JPH0259446B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a multicolor display device using a color filter, and in particular to a method for manufacturing a multicolor display device using a color filter manufactured by a polymer layer formed by electrodeposition. The present invention relates to a method of manufacturing a display device.

FIG. 1 shows an example of a multicolor display device using color filters. In FIG. 1, 1 is a transparent substrate, 2 is a display electrode made of a transparent conductive film patterned with arbitrary figures or characters, and 3 is display electrode 2.
Color filter formed in close contact with the surface, 4
5 is a transparent counter electrode, and 5 is a transparent counter substrate.
The space sandwiched between the two substrates 1 and 5 is filled with a material such as liquid crystal or electrochromic material that functions as an optical shutter that opens and closes when voltage is applied, and the display electrodes 2, 2', 2'' and the counter electrode 4 By selectively applying a voltage between them, the colors of the color filters 3, 3' or 3'' are displayed through the transparent counter substrate 5 at the display electrode when the shutter is open. By forming the color filters 3, 3'' in different color tones, it is possible to display multiple colors according to the above principle.The method for displaying multiple colors using color filters is simple. Since it is easy to obtain a free color tone and can be used in combination with various display materials and methods, the practical effect is extremely large.

However, when manufacturing a multicolor display device using color filters, manufacturing must be done in a way that does not cause misalignment between the pattern of the display electrode and the pattern of the color filter formed on the surface of the display electrode. It won't happen. Particularly when attempting to realize a color graphic display using fine patterns of three primary colors, matching the patterns of the display pole and the color filter is an important problem that is difficult to manufacture.

Generally speaking, methods such as screen printing and photolithography are considered as methods for producing color filters, but screen printing has a limit to the miniaturization of patterns, and the trend is toward multi-color filters. The accuracy of the printing position deteriorates as the printing position increases, resulting in misalignment with the displayed pattern. Although it is possible to create fine patterns using photolithography, it is necessary to go through a photolithography process every time the color is changed, which makes the process extremely complicated, and the advantage of being a simple means of creating multiple colors is lost.

Therefore, in order to provide a color filter that does not cause pattern displacement even if the display pattern becomes fine using a simple method, the present invention forms a pattern using a conductive thin film on a substrate, and then connects the conductive thin film to an electrode. The present invention proposes a multicolor display device using a color filter manufactured by a method of forming a colored layer by electrodepositing an aqueous polymer. According to this method, a conductive thin film is patterned in a desired manner by vapor deposition using a mask, sputtering, etching, etc.
It is possible to selectively electrodeposit the polymer on the conductive portion and form a colored layer that does not shift in pattern position. As long as the surface of the substrate used in this method is insulating, there are no restrictions on its material or shape, as long as a conductive thin film that has good adhesion to the substrate is selected.

Hereinafter, a method for forming a colored layer by electrodeposition of a polymer, which is an important point of the present invention, will be described. One method for electrodepositing a polymer on an electrode is to electrochemically polymerize a monomer on the electrode. As an example of this method, there are reports of polymer films obtained by electrochemically polymerizing various vinyl compounds on iron plates. (Metal Surface Technology Vol. 19, No. 12,
(1968) Recently, research has also been actively conducted on the production of conductive polymer films such as pyrrole and polythienylene on electrodes. However, such a method of directly electrochemically polymerizing monomers is not suitable for use in the present invention because the efficiency is still not good and the obtained film is already colored and lacks coloring arbitrariness. There are problems. Another method for electrodepositing a polymer on an electrode is to insolubilize and precipitate the polymer on the electrode from a polymer solution. One example of this is a method known industrially as electrodeposition painting, in which a pigment is dispersed in an aqueous polymer solution, a metal is immersed, and used as an electrode to electrodeposit a colored layer on the metal. Used for coating, etc. The principle of this method is to use a polymer in which a hydrophilic group, such as a carboxyl group, is neutralized with an inorganic alkali, an organic amine, etc., and made water-soluble. Then, the electrode is immersed in an aqueous solution of the water-soluble polymer,
When a voltage is applied, carboxyl anions dissociated in the aqueous solution undergo electrophoresis and react with protons generated by electrolysis of water on the electrode, thereby insolubilizing and precipitating the polymer. That is, the reaction shown in the following formula occurs on the anode, and polymer precipitation is observed.

In addition, a basic group (e.g. polyamine) is added to the hydrophilic group.
If it is neutralized and water-solubilized using an acid, on the contrary, polymer precipitation will be observed on the cathode.

If the electrodeposited polymer is electrically insulating, the current decreases as the electrode is coated with the polymer, and further coating can be prevented, so an increase in film thickness cannot be expected. Due to the bubbles of oxygen generated by decomposition, complete coverage is avoided and a certain degree of film thickness can be obtained. Furthermore, the obtained polymer film becomes a uniform film with low water content due to the effect of electroosmosis.

