JPH0651325A - Electrooptical device and its production - Google Patents

Abstract

PURPOSE:To improve the image quality of the electrooptical device for which color filters are used and more particularly the electrooptical device having a large display capacity by forming light shielding layers consisting of metallic layers on the color filters and connecting these metallic layers, which are commonly used as electrical conductors, to transparent electrodes for display. CONSTITUTION:The transparent conductive films consisting of ITO are formed on the color filters 2 and the transparent electrodes 3 for display are formed on the color filters. The transparent electrodes 3 for display are formed face to face on the one side of the color filters 2 at this time. The light shielding layers 4 consisting of chromium-gold are formed in a stripe form in the positions corresponding to the parts between the respective color filters 2 in such a manner as to cover the adjacent color filters 2 to each other. Electrical junctures 3 slightly wider than the gaps between the transparent electrodes for display are formed to a projecting shape from the striped parts in the positions where the junctures do not overlap on the counter electrode at this time. These junctures are intersected with the transparent electrodes 3 for display to assure electrical connection. As a result, the dulling of the electrical driving waveforms is prevented and the degradation in the contrast and crosstalks are eliminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electro-optical device. Specifically, it relates to an electro-optical device having a color filter layer and a method for manufacturing the same.

[0002]

2. Description of the Related Art Heretofore, there have been proposed several methods for forming a color filter, materials for a flattening layer and the like. Further, as a method for forming a transparent electrode on a color filter, JP-A-61-198131 and JP-A-61-19811
Japanese Patent Laid-Open No. 233720 and Japanese Patent Laid-Open No. 61-260224 have been proposed. The above-mentioned prior art and JP-A-62-12
An electro-optical device having a large display capacity and capable of color display with high image quality is proposed by combining the electro-optical device proposed in Japanese Patent Publication No. 1701 and a combination of an optical anisotropic cell and an optical anisotropic body for large-capacity display. Proposed. However, when the display capacity is increased, since the electro-optical device uses time division driving, the effective voltage decreases due to electrical resistance due to the wiring resistance of the waveform applied to the display section and the capacity of the liquid crystal layer and the like. However, it is known that the display characteristics are deteriorated.
Therefore, methods such as JP-A-63-273834 have been proposed.

[0003]

However, in the former case of the above-mentioned prior art, when it is applied to an electro-optical device which performs display in a matrix arrangement of row and column electrodes, the duty during dynamic driving is increased in order to increase the capacity. In order to increase the number, a transparent electrode for display must be formed on the color filter to prevent a decrease in effective voltage. However, since the color filter and the flattening layer are mostly formed of an organic resin, for example, when indium oxide-tin oxide (hereinafter ITO) is formed by a vacuum deposition method or a sputtering method, the color filter and the flattening layer are Due to damage such as wrinkles and other damage, the substrate temperature cannot be raised to the level of a normal glass substrate, and the specific resistance can be reduced to only about 1.5 × 10 ⁻⁴ Ω · cm. However, there is a limit in reducing the wiring resistance to a desired value. Therefore, the method shown in the latter of the related art has been proposed, but it has essentially the same problem. Therefore, a method of reducing the wiring resistance by installing a thin wiring made of metal on or below the transparent electrode for display is used, but it improves the display quality by reducing the aperture ratio of the display section. In contrast, it was insufficient. Further, on the metal layer by a color filter forming method, in particular, a method of forming by a photolithographic method using a photosensitive resin in which a pigment is dispersed, or a resin in which a pigment is dispersed is used as a resist with another photosensitive resin. In the method of patterning using, there is a problem that a resin layer that is difficult to develop is likely to remain on the metal layer, and it is very difficult in manufacturing to form an insulating layer and stably secure electrical connection with the metal layer. Was there.

Therefore, the present invention solves such a problem, and an object of the present invention is to improve the image quality of an electro-optical device using a color filter, especially an electro-optical device having a large display capacity. It is the one that provides the method.

