JPH0524493B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a liquid crystal color display device that provides a particularly clear color display with good contrast, and a method for manufacturing the same. [Prior Art] Conventionally, there is a liquid crystal color display device capable of full-color display, as disclosed in, for example, Japanese Patent Laid-Open No. 60-88986. In this method, transparent electrodes serving as a signal electrode and a scanning electrode are formed on the opposing surfaces of two transparent substrates placed opposite each other, and one of the signal-side transparent electrodes has a two-layer structure.
Red, green, and blue color filter films are interposed between the transparent electrodes using a dyeing method, and the electrodes are electrically connected at a portion other than the display section. Thereby, a voltage can be applied uniformly over the entire liquid crystal layer, and a clearer color display can be obtained. [Problems to be Solved by the Invention] However, in the conventional liquid crystal color display device as described above, since the color filter film is formed by a dyeing method, the second layer of transparent electrodes cannot be dyed. When forming by the etching method, the color filter film dissolves in the etching solution and peels off, so there is a problem that it is not suitable for mass production. In addition, when forming the second layer of transparent electrode by the lift-off method, it is not possible to increase the electrode film thickness, and it is difficult to actually form a low-resistance film, that is, to reduce the resistance value of the transparent electrode over the entire area. The problem was that it was very difficult to lower the value. The present invention has been made in view of these problems, and aims to provide a liquid crystal color display device that is highly mass-producible and can provide a color display with good display contrast, and a method for manufacturing the same. . [Means for Solving the Problems] The liquid crystal color display device of the present invention includes a transparent electrode having a two-layer structure provided on a transparent substrate forming a liquid crystal cell, and a color filter film interposed therebetween. A plurality of pinholes are formed in the color filter film, and the transparent electrodes of the first layer and the second layer are electrically connected through the pinholes. Further, the method for manufacturing a liquid crystal color display device of the present invention includes a step of forming a first layer of transparent electrodes on a transparent substrate forming a liquid crystal cell by a photoetching method, and a step of forming a photoresist on the first layer of transparent electrodes. A process of forming dots by lithography and then applying a color filter film by electrodeposition, and heating the transparent substrate at a pre-baking temperature that dissolves the photoresist in a stripping solution but does not dissolve the color filter film. A process of peeling off the photoresist to form a plurality of point-shaped pinholes in the color filter film, and heating the transparent substrate at a main firing temperature to harden the color filter film with the pinholes formed therein. The second step is to form a second layer of transparent electrodes on the cured color filter film by a photoetching method using the same photomask as used for forming the first layer of transparent electrodes, and the second step is to form a second layer of transparent electrodes on the cured color filter film by a photoetching method. This method includes a step of reheating the transparent substrate so as to strengthen the adhesion between the bonded two-layer transparent electrode and the color filter film. [Operation] A plurality of pinholes are provided in the color filter film interposed between the transparent electrodes of the two-layer structure, and the transparent electrodes of the first layer and the second layer are electrically connected through the pinholes. . Therefore, it is possible to apply a uniform drive voltage to the entire area of the liquid crystal cell,
A color display with good display contrast can be obtained. Furthermore, since the color filter film is applied by electrodeposition, it does not dissolve in the photoetching solution when forming the second layer of transparent electrodes, and mass productivity can be improved. [Example] Hereinafter, an example of the present invention will be described with reference to the drawings. FIG. 1 is a plan view showing the main parts of a liquid crystal color display device according to the present invention, and shows a case where a color dot matrix display is performed. Also, the second
Figure 3 is a sectional view taken along the line A-A in Figure 1 and a cross-sectional view taken along line B-
A cross-sectional view taken along the line B is shown. In these figures, reference numerals 1 and 2 indicate glass substrates which are transparent substrates forming a liquid crystal cell, and polarizing plates 3 and 4 are provided on the outside of each substrate, and are arranged to face each other. A two-layer transparent electrode 5 as a signal electrode is laid on one glass substrate 1, and red (R) and green (G) are arranged between the first layer electrode 5a and the second layer electrode 5b. A color filter film 6 of the three primary colors of , blue (B) is interposed, and an alignment film 7 is provided on the transparent electrode 5 . Furthermore, a transparent electrode 8 serving as a scanning electrode is laid down on the inside of the other glass substrate 2, and an alignment film 9 is provided thereon. Furthermore, a liquid crystal 10 is placed between both glass substrates 1 and 2.