Examples of such polymers for electrodeposition include additives of natural drying oil and maleic acid, alkyd resins with carboxyl groups introduced, adducts of epoxy resins with maleic acid, polybutadiene resins with carboxyl groups, acrylic acid or methacrylic acid. A copolymer of an acid and its ester is used, and other polymers or organic compounds having functional groups may be introduced into the skeleton depending on the characteristics of the electrodeposited film. These polymer layers are arbitrarily selected depending on the desired properties of the colored layer. For example, when the colored layer is desired to be transparent, an acrylic polymer is suitable. Methods for producing polymers for electrodeposition differ depending on the type of polymer, but a method for producing acrylic polymers will be described as an example. Acrylic polymers are produced by radical copolymerization of acrylic acid or methacrylic acid having carboxyl groups and acrylic esters or methacrylic esters having neutral groups. In this case, the ratio of carboxyl groups to neutral groups is important; if there are too many carboxyl groups, the electrodeposited polymer will not be sufficiently insolubilized, and if there are too few carboxyl groups, water solubility during neutralization will be insufficient. Become. Also, to increase water solubility
In some cases, an OH group is introduced. Once the monomer composition is determined, polymerization is typically carried out using hydrophilic compounds such as isopropanol, n-butyl alcohol, t-butyl alcohol, methyl cellosolve, ethyl cellosolve, isopropyl cellosolve, butyl cellosolve, diethylene glycol, methyl ether, diethylene glycol ethyl ether, diacetone alcohol, etc. Solution polymerization is carried out using a general radical polymerization initiator in a solvent.

Since the polymer film obtained by electrodeposition cannot be used as a colored layer as it is, a means for coloring it is required. A common method is to disperse pigments in an aqueous polymer solution for electrodeposition. The pigments used include titanium oxide, precipitated barium sulfate, talc, asbestin, china clay, red iron oxide, yellow iron oxide, strontium chromate, basic lead silichromate, phthalocyanine blue, phthalocyanine green, Hansa yellow, and carbon black. The pigment is electrically charged in a polymer solution, and the polymer is adsorbed to its surface, electrophoresed together with the polymer, and incorporated into the electrodeposited film.

However, coloring with such pigments generally lacks transparency and is often inappropriate when forming a multicolor pattern on a transparent substrate such as glass and displaying colors by transmitting the pattern. Therefore, a method for manufacturing a light-transmitting multicolor pattern using a glass substrate will be described below. A transparent conductive film made of tin oxide, indium, etc. is prepared on a glass substrate by a method such as spray coating or sputtering,
Next, patterning is performed using a chemical or dry etching method. A polymer is electrodeposited in a neutralized aqueous solution of a copolymer of acrylic acid or methacrylic acid and its ester using a portion of the transparent conductive film pattern having the same desired color as an anode. After washing and baking, cationic dyes for acrylic resin, such as Aizen, Cathilon, Diacryl,
Sumiacryl, Astrazon, Basacryl, Deorene,
Apply dye using Maxilon, Sevron, etc. (dye delivery column). By repeating this operation, a multicolored pattern with good transparency can be obtained on the glass. Even when other transparent polymers are used, similar effects can be obtained by selecting a dye that is compatible with the polymer. For example, disperse dyes are effective for polyester.

A multicolor display device using the color filter manufactured as described above will be specifically described below in Examples.

Embodiment 1 FIG. 2 is an application example of a multicolor display device to which the method of manufacturing a color filter according to the present invention is applied. A method for manufacturing a multicolor display device as shown in FIG. 2 will be specifically described below.

In patterning step 6, a display substrate made of a transparent material is used, and a tin oxide transparent conductive film is formed on the display substrate by a spray coating method. The transparent conductive film is patterned into stripes by etching to obtain display electrodes 7.

Electrodeposition process Next, polyester-melamine resin paint (Svia ED-3000 manufactured by Shinto Paint) is applied with resin solid content.
The display substrate 6 on which the display electrodes 7 are formed is immersed in an electrodeposition bath containing a 10% by weight aqueous solution. Among the display electrodes 7 patterned in stripes, electrodes to be colored in the same color are selected, and a voltage of 10 to 100 V is applied to the selected electrodes as anodes.
After energizing for several minutes, pull up the board and thoroughly wash it with water. At this time, polymers adhering to areas where voltage is not applied are washed away, but polymers adhering to electrodes to which voltage is applied are insoluble in water, so they are not washed away by water washing. After washing with water,
When dried, a highly transparent polymer film is formed on the selected electrode.

