JPH0237326A - Transparent substrate for color liquid crystal display - Google Patents

Abstract

PURPOSE:To obtain a transparent conductive layer which is thin and has low area resistance and to allow fine patterning without generating side etching and without generating thinning and meandering by using the transparent conductive layer to be provided on a color filter layer to serve as colored picture elements after said layer is sandwiched by metal oxide layers. CONSTITUTION:This substrate consists of the transparent substrate 1, the color filter layer 3 which is formed on the surface of the substrate 1 and to serve as the colored picture elements, and the transparent conductive layer provided on the layer 3. The transparent conductive layer is formed to have the 3-layered structure consisting, successively form the filter layer 3 side, of the 1st layer 5 which is the metal oxide layer, the 2nd layer 6 which is the acid soluble metal or its alloy layer and the 3rd layer 7 which is the acid soluble metal oxide layer. The transparent conductive layer having the low area resistance is obtd. and the etching is executable in a relatively short period of time by adopting the acid soluble metal oxide 7 for the outermost layer. The glass substrate for color liquid crystal display having the transparent conductive layer which allows easy fine patterning of the conductive film and has the low resistance is obtd. in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a transparent substrate for color liquid crystal display suitable for use in a liquid crystal display element capable of color display.

[Prior Art] Liquid crystal displays are currently used in many display devices such as various measuring instruments and information processing devices. It is currently used in large quantities in flat panel displays because it consumes less power, is lightweight, and can be made smaller. However, the display quality has not always received excellent evaluations. In recent years, the technology of liquid crystal displays has made remarkable progress, and the quality has been improved from conventional monochrome displays to color displays.

Currently, the most effective method for color liquid crystal display is the use of micro color filters for full color and multicolor image display. Micro color filters include those that use gelatin or casein dyed with dyes, those that use pre-colored organic resin to create colored pixels using photolithography, and those that use ink mixed with pigments that are printed on transparent glass substrates. Several types of color filters for color liquid crystal displays have been proposed and put into practical use, including those made using this method.

Furthermore, a transparent electrode is provided on the glass substrate on which the color filter is formed, and this electrode has the size of the display screen,
Fine patterning is required depending on the definition. As a glass substrate for performing a color liquid crystal display, a patterned transparent electrode is formed on the glass substrate, and a color filter consisting of colored pixels is formed on the electrode.
There is one in which a color filter consisting of desired colored pixels is formed on a glass substrate, and a transparent conductive layer is formed thereon.

The latter has better display quality because the net drive voltage is applied to the liquid crystal and there is no loss due to the color filter layer. Therefore, in a color liquid crystal display, a color filter that becomes a colored pixel is first provided on a glass substrate, a 31-layer organic image is provided on top of that for flattening, and a single transparent conductive layer is further provided on top of that. . Glass substrates for color liquid crystal displays are used as color displays with high display quality.

In recent years, color LCD screens have become thicker, and as the demand for higher quality display has increased, the size of colored pixels has become smaller and smaller. (doped indium oxide) The line width of the transparent electrode must be narrow.For driving a liquid crystal, a voltage drop due to the line resistance of one conductor is undesirable, so the voltage drop of the transparent electrode is such that the voltage drop does not actually become an obstacle. Therefore, low-resistivity transparent conductive layers have become essential for realizing large-scale, high-definition displays.In contrast, conventional materials with the lowest resistivity have been used to [It is well known that a single film of TO is used as a transparent conductive layer.ITO films can be manufactured by any method such as sputtering, vapor deposition, or dipping, but they have low resistance. To obtain a thin film, the glass substrate is heated to a high temperature of 300°C or higher to perform deposition, or the film is formed on the substrate at room temperature and then deposited for 30 minutes.
It is necessary to undergo a so-called high-temperature process such as heat treatment at a high temperature of 0° C. or higher.