is sealed with a sealing adhesive 11 and an end sealing adhesive 12. A plurality of pinholes (through holes) 13 are formed in the color filter film 6, and the electrodes 5 of the first and second layers are passed through the pinholes 13.
a and 5b are electrically connected. When a driving voltage is applied from the AC power source 14 to the two-layered transparent electrode 5 and the other transparent electrode 8, the dot display section 15 displays dots, and a predetermined color image is displayed as a whole. ing. Note that the same number of pinholes 13 (two in the figure) are provided for each dot display section 15, and back illumination is required to obtain a color display at this time. In the dot matrix liquid crystal color display device configured as described above, a color filter film 6 is provided corresponding to the dot display section 15, and a plurality of pinholes 13 are formed in the color filter film 6. The first and second layers of the two-layer transparent electrode 5 on the signal side are connected through this pinhole 13. Therefore, the electrical resistance value of the signal electrode is the parallel resistance value of the first and second layer electrodes 5a and 5b, and the first layer transparent electrode 5 is sufficiently heat-treated before the color filter film 6 is formed to increase its resistance. This can compensate for the fact that the second layer electrode 5b can only be subjected to heat treatment within the heat resistance limit of the color filter film 6. In other words, the inability to make the resistivity of the second layer electrode 5b sufficiently low can be compensated for by using the parallel resistance value. Therefore, a sufficiently low electrical resistance value can be obtained up to the tip of the signal electrode, making it possible to apply a uniform drive voltage over the entire liquid crystal cell, and providing a clear color display with good display contrast. Moreover, the color filter film 6 is the second layer electrode 5b.
, the capacitance of the color filter film 6 has no effect, and distortion of the driving voltage does not occur. Therefore, color variations can be eliminated, and a color display image with clear display colors can be obtained. Here, the color filter film 6 is connected to the dot display section 1.
It is also formed in parts other than 5, and pinholes 13 are formed there.
It is also possible to provide the electrodes 5a and 5b of the first layer and the second layer to join them. In this case, a better image can be obtained since there is no pinhole 13 in the dot display section 15, but if the diameter of the pinhole 13 is set to 50 μm or less, the size becomes difficult to see with the human eye, which impedes the display effect. It will never become. Further, the pinholes 13 are provided at equal distances from each other,
Moreover, by making the distance smaller than the distance between each display section 15, a clear color image can be obtained without impairing the display effect. Next, a method for manufacturing the liquid crystal color display device having the above structure will be explained. In addition, here, we will focus on the manufacturing method of the transparent electrode 5 with a two-layer structure, and refer to FIGS. 4 to 10.
The process will be explained in order according to the drawings. (a) First, a transparent conductive film (ITO, etc.) is deposited on the glass substrate 1 on which the liquid crystal cell will be formed by sputtering or the like.
After forming a film, a first layer electrode 5a is formed by photoetching (see FIG. 4). (b) A photoresist 16 is coated on the first layer electrode 5a using a roll coater or the like (see FIG. 5). (c) The photoresist 16 is formed into dots (pinhole size) by photolithography. At this time, as shown in FIG. 6, in order to form one row of pinholes 13 for each electrode, a photolithography technique using mask alignment is required.
The light transmission rate of No. 5 and the junction resistance value of the first and second layer electrodes 5a and 5b become uniform. FIG. 6a is a sectional view, and FIG. 6b is a plan view. Further, as shown in FIG. 7, the distances between all adjacent pinholes may be made equal and the distance may be smaller than the pitch of the dot display section 15. In this case, the formation of the pinholes 13 may be There is no need to perform mask alignment, and the above-mentioned variations in the light leakage rate and the electrode junction resistance value can be minimized. Figure 7a
is a sectional view, and FIG. 7b is a plan view. (d) Next, a well-known electrodeposition method (for example,
(Refer to Publication No. 90818), Photoresist 1
A color filter film 6 is coated on the first layer electrode 5a provided with the color filter film 6 (see FIG. 8). At this time, the color filter film 6 is not applied to the dotted photoresist 16 because it is electrically insulated. (E) The photoresist 16 is heated at a pre-baking temperature that dissolves the photoresist 16 in the stripping solution but does not dissolve the color filter film 6.
The plurality of dot-like pinholes 13 are formed in the color filter film 6 by peeling (see FIG. 9). At this time, the reason why the glass substrate 1 is heated at the pre-baking temperature is to temporarily harden the color filter film 6. Table 1 shows experimental data regarding the optimal control conditions for pre-firing.