[0005]

An electro-optical device according to the present invention has a color filter on at least one transparent substrate of two transparent substrates sandwiching a liquid crystal layer via a seal portion. In an electro-optical device having a transparent electrode for display thereon, a light shielding layer is formed of a metal layer on the color filter, and the metal layer also serves as an electric conductor and is electrically connected to the transparent electrode for display. It is characterized by

Further, according to the method of manufacturing an electro-optical device of the present invention, a color filter is provided on at least one of the two transparent substrates sandwiching the liquid crystal layer via the seal portion, and the color filter is provided on the transparent substrate. Has a transparent electrode for display,
In manufacturing an electro-optical device having a metal layer that also serves as an electric conductor, the color filter is printed by a printing method, a photolithographic method using a photosensitive resin in which a pigment is dispersed, and a pigment are dispersed. A method of patterning the resin thus obtained using another photosensitive resin as a resist,
It is characterized in that it is formed by any of the electrodeposition methods, the metal layer is formed by a wet film forming method or a vacuum film forming method, and then patterned by a photolithographic method.

[0007]

According to the above structure of the present invention, the light-shielding layer made of a metal layer is formed in stripes along the color filter, and the metal layer also functions as an electric conductor and is electrically connected to the display transparent electrode. Therefore, there is an effect that the rounding of the electric drive waveform is prevented, the contrast is lowered, and the crosstalk is eliminated.

[0008]

EXAMPLES The present invention will now be described in more detail based on examples. Incidentally, the electro-optical device and the manufacturing method of the present invention have the same basic configuration for clarifying the content of the present invention shown in each embodiment below, but needless to say, the present invention is not limited to the configuration described below. The display has a color filter pitch of 100 μm on the color filter side, a transparent electrode for display on the color filter has a width of 75 μm, and an interelectrode gap 25.
640 lines each corresponding to 3 colors as μm, total of 1920
A book electrode is formed, and the counter electrode is made of ITO and has a film thickness of 2000.
Å, surface resistance 5Ω / □, width 275μm, gap between electrodes 2
400 pieces were formed with a size of 5 μm. The wiring resistance of the display is 4
It was kΩ. The well-known method of rubbing polyimide has been applied for the alignment treatment. However, not only those which are twisted by the alignment treatment but also those which are aligned parallel to the substrate (not twisted), ferroelectric liquid crystal The present invention can also be applied to the case of using, and is not limited to the examples described below. Furthermore, in the case of twist orientation, the twist angle is not limited, but 90 ° to 3 ° from the viewpoint of contrast, display characteristics and manufacturing stability.
60 ° is desirable. However, since the twist angle is not limited, it can be applied at less than 90 ° or at 360 ° or more. In this example, the twist angle was set to 230 ° to the left and the thickness of the liquid crystal layer (hereinafter referred to as cell gap) was set to 7.0 μm.
Further, in the present invention, the color filter is a pigment type in consideration of heat resistance, and three primary colors of red (hereinafter R), green (hereinafter G) and blue (hereinafter B) are used, and general color purity (color Degree) and transmittance (brightness), the film thickness of each color is set to 1.5 to 2.5 μm. However, it is needless to say that there is no problem even if a dye-based material is applied when the heat resistance is not limited by the forming method of each material. The manufacturing method is not limited by the color filter and the flattening layer. Needless to say, there are no restrictions on the method of forming the metal layer and the combination of materials.