[Problem to be solved by the invention]

As mentioned above, the multicolored colored pixels used in color LCD displays all have organic substances as a base material, and the coloring materials themselves are dyes or organic pigments, so they suffer thermal deterioration at high temperatures. A high-temperature process cannot be used to form an ITO film. For this reason, ITO
Due to restrictions regarding the heat resistance strength of colored pixels, the upper limit temperature for film formation is approximately 200° C., and it is necessary to form the film by a low-temperature process below this temperature. However, the resistivity of the ITO film increases as the process temperature (substrate heating temperature during film formation and heat treatment temperature after film formation) decreases. Since a single ITO film produced by a low-temperature process has a large resistance value, if a transparent conductive layer with a small sheet resistance is required, the film thickness will become very large. If the film thickness is large, patterning of fine electrodes required for high-definition display becomes extremely disadvantageous.

In other words, it becomes difficult to ensure the dimensional accuracy of the pattern due to the occurrence of side etching and 7chi phenomena, and it is also difficult to perform completely uniform etching, which makes short circuits and other defects due to poor electrode insulation between electrodes due to etching unevenness more likely to occur. It becomes difficult to perform patterning with a high yield.

Furthermore, as the thickness of the ITO film increases, the internal stress of the film increases, causing wrinkles in the underlying protective film and colored body, resulting in a fatal defect in display quality. Furthermore, the internal stress of the film has the risk of partially damaging its adhesion to the underlying substrate, which has the disadvantage of adversely affecting the reliability of the liquid crystal display device.

[Means to solve the problem]

The present invention is intended to solve the problems of conventionally used glass substrates with color filters, and its purpose is to provide a color filter having a transparent conductive layer with low resistance and easy to finely pattern a conductive film. An object of the present invention is to provide a glass substrate for liquid crystal display.

That is, the present invention provides a color liquid crystal display substrate comprising a transparent substrate, a color filter layer forming colored pixels formed on the surface of the transparent substrate, and a transparent conductive layer provided on the color filter layer. The transparent conductive layer is composed of, from the color filter layer side, a first layer of a metal oxide layer, a second layer of an acid-soluble metal or an alloy layer of the metal, and a third layer of an acid-soluble metal oxide layer. This is a glass substrate for color liquid crystal display characterized by having a three-layer structure.

In the present invention, the color filter layer that becomes the colored pixels is made by patterning gelatin or segaine into a predetermined size and coloring it with dye, or by photolithography using pre-colored photosensitive or non-photosensitive acrylic or polyimide resin. They are manufactured using various materials and manufacturing methods, such as those patterned with organic resin, and those that are printed in a predetermined size using an offset printing method by kneading a coloring agent whose main component is an organic pigment into an organic resin.

In the present invention, a transparent organic protective layer such as polyimide, polyamide, acrylic, or epoxy resin is usually provided between the color filter layer and the transparent conductive layer to flatten the surface of the color filter layer. It is. Further, in the present invention, silver, copper, or an alloy thereof is used as the second layer of the transparent conductive layer. Titanium, chromium, and tin are used as the metals forming the silver alloy and copper alloy, and it is preferable that the content of these components is usually within 10% in order to prevent a decrease in transmittance and to improve corrosion resistance.

Further, in the present invention, the first metal oxide layer of the transparent conductive layer is an electrically conductive layer in which the electrically insulating metal oxide can be removed by etching at the same time as the second N metal or alloy as in the third layer. It may also be a metal oxide. As the electrically insulating oxide, those that are transparent, have good adhesion to the base, and have various refractive index values can be used. For example, TiQz, ZrO,, Hf0Z, Ta205, Alz
03, BjzOz, and Sin, etc. are used.

Inzol and S are also used as electrically conductive metal oxides.
In2O3 doped with n can be used.

Furthermore, the third metal oxide layer of the transparent door tH is usually In doped with 1 nz O:I'P S n;
O, is used.

Therefore, as the transparent conductive layer in the present invention,
2nd layer/3rd layer thickness, 5r(h/Ag/ITO1
Alzoz/Ag/ITO-TrOz/A
g/ITO, , ZrO2/Ag/ rTo, 5jO
z/Ag/IntOx, S:Oz/Cu/I
TO%Alt(h/Cu/ITO, Ti12
/ Cu/ ITO, flfOz/ Cu/InzO-
, , JTO/Ag/ITO, ITO/Cu/)TO are preferably used.

The thickness of each of the first layer and the third layer of the transparent conductive layer is usually in the range of about 100 to 400 layers, and the thickness of the second layer of the transparent conductive layer is usually in the range of 100 to 200 layers. used, the total film thickness of the transparent conductive layer is 300~10
It is usually used in the range of 00 people.