[Table] From Table 1, it can be seen that the optimum conditions are heating at a pre-firing temperature of 80°C to 130°C for 0.5 hours or more. In addition, the stripping liquid for photoresist 16 is 40
℃, and the immersion time was 5 minutes. (f) The glass substrate 1 is heated at a main firing temperature so as to harden the color filter film 6 in which the pinholes 13 are formed. Table 2 shows experimental data regarding the optimum control conditions for main firing.

[Table] From Table 2, it can be seen that the optimum conditions are heating at a main firing temperature of 170°C to 220°C for 1 hour or more. (g) A second layer electrode 5b is formed on the cured color filter film 6 using the same photomask as used for the first layer electrode 5a (see FIG. 10). At this time, as in the case of the first layer, a transparent conductive film is first formed, and then a second layer is formed by photo-etching. At this time, since the same photomask as the first layer is used, the cost of the mask can be saved, and
High alignment accuracy can be obtained. Also, the first and second layer electrodes 5 are inserted through the pinhole 13.
a and 5b are electrically connected to form a transparent electrode 5 having a two-layer structure. (h) In order to strengthen the adhesion between the second layer electrode 5b and the color filter film 6, the glass substrate 1 is reheated at the adhesion treatment temperature. Table 3 shows the optimal control conditions for contact processing.

〔Effect of the invention〕

As explained above, according to the present invention, a plurality of pinholes are provided in the color filter film, and the first layer and the second layer of the transparent electrode of the two-layer structure are bonded through the pinholes. This has the effect of providing a clear color image with good display contrast, and since the color filter film is formed by electrodeposition, it has the effect of improving mass productivity.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the main parts of a liquid crystal color display device according to the present invention, FIG. 2 is a structural diagram showing a cross-sectional view taken along the line A-A in FIG. 1, and FIG. A structural diagram showing a cross section, Figures 4 to 10 are diagrams showing the manufacturing process, Figure 4 is a cross-sectional view showing the state in which the first layer of electrodes is formed, and Figure 5 shows the state in which photoresist is applied. A cross-sectional view, Fig. 6 shows an example in which photoresists for pinholes are provided in one row for each electrode, and Fig. 7 shows photoresists for pinholes arranged at equal distances from each other and smaller than the pitch of the dot display area. Figure 8 is a cross-sectional view showing a state in which a color filter film is formed, Figure 9 is a cross-sectional view showing a state in which pinholes are formed in a color filter film, and Figure 10 is a two-layered structure. FIG. 3 is a cross-sectional view showing a state in which eye electrodes are formed. 1... Glass substrate (transparent substrate), 5... Transparent electrode with two-layer structure, 5a... First layer electrode, 5b...
Second layer electrode, 6... Color filter film, 10...
...Liquid crystal, 16...Photoresist.

Claims (1)

[Claims] 1. A two-layer transparent electrode with the same pattern is provided on a transparent substrate forming a liquid crystal cell, and a color filter film is formed and interposed between the electrodes by electrodeposition, A liquid crystal color display device, characterized in that a plurality of pinholes are formed in the color filter film, and the transparent electrodes of the first layer and the second layer are electrically connected through the pinholes. 2. The liquid crystal color display device according to claim 1, wherein the same number of pinholes are provided in each display section in which the transparent electrode and the color filter film are laminated. 3. The liquid crystal color display device according to claim 1, wherein the pinholes are provided at equal distances from each other and the distance is smaller than the distance between each display section. 4. The liquid crystal color display device according to any one of claims 1 to 3, wherein the pinhole has a diameter of 50 μm or less. 5 A step of forming a first layer of transparent electrode by photoetching on the transparent substrate forming the liquid crystal cell, and forming a photoresist in dots on this first layer of transparent electrode, and then forming a color filter film by electrodeposition. The transparent substrate is heated at a pre-baking temperature such that the photoresist is dissolved in the stripping solution but the color filter film is not dissolved, and then the photoresist is peeled off to form a plurality of dots on the color filter film. a process of forming pinholes, a process of heating the transparent substrate at a main firing temperature to harden the color filter film in which the pinholes are formed, and forming a first layer of transparent electrodes on the hardened color filter film. A step of forming a second layer of transparent electrode by a photoetching method using the same photomask as in step 1, and a step of forming a transparent electrode of this two-layer structure and a color filter film electrically connected to each other through the pinhole. 1. A method for manufacturing a liquid crystal color display device, comprising the step of reheating a transparent substrate to strengthen adhesion. 6. The method for manufacturing a liquid crystal color display device according to claim 5, wherein the transparent substrate is pre-baked at a pre-baking temperature of 80° C. to 130° C. for 0.5 hours or more. 7. The method for manufacturing a liquid crystal color display device according to claim 5 or 6, wherein the main baking of the transparent substrate is performed at a main baking temperature of 170° C. to 220° C. for 1 hour or more. 8. Claims 5 to 8, characterized in that the reheating of the transparent substrate to strengthen the adhesion between the transparent electrode and the color filter film is performed at an adhesion treatment temperature of 100°C to 220°C for 0.5 hours or more. 7. A method for manufacturing a liquid crystal color display device according to any one of Item 7.