Dyeing Step Next is the step of dyeing the polymer membrane, and the dye used can be dyed with a cationic dye because the electrodeposited polymer has carboxyl groups, which are acidic groups. Good results can also be obtained with disperse dyes for polyester resins. Specifically, a cationic dye (Diacryl, manufactured by Mitsubishi Kasei) with a desired color is made into an aqueous solution of pH 3 to 5 with the addition of acetic acid, and the display substrate that has undergone the electrodeposition process is immersed in the solution, followed by boiling until the desired coloring density is achieved. . After cooling and washing with water, the polymers on the selected electrodes are dyed, and the remaining areas to which no polymers are attached are not dyed.

Resist dyeing process Next, the melamine resin contained in the polymer and the carboxyl groups remaining in the polymer are subjected to a condensation reaction by baking, resulting in a resist dyeing process. The polymer film that has been resist dyed will not be dyed again, so for the formation of colored layers for the second time onwards, display electrodes of the same color should be selected, and the process of electrodeposition, dyeing, and resist dyeing should be carried out. This is achieved through repetition. In this example, striped color filters in the order of red, blue, and green are patterned: patterning process → red electrode electrodeposition process → red electrode dyeing process → resist dyeing process → blue electrode electrodeposition process → blue electrode dyeing process →
It was manufactured using the following process: resist dyeing process → electrodeposition process for green electrodes → dyeing process for green electrodes → resist dyeing process, and there was no need for alignment during this process, making it very simple.

In this way, the color filter 8 is formed on the display electrode 7, and the display substrate 6 has a transparent counter electrode 9 patterned in stripes in a direction perpendicular to the display electrode 7. are integrated with each other via a spacer 11 to form a cell. TN- as the display material 12 in the cell.
A multicolor liquid crystal display device was fabricated by filling FEN liquid crystal. In this case, a voltage is applied between the display electrode 7 and the counter electrode 9, the cell is sandwiched between a polarizer and an analyzer whose transmission axes are parallel, and the color of the transparent color filter 8 when viewed from the direction of the display substrate 6 is is displayed and turns black when voltage application is stopped. When the light is irradiated from the direction of the counter substrate 10, the transparency of the cell is good.
The colors of the color filter 8 are displayed more effectively. If a transparent conductive film whose pattern matches the display electrode 7 is provided on the color filter 8 and the transparent conductive film is used as a voltage application electrode, a multicolor display device suitable for multi-division driving with a low driving voltage can be obtained. As for the effect, despite the simple manufacturing method, there was no color shift from the display area, and a clear multicolor display was obtained by simply selecting electrodes arranged in a matrix and applying voltage. It became clear that it was suitable for color graphic display in combination with patterns.

Example 2 The electrodeposition bath in Example 1 was changed to an aqueous solution of acrylic-melamine resin paint (Powermite 3000-10 manufactured by Nippon Paint) with a resin solid content of 8% by weight, and a multicolor liquid crystal was prepared in the same manner as in Example 1. When a display device was manufactured, the same effects as in Example 1 were obtained.

Example 3 An acrylic acid-methyl acrylate copolymer (acrylic acid content: 5 to 35% by weight) obtained by solution polymerization in methyl cellosolve using the electrodeposition bath in Example 1 was brought to pH 7.5 with aqueous ammonia or triethylamine.
~8.0, and an aqueous solution with a resin solid content of 10% by weight was used. A multicolor liquid crystal display device was manufactured in the same manner as in Example 1, and the same effects as in Example 1 were obtained. Since the resin used in this example does not contain a melamine resin for curing, a method of inactivating carboxyl groups with an adsorbent was adopted as the resist dyeing treatment. Alternatively, a method of applying hexamethoxymethylmelamine or the like later and condensing it by heating can also be adopted.

Example 4 The display material 12 in Example 1 was replaced with a negative type guest host liquid crystal using a dichroic dye, and the display substrate 6
A multicolor liquid crystal display device was produced in the same manner as in Example 1 using the material as a white material (white ceramic). In this case, a voltage is applied between the display electrode 7 and the counter electrode 9, and when viewed from the direction of the transparent counter substrate 10 through the polarizing plate, the color of the color filter 8 is displayed brightly, and when the voltage application is stopped, the color of the color filter 8 is bright. The color is a mixture of dichroic dye and color filter. If the color of the dichroic dye is selected to be dark, the mixed color will be almost black, resulting in display by switching between black and the color of the color filter. In this example as well, the same effects as in Example 1 were obtained.