[For production]

The present invention uses a transparent conductive layer provided on the color filter layer that becomes the colored pixel, which is made by sandwiching a metal or metal alloy with a metal oxide layer. At the same time, by making the outermost metal oxide layer of the transparent conductive layer acid-soluble, the metal or metal alloy of the transparent conductive layer can be made into a desired state in a relatively short time. The pattern can be etched with acid.

In addition, the present invention allows for optical interference effects by selecting the thickness and type (M refractive index) of each of the three layers constituting the transparent conductive layer.
Transmittance of a transparent substrate for color liquid crystal display can be increased.

〔Example〕

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

2 parts by weight of Lake Red C (red lubricant manufactured by Dainichi Seikagaku Co., Ltd.) are mixed with 10 parts by weight of polyvinyl alcohol having an average degree of polymerization of 500 and a degree of saponification of 90 mol%, and the colorant in the supernatant portion of the resulting mixture is 3 parts by weight and an average degree of polymerization of 500 and a saponification degree of 9.
Photosensitive resin composition (A) in which 6 mol% of P-formylstyrylpyridine is added to 0 mol% polyvinyl alcohol
adjusted. Next, this night is 100m x 100m
Coat with a spinner to a film thickness of approximately 1 μm on a 1 x 1.0 day glass substrate (1), dry for 30 minutes, then pattern exposure through a mask, then select the non-exposed areas with isopropyl alcohol. After removing the
The mixture was heated for 0 minutes to form a dot-shaped filter layer (3) shown in red (R). Similarly, Lionor Green 2Y-
A green photosensitive resin composition (B) containing 301 (a green pigment manufactured by Toyo Ink Manufacturing Co., Ltd.) as a coloring component and a blue photosensitive resin composition containing Fastgen Blue GNPS (a blue pigment manufactured by Dainippon Ink Chemical Co., Ltd.) as a coloring component. The resin composition (C) was adjusted to form a dot-shaped green (G) filter layer (3) and a blue (B) filter layer (3) in the same manner as the red (R) filter layer (3) as shown in Figure 2. A color filter layer (3) as shown was formed.

Next, in order to flatten the surface of the filter layer (3), a thickness of 1.5 μm was applied to cover the color filter layer (3).
A protective layer (4) was formed by spin-coding an arylic resin (trade name: Optomer SS of Nippon Synthetic Rubber 11).

A transparent conductive film (2) was formed on this resin protective layer (4). The transparent conductive layer (2) includes a 1N metal oxide layer (5),
It consists of a metal layer (6) and a metal oxide layer (7).

The metal oxide layer (5) is made of three types of SiO□, A1. ．． 03
, and TiO2 were selected to prepare respective samples. In other words,
The SiO□ layer (5) is deposited to a predetermined thickness by high-frequency magnetron sputtering in an argon atmosphere, and A 12
The 03 layer (5) and the Tioz layer (5) were deposited to a predetermined thickness by direct current reactive sputtering in a mixed gas atmosphere of argon and oxygen using respective metal targets.

Next, Ag or Cu was selected for the metal layer (6), and each metal target was deposited on the metal oxide layer (5) to a predetermined thickness by direct current sputtering in an argon gas atmosphere. Furthermore, the metal oxide layer (7) is IT containing 10% by weight of SnO□.
By direct current sputtering in a mixed gas atmosphere of argon and a small amount of oxygen using an O sintered body as a target, a predetermined thickness of I
A TO layer (7) was deposited on the metal layer (5).

Metal oxide @ (5) (71 and the glass plate (11) was not particularly heated when forming the metal layer (6), but when forming the metal layer (6), particle growth developed and agglomerated to form particles. The glass plate (1) may be heated to the extent that it does not become shaped.

On the other hand, as a comparative example, glass Fi (11) in which the color filter layer (3), the resin protective layer (4), and 150 SjO layers were sequentially formed was heated to 180°C, and a small amount of argon gas was added. Using a sputtering method in a mixed gas atmosphere with oxygen,
It was formed on the 02 layer.