[First Embodiment] A description will be given with reference to FIG. A glass substrate 1 is coated with a color resist in which red, green, and blue pigments are dispersed in an ultraviolet curable resin, and the exposure-development process is repeated three times, and color filters 2 are adjacent to each other with a width of 95 μm. Are formed in a stripe shape with a thickness of 1.2 μm so that they do not at least overlap. Then, 1000 liters of transparent conductive film made of ITO was formed on the color filter by a low temperature magnetron sputtering method at a film forming temperature of 180 ° C., and a transparent electrode 3 for display was formed on the color filter 2 by a photolithography method. . At this time, the display transparent electrode 3 was formed on one side of the color filter 2 so as to be face-to-face. Next, a light-shielding layer 4 made of chrome-gold was formed in a stripe shape with a width of 15 μm so as to cover adjacent color filters between the color filters. At this time, the electrical connection portion 5 is formed at a position not overlapping the counter electrode so as to be convex from the stripe-shaped portion with a width of 30 μm wider than the gap between the transparent electrodes for display, and is formed by intersecting with the transparent electrode 3 for display. Secured the connection.
The light-shielding layer 4 formed in this manner is spaced from the adjacent display transparent electrode by 10 μm. However, it goes without saying that the interval can be set based on the display characteristics and the processing accuracy. Further, chromium and gold of the light-shielding layer 4 were continuously deposited by vacuum vapor deposition with about 500 Å of chromium and about 1000 Å of gold, and then patterned by photolithography. Chromium was etched with diammonium cerium nitrate, and gold was etched with iodine-potassium iodide. FIG. 2 shows AA ′ of FIG.
FIG. 3 is a diagram showing the structure seen more, and FIG. 3 is a diagram showing the structure seen from BB 'in FIG. Next, the structure of the electro-optical device of the present invention will be described with reference to FIG. Similar to the glass substrate 1 shown in FIG. 1, the counter electrode 7 is formed of ITO on the glass substrate 6 so as to form a matrix. After that, the alignment film 8 was formed to a thickness of 300 to 400 Å using polyimide. Seal 9
After bonding the substrates 1 and 6 with the liquid crystal 11 through the gap material 10.
Was enclosed. In this example, the resistance of the display portion on each color as the substrate including the above-mentioned transparent electrode 3 for display was measured and found to be 4 kΩ. This electro-optical device and the transparent electrode on the color filter without the light-shielding layer are also 2000 Å (sheet resistance 20Ω /
□), when the display was compared using the same electro-optical device except that the wiring resistance of the display section was 25 kΩ, the electro-optical device produced by the method of this example was able to obtain high quality without crosstalk. . In addition, the electro-optical device manufactured in this example was subjected to a standing test at 60 ° C.-90 RH% constant temperature and humidity for 300
In the current-carrying test under constant temperature and constant humidity of 50 ° C.-90 RH%, there was no change over time, and 250 hours of electrolytic corrosion and no change in image quality were confirmed, and good stability could be obtained. Incidentally, the display transparent electrode 3 and the light-shielding layer 4 may be formed by first forming the light-shielding layer 4 and then forming the display transparent electrode 3 contrary to the one shown in the first embodiment.

[Second Embodiment] A second embodiment will be described with reference to FIG. After the color filter 2 was formed on the glass substrate 1 in the same manner as in Example 1, the epoxy acrylate resin was imparted with ultraviolet curing photosensitivity and was coated by a spin coating method to a thickness of 1.2 μm, and then was irradiated with ultraviolet rays to be flattened. Layer 12 was formed. FIG. 6 shows a structure of FIG. 5 seen from AA ′, and FIG. 7 shows FIG.
The structure seen from B'is shown. Next, in the same manner as in Example 1, the light shielding layer 4 and the display transparent electrode 3 were formed. Using the substrate 1 with a color filter shown in the second embodiment, an electro-optical device was prepared by combining with the counter substrate 6 via the seal 9 as shown in FIG. At this time, the flattening layer 12 is formed under the seal 9 in this embodiment so that the cell thickness can be easily controlled, but it goes without saying that the same result can be obtained inside or outside the seal 9. The electro-optical device produced in this manner was evaluated in terms of image quality such as crosstalk in the same manner as in Example 1, and the same good results could be obtained and also good results in stability could be obtained. It was

Although the structure of the present invention has been described with reference to Examples 1 and 2, another color filter forming method (for example, an electrodeposition method, a method of forming a color filter by dispersing a pigment in a printing ink, for example, an offset printing method, A method in which a pigment is dispersed in a substrate such as a polyimide resin and a color filter is patterned using a photoresist), or a material made of another material (for example, a thermosetting melamine resin, an epoxy resin, a silicone resin) as a flattening layer. ,
There is no restriction on the forming method.

[Embodiment 3] The light-shielding layer 4 of the substrate described in Embodiments 1 and 2 is selectively patterned by electroless plating after patterning nickel by vacuum deposition and gold by photolithography. A color filter and a transparent electrode for display were prepared in the same manner except that they were deposited on nickel and formed to have the same film thickness as in Example 2 and the substrate was used in the same manner as the counter electrode to prepare the grain system. When the cell gap was set to 2 μm using the glass beads as the gap material 10, the ferroelectric liquid crystal was injected, and the display was confirmed by changing the pulse width and refresh driving frequency. The pulse width was about 60 μs, and the refresh driving frequency was good up to about 20 Hz. It responded in the waveform saturation state. In contrast to the electro-optical device of this embodiment, the electro-optical device having the conventional structure in which the light-shielding layer made of a metal layer is not formed has a pulse width of about 250 μs and a refresh driving frequency of about 8 Hz, and a display with conspicuous flicker is obtained. As described above, it has become possible to produce a ferroelectric liquid crystal display device that exhibits good color display.