Example 5 The display material 12 in Example 1 was DSM liquid crystal, and display electrodes 7 were formed by patterning aluminum on the display substrate 6 by mask vapor deposition. Then, the number of desired colors is prepared in the electrodeposition bath in which the pigment of the desired color of the electrodeposition bath in Example 1 is dispersed. Next, the substrate is immersed in an electrodeposition bath of the initially selected color, and electrodeposition is performed under the same conditions as in Example 1, using the display electrode 2 to be colored in that color as an anode. washing with water,
After baking, color filter 8 could be obtained by repeating the same operation for the remaining colors. In the manufacturing method according to this embodiment, there is no need for resist dyeing treatment because there is no dyeing step, but the number of electrodeposition baths equal to the number of desired color tones is required. The resulting color filter has an opaque color. Thereafter, a multicolor liquid crystal display device was manufactured in the same manner as in Example 1. In this case, a voltage is applied between the display electrode 7 and the counter electrode 9, and when viewed from the direction of the transparent counter substrate 10,
The DSM liquid crystal enters a light scattering state, and the color of the color filter 8 is displayed in a milky white color. When the voltage application is stopped, the light scattering state disappears, resulting in a dark state. Note that in order to efficiently generate the light scattering state of the DSM liquid crystal, it is necessary to flow a certain amount of ion current, and the high resistance of the color filter 8 becomes an obstacle. Therefore, by providing a transparent electrode whose pattern matched that of the display electrode 7 on the color filter 8 and using the transparent electrode as a voltage application electrode, the driving voltage could be reduced and the same effect as in Example 1 could be obtained.

Example 6 The display material 12 in Example 1 was a solution in which titanium oxide powder was dispersed as a white background in a 0.3 mo/KBr aqueous solution containing benzyl viologen dibromide. A display device was created. When an electrochromic substance is used as a display material, a large current flows during display, so a transparent electrode whose pattern matches the display electrode 7 is formed on the color filter 8, and the transparent electrode is used as a voltage applying electrode. That is essential. In this case, when the transparent electrode on the color filter is set to a negative potential and the counter electrode is set to a positive potential, a mixed color of the color of the color filter 8 and the purple of the benzyl viologen radical is displayed on a white background when viewed from the direction of the display substrate 6. When a potential in the opposite direction was applied, the viologen radicals disappeared, and the color of the color filter 8 became independent, and the same effect as in Example 1 was obtained without any deviation between the color of the viologen radicals and the color of the color filter.

As specifically described in the embodiments above, although the method for manufacturing a multicolor display device according to the present invention is simple, its versatility and effects are great. In particular, the color filter manufacturing method allows the colored layer to be formed directly on the patterned display electrode, so there is no need for accurate positioning.
It is possible to achieve high display quality without pattern deviation during manufacturing. It goes without saying that by selecting the polymer used and the coloring method, it can be applied to either a transmissive type or a reflective type display device.

[Brief explanation of drawings]

Figure 1 is an example of a multicolor display device that uses color filters. FIG. 2 is an example of a multicolor display device manufactured by the manufacturing method of the present invention. 1, 6... display substrate, 2, 7... display electrode,
3, 8... Color filter, 4, 9... Counter electrode, 5, 10... Counter substrate, 12... Display material.

Claims (1)

[Claims] 1. In a method of manufacturing a multicolor display device using a color filter, the color filter is formed by forming a plurality of conductive layers arranged insulated from each other on a substrate, and then 1. A method for manufacturing a multicolor display device, characterized in that it is manufactured by a method of repeatedly forming a colored layer based on a polymer layer selectively electrodeposited on a conductive layer. 2. Formation of a colored layer based on a polymer layer electrodeposited on a conductive layer according to claim 1 is performed by depositing a colored layer on the conductive layer from a solution containing an electrodepositable polymer and a dye as a solute. A method for manufacturing a multicolor display device, which involves forming a colored layer made of a mixture of an electrodepositable polymer and a dye. 3. Formation of a colored layer based on a polymer layer electrodeposited on a conductive layer according to claim 1 is performed by first depositing a polymer layer on the conductive layer from a solution containing an electrodepositable polymer as a solute. A method for manufacturing a multicolor display device, comprising forming a colored layer by electrodepositing a layer, and then dyeing the electrodeposited polymer layer in a solution containing a dye. 4. The plurality of conductive layers arranged insulated from each other on the substrate are transparent conductive layers containing tin oxide, indium oxide, or antimony oxide as a main component, and selectively coated on these transparent conductive layers. Formation of a colored layer based on a polymer layer electrodeposited on a substrate is basically the formation of a colored layer based on a polymer layer electrolytically deposited by anodic electrolysis from a solution containing an anionic electrodepositable polymer. A method for manufacturing a multicolor display device according to any one of claims 1, 2, and 3. 5. Claim 4, wherein the anionic electrodepositable polymer is a copolymerizable polymer of acrylic acid and acrylic ester, or a copolymerizable polymer of acrylic resin and melamine resin. A method for manufacturing a multicolor display device.