are not required. Therefore, the bonded upper and lower substrates 113 and 14 can be easily fixed by the seal portions 117a and 117b for UV curing.

Hereinafter, examples carried out to confirm the effects of the present invention will be described, but the present invention is not limited to these examples.

In Example 1, the display panel 10 was created based on the manufacturing method of the first embodiment. In addition, in the coating process of the dispersion liquid 61, a dispersion liquid having a dispersion of 1 wt% of a spherical spacer having a diameter of 30 μm (Micropearl GS-230 manufactured by Sekisui Chemical Co., Ltd.) in an ethylene glycol solvent is used as the dispersion liquid 61. Discharged. In the drying process of the dispersion 61, the hot plate 65 heats the lower substrate 14 at about 200 ° C. for about 5 minutes.

On the other hand, in the comparative example, a display panel in which the spherical spacer 19 was supplied to the lower substrate 14 by a dry spraying method and then supplied to the lower substrate 14 as the electrolytic solution 18 was created.

Table 1 shows the experimental results of the display panels created in Example 1 and the comparative example. When the display panel 10 is arranged as shown in FIG. 1 in each field (each column) of “upper left”, “lower left”, “center”, “upper right”, and “lower right” in Table 1. 2 shows gap G values (unit: μm) in the upper left, lower left, center, upper right, and lower right portions on the display unit 12.

As shown in Table 1, the fluctuation range of the gap G value in each part of the display unit 12 of Example 1 (a value obtained by subtracting the minimum gap G value from the maximum gap G value) R1 is 0.7 (μm). On the other hand, the fluctuation range R2 of the gap G value in the comparative example is 17.4 (μm). That is, the variation in the gap G value in Example 1 is very small compared to that in the comparative example.

As described above, by using the manufacturing method of Example 1, the spherical spacers 19 are uniformly dispersed in the electrolytic solution 18, and the gap G between the substrates 13 and 14 is kept substantially uniform in each part of the display unit 12. It is. Therefore, unlike the comparative example, the display panel 10 created by the manufacturing method of Example 1 can suppress display unevenness due to the gap G value variation.

DESCRIPTION OF SYMBOLS 1,100 Display system 10,110 Display panel 12 Display part 13,113 Upper board | substrate 14 Lower board | substrate 17,117 Seal part 18 Electrolytic solution 19 Spherical spacer 20 Upper electrode driver 30 Lower electrode driver 40 Controller board 50 Seal dispenser 51 Sealant 60 Dispersion dispenser 61 Spacer dispersion 62 Dispersion application part 70 Electrolyte dispenser 72 Electrolyte application part 90 Vacuum device

Claims (4)

1. An electrolyte containing a polymer binder and metal oxide fine particles, applying the electrolyte on one of opposing substrates, and bonding the other substrate in a reduced-pressure atmosphere to form a display portion In a method for manufacturing a chemically operated display device,
   Before applying the electrolytic solution, a dispersion solvent in which spherical spacers are dispersed is applied to a first application position on a substrate, and the electrolytic solution is applied after the dispersion solvent is dried. Manufacturing method.
2. The manufacturing method according to claim 1, wherein the first application position of the dispersion solvent and the second application position of the electrolytic solution are substantially the same.
3. The manufacturing method according to claim 2, wherein an area in which the applied dispersion solvent spreads on the one substrate is smaller than an area in which the applied electrolytic solution spreads on the one substrate.
4. The manufacturing method according to claim 1, wherein the dispersion solvent contains a solvent contained in the electrolytic solution.

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