Example 4 The structure of the electro-optical device of Example 4 will be described with reference to FIG. The electro-optical device described in the second embodiment is used as a display cell to perform optical switching S
It was a cell. In this embodiment, as the optically anisotropic substance, the same birefringence as that of the S cell (cell gap: d and product of refractive index anisotropy of liquid crystal or optically anisotropic substance: Δn: Δn × d = 0.
9, Δn = 0.129), and a liquid crystal cell was installed between the polarizers 14 and 15 so that the S cell could be optically compensated. In this embodiment, the liquid crystal cell has Δn × d = 0.9, d = 8 μm, and Δn = 0.113. Here, the angle formed by the orientation directions of the surfaces of the S cells and the liquid crystal cells that contact each other is 70
The range is preferably in the range of 90 ° to 110 °, more preferably 90 °. In this embodiment, the angle is 90 °. Further, the angle between the polarization axis of each polarizer and the orientation direction of the S-cell and liquid-crystal cell facing each other is set to 20 to 50 °, and the values of birefringence and refractive index dispersion used in this example are set. The condition for turning black when not lit and white when all lit is 45 °. However, whether the change axis with respect to the orientation direction is right or left as viewed from above the electro-optical device is positive or negative, and in the present embodiment, it is made negative. However, as described above, S is an optically anisotropic substance.
If it has the same birefringence as the cell, there is a similar effect,
For example, a stretched polymer film such as polyvinyl alcohol or polycarbonate may be used without any limitation. When the electro-optical device produced in this manner was displayed and the image quality was evaluated, it was possible to obtain a high-quality color display with good black-and-white color development.

[Embodiment 5] With respect to the structure described in Embodiments 1, 2 and 3, it is expected that the signal input method will be further miniaturized in response to future increase in display capacity. For example, a method of connecting a tape in which a driving driver is mounted on a flexible tape to a glass substrate via an anisotropic conductive adhesive is made minute, and a metal layer (for example, aluminum, on the signal input terminal portion on the glass substrate side is used. In order to deal with the method of forming a gold (for example) and connecting it to the driver mounting substrate using the wire bonding technique, or the method of mounting the driving driver directly on the glass substrate (a method generally called COG). The light shielding layer 4 shown in Example 2
As shown in FIG. 10, the portion other than the display portion is extended and connected to the display transparent electrode 3 at the lead portion between the normal signal input terminal portion and the display portion in the portion without the color filter, and the light shielding layer 4 is used as it is. The routing portion and the signal input terminal portion 15 were formed. When a gold wire was used for the signal input terminal portion 15 to perform wire bonding, a good eutectic bonding state could be confirmed. Also, COG mounting was performed, but in the case of a normal electro-optical device, a method of observing the input of the drive driver and the output of the substrate side by performing a mold treatment or simply a mold treatment on a portion inside the liquid crystal cell is performed. It was possible to obtain good results for 250 hours in the test in which the substrate was left in a constant temperature and constant humidity test at 60 ° C.-90 RH% for 250 hours without any problems. For the structure described above, the metal system can be selected according to the mounting method.

[0015]

As described above, the wiring resistance is greatly reduced by the method of forming the light shielding layer and the electric conductor of the present invention by using the metal layer and electrically connecting with the transparent electrode for display. It is possible to provide a high-quality electro-optical device in which the applied drive waveform is not blunted and crosstalk and contrast are not deteriorated. Further, there is an effect that it is possible to provide an electro-optical device having a high yield and capable of dealing with an electro-optical device having a higher duty by an easy process. Moreover, by forming the light-shielding layer extending to the signal input terminal portion, it is possible to cope with various mounting methods such as COG and wire bonding. Further, since the metal layer and the transparent electrode for display are formed after forming the color filter and the flattening film which is formed if necessary, it is possible to provide a highly reliable electro-optical device and a manufacturing method which are stable in the process. The effect also occurs.