The transparent conductive layer (2) of the transparent substrate for color liquid crystal display obtained as described above was examined for electrode patterning properties, durability evaluation by cold/warm cycle test, sheet resistance, and light transmittance. The results are shown in Table 1. Samples 1 to 5 were etched with 1N hydrochloric acid at 40°C for 4 to 5 minutes using a predetermined mask pattern and masking resist, and sample 6 (comparative example) could not be etched at this concentration. Unwanted portions were etched with 5N hydrochloric acid at 45° C. for 8 to 10 minutes.

Samples 1 to 5 all have sheet resistance of intermediate layer translucent A.
Low (10Ω/Sq or less) due to the effect of g film or Cu film
At the same time, the transmittance at a wavelength of 550 μm was as high as 70% or more, and it was possible to perform patterning with a smooth edge shape in a short time using dilute hydrochloric acid. By photolithography using a commonly used photoresist and mask, parallel striped transparent electrode patterns with an electrode line width of 50 μm and an inter-electrode space of IO μm were fabricated on samples 1 to 5.
It was possible. (However, the first layer of samples 1 to 4 is not etched.) However, in sample 6 (comparative example), although the sheet resistance is less than 10Ω/Sq, the film thickness is Therefore, pattern etching with hydrochloric acid causes side etching, and if thin, meandering occurs, resulting in poor electrode patterning properties and difficulty in microfabrication.

As shown in Table 3, a color liquid crystal display glass substrate (1) having striped transparent electrodes (2) extending perpendicularly to the plane of the paper, and a striped transparent electrode (9) made of ITO are shown in Table 3.
A color liquid crystal display element is produced, which is composed of the other glass substrate (8) having a glass substrate (8) and a liquid crystal aυ filled in a space formed by a sealing material (00) provided around the glass substrate (8).

〔Effect of the invention〕

As described above, the present invention uses a thin transparent conductive layer provided on the color filter layer that becomes the colored pixel by using a metal or metal alloy sandwiched with a metal oxide layer. Since a product with a low sheet resistance can be obtained, side etching does not occur, and if thin and thin, no meandering occurs, allowing fine pattern processing.

Moreover, in the present invention, by selecting the thickness and refractive index of each of the three layers constituting the transparent conductive layer, the transmittance of the transparent substrate for color liquid crystal display can be increased due to the optical interference effect.

Therefore, the color liquid crystal display element of the present invention is suitable for use as a large-screen, high-definition, bright color liquid crystal display element.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, in which Fig. 1 is a cross-sectional view of a glass substrate for color liquid crystal display, Fig. 2 is a plan view of Fig. 1, and Fig. 3 is a glass substrate for color liquid crystal display. 2 is a cross-sectional view of an RGB liquid crystal display element using ■, 8 glass plate, 2: transparent conductive layer, 3: color filter layer, 4: resin protective layer, 5: first layer metal oxide layer, 6
: metal or alloy layer, 7: third metal oxide layer, 9: transparent electrode, 10: sealing material, 11: liquid crystal. Figure / Figure Figure

Claims (6)

[Claims] (1) In a color liquid crystal display substrate comprising a transparent substrate, a color filter layer forming colored pixels formed on the surface of the transparent substrate, and a transparent conductive layer provided on the color filter layer, the transparent conductive The layer has a three-layer structure consisting of, from the color filter layer side, a first layer of a metal oxide layer, a second layer of an acid-soluble metal or an alloy layer of the metal, and a third layer of an acid-soluble metal oxide layer. A transparent substrate for color liquid crystal display characterized by: (2) A color liquid crystal display according to claim 1, wherein a transparent organic protective layer is provided between the color filter layer and the transparent conductive layer for flattening the surface of the color filter layer. Transparent substrate. (3) The transparent substrate for a color liquid crystal display according to claim 1 or 2, wherein the second layer of the transparent conductive layer is a layer of silver, copper, or an alloy thereof. (4) The transparent substrate for a color liquid crystal display according to any one of claims 1 to 3, wherein the first layer of the transparent conductive layer is a conductive and acid-soluble film. (5) The transparent substrate for a color liquid crystal display according to any one of claims 1 to 3, wherein the first layer of the transparent conductive layer is electrically insulating. (6) The color according to any one of claims 1 to 3, wherein the first layer or the third layer of the transparent conductive layer is made of indium oxide or a metal oxide containing indium oxide as a main component. Transparent substrate for liquid crystal display.