[Brief description of drawings]

FIG. 1 is a structural diagram of a substrate with a color filter shown in a first embodiment of the present invention.

FIG. 2 is a structural diagram of the substrate with a color filter shown in Example 1 of the present invention as seen from the AA ′ cross section.

FIG. 3 is a structural view of the color filter-attached substrate shown in Example 1 of the present invention as seen from a BB ′ cross section.

FIG. 4 is a structural diagram of an electro-optical device shown in a second embodiment of the present invention.

FIG. 5 is a structural diagram of a substrate with a color filter shown in Example 2 of the present invention.

FIG. 6 is a structural diagram of a substrate with a color filter shown in Example 2 of the present invention as seen from a section AA ′.

FIG. 7 is a structural diagram of a substrate with a color filter shown in Example 2 of the present invention as seen from a BB ′ cross section.

FIG. 8 is a structural diagram of the electro-optical device shown in Example 2 of the present invention.

FIG. 9 is a configuration diagram of the electro-optical device shown in Example 4 of the present invention.

FIG. 10 is a structural diagram of a substrate with a color filter shown in Example 5 of the present invention.

[Explanation of symbols]

 1. Glass substrate 2. Color filter 3. Transparent electrode for display 4. Light-shielding layer 5. Electrical connection 6. Glass substrate 7. Counter electrode 8. Alignment film 9. Seal 10. Gap material 11. Liquid crystal 12. Planarization layer 13. Polarizer 14. Polarizer 15. Signal input terminal

Claims (12)

[Claims] 1. An electric device having a color filter on at least one transparent substrate of two transparent substrates sandwiching a liquid crystal layer via a seal portion, and a display transparent electrode on the color filter. In the optical device, the light-shielding layer is formed of a metal layer on the color filter, and the metal layer also serves as an electric conductor and is electrically connected to the display transparent electrode. 2. The metal layer is formed in a stripe shape along a color filter, and a transparent electrode for display is also formed in a stripe shape on the color filter and the metal layer,
2. A convex portion is formed on the metal layer at a portion other than a row and column matrix intersection with the opposing electrode, and the convex portion is electrically connected to the display transparent electrode.
The electro-optical device described. 3. The electro-optical device according to claim 1, wherein the metal layer is formed on the display transparent electrode. 4. The metal layer is formed on the boundary between adjacent color filters so as to cover each of the adjacent color filters,
4. The electro-optical device according to claim 1, wherein the display transparent electrode is formed close to one side of the color filter formed in a stripe shape. 5. A transparent electrode for display is formed on the color filter through at least one inorganic layer or organic resin layer or a planarizing layer formed by laminating an organic resin layer and an inorganic layer. Claim 1 or 2 or 3
Alternatively, the electro-optical device according to item 4. 6. The flattening layer is selectively formed centering on the color filter.
The electro-optical device described. 7. The electro-optical device according to claim 1, wherein a nematic liquid crystal having a twist angle of 90 ° or more and 360 ° or less is used. 8. The electro-optical device according to claim 7, further comprising at least one or more optically anisotropic bodies other than the display portion having a color filter between a pair of polarizers. 9. The electro-optical device according to claim 1, wherein the liquid crystal layer has ferroelectricity. 10. The metal layer is formed of at least aluminum, chromium-gold stack, nickel-gold stack, nickel, tantalum, or copper. The electro-optical device according to at least one of 5, 5, 6, 7, 8, and 9. 11. The metal layer and the transparent electrode for display are formed in a direction orthogonal to the color filter, and electrodes facing each other in a direction parallel to the color filter are formed on a facing substrate. Claims 3, 5, 6,
An electro-optical device according to at least one of 7, 8, 9, and 10. 12. A color filter is provided on at least one of the two transparent substrates sandwiching a liquid crystal layer with a seal portion interposed therebetween, and a transparent electrode for display is provided on the color filter. In manufacturing an electro-optical device having a metal layer also serving as a conductor, the color filter was formed by a printing method, a photolithographic method using a photosensitive resin in which a pigment was dispersed, and a pigment was dispersed. The resin is formed by patterning using another photosensitive resin as a resist or by an electrodeposition method, and the metal layer is formed by a wet film forming method or a vacuum film forming method, and then a photolithographic method is used. A method for manufacturing an electro-optical device, which comprises patterning.